Organic light emitting device, display panel and display device

Abstract

The present disclosure provides an organic light-emitting device, a display panel and a display device. The organic light-emitting device comprises a first electrode layer, a hole transport layer, an electron transport layer and a second electrode layer which are sequentially stacked, a plurality of light-emitting units arranged in the same layer between the hole transport layer and the electron transport layer, the light-emitting unit comprising a light-emitting auxiliary layer and a light-emitting layer which are sequentially stacked, the light-emitting auxiliary layer being located on the side close to the hole transport layer, the first light-emitting unit having the fastest light-emitting response speed in the plurality of light-emitting units, the green light-emitting unit and the red light-emitting unit, the integral area of the capacitance-voltage curve of the first light-emitting unit being Q1, Q1 satisfying: |Q n -Q1|≤0.5, Q n being the integral area of the capacitance-voltage curve of the nth light-emitting unit having a light-emitting response speed greater than that of the first light-emitting unit.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, and in particular, to an organic light-emitting device, a display panel and a display device. BACKGROUND

[0002] With the development of display technology, users' requirements for display effect are also increasing, such as the demand for screen refresh rate of display panel. Screen refresh rate refers to the number of times a display screen refreshes per second. The higher the screen refresh rate, the more smooth the display of dynamic pictures. High refresh rate display panel can bring users a more realistic picture quality and a more smooth visual experience. However, the current display panel still has display tailing and other defects, and the display tailing defect is particularly obvious under high refresh rate display.

[0003] Therefore, the current display panel still needs to be further improved. SUMMARY

[0004] The present disclosure provides an organic light-emitting device. The organic light-emitting device can reduce the difference in capacitance value of different light-emitting units, such as green light-emitting units and red light-emitting units, improve the consistency of response speed of green and red light-emitting units, and thus improve the first-frame display redness and display tailing and other defects of the display panel.

[0005] In one aspect of the present application, an organic light-emitting device is provided. The organic light-emitting device includes a first electrode layer, a hole transport layer, an electron transport layer and a second electrode layer which are sequentially stacked, a plurality of light-emitting units arranged in the same layer between the hole transport layer and the electron transport layer, the light-emitting unit includes a light-emitting auxiliary layer and a light-emitting layer which are sequentially stacked, the light-emitting auxiliary layer is located close to the hole transport layer side, the light-emitting unit with the fastest light-emitting response speed in the plurality of light-emitting units is a first light-emitting unit, the capacitance-voltage curve integral area of the first light-emitting unit is Q1, Q1 satisfies: |Q n -Q1|≤0.5, Q n The capacitance-voltage curve integral area of the nth light-emitting unit with light-emitting response speed greater than the first light-emitting unit.

[0006] Further, the plurality of light-emitting units include red light-emitting units, green light-emitting units and blue light-emitting units, the first light-emitting unit is the red light-emitting unit, and the nth light-emitting unit is the green light-emitting unit.

[0007] Further, the integral area of the capacitance-voltage curve is the integral area in the interval of -3V to 3V.

[0008] Further, the HOMO energy level of the hole transport layer HOMO HTLHOMO of the light-emitting auxiliary layer of the nth light-emitting unit prime-n HOMO of the light-emitting auxiliary layer of the first light-emitting unit prime1 at least one of the following conditions is satisfied:

[0009] HOMO HTL HOMO prime-n HOMO prime1 ;

[0010] HOMO HTL HOMO prime1 |≤0.2eV;

[0011] HOMO prime1 HOMO prime-n |≥0.1eV.

[0012] Further, the hole mobility μ prime1 of the light-emitting auxiliary layer of the first light-emitting unit prime-n at least one of the following conditions is satisfied:

[0013] μ prime-n <μ prime1 ;

[0014] μ prime-n / μ prime1 ≤0.5.

[0015] Further, the light-emitting auxiliary layer of the green light-emitting unit comprises a first sub-film layer and a second sub-film layer which are arranged in a stacked manner, and the first sub-film layer is arranged towards the hole transport layer.

[0016] Further, the hole transport layer has a HOMO energy level HOMO HTL , the light-emitting auxiliary layer of the red light-emitting unit has a HOMO energy level HOMO R-prime and a hole mobility μ R-prime , the first sub-film layer of the green light-emitting unit has a HOMO energy level HOMO G-primeA and a hole mobility μ G-primeA , the second sub-film layer of the green light-emitting unit has a HOMO energy level HOMO G-primeB and a hole mobility μ G-primeB ,

[0017] The organic light-emitting device satisfies at least one of the following conditions:

[0018] HOMO HTL HOMO G-primeA HOMO R-prime ;

[0019] HOMO HTL -HOMO G-primeA ≤0.2eV;

[0020] HOMO G-primeA -HOMO R-prime ≥0.1eV;

[0021] HOMO G-primeA -HOMO G-primeB ≤0.3eV;

[0022] μ G-primeB <μ G-primeA <μ R-prime ;

[0023] μ G-primeB / μ G-primeA ≤0.5;

[0024] μ G-primeA / μ R-prime ≤0.5.

[0025] Further, the light-emitting layer of the green light-emitting unit comprises a first host material, a sensitizer material and a first dopant material, the sensitizer material comprises at least one of a thermally activated delayed fluorescence material and a phosphorescent material; the first dopant material comprises a boron-containing fluorescent dye; the light-emitting layer of the green light-emitting unit comprises 60-90 parts by weight of the first host material, 10-40 parts by weight of the sensitizer material and 0.5-5 parts by weight of the first dopant material.

[0026] Further, the first host material has a HOMO energy level HOMO G-host , a LUMO energy level LUMO G-host , a hole mobility μ hG-host , an electron mobility μ eG-host , the sensitizer material has a LUMO energy level LUMO G-sens and a hole mobility μ hG-sens , an electron mobility μ eG-sens , the first dopant material has a HOMO energy level HOMO G-dop , the light-emitting auxiliary layer of the green light-emitting unit has a HOMO energy level HOMO G-prime , the organic light-emitting device satisfies at least one of the following conditions:

[0027] |HOMO G-host -HOMO G-prime |≤0.2eV;

[0028] μ hG-host / μ eG-host ≥5;

[0029] μ eG-sens / μ hG-sens ≥5;

[0030] LUMO G-host -LUMO G-sens ≥0.6eV;

[0031] |HOMO G-host -HOMO G-dop |≤0.2eV。

[0032] Further, the light-emitting layer of the red light-emitting unit comprises a second host material and a second dopant material; the second dopant material comprises a phosphorescent material; the light-emitting layer of the red light-emitting unit comprises 90-99 parts by weight of the second host material and 1-10 parts by weight of the second dopant material.

[0033] Further, the second host material has a HOMO energy level HOMO R-host , the light-emitting auxiliary layer of the red light-emitting unit has a HOMO energy level HOMO R-prime , the second dopant material has a HOMO energy level HOMO R-dop , and the organic light-emitting device satisfies at least one of the following conditions:

[0034] |HOMO R-host -HOMO R-prime |≥0.2eV;

[0035] |HOMO R-host -HOMO R-dop |≥0.2eV.

[0036] In another aspect of the present application, the present application provides a display panel. The display panel comprises the aforementioned organic light-emitting device.

[0037] In an aspect of the present application, the present application provides a display device comprising the aforementioned display panel. BRIEF DESCRIPTION OF DRAWINGS

[0038] In the drawings, like reference numerals refer to like elements throughout the various drawings. These drawings are not necessarily to scale, and the proportions of certain parts have been exaggerated for the sake of clarity. It should be understood that these drawings are only illustrative and are not intended to limit the scope of the disclosure.

[0039] Figure 1 A structural schematic diagram of a display panel according to an embodiment of the present application is shown;

[0040] Figure 2A structural schematic diagram of a display panel according to yet another embodiment of the present application is shown.

[0041] Figure 3 A structural schematic diagram of a display panel according to yet another embodiment of the present application is shown.

[0042] Figure 4 Capacitance-voltage curves of the green light emitting unit and the red light emitting unit in Example 1 are shown.

[0043] Figure 5 Capacitance-voltage curves of the green light emitting unit and the red light emitting unit in Comparative Example 1 are shown.

[0044] Figure 6 Capacitance-voltage curves of the green light emitting unit and the red light emitting unit in Comparative Example 2 are shown.

[0045] Figure 7 Capacitance-voltage curves of the green light emitting unit and the red light emitting unit in Comparative Example 3 are shown. DETAILED DESCRIPTION

[0046] Hereinafter, only certain exemplary embodiments are simply described. As can be appreciated by those skilled in the art, the described embodiments can be modified in various different manners, and different embodiments can be combined arbitrarily without conflict, without departing from the spirit or scope of the present disclosure. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0047] In the description of the present application, all the numbers disclosed herein are approximations. The numerical value of each numerical value can vary by 10% or a reasonable variation as recognized by those skilled in the art, such as 1%, 2%, 3%, 4%, or 5%.

[0048] In one aspect of the present application, the present application proposes an organic light emitting device, referring to Figure 1 which includes a plurality of light emitting units.

[0049] The organic light emitting device includes a first electrode layer 110, a hole transport layer 220, an electron transport layer 420, and a second electrode layer 120 which are sequentially stacked. The light emitting units are located between the hole transport layer 220 and the electron transport layer 420, and the plurality of light emitting units are arranged in the same layer. Each light emitting unit includes a light emitting auxiliary layer and a light emitting layer which are sequentially stacked. The light emitting unit with the fastest light emitting response speed in the plurality of light emitting units is a first light emitting unit, and the integral area of the capacitance-voltage curve of the first light emitting unit is Q1, which satisfies: |Q n 1|≤0.5. The integral area of the capacitance-voltage curve of the second light emitting unit is Q2, which satisfies: |Q nThe integral area of a capacitance-voltage curve of an nth light emitting unit having a light emitting response speed greater than that of the first light emitting unit.

[0050] For the convenience of understanding, the principle of the display panel in the present application having the aforementioned beneficial effects is briefly described as follows:

[0051] The present inventors found that in OLED (Organic Light-Emitting Diode) display panels, especially high refresh rate OLED display panels, display tailing and other malfunctions are prone to occur. This is mainly due to the fact that in the light emitting device of the display panel, some hierarchical structures are common layers, such as the first electrode layer 110, the hole transport layer 220, the electron transport layer 420 and the second electrode layer 120 as described above. However, different colors of light emitting units use different materials, so when the device is loaded with current, charges will accumulate at the cross section of each layer, showing a capacitance characteristic. Taking the design of red, green and blue pixels as an example, since the capacitance value of the red light emitting unit is usually small, and the capacitance value of the light emitting unit is negatively correlated with the response speed of the pixel unit, when the same voltage is applied to different light emitting units in the display panel, the red light emitting unit will emit light earlier than other light emitting units, i.e. the light emitting response speed is the fastest. When the display panel displays a white light picture, since the red light emitting unit will light up earlier than the green and blue light emitting units, it will cause the display panel to display a red-biased first frame picture. More specifically, the capacitance of the red light emitting unit is small, and the red light emitting unit accumulates less charge after the RGB pixel is lit up. When the second frame picture is switched, the charge in the red light emitting unit can be released faster, and the release is accompanied by a radiation light emitting process. While the green and blue light emitting units with larger capacitance accumulate more charge after being lit up, when the second frame picture is switched, the charge in the green and blue light emitting units is released more slowly, resulting in the fact that the red light emitting unit has already started to display the second frame picture, but the green and blue light emitting units are still displaying the previous frame picture. Although the ideal situation is to make the RGB light emitting units have no capacitance characteristics, this design idea relies on existing materials and is difficult to achieve.

[0052] Therefore, the present application selectively adjusts the characteristics of the light emitting unit with the fastest light emitting response speed and other light emitting units, so that the RGB capacitances of different light emitting colors tend to be close, which can suppress the redness of the first frame picture and make the switching transition of each frame picture smoother, and can also avoid the problem of a substantial increase in cost caused by the development of new materials.

[0053] Specifically, the aforementioned capacitance is generated from the accumulation of charges between each film layer and inside the light-emitting layer. Adjusting the HOMO (highest occupied molecular orbital) / LUMO (lowest unoccupied molecular orbital) energy levels of each layer of material can control the accumulation of charges between interfaces. The greater the energy difference between the HOMO / LUMO energy levels, the more charges accumulate. In addition, adjusting the electron mobility, hole mobility can also control the speed of charge movement within the film layer, and also control the amount of charge accumulation. The inventors have found that when the integral area Q1 of the capacitance-voltage curve of the first light-emitting unit satisfies |Q n -Q1|≤0.5, the accumulation of charges at the interface in the device can be better alleviated.

[0054] Specifically, within the above voltage range, the amount of charge accumulation of the green light-emitting unit and the red light-emitting unit is relatively close, and when the organic light-emitting device is powered on, the capacitance difference between the green light-emitting unit and the red light-emitting unit is small, and the green light-emitting unit and the red light-emitting unit have high consistency in response speed, so that when different display pictures are switched, the change speed of light-emitting units of different colors is relatively consistent, effectively improving the first frame display redness, display tailing and other display panel display defects.

[0055] In an embodiment of the present application, the materials of the light-emitting auxiliary layer and the light-emitting layer of the plurality of light-emitting units are not particularly limited. For example, the materials of the light-emitting auxiliary layers of different color light-emitting units are not completely the same, and the host materials of the light-emitting layers are also not completely the same. The red light-emitting unit can have a red light-emitting auxiliary layer 311 and a red light-emitting layer 312, the green light-emitting unit can have a green light-emitting auxiliary layer 321 and a green light-emitting layer 322, and the blue light-emitting unit can include a blue light-emitting auxiliary layer 331 and a blue light-emitting layer 332.

[0056] As an example, the aforementioned capacitance-voltage curve can be obtained in the range of -3V to 3V. The specific test conditions can be: test frequency 1kHz, current amplitude 100mV.

[0057] Specifically, the capacitance-voltage curve test can be performed on the backplane to form the aforementioned organic light-emitting device film layer, the encapsulation layer and the polarizer. The interface can be set to light up R / G / B single color pixels respectively, and then the capacitance under the single color picture is tested respectively. The test equipment is a capacitance inductance tester, and the test environment is room temperature and atmospheric environment.

[0058] According to the embodiments of the present application, by selecting materials with specific material properties, especially adjusting the parameter conditions of the red light-emitting unit and the green light-emitting unit, |Q n -Q1| satisfies the aforementioned conditions. The specific conditions for adjustment include the HOMO energy level, the LUMO energy level, the electron mobility, the hole mobility, etc. of the light-emitting layer.

[0059] As understood by those skilled in the art, HOMO (Highest Occupied Molecular Orbital) refers to the highest energy level of an orbit occupied by electrons, referred to as the highest occupied orbit, in which there are electrons, and also referred to as the valence band top. The higher the HOMO energy level, the easier the substance loses electrons. LUMO (Lowest Unoccupied Molecular Orbital) refers to the lowest energy level of an orbit not occupied by electrons, referred to as the lowest unoccupied orbit, which is the lowest energy in all empty orbits, and also referred to as the conduction band bottom. The lower the LUMO energy level, the easier the substance gains electrons.

[0060] The inventors have also found that the hole transport layer 220 can also adjust the injection speed and amount of holes, and the electron transport layer 420 can adjust the injection speed and amount of electrons. The injected electrons and holes act in the light-emitting layer, combine in a bound state to form excitons, and the excitons decay to radiate photons to emit light. Therefore, the light-emitting auxiliary layer located between the hole transport layer 220 and the light-emitting layer can improve the migration efficiency of holes, while blocking the further transport of electrons to the side of the first electrode layer 110, thereby further improving the combination effect of electrons and holes in the light-emitting layer and improving the light-emitting efficiency of the light-emitting layer.

[0061] According to some embodiments of the present application, in order to facilitate the preparation of the display panel and simplify the process flow, the material physical properties and interface characteristics of other film layers can be kept consistent for different light-emitting units in the organic light-emitting device, except for the light-emitting layer and the auxiliary light-emitting layer. For example, referring to Figure 1 , the green light-emitting unit and the red light-emitting unit can share the first electrode layer 110, the hole transport layer 220, the electron transport layer 420, and the second electrode layer 120. The first electrode layer 110 can be an anode layer, and the second electrode layer 120 can be a cathode layer. When the pixel unit structure further includes a blue light-emitting unit, the green, red, and blue light-emitting units can share the first electrode layer 110, the hole transport layer 220, the electron transport layer 420, and the second electrode layer 120.

[0062] According to some embodiments of the present application, the materials of the hole transport layer 220, the light-emitting auxiliary layer of the first light-emitting unit with the fastest light-emitting response speed, and the other light-emitting auxiliary layers (the nth light-emitting unit) can be selected so that the HOMO energy level HOMO HTL of the hole transport layer, the HOMO energy level HOMO prime-n of the light-emitting auxiliary layer of the nth light-emitting unit, and the energy level HOMO prime1 of the light-emitting auxiliary layer of the first light-emitting unit satisfy at least one of the following conditions:

[0063] HOMO HTL > HOMO prime-n > HOMO prime1;

[0064] |HOMO HTL -HOMO prime1 |≤0.2eV;

[0065] |HOMO prime1 -HOMO prime-n |≥0.1eV.

[0066] In some examples, the first light emitting unit can be a red light emitting unit, and the nth light emitting unit can be a green light emitting unit.

[0067] In some embodiments, the hole mobility μ prime1 of the light emitting auxiliary layer of the first light emitting unit can be made to satisfy at least one of the following conditions: prime-n

[0068] μ prime-n <μ prime1 ;

[0069] μ prime-n / μ prime1 ≤0.5.

[0070] Similarly, the first light emitting unit can be a red light emitting unit, and the nth light emitting unit can be a green light emitting unit.

[0071] The inventors have found that, under the action of an electric field, holes are injected from the anode layer to the HOMO of the hole transport layer, and then to the HOMO of the light emitting layer. Specifically, when the light emitting layer includes a light emitting layer and a light emitting auxiliary layer, holes are injected from the anode layer to the HOMO of the hole transport layer, and then to the HOMO of the light emitting auxiliary layer. When the HOMO level of the green light emitting auxiliary layer 321 is greater than the HOMO level of the red light emitting auxiliary layer 311, the charge accumulation on the interface between the hole transport layer and the green light emitting auxiliary layer, and inside the green light emitting auxiliary layer, is less, which can reduce the capacitance of the green light emitting unit.

[0072] According to some embodiments of the present application, μ G-prime <μ R-prime , where μ G-prime is the hole mobility of the green light emitting auxiliary layer 321, and μ R-prime is the hole mobility of the red light emitting auxiliary layer 311. When the hole mobility of the green light emitting auxiliary layer 321 is less than the hole mobility of the red light emitting auxiliary layer 311, the hole mobility in the green light emitting auxiliary layer 321 is slower, which can reduce the charge accumulation in the green light emitting auxiliary layer 321 and reduce the capacitance of the green light emitting unit.

[0073] ​According to some embodiments of the present application, the structure of the green light-emitting auxiliary layer is not particularly limited, for example, referring to Figure 1 and Figure 2 , the green light-emitting auxiliary layer can only include one light-emitting auxiliary layer 321, and for another example, referring to Figure 3 , the green light-emitting auxiliary layer can include a first sub-film layer 3211 and a second sub-film layer 3212 arranged in a stack, and the first sub-film layer 3211 is arranged towards the hole transport layer 220.

[0074] According to some embodiments of the present application, when the light-emitting auxiliary layer of the green light-emitting unit can include a first sub-film layer 3211 and a second sub-film layer 3212 arranged in a stack, the hole transport layer 220 has a HOMO energy level HOMO HTL , the red light-emitting auxiliary layer 311 has a HOMO energy level HOMO R-prime and a hole mobility μ R-prime , the first sub-film layer 3211 of the green light-emitting auxiliary layer has a HOMO energy level HOMO G-primeA and a hole mobility μ G-primeA , the second sub-film layer 3212 of the green light-emitting auxiliary layer has a HOMO energy level HOMO G-primeB and a hole mobility μ G-primeB , and HOMO HTL >HOMO G-primeA >HOMO R-prime When the HOMO energy level of the first sub-film layer 3211 is greater than the HOMO energy level of the red light-emitting auxiliary layer 311, the charge accumulation on the interface between the hole transport layer and the first sub-film layer 3211 of the green light-emitting unit, as well as the charge accumulation inside the light-emitting auxiliary layer of the green light-emitting unit, are both less, which can reduce the capacitance value of the green light-emitting unit.

[0075] According to some specific embodiments of the present application, the organic light-emitting device can also satisfy at least one of the following conditions:

[0076] HOMO HTL -HOMO G-primeA ≤0.2eV;

[0077] HOMO G-primeA -HOMO R-prime ≥0.1eV;

[0078] HOMO G-primeA -HOMO G-primeB ≤0.3eV;

[0079] μ G-primeB <μ G-primeA <μ R-prime ;

[0080] μ G-primeB / μ G-primeA ≤0.5;

[0081] μ G-primeA / μ R-prime ≤0.5.

[0082] Therefore, the charge accumulation between the light-emitting auxiliary layer and the hole transport layer 220 can be improved.

[0083] The inventors have found that when the hole mobility of the second sub-film layer 3212 of the green light-emitting unit is less than the hole mobility of the first sub-film layer 3211 of the green light-emitting unit, the overall hole mobility of the green light-emitting auxiliary layer is slower, thereby reducing the charge accumulation in the light-emitting auxiliary layer of the green light-emitting unit and reducing the capacitance value of the green light-emitting unit.

[0084] According to some embodiments of the present application, the light-emitting layer of the green light-emitting unit can be a superfluorescent system, for example, the light-emitting layer of the green light-emitting unit can include a first host material, a sensitizer material and a first dopant material, specifically, the sensitizer material can include at least one of a thermally activated delayed fluorescence material and a phosphorescent material; the first dopant material can include a boron-containing fluorescent dye. According to some specific embodiments of the present application, the light-emitting layer of the green light-emitting unit can include 60-90 parts by weight of the first host material, 10-40 parts by weight of the sensitizer material, and 0.5-5 parts by weight of the first dopant material.

[0085] The host material in the light-emitting layer is a light-emitting material with hole transport or electron transport function, which can be excited first and then transfer energy to the dopant material to make the dopant material excited and emit light according to the energy demand of different colors while emitting light by itself, thereby improving the light-emitting ability of the dopant material. The host material doped with the dopant material can have high-efficiency light-emitting effect and effectively prolong the service life of the device. The sensitizer material can transfer the energy absorbed by itself to the host material to enhance the light-emitting phenomenon of the host material. The first host material has a HOMO energy level HOMO G-host , a LUMO energy level LUMO G-host , a hole mobility μ hG-host , an electron mobility μ eG-host , the sensitizer material has a LUMO energy level LUMO G-sens , a hole mobility μ hG-sens , an electron mobility μ eG-sens , the first dopant material has a HOMO energy level HOMO G-dop , and the green light-emitting auxiliary layer has a HOMO energy level HOMO G-prime The organic light-emitting device satisfies at least one of the following conditions:

[0086] |HOMO G-host -HOMOG-prime |≤0.2eV;

[0087] μ hG-host / μ eG-host ≥5;

[0088] μ eG-sens / μ hG-sens ≥5;

[0089] LUMO G-host -LUMO G-sens ≥0.6eV;

[0090] |HOMO G-host -HOMO G-dop |≤0.2eV.

[0091] When the energy level, hole or electron mobility of each layer material satisfies at least one of the above conditions, the amount of charge accumulation on the interface between the light-emitting auxiliary layer and the light-emitting layer in the green light-emitting unit can be reduced, and the capacitance value of the green light-emitting unit can be reduced.

[0092] Specifically, controlling the hole and electron mobility of the first host material to satisfy the above conditions helps to improve the hole transport capability of the first host material. Controlling the hole and electron mobility of the sensitizing agent material to satisfy the above conditions helps to improve the electron transport capability of the sensitizing agent material. Controlling the LUMO energy level of the sensitizing material and the first host material helps the sensitizing agent to obtain electrons. Controlling the HOMO energy level of the first dopant material helps the hole to transfer between the first host material and the first dopant material, and reduces the charge accumulation amount of the light-emitting layer.

[0093] According to some embodiments of the present application, the light-emitting layer of the red light-emitting unit can be a phosphorescent system, for example, the light-emitting layer of the red light-emitting unit can include a second host material and a second dopant material, specifically, the second dopant material can include a phosphorescent material. According to some specific embodiments of the present application, the light-emitting layer of the red light-emitting unit includes 90-99 parts by weight of the second host material and 1-10 parts by weight of the second dopant material. Alternatively, it contains 90wt%-99wt% of the second host material and 1wt%-10wt% of the second dopant material. In this way, the display effect of the red light-emitting unit can be improved.

[0094] According to some embodiments of the present application, the second host material has a HOMO energy level HOMO R-host , the red light-emitting auxiliary layer has a HOMO energy level HOMO R-prime , the second dopant material has a HOMO energy level HOMO R-dop , and the organic light-emitting device satisfies at least one of the following conditions:

[0095] |HOMO R-hostHOMO R-prime ≥ 0.2 eV;

[0096] HOMO R-host HOMO R-dop ≥ 0.2 eV.

[0097] Thus, the amount of charge accumulation on the interface between the light-emitting auxiliary layer and the light-emitting layer in the red light-emitting unit can be increased, the capacitance value of the red light-emitting unit can be improved, or the transfer of holes between the second host material and the second dopant material can be inhibited by controlling the relevant properties of the second dopant material, thereby increasing the amount of charge accumulation in the red light-emitting layer.

[0098] According to some embodiments of the present application, when the pixel unit structure includes a blue light-emitting unit, the light-emitting layer of the blue light-emitting unit can be a fluorescent system, for example, the light-emitting layer of the blue light-emitting unit can include a third host material and a third dopant material, wherein the third dopant material can be a fluorescent material. According to some specific embodiments of the present application, the light-emitting layer of the blue light-emitting unit includes 95wt%-99wt% of the third host material and 1wt%-5wt% of the third dopant material.

[0099] According to some embodiments of the present application, the organic light-emitting device can further include other film layers for improving quantum efficiency or light-emitting efficiency. For example, referring to Figure 3 The organic light-emitting device can have a hole injection layer 210 between the hole transport layer 220 and the first electrode layer 110, a hole blocking layer 230 between the hole transport layer 220 and the light-emitting layer, an electron blocking layer 410 between the electron transport layer 420 and the second electrode layer 120, a capping layer 500 on the side of the second electrode layer 120 away from the electron transport layer 420, and the like. The specific materials of the above structures are not particularly limited, and can be selected by a person skilled in the art according to the actual situation.

[0100] When the organic light-emitting device is applied to a pixel unit in a display panel, the light-emitting of the pixel unit of the panel can include the following steps: under the driving of an external electric field, (1) injection of carriers, including injection of electrons from the cathode to the electron injection layer 410 and injection of holes from the anode to the hole injection layer 210; (2) transport of carriers, including injection of electrons from the electron injection layer 410 to the electron transport layer 420 and finally to the light-emitting layer, and injection of holes from the hole injection layer 210 to the hole transport layer 220 and finally to the light-emitting layer; (3) generation of excitons, in which excitons are generated by recombination of electrons and holes in the organic light-emitting layer; (4) radiation and light emission, in which the excitons transition back to the ground state and emit light.

[0101] The anode layer is used to inject holes into the highest occupied molecular orbital of the light-emitting layer, the hole injection layer is used to enable the holes to migrate from the anode layer to the hole transport layer, the hole transport layer is used to enable the holes injected from the anode layer to migrate through the hole transport layer to the light-emitting layer, and to prevent the holes from the anode layer from directly migrating to the cathode layer. In addition, since the hole mobility of the hole transport material is generally higher than the electron mobility of the electron transport material, and the hole injection efficiency of the anode layer is also higher than the electron injection efficiency of the cathode layer, the holes are more likely to migrate from the light-emitting layer to the anode layer. By providing the hole blocking layer, the holes can be more likely to stay in the light-emitting layer, thereby improving the light-emitting efficiency of the light-emitting layer.

[0102] The cathode layer is used to inject electrons into the lowest unoccupied molecular orbital of the light-emitting layer, the electron injection layer is used to enable the electrons to migrate from the cathode layer to the electron transport layer, the electron transport layer is used to enable the electrons injected from the cathode layer to migrate through the electron transport layer to the light-emitting layer, and to prevent the holes from the anode layer from directly migrating to the cathode layer.

[0103] In another aspect of the present application, the present application provides a display panel. The display panel comprises the organic light-emitting device described above. Thus, the display panel has all the features and advantages of the organic light-emitting device described above, which will not be repeated here.

[0104] In one aspect of the present application, the present application provides a display device comprising the display panel described above. Thus, the display device has all the features and advantages of the display panel described above, which will not be repeated here.

[0105] The scheme of the present application will be described below through specific examples. It should be noted that the following examples are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. If the specific technology or condition is not specified in the examples, the technology or condition described in the literature in the art or according to the product manual is used. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be obtained by purchase.

[0106] Example 1

[0107] The organic light-emitting device has a structure as shown in Figure 3 , wherein the materials of each layer are as follows: the hole transport layer: arylamine carbazole compound;

[0108] The light-emitting layer of the green light-emitting unit: comprising a first host material: a biscalbazole compound, a first dopant material: a boron-nitrogen condensed ring compound, a sensitizer material: a cyano benzocarbazole compound;

[0109] The first sub-film layer of the green light-emitting unit: arylamine carbazole compound;

[0110] The second sub-film layer of the green light emitting unit: an arylamine carbazole compound;

[0111] The light emitting layer of the red light emitting unit comprises a second host material: a biscarbazole compound, and a second dopant material: an iridium complex;

[0112] The light emitting auxiliary layer of the red light emitting unit: an arylamine carbazole compound;

[0113] The HOMO energy levels of the materials of each layer are shown in Table 1:

[0114] Table 1

[0115]

[0116] Comparative Example 1

[0117] The rest of the structure is the same as that of Example 1, except that the HOMO HTL of the arylamine carbazole compound in Comparative Example 1 is -5.45 eV, the HOMO G-primeA of the biscarbazole compound is -5.71 eV, the HOMO R-prime of the iridium complex is -5.51 eV.

[0118] Comparative Example 2

[0119] The rest of the structure is the same as that of Example 1, except that the HOMO G-host of the arylamine carbazole compound in Comparative Example 2 is -5.89 eV, the HOMO G-primeB of the biscarbazole compound is -5.67 eV, the HOMO R-host of the iridium complex is -5.80 eV, and the HOMO R-prime of the arylamine carbazole compound is -5.76 eV.

[0120] Comparative Example 3

[0121] The rest of the structure is the same as that of Example 1, except that the HOMO G-host of the arylamine carbazole compound in Comparative Example 3 is -5.82 eV, the HOMO G-dop of the biscarbazole compound is -5.50 eV, the HOMO R-host of the iridium complex is -5.40 eV, and the HOMO R-dop of the arylamine carbazole compound is -5.35 eV.

[0122] The test results are shown in Table 2. Figures 4-7 The integral area of the capacitance-voltage curve of the green light emitting unit in the range of -3V to 3V is QG, the integral area of the capacitance-voltage curve of the red light emitting unit in the range of -3V to 3V is QR, and the results of |QG-QR| in Example 1 and Comparative Examples 1-3 are shown in Table 2.

[0123] Table 2

[0124] |Q G -Q R |@-3V~3V]]> CIE(x, y) @ W Example 1 0.19 CIE (0.34, 0.33) Comparative Example 1 1.21 CIE (0.40, 0.31) Comparative Example 2 1.34 CIE (0.43, 0.30) Comparative Example 3 1.09 CIE (0.39, 0.31)

[0125] CIE(x, y)@W was measured at 1 nit brightness in the first frame of white light, where the coordinates of white light in the CIE1931 chromaticity diagram are (0.33, 0.33).

[0126] Test results show that in Comparative Examples 1-3, due to the unmet requirements of material energy level constraints, the capacitance difference between green and red sub-pixels is large, while the capacitance of the red sub-pixels is relatively small. This results in an increased proportion of red light in the first frame of white light, causing the white light image to appear reddish and leading to a trailing phenomenon. The material energy level configuration in Example 1 ensures that the difference in integral surface value |QG-QR| between the green and red light-emitting units within the range of -3V to 3V is less than 0.5. This effectively reduces the capacitance of the green light-emitting unit and increases the capacitance of the red light-emitting unit, thereby reducing the capacitance difference between the green and red light-emitting units, resulting in a stable first frame of white light and improving the trailing phenomenon.

[0127] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the 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 this disclosure, "multiple" means two or more, unless otherwise explicitly specified.

[0128] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0129] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0130] The above disclosure provides many different embodiments or examples for implementing various aspects of the present disclosure. For simplicity of the disclosure, the foregoing description has focused on certain examples and / or on certain aspects of the examples. In the interest of clarity, not all aspects of the examples have been described. It will be appreciated that those skilled in the relevant art will be able to devise many

[0131] The above merely provides specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and any person skilled in the art can easily think of various changes or replacements within the technical scope disclosed by the present disclosure, and these should be encompassed in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. An organic light-emitting device, characterized in that, The organic light-emitting device comprises a first electrode layer, a hole transport layer, an electron transport layer and a second electrode layer which are sequentially stacked, a plurality of light-emitting units arranged in the same layer between the hole transport layer and the electron transport layer, the light-emitting unit comprises a light-emitting auxiliary layer and a light-emitting layer which are sequentially stacked, the light-emitting auxiliary layer is located close to the hole transport layer, and the first light-emitting unit has the fastest light-emitting response speed in the plurality of light-emitting units; the plurality of light-emitting units comprises a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit, the first light-emitting unit is the red light-emitting unit, and the nth light-emitting unit is the green light-emitting unit. The integral area of the capacitance-voltage curve of the first light emitting unit is Q1, Q1 satisfies: |Q n -Q1|≤0.5, Q n is an integral area of a capacitance-voltage curve of an n-th light emitting unit for which a light emission response speed is greater than that of the first light emitting unit. The light-emitting layer of the green light-emitting unit comprises a first host material, a sensitizer material and a first dopant material, the sensitizer material comprises at least one of a thermally activated delayed fluorescence material and a phosphorescent material, the first dopant material comprises a boron-containing fluorescent dye, the light-emitting layer of the green light-emitting unit comprises 60-90 parts by weight of the first host material, 10-40 parts by weight of the sensitizer material and 0.5-5 parts by weight of the first dopant material; and / or the light-emitting layer of the red light-emitting unit comprises a second host material and a second dopant material, the second dopant material comprises a phosphorescent material, the light-emitting layer of the red light-emitting unit comprises 90-99 parts by weight of the second host material and 1-10 parts by weight of the second dopant material. wherein the first host material has a HOMO energy level HOMO G-host , a LUMO energy level LUMO G-host , a hole mobility μ hG-host , an electron mobility μ eG-host , the sensitizer material has a LUMO energy level LUMO G-sens and a hole mobility μ hG-sens , an electron mobility μ eG-sens , the first dopant material has a HOMO energy level HOMO G-dop , the light-emitting auxiliary layer of the green light-emitting unit has a HOMO energy level HOMO G-prime , the organic light-emitting device satisfies at least one of the following conditions: |HOMO G-host -HOMO G-prime |≤0.2eV; μ hG-host / μ eG-host ≥5; μ eG-sens / μ hG-sens ≥5; LUMO G-host -LUMO G-sens ≥0.6eV; |HOMO G-host -HOMO G-dop |≤0.2eV; the second host material has a HOMO energy level HOMO R-host the light-emitting auxiliary layer of the red light-emitting unit has a HOMO energy level HOMO R-prime the second dopant material has a HOMO energy level HOMO R-dop the organic light-emitting device satisfies at least one of the following conditions: | HOMO R-host | HOMO R-prime | HOMO R-host | HOMO R-dop | HOMO 2. The organic light emitting device according to claim 1, wherein The integral area of the capacitance-voltage curve is the integral area in the range of -3V to 3V.

3. The organic light-emitting device according to claim 1, characterized in that, a HOMO energy level HOMO of the hole transport layer HTL a HOMO energy level HOMO of the light-emitting auxiliary layer of the nth light-emitting unit prime-n a HOMO energy level HOMO of the light-emitting auxiliary layer of the first light-emitting unit prime1 at least one of the following conditions is satisfied: HOMO HTL HOMO prime-n HOMO prime-1 ; | HOMO HTL - HOMO prime1 |≤0.2 eV; | HOMO prime1 - HOMO prime-n | ≥ 0.1 eV.

4. The organic light-emitting device according to claim 1, characterized in that, a hole mobility μ of the light emitting auxiliary layer of the first light emitting unit prime1 a hole mobility μ of the light emitting auxiliary layer of the nth light emitting unit prime-n at least one of the following conditions is satisfied: μ prime-n <μ prime1 ; μ prime-n / μ prime1 ≤0.

5.

5. The organic light emitting device of claim 1, wherein The light-emitting auxiliary layer of the green light-emitting unit comprises a first sub-film layer and a second sub-film layer which are sequentially stacked, and the first sub-film layer is arranged towards the hole transport layer.

6. The organic light emitting device of claim 5, wherein, The hole transport layer has a HOMO energy level HOMO HTL The light-emitting auxiliary layer of the red light-emitting unit has a HOMO energy level HOMO R-prime and a hole mobility μ R-prime The first sub-film layer of the green light-emitting unit has a HOMO energy level HOMO G-primeA and a hole mobility μ G-primeA The second sub-film layer of the green light-emitting unit has a HOMO energy level HOMO G-primeB and a hole mobility μ G-primeB , The organic light-emitting device satisfies at least one of the following conditions: HOMO HTL HOMO G-primeA HOMO R-prime ; HOMO HTL HOMO G-primeA ≤ 0.2 eV; HOMO G-primeA HOMO R-prime ≥ 0.1 eV; HOMO G-primeA HOMO G-primeB ≤ 0.3 eV; μ G-primeB < μ G-primeA < μ R-prime ; μ G-primeB / μ G-primeA ≤0.5; μ G-primeA / μ R-prime ≤0.

5.

7. A display panel, characterized by The organic light-emitting device comprises the organic light-emitting device according to any one of claims 1-6.

8. A display device, characterized by comprising: The display panel comprises the display panel according to claim 7.

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