CN111725290B - Display panel and display device - Google Patents

Display panel and display device Download PDF

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CN111725290B
CN111725290B CN202010768176.7A CN202010768176A CN111725290B CN 111725290 B CN111725290 B CN 111725290B CN 202010768176 A CN202010768176 A CN 202010768176A CN 111725290 B CN111725290 B CN 111725290B
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blue
energy level
pixel
light emitting
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CN111725290A (en
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黄智�
李贵芳
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Kunshan New Flat Panel Display Technology Center Co Ltd
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Kunshan New Flat Panel Display Technology Center Co Ltd
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/30—Devices specially adapted for multicolour light emission
    • H10K59/35—Devices specially adapted for multicolour light emission comprising red-green-blue [RGB] subpixels
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H10K50/12—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers comprising dopants
    • H10K50/121—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers comprising dopants for assisting energy transfer, e.g. sensitization
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2101/00—Properties of the organic materials covered by group H10K85/00
    • H10K2101/10—Triplet emission
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2101/00—Properties of the organic materials covered by group H10K85/00
    • H10K2101/40—Interrelation of parameters between multiple constituent active layers or sublayers, e.g. HOMO values in adjacent layers

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  • Electroluminescent Light Sources (AREA)

Abstract

The invention provides a display panel and a display device. A pixel layer is arranged between the first electrode layer and the second electrode layer and at least comprises a blue sub-pixel layer, a green sub-pixel layer and a red sub-pixel layer. The blue sub-pixel layer includes a blue light emitting layer and an auxiliary layer stacked together, and the auxiliary layer includes a phosphorescent light emitting material. The triplet energy level of the material of the auxiliary layer is greater than the triplet energy level of the blue host material in the blue light emitting layer. The invention can prolong the service life of blue light and reduce the deterioration of blue luminescent materials, thereby improving the luminescent service life of the display panel and the display device and optimizing the luminescent efficiency.

Description

Display panel and display device
Technical Field
The invention relates to the technical field of display, in particular to a display panel and a display device.
Background
With the rapid development of electronic display technology, Organic Light-Emitting diodes (OLEDs) are widely used in display devices such as terminal devices and wearable devices, because they have excellent properties such as low power consumption, high color saturation, wide viewing angle, thin thickness, flexibility, and no need of backlight.
The existing OLED display device is commonly used in a light-emitting colorization mode of an RGB trichromatic method, that is, in a display panel preparation process of the OLED display device, an organic light-emitting layer is configured with a red pixel layer, a blue pixel layer and a green pixel layer, and the three pixel layers respectively emit light of three colors of red, green and blue. Among them, the blue lifetime is shorter than those of green and red light, and thus the lifetime of the display device is mainly determined by the emission lifetime of the blue pixel layer. And, the combination of electrons and holes in the blue light emitting process is mainly realized in the present layer of the blue pixel layer, and after the combination of electrons and holes is realized, excitons transition to the ground state to radiate blue photons.
However, accumulation of electrons and holes occurs in the current blue pixel layer, resulting in a low emission lifetime and emission efficiency of the blue pixel layer, and resulting in degradation of the blue pixel layer material, reducing the emission lifetime of the blue pixel layer and the OLED display device.
Disclosure of Invention
In order to solve at least one of the problems mentioned in the background art, the present invention provides a display panel and a display device, which can prolong the blue light lifetime and reduce the degradation of a blue light emitting material, thereby improving the light emitting lifetime of the display panel and the display device and optimizing the light emitting efficiency.
In order to achieve the above object, in a first aspect, the present invention provides a display panel including a base substrate and a first electrode layer and a second electrode layer which are stacked and provided on the base substrate.
A pixel layer is arranged between the first electrode layer and the second electrode layer and at least comprises a blue sub-pixel layer, a green sub-pixel layer and a red sub-pixel layer.
The blue sub-pixel layer comprises a blue light-emitting layer and an auxiliary layer which are stacked, wherein the auxiliary layer contains a phosphorescent light-emitting material.
The triplet energy level of the material of the auxiliary layer is greater than the triplet energy level of the blue host material in the blue light-emitting layer.
According to the display panel provided by the invention, the first electrode layer and the second electrode layer are arranged on the substrate in a stacking manner, the pixel layer is arranged in the first electrode layer and the second electrode layer, an electric field is formed at the pixel layer by utilizing the first electrode layer and the second electrode layer, electrons and holes in the first electrode layer and the second electrode layer are driven to migrate to the pixel layer, the electrons and the holes are combined in the pixel layer to generate excitons, and the excitons jump to the ground state and radiate light. By providing the blue light emitting layer and the auxiliary layer arranged in a stack in the blue sub-pixel layer of the pixel layer, and the triplet energy level of the material of the auxiliary layer is set to be larger than the triplet energy level of the blue host material in the blue light-emitting layer, so that electrons and holes in the blue sub-pixel layer are mainly accumulated and recombined in the auxiliary layer, energy of the generated excitons may be transferred to the blue light-emitting layer, the excitons transition to a ground state in the blue light-emitting layer to emit blue light, therefore, two processes of recombination of electrons and holes and transition of excitons to a ground state occur in the auxiliary layer and the blue light emitting layer, respectively, accumulation of electrons and holes in the blue light emitting layer is prevented, quenching of excitons by an excessive number of electrons and holes and deterioration of materials are prevented, and the light emitting life of the blue light emitting layer is prolonged, thereby prolonging the light emitting life of the entire display panel and improving the light emitting efficiency.
In the above display panel, optionally, the blue light emitting layer includes a blue host material and a blue light emitting guest material doped in the blue host material.
The singlet energy level of the blue light emitting guest material is lower than the singlet energy level of the blue host material.
The triplet energy level of the blue light-emitting guest material is higher than the triplet energy level of the blue host material.
Such an arrangement can ensure that the energy of the singlet excitons of the blue host material can be transferred to the singlet excitons of the blue emissive guest material, thereby achieving the process of emission.
In the above display panel, optionally, the auxiliary layer includes an auxiliary host material and a phosphorescent light emitting material doped in the auxiliary host material.
The triplet energy level of the phosphorescent light emitting material is greater than the triplet energy level of the blue host material. Such an arrangement can accomplish recombination of electrons and holes in the auxiliary layer and transfer energy of the generated excitons to the blue light-emitting layer, where the excitons complete transition and emission processes, and can extend the light emission life while achieving light emission.
In the display panel described above, the auxiliary layer may be made of the same material as that of the green sub-pixel layer or the red sub-pixel layer.
In the above display panel, optionally, the singlet energy level of the blue host material is greater than the singlet energy level of the phosphorescent light emitting material, and at least one barrier layer is disposed between the blue light emitting layer and the auxiliary layer.
The triplet energy level of the blocking layer is less than the triplet energy level of the phosphorescent light-emitting material and greater than the triplet energy level of the blue host material, and the singlet energy level of the blocking layer is greater than the singlet energy level of the phosphorescent light-emitting material and the singlet energy level of the blue host material.
The arrangement can prevent the energy of excitons in the blue host material from being transmitted back to the auxiliary layer phosphorescent light-emitting material, and ensure the stability of light emission.
In the above display panel, optionally, the first electrode layer is one of an anode layer and a cathode layer, and the second electrode layer is the other of the anode layer and the cathode layer.
In the above display panel, optionally, the blue host material in the blue light emitting layer is of an electron type, and the blue sub-pixel layer is located on one side of the auxiliary layer close to the cathode layer.
Or the blue main body material in the blue light-emitting layer is of a hole type, and the blue light-emitting layer is positioned on one side of the auxiliary layer close to the anode layer. Such an arrangement can facilitate the entry of electrons or holes into the auxiliary layer, reduce the accumulation of electrons or holes in the blue light-emitting layer, and prolong the light-emitting lifetime.
In the above display panel, optionally, a doping ratio of the blue light emitting guest material in the blue host material, and/or a doping ratio of the phosphorescent light emitting material in the auxiliary host material may range from 0.1 to 50%.
In the above display panel, optionally, the thickness of the blue light emitting layer and/or the auxiliary layer is in a range of 5 to 50 nm.
And/or the thickness of the barrier layer is in the range of 0.5-10 nm.
In the above display panel, optionally, a first functional layer is disposed between the anode layer and the pixel layer, and a second functional layer is disposed between the cathode layer and the pixel layer.
The first functional layer comprises a hole injection layer, a hole transport layer and an electron blocking layer which are arranged on the anode layer in a stacked mode, and the second functional layer comprises an electron injection layer, an electron transport layer and a hole blocking layer which are arranged on the cathode layer in a stacked mode.
The pixel layer is located between the electron blocking layer and the hole blocking layer.
The difficulty of entering the pixel layer by electrons and holes can be reduced by arranging the first functional layer and the second functional layer, and the luminous efficiency is improved.
In a second aspect, the present invention provides a display device, including the display panel.
According to the display device provided by the invention, the first electrode layer and the second electrode layer are arranged on the substrate of the display panel in a stacking manner, the pixel layer is arranged in the first electrode layer and the second electrode layer, an electric field is formed at the pixel layer by utilizing the first electrode layer and the second electrode layer, electrons and holes in the first electrode layer and the second electrode layer are driven to migrate to the pixel layer, so that the electrons and the holes are recombined in the pixel layer to generate excitons, and the excitons jump to the ground state and radiate light. By providing the blue light emitting layer and the auxiliary layer arranged in a stack in the blue sub-pixel layer of the pixel layer, and the triplet energy level of the material of the auxiliary layer is set to be larger than the triplet energy level of the blue host material in the blue light-emitting layer, so that electrons and holes in the blue sub-pixel layer are mainly accumulated and recombined in the auxiliary layer, energy of the generated excitons may be transferred to the blue light-emitting layer, the excitons transition to a ground state in the blue light-emitting layer to emit blue light, therefore, two processes of recombination of electrons and holes and transition of excitons to a ground state occur in the auxiliary layer and the blue light emitting layer, respectively, accumulation of electrons and holes in the blue light emitting layer is prevented, quenching of excitons by an excessive number of electrons and holes and deterioration of materials are prevented, and the light emitting life of the blue light emitting layer is extended, thereby extending the light emitting life of the entire display panel and display device and improving the light emitting efficiency.
The construction of the present invention and other objects and advantages thereof will be more apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a display panel according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a blue sub-pixel layer of a display panel according to an embodiment of the invention;
fig. 3 is a schematic structural diagram of a display panel provided with a first functional layer and a second functional layer according to a first embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating energy transfer of a blue sub-pixel layer of a display panel according to an embodiment of the invention;
fig. 5 is a schematic diagram illustrating energy transmission of a blue sub-pixel layer provided with a blocking layer in a display panel according to a second embodiment of the present invention.
Description of reference numerals:
10-a first electrode layer;
20-a second electrode layer;
30-a pixel layer;
31-blue subpixel layer;
311-blue light emitting layer;
311 a-blue host material;
311 b-a blue light emitting guest material;
312 — an auxiliary layer;
312 a-a secondary host material;
312 b-phosphorescent light-emitting material;
313-a barrier layer;
32-green subpixel layer;
33-red subpixel layer;
40-a first functional layer;
41-hole injection layer;
42-hole transport layer;
43-electron blocking layer;
50-a second functional layer;
51-electron injection layer;
52-an electron transport layer;
53-hole blocking layer.
Detailed Description
The inventors of the present application found in the course of practical research that, in the current display device having an organic light emitting layer configured with a red pixel layer, a blue pixel layer, and a green pixel layer, the blue lifetime is shorter than that of green and red light, and thus the lifetime of the display device is mainly dependent on the emission lifetime of the blue pixel layer. And, the combination of electrons and holes in the blue light emitting process is mainly realized in the present layer of the blue pixel layer, and after the combination of electrons and holes is realized, excitons transition to the ground state to radiate blue photons. However, in the current blue pixel layer, accumulation of electrons and holes occurs, and the accumulation of the electrons and the holes causes exciton energy in the blue pixel layer to be transferred to the electrons or the holes, resulting in exciton quenching and reducing the light emitting efficiency. And the large number of electrons or holes may cause the degradation of the blue pixel layer material, reducing the light emitting life of the blue pixel layer and the OLED display device. At present, the commonly used solution to this problem is to adjust the type of the material selected for the light-emitting layer, so as to improve the stability of the light-emitting material, and to prolong the lifetime of the blue light-emitting material as much as possible, and then the improvement effect is not ideal.
In view of this, embodiments of the present invention provide a display panel and a display device, in which a first electrode layer and a second electrode layer are stacked on a substrate of the display panel, and a pixel layer is disposed in the first electrode layer and the second electrode layer, an electric field is formed at the pixel layer by the first electrode layer and the second electrode layer, electrons and holes in the first electrode layer and the second electrode layer are driven to migrate to the pixel layer, the electrons and the holes are recombined in the pixel layer to generate excitons, and the excitons jump to a ground state and emit light. By providing the blue light-emitting layer and the auxiliary layer in a stacked arrangement in the blue sub-pixel layer of the pixel layer, and the triplet energy level of the material of the auxiliary layer is set to be larger than the triplet energy level of the blue host material in the blue light-emitting layer, so that electrons and holes in the blue sub-pixel layer are mainly accumulated and recombined in the auxiliary layer, energy of generated excitons may be transferred to the blue light-emitting layer, the excitons transition to a ground state in the blue light-emitting layer to emit blue light, therefore, two processes of recombination of electrons and holes and transition of excitons to a ground state occur in the auxiliary layer and the blue light emitting layer, respectively, accumulation of electrons and holes in the blue light emitting layer is prevented, quenching of excitons by an excessive number of electrons and holes and deterioration of materials are prevented, and the light emitting life of the blue light emitting layer is prolonged, thereby prolonging the light emitting life of the entire display panel and display device and improving the light emitting efficiency.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in the preferred embodiments of the present invention. In the drawings, the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The described embodiments are illustrative of some, but not all embodiments of the invention. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
Example one
Fig. 1 is a schematic structural diagram of a display panel according to an embodiment of the present invention. Fig. 2 is a schematic structural diagram of a blue sub-pixel layer of a display panel according to an embodiment of the invention. Fig. 3 is a schematic structural diagram of a display panel provided with a first functional layer and a second functional layer according to a first embodiment of the present invention. Fig. 4 is a schematic diagram illustrating energy transmission of a blue sub-pixel layer of a display panel according to an embodiment of the invention. Fig. 5 is a schematic energy transmission diagram of a blue sub-pixel layer provided with a blocking layer in a display panel according to a second embodiment of the present invention.
Referring to fig. 1 to 5, the present invention provides a display panel including a base substrate and a first electrode layer 10 and a second electrode layer 20 stacked on the base substrate.
A pixel layer 30 is disposed between the first electrode layer 10 and the second electrode layer 20, and the pixel layer 30 includes at least a blue sub-pixel layer 31, a green sub-pixel layer 32, and a red sub-pixel layer 33.
The blue sub-pixel layer 31 includes a blue light-emitting layer 311 and an auxiliary layer 312, which are stacked, and the material of the auxiliary layer 312 includes a phosphorescent light-emitting material.
The material of the auxiliary layer 312 is the same as that of the green sub-pixel layer 32 or the red sub-pixel layer 33.
The triplet energy level of the material of the auxiliary layer 312 is greater than the triplet energy level of the blue host material 311a in the blue light-emitting layer 311.
It should be noted that the display panel provided in this embodiment may include a substrate, and the substrate may include, but is not limited to, a glass substrate and a PI (Polyimide) substrate, a light-transmitting PET (Polyethylene terephthalate) substrate, and a flexible glass substrate. In a first electrode layer 10 and a second electrode layer 20 stacked on a substrate, the first electrode layer 10 is one of an anode layer and a cathode layer, and the second electrode layer 20 is the other of the anode layer and the cathode layer. The anode layer may be made of an inorganic material or an organic conductive polymer, such as Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO). The cathode layer can be made of metal materials with low work functions such as lithium, calcium, strontium, aluminum and indium, or alloy of the metal materials and copper, gold and silver, or can be made of electrode layers formed by alternatively using metal and metal fluoride, and the metal fluoride can be made of lithium fluoride and aluminum fluoride. In this embodiment, the first electrode layer 10 is an anode layer, and the second electrode layer 20 is a cathode layer.
Specifically, the pixel layer 30 in the first electrode layer 10 and the second electrode layer 20 is a main light emitting layer, and an organic material, such as a high molecular polymer or a small molecular organic compound, may be selected. The pixel layer 30 may include a green sub-pixel layer 32 emitting green light, a red sub-pixel layer 33 emitting red light, and a blue sub-pixel layer 31 emitting blue light. The three sub-pixel layers are arranged in the pixel layer 30, and the light rays of three colors are mixed based on the RGB three-color matching principle, so that the display panel emits white light rays. The present embodiment does not limit the pixel arrangement of the three sub-pixel layers, nor the arrangement shown in fig. 1.
It is to be noted that, unlike the blue pixel layer in the related art, the blue sub-pixel layer 31 of the present embodiment includes not only the blue light-emitting layer 311 but also an auxiliary layer 312. Referring to fig. 1, the blue light emitting layer 311 and the auxiliary layer 312 may be stacked, that is, they have abutting surfaces to facilitate energy transmission therebetween. Moreover, the auxiliary layer 312 of the embodiment is made of the same material as the green sub-pixel layer 32 or the red sub-pixel layer 33, on one hand, the arrangement can reduce the types of materials used in the display panel, and reduce the difficulty in manufacturing the display panel; on the other hand, because the emission lifetimes of the red sub-pixel layer 33 and the green sub-pixel layer 32 are both high, the auxiliary layer 312 may be made of two materials to improve the emission lifetime of the display panel.
Referring to fig. 4, during light emission of the display panel, the electric field drives electrons and holes into the pixel layer 30, which are collected in the auxiliary layer 312. Compared with the prior art in which electrons and holes are accumulated in the blue light emitting layer, the present embodiment adjusts the accumulation positions of the electrons and the holes to the auxiliary layer 312, which can effectively avoid accumulation of the electrons and the holes in the blue light emitting layer 311, thereby avoiding exciton quenching in the blue light emitting layer 311 caused by the electrons or the holes, and avoiding material degradation of the blue light emitting layer 311, thereby prolonging the light emitting lifetime of the blue light emitting layer 311, and improving the light emitting efficiency thereof. When the light emitting lifetime and the light emitting efficiency of the blue light emitting layer 311 are improved, the light emitting lifetime and the light emitting efficiency of the entire display panel are increased.
Based on the triplet energy level T of the material of the auxiliary layer 3121Is greater than the triplet energy level T of the blue host material 311a in the blue light emitting layer 3111Energy of triplet excitons generated after recombination of electrons and holes in the auxiliary layer 312 is transferred to the blue light-emitting layer 311, thereby completing transition and radiative light-emitting processes in the blue light-emitting layer 311. Therefore, in this embodiment, the recombination process of electrons and holes and the process of exciton transition radiation luminescence are respectively implemented in the auxiliary layer 312 and the blue light emitting layer 311, and the two processes are completed in different regions, so that the influence of the electrons and the holes on the material of the blue light emitting layer 311 can be effectively avoided, and the light emitting life and the light emitting efficiency of the blue light emitting layer 311 are improved.
Specifically, the blue light emitting layer 311 includes a blue host material 311a and a blue light emitting guest material 311b doped in the blue host material 311 a. The wavelengths of the emitted light of the blue host material 311a and the blue emitting guest material 311b are both in the blue wavelength band region. The blue host material 311a may receive energy, and triplet excitons and singlet excitons are formed in the blue host material 311 a. The blue host material 311a may be selected from materials containing a group such as anthracene and naphthalene, for example, 9, 10-di (2-naphthyl) anthracene or 2-methyl-9, 10-di (2-naphthyl) anthracene. The blue light emitting guest material 311b may be selected from diarylanthracene derivatives, and the materials of the two are not limited in this embodiment, and are not limited to the above examples.
Further, the auxiliary layer 312 includes an auxiliary host material 312a and a phosphorescent light emitting material 312b doped in the auxiliary host material 312 a. The auxiliary host material 312a may be the same as the host material in the red sub-pixel layer 33 or the green sub-pixel layer 32, and the phosphorescent light emitting material 312b is a red phosphorescent light emitting material or a green phosphorescent light emitting material.
Referring to fig. 4, the triplet energy level T of the phosphorescent light-emitting material 312b1Greater than the triplet energy level T of the blue host material 311a1. Singlet level S of blue light emitting guest material 311b1Lower than the singlet level S of the blue host material 311a1。
In the light emission process of the blue sub-pixel layer 31, an exciton may be generated by recombination of an electron and a hole in the phosphorescent light-emitting material 312b of the auxiliary layer 312, and the triplet energy level of the exciton may be the triplet energy level T of the phosphorescent light-emitting material 312b1. In this case, the triplet excitons of the phosphorescent light-emitting material 312b do not emit light directly, and the triplet energy level T of the phosphorescent light-emitting material 312b is based on1Greater than the triplet energy level T of the blue host material 311a1Therefore, the energy of the excitons is transferred from the triplet excitons of the phosphorescent light-emitting material 312b to the triplet excitons of the blue host material 311 a. The triplet excitons of the blue host material 311a are transferred to singlet excitons through a triplet-triplet annihilation (TTA) process. Further, the singlet level S based on the blue light emitting guest material 311b1Lower than the singlet energy level S of the blue host material 311a1So that the energy of the exciton willThe singlet excitons of the blue host material 311a are transferred to the singlet excitons of the blue light-emitting guest material 311 b. The singlet excitons of the blue light emitting guest material 311b transition to the ground state S0And simultaneously, energy is radiated to the outside in the form of photons, thereby realizing light emission. In the process, the triplet excitons are converted into the singlet excitons, so that the rotation, expansion and collision processes of the triplet excitons in the electroluminescent material caused by the Pauli exclusion principle (Pauli exclusion principle) can be reduced, the heat energy generated in the processes is further reduced, and the temperature rise of the display panel is avoided.
Referring to fig. 2, 4 and 5, it is noted that the singlet level S of the blue host material 311a is based1Greater than the singlet energy level S of the phosphorescent light-emitting material 312b1There is a possibility that the energy of the exciton is transmitted back from the blue host material 311a to the phosphorescent light emitting material 312b, and this transition method cannot ensure that the energy of the exciton is transmitted to the blue light emitting guest material 311b, thereby completing light emission. Therefore, in order to prevent the energy of the exciton from being transmitted back from the blue host 311a to the phosphorescent light emitting material 312b, at least one blocking layer 313 is disposed between the blue light emitting layer 311 and the auxiliary layer 312. The barrier layer 313 may be stacked between the blue sub-pixel layer 311 and the auxiliary layer 312.
Wherein, referring to FIG. 5, the triplet energy level T of the blocking layer 3131Less than the triplet energy level T of the phosphorescent light-emitting material 312b1And is greater than the triplet energy level T of the blue host material 311a1. Such an arrangement can ensure that the energy of the excitons is transferred from the triplet excitons of the phosphorescent light-emitting material 312b to the triplet excitons of the blocking layer 313 first and then from the triplet excitons of the blocking layer 313 to the triplet excitons of the blue host material 311 a. The transfer of the energy of the excitons illustrated in fig. 4 from the triplet excitons of the phosphorescent light-emitting material 312b to the triplet excitons of the blue host material 311a is accomplished through the above-described process.
At the same time, the singlet level S of the barrier layer 3131Greater than the singlet energy level S of the phosphorescent light-emitting material 312b1And singlet level S of blue host material 311a1. Such an arrangement prevents energy of the singlet excitons from being transferred from the phosphorescent light-emitting material 312b to the blocking layer 313. The energy of the singlet excitons may also not be transferred from the blue host material 311a to the blocking layer 313 and thus may also not be transferred to the phosphorescent light emitting material 312 b. By providing the blocking layer 313, the energy of the excitons can be blocked from being transferred from the blue host 311a to the phosphorescent light emitting material 312b, so that the energy of the excitons is ensured to be transferred from the blue host 311a to the blue light emitting guest 311b, and the light emission process is completed by the transition to the ground state of the blue light emitting guest 311b, and thus the provision of the blocking layer 313 can ensure that the blue sub-pixel layer 31 can stably emit light. The material of the blocking layer 313 may be 9, 10-diphenylanthracene or 1- (2, 5-dimethyl-4- (1-pyrenyl) phenyl) pyrene, which is not limited in this embodiment.
As an achievable embodiment, the blue host material 311a in the blue light-emitting layer 311 is of an electron type, the blue light-emitting layer 311 being located at the side of the auxiliary layer 312 close to the cathode layer. Since the blue host material 311a is of an electron type and has an electrophilic property, when it is disposed on a side closer to the cathode layer, electrons provided from the cathode layer can be guided to the auxiliary layer 312 through the blue light-emitting layer 311, thereby improving the electron transport efficiency.
As another realizable embodiment, the blue host material 311a in the blue sub-pixel layer 311 is of a hole type, and the blue light emitting layer 311 is located on the side of the auxiliary layer 312 close to the anode layer. Since the blue host material 311a is of a hole type and has a hole-attracting property, it is disposed on a side closer to the anode layer, and holes provided from the anode layer can be guided to the auxiliary layer 312 through the blue light-emitting layer 311, thereby improving the hole transport efficiency. The two setting modes can reduce the difficulty of the recombination of electrons and holes and improve the luminous efficiency.
As an achievable embodiment, the doping ratio of the blue light emitting guest material 311b in the blue host material 311a and the doping ratio of the phosphorescent light emitting material 312b in the auxiliary host material 312a range from 0.1 to 50%. It should be noted that, referring to fig. 1 and fig. 2, the doping ratio of the blue light emitting guest material 311b in the blue host material 311a and the doping ratio of the phosphorescent light emitting material 312b in the auxiliary host material 312a are small, and fig. 1 and fig. 2 are only an example of the drawings, and in actual use, the doping ratio of the blue light emitting guest material 311b and the phosphorescent light emitting material 312b is limited based on the above numerical value range.
As an achievable embodiment, the thickness of the blue sub-pixel layer 311 and/or the auxiliary layer 312 is in the range of 5-50nm, the thickness of the blue sub-pixel layer 311 may be a portion shown in a of fig. 2, and the thickness of the auxiliary layer 312 may be a portion shown in b of fig. 2. As an achievable embodiment, the thickness of the barrier layer 313 is in the range of 0.5-10nm, and the thickness of the barrier layer 313 may be the portion shown in c in fig. 2.
Referring to fig. 3, the present embodiment provides a first functional layer 40 disposed between the anode layer and the pixel layer 30, and a second functional layer 50 disposed between the cathode layer and the pixel layer 30.
The first functional layer 40 includes a hole injection layer 41, a hole transport layer 42, and an electron blocking layer 43, which are stacked on the anode layer, and the second functional layer 50 includes an electron injection layer 51, an electron transport layer 52, and a hole blocking layer 53, which are stacked on the cathode layer. The pixel layer 30 is located between the electron blocking layer 43 and the hole blocking layer 53.
It should be noted that the first functional layer 40 can increase the efficiency of hole transport from the anode layer to the pixel layer 30, and the second functional layer 50 can increase the efficiency of electron transport from the cathode layer to the pixel layer 30, thereby improving the light emitting efficiency of the pixel layer 30.
Example two
On the basis of the first embodiment, a second embodiment of the invention provides a display device.
Specifically, the display device provided in this embodiment may be any product or component having a display function, such as a television, a digital camera, a mobile phone, a tablet computer, a smart watch, an electronic book, and a navigator that include the display panel.
Other technical features are the same as those of the first embodiment and can achieve the same technical effects, and are not described in detail herein.
In the description of the embodiments of the present invention, it should be understood that the terms "mounted," "connected," and "connected" are to be construed broadly and may include, for example, a fixed connection, an indirect connection through intervening media, a communication between two elements, or an interaction between two elements unless expressly specified otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations. The terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships that are based on the orientations or positional relationships shown in the drawings, and are intended to be used only for convenience in describing and simplifying the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated in a particular orientation, and therefore, should not be construed as limiting the invention. In the description of the present invention, "a plurality" means two or more unless specifically stated otherwise.
The terms "first," "second," "third," "fourth," and the like in the description and claims of this application and in the above-described drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and these modifications or substitutions do not depart from the spirit of the corresponding technical solutions of the embodiments of the present invention.

Claims (11)

1. A display panel is characterized by comprising a substrate base plate, a first electrode layer and a second electrode layer which are stacked on the substrate base plate;
a pixel layer is arranged between the first electrode layer and the second electrode layer and at least comprises a blue sub-pixel layer, a green sub-pixel layer and a red sub-pixel layer;
the blue sub-pixel layer comprises a blue light-emitting layer and an auxiliary layer which are arranged in a stacked mode, and the auxiliary layer contains a phosphorescent light-emitting material;
the triplet energy level of the material of the auxiliary layer is greater than the triplet energy level of the blue host material in the blue light emitting layer.
2. The display panel according to claim 1, wherein the blue light emitting layer comprises a blue host material and a blue light emitting guest material doped in the blue host material;
the singlet state energy level of the blue light-emitting guest material is lower than that of the blue host material;
the triplet energy level of the blue light emitting guest material is higher than the triplet energy level of the blue host material.
3. The display panel according to claim 2, wherein the auxiliary layer comprises an auxiliary host material and a phosphorescent light-emitting material doped in the auxiliary host material;
the triplet energy level of the phosphorescent light emitting material is greater than the triplet energy level of the blue host material.
4. The display panel according to claim 3, wherein the auxiliary layer is made of the same material as the green sub-pixel layer or the red sub-pixel layer.
5. The display panel according to claim 3, wherein the singlet energy level of the blue host material is greater than the singlet energy level of the phosphorescent light-emitting material, and at least one barrier layer is disposed between the blue light-emitting layer and the auxiliary layer;
the triplet energy level of the blocking layer is less than the triplet energy level of the phosphorescent light-emitting material and greater than the triplet energy level of the blue host material, and the singlet energy level of the blocking layer is greater than the singlet energy level of the phosphorescent light-emitting material and the singlet energy level of the blue host material.
6. The display panel according to any one of claims 2 to 5, wherein the first electrode layer is one of an anode layer and a cathode layer, and the second electrode layer is the other of the anode layer and the cathode layer.
7. The display panel according to claim 6, wherein the blue host material in the blue light emitting layer is of an electron type, the blue light emitting layer being located on a side of the auxiliary layer adjacent to the cathode layer;
or, the blue main body material in the blue light-emitting layer is of a hole type, and the blue light-emitting layer is positioned on one side of the auxiliary layer close to the anode layer.
8. The display panel according to claim 3, wherein the doping ratio of the blue light emitting guest material in the blue host material, and/or the doping ratio of the phosphorescent light emitting material in the auxiliary host material is in the range of 0.1 to 50%.
9. The display panel according to claim 5, wherein the thickness of the blue sub-pixel layer and/or the auxiliary layer is in the range of 5-50 nm;
and/or the thickness of the barrier layer ranges from 0.5 nm to 10 nm.
10. The display panel of claim 6, wherein a first functional layer is disposed between the anode layer and the pixel layer, and a second functional layer is disposed between the cathode layer and the pixel layer;
the first functional layer comprises a hole injection layer, a hole transmission layer and an electron blocking layer which are arranged on the anode layer in a laminated mode, and the second functional layer comprises an electron injection layer, an electron transmission layer and a hole blocking layer which are arranged on the cathode layer in a laminated mode;
the pixel layer is located between the electron blocking layer and the hole blocking layer.
11. A display device characterized by comprising the display panel according to any one of claims 1 to 10.
CN202010768176.7A 2020-08-03 2020-08-03 Display panel and display device Active CN111725290B (en)

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CN102074656A (en) * 2009-11-24 2011-05-25 乐金显示有限公司 White organic light emitting device
CN109616581A (en) * 2018-11-12 2019-04-12 成都中电熊猫显示科技有限公司 Display panel and display device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102074656A (en) * 2009-11-24 2011-05-25 乐金显示有限公司 White organic light emitting device
CN109616581A (en) * 2018-11-12 2019-04-12 成都中电熊猫显示科技有限公司 Display panel and display device

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