Light-emitting device and display panel

Abstract

The invention provides a light-emitting device and a display panel, and belongs to the technical field of display. The light-emitting device (20) comprises a substrate (10), a first electrode (100), a light-emitting unit and a second electrode (200), the light-emitting unit comprises a plurality of sub-light-emitting units which are stacked in the direction perpendicular to the substrate 10 and charge generation layers (500) located between the adjacent sub-light-emitting units; among the plurality of sub-light-emitting units, the sub-light-emitting unit close to the second electrode (200) is a white light-emitting unit. The present disclosure helps to improve the problem that the light emitting quality of the light emitting device (20) differs greatly when the driving voltage changes from low to high.

Description

Light-emitting device and display panel Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a light-emitting device and a display panel. Background Art

[0002] In some OLED displays, pixels are characterized by the fact that within the pixel's light-emitting area, the first electrode layer or the layers beneath it are not flat. Instead, they lie on different planes in different areas, with varying heights. During evaporation, the multi-layer structure deposited on the first electrode layer has varying thicknesses, particularly at the transition between the two planes. This results in devices with varying thicknesses in the plane and transition regions, creating the illusion of normal and abnormal devices.

[0003] In the prior art, white light devices are typically formed by connecting two or more light-emitting units emitting different colors in series. In such white light devices, the thickness difference between the light-emitting unit near the first electrode and the light-emitting unit far from the first electrode in the abnormal region is large, thus affecting the light emission quality of the white light device.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.

[0005] Summary of the Invention

[0006] The present disclosure aims to provide a light-emitting device and a display panel, which are helpful in improving the problem that the light-emitting device has a large difference in light-emitting quality when the driving voltage changes from low to high.

[0007] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0008] According to a first aspect of the present disclosure, there is provided a light emitting device comprising a substrate and a first electrode, a light emitting unit, and a second electrode stacked in a direction away from the substrate;

[0009] The light-emitting unit includes a plurality of sub-light-emitting units stacked in a direction perpendicular to the substrate and a charge generation layer located between adjacent sub-light-emitting units;

[0010] Among the plurality of sub-light emitting units, the sub-light emitting unit close to the second electrode is a white light emitting unit.

[0011] In an exemplary embodiment of the present disclosure, the plurality of sub-light emitting units include at least a second light emitting unit and a first light emitting unit stacked in a direction away from the substrate, and the first light emitting unit is a white light emitting unit.

[0012] In an exemplary embodiment of the present disclosure, the first light-emitting unit includes a first light-emitting layer, and the first light-emitting layer includes a first sub-light-emitting layer and a second sub-light-emitting layer stacked in a direction away from the substrate;

[0013] One of the first sub-light emitting layer and the second sub-light emitting layer is a blue light emitting layer, and the other is a yellow light emitting layer.

[0014] In an exemplary embodiment of the present disclosure, the first sub-light emitting layer is a blue light emitting layer, the second sub-light emitting layer is a yellow light emitting layer, and the material in the first sub-light emitting layer is a phosphorescent light emitting material; or

[0015] The first sub-light emitting layer is a yellow light emitting layer, the second sub-light emitting layer is a blue light emitting layer, and a material of the second sub-light emitting layer is a fluorescent light emitting material.

[0016] In an exemplary embodiment of the present disclosure, the first light-emitting layer further includes a first spacer layer, and the first spacer layer is disposed between the first sub-light-emitting layer and the second sub-light-emitting layer.

[0017] In an exemplary embodiment of the present disclosure, the second light-emitting unit includes a second light-emitting layer, and the first light-emitting layer and / or the second light-emitting layer include at least one optical adjustment layer, and the optical adjustment layer is used to adjust the light-emitting characteristics of the light-emitting unit.

[0018] In an exemplary embodiment of the present disclosure, the optical adjustment layer includes at least one of a blue light emitting layer, a yellow light emitting layer, a green light emitting layer or a red light emitting layer.

[0019] In an exemplary embodiment of the present disclosure, the first light-emitting layer further includes an optical adjustment layer, and the optical adjustment layer of the first light-emitting layer is located on a side of the second sub-light-emitting layer away from the substrate;

[0020] The second light-emitting layer includes one optical adjustment layer, and the optical adjustment layer in the second light-emitting layer is a yellow light-emitting layer or a red light-emitting layer.

[0021] In an exemplary embodiment of the present disclosure, when the optical adjustment layer in the second light-emitting layer is a yellow light-emitting layer, the first sub-light-emitting layer is a blue light-emitting layer, the second sub-light-emitting layer is a yellow light-emitting layer, and the optical adjustment layer of the first light-emitting layer is a blue light-emitting layer.

[0022] In an exemplary embodiment of the present disclosure, when the optical adjustment layer in the second light-emitting layer is a red light-emitting layer, the first sub-light-emitting layer is a yellow light-emitting layer, the second sub-light-emitting layer is a blue light-emitting layer, and the optical adjustment layer of the first light-emitting layer is a green light-emitting layer.

[0023] In an exemplary embodiment of the present disclosure, the second light-emitting layer includes two optical adjustment layers, one of which is a blue light-emitting layer and the other is a red light-emitting layer. The blue light-emitting layer is located on a side of the red light-emitting layer away from the substrate, and the material of the blue light-emitting layer is a fluorescent material.

[0024] In an exemplary embodiment of the present disclosure, the first sub-light emitting layer is a yellow light emitting layer, the second sub-light emitting layer is a blue light emitting layer, and the material of the second sub-light emitting layer is a fluorescent light emitting material;

[0025] The first light-emitting layer further includes a first spacer layer, and the first spacer layer is provided between the first sub-light-emitting layer and the second sub-light-emitting layer;

[0026] The second light-emitting layer further includes a second spacer layer, and the second spacer layer is disposed between the two optical adjustment layers of the second light-emitting layer.

[0027] In an exemplary embodiment of the present disclosure, the first light-emitting layer further includes the optical adjustment layer, and the optical adjustment layer in the first light-emitting layer is a red light-emitting layer and is located on a side of the second sub-light-emitting layer away from the substrate;

[0028] The second light-emitting layer includes two optical adjustment layers, and both of the optical adjustment layers in the second light-emitting layer are blue light-emitting layers.

[0029] In an exemplary embodiment of the present disclosure, the first sub-light emitting layer is a blue light emitting layer, and the second sub-light emitting layer is a yellow light emitting layer;

[0030] The first light-emitting layer further includes a first spacer layer, which is disposed between the first sub-light-emitting layer and the second sub-light-emitting layer. The optical adjustment layer in the first light-emitting unit is disposed on a side of the second sub-light-emitting layer away from the substrate.

[0031] In an exemplary embodiment of the present disclosure, when the first sub-light-emitting layer is a blue light-emitting layer and the second sub-light-emitting layer is a yellow light-emitting layer, the second light-emitting layer includes two layers of the optical adjustment layer, and the two layers of the optical adjustment layer are a blue light-emitting layer and a yellow light-emitting layer stacked in a direction away from the substrate.

[0032] In an exemplary embodiment of the present disclosure, when the first sub-light emitting layer is a blue light emitting layer and the second sub-light emitting layer is a yellow light emitting layer, the second light emitting layer includes three layers of the optical adjustment layer;

[0033] The three optical adjustment layers are a blue light emitting layer, a red light emitting layer and a green light emitting layer stacked in a direction away from the substrate.

[0034] In an exemplary embodiment of the present disclosure, the substrate includes a first region and a second region located on one side of the first region; the thickness of the light-emitting unit located in the first region is greater than the thickness of the light-emitting unit located in the second region;

[0035] The plurality of sub-light emitting units at least include a second light emitting unit and a first light emitting unit stacked in a direction away from the substrate, wherein the thickness of the second light emitting unit located in the second area is less than the thickness of the second light emitting unit located in the first area;

[0036] The thickness of the first light-emitting unit located in the second area is less than or equal to the thickness of the first light-emitting unit located in the first area;

[0037] The thickness of the first light emitting unit located in the second area of ​​the substrate is greater than the thickness of the second light emitting unit located in the second area of ​​the substrate.

[0038] In an exemplary embodiment of the present disclosure, the thickness of the yellow light-emitting layer in the first light-emitting layer is 0.1 nm-5 nm.

[0039] According to a second aspect of the present disclosure, a display panel is provided, comprising the light-emitting device according to the first aspect.

[0040] The light-emitting device provided by the present disclosure includes multiple sub-light-emitting units, wherein the sub-light-emitting unit close to the second electrode is a white light-emitting unit to ensure that at least one light-emitting unit emits white light. This helps to improve the problem of large differences in light-emitting quality of the light-emitting device when the driving voltage changes from low to high. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and other features and advantages of the present disclosure will become more apparent by describing in detail example embodiments thereof with reference to the accompanying drawings.

[0042] FIG1 is a schematic diagram of a substrate structure in an exemplary embodiment of the present disclosure;

[0043] 2 to 7 are schematic structural diagrams of light-emitting devices in different exemplary embodiments of the present disclosure.

[0044] The main components in the figure are described as follows:

[0045] 10-substrate; 11-first surface; 12-second surface; 121-first sub-surface; 122-second sub-surface; 123-transition surface; 124-first region; 125-second region; 20-light-emitting device; 100-first electrode; 200-second electrode; 300-first light-emitting unit; 301-first light-emitting layer; 3011-first sub-light-emitting layer; 3012-second sub-light-emitting layer; 3013-first spacer layer; 302-first hole transport layer; 303-first electron transport layer; 400-second light-emitting unit; 401-second light-emitting layer; 402-second hole transport layer; 403-second electron transport layer; 404-second spacer layer; 500-charge generation layer; 600-optical adjustment layer. DETAILED DESCRIPTION

[0046] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of the embodiments of the present disclosure.

[0047] In the drawings, the thickness of regions and layers may be exaggerated for clarity. The same reference numerals in the drawings denote the same or similar structures, and thus their detailed description will be omitted.

[0048] The described features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure can be practiced without one or more of the specific details, or other methods, components, materials, etc. can be adopted. In other cases, well-known structures, materials or operations are not shown or described in detail to avoid obscuring the main technical ideas of the present disclosure.

[0049] When a structure is “on” another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is “directly” disposed on the other structure, or that the structure is “indirectly” disposed on the other structure via another structure.

[0050] The terms "a," "an," and "the" are used to indicate the presence of one or more elements / components; the terms "including" and "having" are used to indicate an open-ended inclusiveness and mean that additional elements / components / etc. may be present in addition to the listed elements / components / etc. The terms "first," "second," etc. are used merely as labels and do not limit the quantity of the items to which they refer.

[0051] White light devices are typically constructed from two or more light-emitting units emitting different colors in series. The first electrode layer or the layers beneath it in some white light devices are not planar; rather, they lie on different planes in different regions, with height differences between them. During evaporation, the multi-layer structure deposited on the first electrode layer exhibits inconsistent thicknesses, particularly in the transition region between the two planes. The thickness distortion of the first-deposited layer is greater in the transition region, and the structural distortion of the first-deposited unit is also significant. Consequently, the combined emission spectrum of the upper and lower units in the planar and transition regions differs significantly, as do the current-voltage characteristics and voltage-luminance-chromaticity. For example, the turn-on voltage of an abnormal device in the transition region is lower than that in the planar region. In some cases, at low drive voltages, only the later-deposited unit in the abnormal device in the transition region emits light. At higher voltages, both units in the normal device in the planar region emit light simultaneously. Consequently, when the drive voltage changes from low to high, the color of the pixel light varies significantly, resulting in a color difference between high and low brightness levels in the displayed image, and abnormal grayscale color points.

[0052] For example, in the related art, a white pixel is composed of a blue light-emitting unit and a yellow light-emitting unit connected in series, wherein the yellow light-emitting unit is located on the side of the blue light-emitting unit close to the first electrode. In order to increase the light-emitting area, a pit is provided on the substrate below the first electrode, and the first electrode covers the pit. The yellow light-emitting unit and the blue light-emitting unit are sequentially arranged on the side of the first electrode away from the substrate. A charge generation layer is also provided between the yellow light-emitting unit and the blue light-emitting unit. Due to the influence of the pit, when the light-emitting film layer of the yellow light-emitting unit is deposited, the thickness of the film layer formed in the side wall area of ​​the pit is less than the thickness of the film layer in the middle area of ​​the pit. The closer to the first electrode, the greater the difference in film thickness between the side wall area of ​​the pit and the normal area. Typically, the thickness of the film layer located in the sidewall region of the pit in the blue light-emitting unit is greater than the thickness of the film layer located in the sidewall region of the pit in the yellow light-emitting unit, while the thickness of the film layer located in the middle region of the pit in the blue light-emitting unit is roughly equal to the thickness of the film layer located in the middle region of the pit in the yellow light-emitting unit, and the difference in thickness between the film layer located in the sidewall region of the pit and the film layer located in the middle region in the yellow light-emitting unit is larger, while the difference in thickness between the film layer located in the sidewall region of the pit and the film layer located in the middle region of the pit in the blue light-emitting unit is smaller.

[0053] For such white pixels, various undesirable light-emitting phenomena may occur during light emission, for example, the white pixel exhibits different light emission spectra when driven at a lower voltage and a higher voltage.

[0054] One scenario involves a decrease in the thickness of the film layer in the yellow light-emitting unit located in the sidewall region of the pit, leading to a decrease in the driving voltage. Furthermore, due to the sharp decrease in the thickness of the yellow light-emitting unit in this region, the excitons generated by carrier injection are severely quenched, causing the portion of the yellow light-emitting unit located in the sidewall region to remain luminescent. Consequently, when a gradually increasing driving voltage is applied to the white pixel, at lower voltages, the turn-on voltage of the light-emitting device corresponding to the sidewall region is lower than that of the normal region. When driven at this lower voltage, the normal region remains luminous, while the sidewall region emits blue light from the blue light-emitting unit. When the voltage is increased to exceed the turn-on voltage of the normal region, both the blue and yellow light-emitting units in the normal region emit light simultaneously. Overall, the pixel emits blue light at low voltages and white light at high voltages.

[0055] Furthermore, in another scenario, the thickness of the yellow light-emitting unit located in the sidewall region of the pit decreases, lowering the turn-on voltage for the yellow light-emitting unit. At lower voltages, the yellow light-emitting unit lights up before the blue light-emitting unit, emitting yellow light. As the voltage increases further, the blue light-emitting unit in the sidewall region also lights up, and further, the blue and yellow light-emitting units in the normal region light up simultaneously. The overall effect is that the pixel emits yellow light at low voltages and white light at high voltages. This results in white pixels exhibiting different emission spectra when driven at lower and higher voltages.

[0056] As shown in Figures 1 and 2, the present disclosure provides a light-emitting device 20, including a substrate 10 and a first electrode 100, a light-emitting unit and a second electrode 200 stacked in a direction away from the substrate 10; the light-emitting unit includes a plurality of sub-light-emitting units stacked in a direction perpendicular to the substrate 10 and a charge generation layer 500 located between adjacent sub-light-emitting units; among the plurality of sub-light-emitting units, the sub-light-emitting unit close to the second electrode 200 is a white light-emitting unit.

[0057] The light-emitting device 20 provided in the present disclosure includes a plurality of sub-light-emitting units, wherein the sub-light-emitting unit close to the second electrode 200 is a white light-emitting unit to ensure that at least one light-emitting unit emits white light. This helps to improve the problem of large differences in light-emitting quality of the light-emitting device 20 when the driving voltage changes from low to high.

[0058] The components of the light emitting device 20 provided by the present disclosure will be described in detail below with reference to the accompanying drawings and specific embodiments:

[0059] As shown in Figures 1 and 2, the present disclosure provides a light-emitting device 20, which can be a white light device used in a display panel as a white pixel. The light-emitting device 20 includes a substrate 10 and a first electrode 100, a light-emitting unit, and a second electrode 200 stacked in a direction away from the substrate 10.

[0060] In some embodiments of the present disclosure, the substrate 10 includes a first region 124 and a second region 125 located to one side of the first region 124. Part of the light-emitting unit is located in the first region 124 of the substrate 10, and part of the light-emitting unit is located in the second region 125 of the substrate 10. That is, when each film layer in the light-emitting unit is deposited, the orthographic projection of the film layer on the substrate 10 is partially located in the first region 124 of the substrate 10, and partially located in the second region 125 of the substrate 10. In the present disclosure, the positional relationship between the first region 124 and the second region 125 of the substrate 10 is not specifically limited, and the number of first regions 124 and second regions 125 can be one, two, or more.

[0061] In some embodiments of the present disclosure, the substrate 10 has a first surface 11 and a second surface 12 arranged opposite to each other, the first surface 11 being the bottom surface, and at least part of the bottom surface is located in the same horizontal plane, with the horizontal plane being the reference plane. The distances between different areas of the second surface 12 and the reference plane are different. For example, the first surface 11 includes a first sub-surface 121, a second sub-surface 122, and a transition surface 123 connecting the first sub-surface 121 and the second sub-surface 122, and the distance between the first sub-surface 121 and the reference plane is smaller than the distance between the second sub-surface 122 and the reference plane. The transition surface 123 connects the first sub-surface 121 and the second sub-surface 122. The first sub-surface 121 and the second sub-surface 122 can be roughly parallel to the reference plane. Among them, the first sub-surface 121 and the second sub-surface 122 can be planes or arc surfaces. When they are arc surfaces, the arc radius corresponding to the arc surface is larger, so that the arc surface can be approximately parallel to the reference plane to a certain extent. In this type of embodiment, the first region 124 of the substrate 10 includes the first sub-surface 121 and does not include the transition surface 123 and the second sub-surface 122. The second region 125 of the substrate 10 includes the transition surface 123 and does not include the first sub-surface 121 and the second sub-surface 122. The first region 124 of the substrate 10 may be the region including the first sub-surface 121, and the second region 125 of the substrate 10 may be the region including the transition surface 123. Furthermore, in a specific embodiment, the first sub-surface 121 and the transition surface 123 of the substrate 10 form a groove on the substrate 10, and the cross-section of the groove may be a circular arc, an inverted trapezoid, or the like.

[0062] Optionally, the first electrode 100 includes the following first electrode material, which is preferably a material with a large work function that facilitates hole injection into the functional layer. Specific examples of the first electrode material include: metals such as nickel, platinum, vanadium, chromium, copper, zinc, and gold or their alloys; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combined metals and oxides such as ZnO:Al or SnO2:Sb; or conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDT), polypyrrole, and polyaniline, but are not limited thereto. Preferably, a transparent electrode comprising indium tin oxide (ITO) is included as the first electrode 100. The first electrode 100 can serve as the anode of the light-emitting device 20.

[0063] Optionally, the second electrode 200 includes a second electrode material having a small work function that facilitates electron injection into the functional layer. Specific examples of second electrode materials include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof; or multilayer materials such as LiF / Al, Liq / Al, LiO2 / Al, LiF / Ca, LiF / Al, and BaF2 / Ca, but are not limited thereto. A metal electrode containing silver and magnesium is preferably used as the second electrode 200. The second electrode 200 can serve as the cathode of the light-emitting device 20.

[0064] The plurality of sub-light-emitting units include at least a second light-emitting unit 400 and a first light-emitting unit 300 stacked in a direction away from the substrate 10, with the first light-emitting unit 300 being a white light-emitting unit. A charge generation layer 500 is disposed between the second light-emitting unit 400 and the first light-emitting unit 300. The charge generation layer 500 may include a hole generation layer and an electron generation layer, with the hole generation layer disposed on a side of the electron generation layer away from the first electrode 100.

[0065] The thickness of the light-emitting unit located in the first region 124 of the substrate 10 is greater than the thickness of the light-emitting unit located in the second region 125 of the substrate 10. For example, the sum of the thicknesses of the first light-emitting unit 300, the charge generation layer 500, and the second light-emitting unit 400 located in the first region 124 of the substrate 10 is greater than the sum of the thicknesses of the first light-emitting unit 300, the charge generation layer 500, and the second light-emitting unit 400 located in the second region 125 of the substrate 10. For example, the first light-emitting unit 300, the charge generation layer 500, and the second light-emitting unit 400 each include a third region and a fourth region, the third region being arranged perpendicular to the substrate 10 and corresponding to the first region 124 of the substrate 10, and the fourth region being arranged perpendicular to the substrate 10 and corresponding to the second region 125 of the substrate 10. Therefore, the sum of the thicknesses of the third regions of the first light-emitting unit 300, the charge generation layer 500, and the second light-emitting unit 400 is greater than the sum of the thicknesses of the fourth regions of the first light-emitting unit 300, the charge generation layer 500, and the second light-emitting unit 400.

[0066] In some embodiments of the present disclosure, the thickness of the second light-emitting unit 400 located in the second region 125 of the substrate 10 is less than the thickness of the second light-emitting unit 400 located in the first region 124. The thickness of the first light-emitting unit 300 located in the second region 125 of the substrate 10 is less than or equal to the thickness of the first light-emitting unit 300 located in the first region 124. The thickness of the first light-emitting unit 300 located in the second region 125 of the substrate 10 is greater than the thickness of the second light-emitting unit 400 located in the second region 125 of the substrate 10.

[0067] In some embodiments of the present disclosure, the thickness of the first light-emitting unit 300 located in the second region 125 of the substrate 10 is greater than the thickness of the second light-emitting unit 400 located in the second region 125 of the substrate 10, and the difference in thickness is h1. In other words, the thickness of the fourth region of the first light-emitting unit 300 is greater than the thickness of the fourth region of the second light-emitting unit 400, and the difference in thickness is h1.

[0068] The difference between the thickness of the first light-emitting unit 300 located in the first region 124 of the substrate 10 and the thickness of the second light-emitting unit 400 located in the first region 124 of the substrate 10 is h2, where h1>h2 and 0μm≤h2≤0.5μm. That is, the difference between the thickness of the fourth region of the first light-emitting unit 300 and the thickness of the fourth region of the second light-emitting unit 300 is h2. Furthermore, the thickness of the third region of the second light-emitting unit 400 is greater than the thickness of the fourth region of the second light-emitting unit 400.

[0069] In the first light-emitting unit 300 and the second light-emitting unit 400, the first light-emitting unit 300 may be a white light-emitting unit, or both may be white light-emitting units. In one embodiment, the white light-emitting unit may be a light-emitting unit including a yellow light-emitting layer (Y-EML) and a blue light-emitting layer (B-EML), or a light-emitting unit including a red light-emitting layer (H-EML), a green light-emitting layer (G-EML), and a blue light-emitting layer.

[0070] In the present disclosure, the film layer structures included in the first light-emitting unit 300 and the second light-emitting unit 400 may be various. The film layer structures in the first light-emitting unit 300 and the second light-emitting unit 400 will be described in detail below with reference to specific embodiments.

[0071] As shown in Figures 2 to 7, the first light-emitting unit 300 includes a first light-emitting layer 301, and the first light-emitting layer 301 includes a first sub-light-emitting layer 3011 and a second sub-light-emitting layer 3012 stacked in a direction away from the substrate 10; among the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012, one is a blue light-emitting layer and the other is a yellow light-emitting layer.

[0072] In some embodiments of the present disclosure, the first light-emitting unit 300 further includes a first hole transport layer (HTL) 302 and a first electron transport layer (ETL) 303, the first hole transport layer 302 is arranged between the charge generation layer 500 and the first light-emitting layer 301, and the first electron transport layer 303 is arranged between the second electrode 200 and the first light-emitting layer 301.

[0073] Optionally, the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012 may be composed of a single light-emitting material, or may include a host material and a guest material. Optionally, in one embodiment, the first sub-light-emitting layer 3011 and / or the second sub-light-emitting layer 3012 are composed of a single light-emitting material. In this embodiment, the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012 may be made into a thin film layer, for example, the thickness of the first sub-light-emitting layer 3011 or the second sub-light-emitting layer 3012 may not exceed 10 nm. In this way, it helps to reduce the difference between the thickness of the fourth region in the first light-emitting unit 300 and the thickness of the fourth region in the second light-emitting unit 400, thereby improving the luminescence difference between the fourth region of the first light-emitting unit 300 and the fourth region of the second light-emitting unit 400 to a certain extent.

[0074] In another embodiment, the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012 are composed of a host material and a guest material. The holes injected into the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012 and the electrons injected into the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012 can recombine in the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012 to form excitons. The excitons transfer energy to the host material, and the host material transfers energy to the guest material, thereby enabling the guest material to emit light.

[0075] The main materials of the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012 can be metal chelate compounds, bisphenylethylene derivatives, aromatic amine derivatives, dibenzofuran derivatives or other types of materials, and the present disclosure does not impose any special restrictions on this.

[0076] The guest materials of the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012 can be compounds having condensed aromatic rings or derivatives thereof, compounds having heteroaromatic rings or derivatives thereof, aromatic amine derivatives or other materials, and the present disclosure does not impose any special restrictions on this.

[0077] In some embodiments of the present disclosure, the first sub-light-emitting layer 3011 is a blue light-emitting layer, the second sub-light-emitting layer 3012 is a yellow light-emitting layer, and the material in the first sub-light-emitting layer 3011 is a phosphorescent material; or the first sub-light-emitting layer 3011 is a yellow light-emitting layer, the second sub-light-emitting layer 3012 is a blue light-emitting layer, and the material of the second sub-light-emitting layer 3012 is preferably a fluorescent material.

[0078] As shown in Figures 3 and 5 , the first light-emitting layer 301 further includes a first spacer layer 3013. The material of the first spacer layer 3013 can be an organic material or an inorganic material, and is used to regulate carrier transport between the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012. The first spacer layer 3013 is provided between the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012.

[0079] The second light-emitting unit 400 includes a second light-emitting layer 401. As shown in Figures 2 to 7, to further adjust the white light characteristics of the light-emitting device 20, the first light-emitting layer 301 and / or the second light-emitting layer 401 include at least one optical adjustment layer 600. The optical adjustment layer 600 is used to adjust the luminescent characteristics of the light-emitting unit. The optical adjustment layer 600 includes at least one of a blue light-emitting layer, a yellow light-emitting layer, a green light-emitting layer, or a red light-emitting layer. The optical adjustment layer 600 can be selected based on the luminescent characteristics of the first and second sub-light-emitting layers 3011 and 3012. For example, if the light generated by the combination of the first and second sub-light-emitting layers 3011 and 3012 does not produce sufficient green light, the optical adjustment layer 600 can be a green light-emitting layer. If the light generated by the combination of the first and second sub-light-emitting layers 3011 and 3012 does not produce sufficient red light, the optical adjustment layer 600 can be a red light-emitting layer. If the light generated by the combination of the first and second sub-light-emitting layers 3011 and 3012 does not produce sufficient blue light, the optical adjustment layer 600 can be a blue light-emitting layer. The optical adjustment layer 600 may be composed of a single luminescent material, or may include a host material and a guest material, and the specific composition may be adjusted according to actual needs.

[0080] The following will illustrate the configuration of the optical adjustment layer 600 in combination with different embodiments.

[0081] As shown in Figures 2 and 4 , in one embodiment of the present disclosure, one of the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012 is a blue light-emitting layer, and the other is a yellow light-emitting layer. The first light-emitting layer 301 also includes an optical adjustment layer 600, which is located on the side of the second sub-light-emitting layer 3012 away from the substrate 10. The second light-emitting layer 401 includes an optical adjustment layer 600, which is either a yellow light-emitting layer or a red light-emitting layer.

[0082] As shown in FIG2 , in this embodiment, the optical adjustment layer 600 in the second light-emitting layer 401 is a yellow light-emitting layer, and the optical adjustment layer 600 in the first light-emitting layer 301 is a blue light-emitting layer. The blue light optical adjustment layer 600 in the first light-emitting layer 301 and the yellow light optical adjustment layer 600 in the second light-emitting layer 401 can complete the blue light and yellow light compensation of the light-emitting unit.

[0083] Furthermore, in this embodiment, one of the first and second sub-light-emitting layers 3011 and 3012 is a blue light-emitting layer, and the optical adjustment layer 600 in the first light-emitting layer 301 is a blue light-emitting layer. The luminescent materials of the two blue light-emitting layers can be the same or different. Preferably, the two materials are different, that is, different blue light-emitting materials are selected. Different blue light-emitting materials may emit different blue light spectra, thereby facilitating adjustment of the white light color gamut. Similarly, the other of the first and second sub-light-emitting layers 3011 and 3012 is a yellow light-emitting layer, and the optical adjustment layer 600 in the second light-emitting layer 401 is a yellow light-emitting layer. The luminescent materials of the two yellow light-emitting layers can be the same or different. Preferably, the two materials are different, that is, different yellow light-emitting materials are selected. Different yellow light-emitting materials may emit different yellow light spectra, thereby facilitating adjustment of the white light color gamut.

[0084] Furthermore, in this embodiment, the yellow light-emitting layer in the first light-emitting sub-layer 3011 and the second light-emitting sub-layer 3012 is relatively thin. This helps reduce the difference in thickness between the fourth region of the first light-emitting unit 300 and the fourth region of the second light-emitting unit 400, thereby, to a certain extent, improving the luminous difference between the fourth region of the first light-emitting unit 300 and the fourth region of the second light-emitting unit 400. For example, even at a low voltage, the driving voltage of the fourth region of the first light-emitting unit 300 can be reached to drive it to emit light. This helps reduce the difference in the luminous spectrum of the light-emitting device 20 when driven at a lower voltage and a higher voltage.

[0085] Specifically, the thickness of the yellow light emitting layer in the first sub-light emitting layer 3011 and the second sub-light emitting layer 3012 is 0.1nm-5nm, which can be 0.1nm, 0.5nm, 1nm, 1.2nm, 1.4nm, 1.6nm, 1.8nm, 2nm, 2.2nm, 2.4nm, 2.6nm, 2.8nm, 3nm, 3.2nm, 3.4nm, 3.6nm, 3.8nm, 4nm, 4.2nm, 4.4nm, 4.6nm, 4.8nm or 5nm, but is not limited to this.

[0086] Furthermore, in this embodiment, the yellow light-emitting layer in the first light-emitting sub-layer 3011 and the second light-emitting sub-layer 3012 can be composed of a single light-emitting material. That is, the light-emitting material in the yellow light-emitting layer in the first light-emitting sub-layer 3011 and the second light-emitting sub-layer 3012 is an undoped material. Undoped materials facilitate the formation of thinner light-emitting film layers, thereby reducing process complexity and improving device yield.

[0087] In this embodiment, except for the yellow light emitting layer in the first sub-light emitting layer 3011 and the second sub-light emitting layer 3012, the thickness of other light emitting layers is not limited and can be 15 nm-30 nm or other thicknesses.

[0088] Furthermore, the first sub-light emitting layer 3011 is a blue light emitting layer, the second sub-light emitting layer 3012 is a yellow light emitting layer, and the optical adjustment layer 600 in the first light emitting layer 301 is located on a side of the second sub-light emitting layer 3012 away from the substrate 10 .

[0089] As shown in Figure 4, in another embodiment of the present disclosure, the optical adjustment layer 600 in the second light-emitting layer 401 is a red light-emitting layer, and the optical adjustment layer 600 in the first light-emitting layer 301 is a green light-emitting layer. In this embodiment, the green light optical adjustment layer 600 in the first light-emitting layer 301 and the red light optical adjustment layer 600 in the second light-emitting layer 401 can compensate for the green and red light of the light-emitting unit.

[0090] Furthermore, in this embodiment, the thickness of each film layer is not particularly limited. It can be 15 nm to 30 nm, or other thicknesses. Preferably, the yellow light-emitting layer in the first light-emitting sub-layer 3011 and the second light-emitting sub-layer 3012 is relatively thin. This helps to reduce the difference in thickness between the fourth region of the first light-emitting unit 300 and the fourth region of the second light-emitting unit 400, thereby improving the luminescence difference between the fourth region of the first light-emitting unit 300 and the fourth region of the second light-emitting unit 400 to a certain extent.

[0091] Specifically, the thickness of the yellow light emitting layer in the first sub-light emitting layer 3011 and the second sub-light emitting layer 3012 is 0.1nm-5nm, which can be 0.1nm, 0.5nm, 1nm, 1.2nm, 1.4nm, 1.6nm, 1.8nm, 2nm, 2.2nm, 2.4nm, 2.6nm, 2.8nm, 3nm, 3.2nm, 3.4nm, 3.6nm, 3.8nm, 4nm, 4.2nm, 4.4nm, 4.6nm, 4.8nm or 5nm, but is not limited to this.

[0092] Furthermore, in this embodiment, the yellow light-emitting layer in the first light-emitting sub-layer 3011 and the second light-emitting sub-layer 3012 can be composed of a single light-emitting material. That is, the light-emitting material in the yellow light-emitting layer in the first light-emitting sub-layer 3011 and the second light-emitting sub-layer 3012 is an undoped material. Undoped materials facilitate the formation of thinner light-emitting film layers, thereby reducing process complexity and improving device yield.

[0093] Furthermore, in this embodiment, the first sub-light emitting layer 3011 is a yellow light emitting layer, the second sub-light emitting layer 3012 is a blue light emitting layer, and the optical adjustment layer 600 in the first light emitting layer 301 is disposed on a side of the second sub-light emitting layer 3012 away from the substrate 10 .

[0094] As shown in Figure 3, in another embodiment of the present disclosure, the second light-emitting layer 401 includes two optical adjustment layers 600. Of the two optical adjustment layers 600 in the second light-emitting layer 401, one optical adjustment layer 600 is a blue light-emitting layer, and the other optical adjustment layer 600 is a red light-emitting layer. In this embodiment, the blue and red optical adjustment layers 600, 600, in the second light-emitting layer 401 can compensate for the blue and red light emitted by the light-emitting unit.

[0095] Furthermore, in this embodiment, one of the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012 is a blue light-emitting layer, and one optical adjustment layer 600 in the second light-emitting layer 401 is a blue light-emitting layer. The luminescent materials of the two blue light-emitting layers can be the same or different. Preferably, the two materials are different, that is, different blue light-emitting materials are selected. Different blue light-emitting materials may emit different blue light spectra, thus facilitating adjustment of the white light color gamut.

[0096] In this embodiment, the material of the blue light-emitting layer can be a fluorescent material or a phosphorescent material. Different types of light-emitting materials may have different locations for the blue light-emitting layer. For example, the first sub-light-emitting layer 3011 is a yellow light-emitting layer, and the second sub-light-emitting layer 3012 is a blue light-emitting layer. The material of the second sub-light-emitting layer 3012 is preferably a fluorescent material. The first light-emitting layer 301 also includes a first spacer layer 3013, which is disposed between the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012. Of the two optical adjustment layers 600 in the second light-emitting layer 401, the blue light-emitting layer is located on the side of the red light-emitting layer away from the substrate 10, and the material of the blue light-emitting layer is preferably a fluorescent material. The second light-emitting layer 401 also includes a second spacer layer 404, which is disposed between the two optical adjustment layers 600 in the second light-emitting layer 401.

[0097] Furthermore, in this embodiment, the thickness of each film layer is not particularly limited and can be 15 nm to 30 nm, or other thicknesses. Preferably, the thickness of the first sub-light-emitting layer 3011 in the first light-emitting unit 300 is relatively thin. This helps to reduce the difference in thickness between the fourth region of the first light-emitting unit 300 and the fourth region of the second light-emitting unit 400, thereby improving the luminous difference between the fourth region of the first light-emitting unit 300 and the fourth region of the second light-emitting unit 400 to a certain extent. Specifically, the thickness of the first sub-light-emitting layer 3011 can be less than 10nm, or less than 5nm, or if it is 0.1nm-5nm, it can be 0.1nm, 0.5nm, 1nm, 1.2nm, 1.4nm, 1.6nm, 1.8nm, 2nm, 2.2nm, 2.4nm, 2.6nm, 2.8nm, 3nm, 3.2nm, 3.4nm, 3.6nm, 3.8nm, 4nm, 4.2nm, 4.4nm, 4.6nm, 4.8nm or 5nm, but is not limited to this.

[0098] As shown in Figure 5, in another embodiment of the present disclosure, the first light-emitting layer 301 further includes an optical adjustment layer 600, where the optical adjustment layer 600 in the first light-emitting layer 301 is a red light-emitting layer. The second light-emitting layer 401 includes two optical adjustment layers 600, where both optical adjustment layers 600 in the second light-emitting layer 401 are blue light-emitting layers. In this embodiment, the red light optical adjustment layer 600 in the first light-emitting layer 301 and the two blue-red light optical adjustment layers 600 in the second light-emitting layer 401 can compensate for the red and blue light emitted by the light-emitting unit.

[0099] The materials used for the two blue light optical adjustment layers 600 in the second light-emitting layer 401 can be the same or different. Preferably, the two blue light optical adjustment layers 600 are made of different materials, that is, different blue light-emitting materials. Different blue light-emitting materials may emit different blue light spectra, thus facilitating adjustment of the white light color gamut. Furthermore, by selecting different wavelengths for the two blue light-emitting layers in the second light-emitting layer 401, both high color temperature and reduced blue light damage can be achieved.

[0100] Furthermore, in this embodiment, the thickness of each film layer is not particularly limited. It can be 15 nm to 30 nm, or other thicknesses. Preferably, the yellow light-emitting layer in the first light-emitting sub-layer 3011 and the second light-emitting sub-layer 3012 is relatively thin. The thickness range can refer to any of the above embodiments and is not further described here.

[0101] Specifically, the first sub-light-emitting layer 3011 is a blue light-emitting layer, and the second sub-light-emitting layer 3012 is a yellow light-emitting layer; the first light-emitting layer 301 further includes a first spacer layer 3013, which is arranged between the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012, and the optical adjustment layer 600 in the first light-emitting layer 301 is arranged on the side of the second sub-light-emitting layer 3012 away from the substrate 10.

[0102] As shown in FIG6 , in one embodiment of the present disclosure, the second light-emitting unit 400 includes a second light-emitting layer 401 . The second light-emitting layer 401 includes two optical adjustment layers 600 . The two optical adjustment layers 600 are a blue light-emitting layer and a yellow light-emitting layer stacked in a direction away from the substrate.

[0103] In this embodiment, the first light-emitting unit 300 includes a first light-emitting layer 301, and the first light-emitting layer 301 includes a first sub-light-emitting layer 3011 and a second sub-light-emitting layer 3012 stacked in a direction away from the substrate 10; among the first sub-light-emitting layer 3011 and the second sub-light-emitting layer 3012, the first sub-light-emitting layer 3011 is a blue light-emitting layer, and the second sub-light-emitting layer 3012 is a yellow light-emitting layer.

[0104] The blue light-emitting layer in the first light-emitting unit 300 and the second light-emitting layer 401 can be made of a phosphorescent material or a fluorescent material. Different types of light-emitting materials can have different positions between the light-emitting layers. For example, the first sub-light-emitting layer 3011 is a blue light-emitting layer, and the second sub-light-emitting layer 3012 is a yellow light-emitting layer. The blue light-emitting layer is made of a phosphorescent material.

[0105] Furthermore, the first sub-light-emitting layer 3011 and the optical adjustment layer 600 (blue light-emitting layer) in the second light-emitting layer 401 can use the same or different blue light-emitting materials, preferably different blue light-emitting materials. The second sub-light-emitting layer 3012 and the optical adjustment layer 600 (yellow light-emitting layer) in the second light-emitting layer 401 can use the same or different yellow light-emitting materials, preferably different yellow light-emitting materials.

[0106] Similar to the above embodiment, the yellow light emitting layer in the first light emitting layer 301 can be set to be thinner. The principle, specific thickness range, and material selection can refer to any of the above embodiments.

[0107] As shown in FIG. 7 , in another embodiment of the present disclosure, the second light-emitting unit 400 includes a second light-emitting layer 401 , and the second light-emitting layer 401 includes three optical adjustment layers 600 ; the three optical adjustment layers 600 are stacked in a direction away from the substrate 10 , comprising a blue light-emitting layer, a red light-emitting layer, and a green light-emitting layer.

[0108] In this embodiment, the first light-emitting unit 300 includes a first light-emitting layer 301, and the first light-emitting layer 301 includes a first sub-light-emitting layer 3011 and a second sub-light-emitting layer 3012 stacked in a direction away from the substrate 10; the first sub-light-emitting layer 3011 is a blue light-emitting layer, and the second sub-light-emitting layer 3012 is a yellow light-emitting layer.

[0109] Furthermore, the optical adjustment layer 600 (blue light emitting layer) in the first sub-light emitting layer 3011 and the second light emitting layer 401 may be made of the same or different blue light emitting materials, preferably different blue light emitting materials.

[0110] The second sub-light-emitting layer 3012 in the first light-emitting layer 301 can be thinner, for example, 1 nm to 10 nm, such as, but not limited to, 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, 5 nm, 5.5 nm, 6 nm, 6.5 nm, 7 nm, 7.5 nm, 8 nm, 8.5 nm, 9 nm, 9.5 nm, or 10 nm. The second sub-light-emitting layer 3012 can be made of a single light-emitting material, i.e., an undoped material. Undoped materials facilitate the formation of thinner light-emitting film layers, thereby reducing process complexity and improving device yield.

[0111] As shown in Figures 6 and 7, in the present disclosure, the first light-emitting unit 300 and the second light-emitting unit 400 can both be white light-emitting units. In such embodiments, even if only a portion of a light-emitting unit emits light under low voltage, the light-emitting device 20 can still emit white light.

[0112] As shown in Figures 2 to 7, in some embodiments of the present disclosure, the second light-emitting unit 400 also includes a second hole transport layer 402 and a second electron transport layer 403, the second hole transport layer 402 is arranged between the first electrode 100 and the second light-emitting layer 401, and the second electron transport layer 403 is arranged between the second light-emitting layer 401 and the charge generation layer 500.

[0113] The first hole transport layer 302 and the second hole transport layer 402 may include one or more hole transport materials. The hole transport materials may be selected from carbazole polymers, carbazole-linked triarylamine compounds or other types of compounds, which are not particularly limited in the present disclosure.

[0114] The first electron transport layer 303 and the second electron transport layer 403 may include one or more electron transport materials. The electron transport materials may be selected from benzimidazole derivatives, oxadiazole derivatives, quinoxaline derivatives or other electron transport materials, which are not particularly limited in the present disclosure.

[0115] In the present disclosure, when the blue, green, and red light-emitting layers are composed of a host material and a shell material, the host material of the blue light-emitting layer can be selected from anthracene derivatives such as ADN and MADN; the guest material can be a pyrene derivative, a fluorene derivative, a perylene derivative, a styrylamine derivative, or a metal complex, such as TBPe, BDAVBi, DPAVBi, or FIrpic. The host material of the green light-emitting layer can be selected from coumarin dyes, quinacrine copper derivatives, polycyclic aromatic hydrocarbons, diamine anthracene derivatives, or carbazole derivatives, such as DMQA, BA-NPB, or Alq3. The guest material can be a metal complex, such as Ir(ppy)3 and Ir(ppy)2(acac). The red light-emitting host material can be selected from DCM series materials, such as DCM, DCJTB, DCJTI, etc., and the guest material can be a metal complex, such as Ir(piq)2(acac), PtOEP, Ir(btp)2(acac), etc., but is not limited thereto.

[0116] The present disclosure further provides a display panel including the light emitting device 20 of any of the above embodiments. The display panel includes a base substrate and a driving circuit layer provided on one side of the base substrate. The driving circuit layer may include the base 10 of the light emitting device 20 .

[0117] It should be understood that the present disclosure is not limited in its application to the detailed structure and arrangement of the components set forth in this specification. The present disclosure is capable of other embodiments and can be implemented and executed in a variety of ways. The aforementioned variations and modifications fall within the scope of the present disclosure. It should be understood that the present disclosure disclosed and defined in this specification extends to all alternative combinations of two or more individual features mentioned or evident in the text and / or the drawings. All of these different combinations constitute multiple alternative aspects of the present disclosure. The embodiments of this specification illustrate the best mode known for implementing the present disclosure and will enable those skilled in the art to utilize the present disclosure.

Claims

1. A light emitting device, wherein: It comprises a substrate and a first electrode, a light-emitting unit and a second electrode stacked in a direction away from the substrate; The light-emitting unit includes a plurality of sub-light-emitting units stacked in a direction perpendicular to the substrate and a charge generation layer located between adjacent sub-light-emitting units; Among the plurality of sub-light emitting units, the sub-light emitting unit close to the second electrode is a white light emitting unit.

2. The light emitting device according to claim 1, wherein The plurality of sub-light emitting units at least include a second light emitting unit and a first light emitting unit stacked in a direction away from the substrate, and the first light emitting unit is a white light emitting unit.

3. The light emitting device according to claim 2, wherein The first light-emitting unit includes a first light-emitting layer, and the first light-emitting layer includes a first sub-light-emitting layer and a second sub-light-emitting layer stacked in a direction away from the substrate; One of the first sub-light emitting layer and the second sub-light emitting layer is a blue light emitting layer, and the other is a yellow light emitting layer. The light emitting device according to claim 3 , wherein: The first sub-light emitting layer is a blue light emitting layer, the second sub-light emitting layer is a yellow light emitting layer, and the material in the first sub-light emitting layer is a phosphorescent material; or The first sub-light emitting layer is a yellow light emitting layer, the second sub-light emitting layer is a blue light emitting layer, and a material of the second sub-light emitting layer is a fluorescent light emitting material. The light emitting device according to claim 3 , wherein: The first light-emitting layer further includes a first spacer layer, and the first spacer layer is arranged between the first sub-light-emitting layer and the second sub-light-emitting layer. The light emitting device according to claim 3 , wherein: The second light-emitting unit includes a second light-emitting layer, and the first light-emitting layer and / or the second light-emitting layer include at least one optical adjustment layer, and the optical adjustment layer is used to adjust the light-emitting characteristics of the light-emitting unit.

7. The light emitting device according to claim 6, wherein The optical adjustment layer includes at least one of a blue light emitting layer, a yellow light emitting layer, a green light emitting layer or a red light emitting layer. The light emitting device according to claim 6 , wherein: The first light-emitting layer further includes an optical adjustment layer, and the optical adjustment layer of the first light-emitting layer is located on a side of the second sub-light-emitting layer away from the substrate; The second light-emitting layer includes one optical adjustment layer, and the optical adjustment layer in the second light-emitting layer is a yellow light-emitting layer or a red light-emitting layer.

9. The light emitting device according to claim 8, wherein When the optical adjustment layer in the second light-emitting layer is a yellow light-emitting layer, the first sub-light-emitting layer is a blue light-emitting layer, the second sub-light-emitting layer is a yellow light-emitting layer, and the optical adjustment layer in the first light-emitting layer is a blue light-emitting layer.

10. The light emitting device according to claim 8, wherein When the optical adjustment layer in the second light-emitting layer is a red light-emitting layer, the first sub-light-emitting layer is a yellow light-emitting layer, the second sub-light-emitting layer is a blue light-emitting layer, and the optical adjustment layer in the first light-emitting layer is a green light-emitting layer. The light emitting device according to claim 6 , wherein: The second light-emitting layer includes two optical adjustment layers, one of which is a blue light-emitting layer and the other is a red light-emitting layer. The blue light-emitting layer is located on a side of the red light-emitting layer away from the substrate, and the material of the blue light-emitting layer is a fluorescent material.

12. The light emitting device according to claim 11, wherein The first sub-light emitting layer is a yellow light emitting layer, the second sub-light emitting layer is a blue light emitting layer, and the material of the second sub-light emitting layer is a fluorescent light emitting material; The first light-emitting layer further includes a first spacer layer, and the first spacer layer is provided between the first sub-light-emitting layer and the second sub-light-emitting layer; The second light-emitting layer further includes a second spacer layer, and the second spacer layer is disposed between the two optical adjustment layers of the second light-emitting layer.

13. The light emitting device according to claim 6, wherein The first light-emitting layer further includes the optical adjustment layer, wherein the optical adjustment layer in the first light-emitting layer is a red light-emitting layer and is located on a side of the second sub-light-emitting layer away from the substrate; The second light-emitting layer includes two optical adjustment layers, and both of the optical adjustment layers in the second light-emitting layer are blue light-emitting layers. The light emitting device according to claim 13 , wherein: The first sub-light emitting layer is a blue light emitting layer, and the second sub-light emitting layer is a yellow light emitting layer; The first light-emitting layer further includes a first spacer layer, which is provided on the first Between the sub-light emitting layer and the second sub-light emitting layer, the optical adjustment layer in the first light emitting unit is provided on a side of the second sub-light emitting layer away from the substrate.

15. The light emitting device according to claim 6, wherein When the first sub-light emitting layer is a blue light emitting layer and the second sub-light emitting layer is a yellow light emitting layer, the second light emitting layer includes two optical adjustment layers, and the two optical adjustment layers are a blue light emitting layer and a yellow light emitting layer stacked in a direction away from the substrate.

16. The light emitting device according to claim 6, wherein: When the first sub-light emitting layer is a blue light emitting layer and the second sub-light emitting layer is a yellow light emitting layer, the second light emitting layer includes three layers of the optical adjustment layer; The three optical adjustment layers are a blue light emitting layer, a red light emitting layer and a green light emitting layer stacked in a direction away from the substrate.

17. The light emitting device according to claim 1, wherein: The substrate includes a first area and a second area located on one side of the first area; the thickness of the light-emitting unit located in the first area is greater than the thickness of the light-emitting unit located in the second area; The plurality of sub-light emitting units at least include a second light emitting unit and a first light emitting unit stacked in a direction away from the substrate, wherein the thickness of the second light emitting unit located in the second area is less than the thickness of the second light emitting unit located in the first area; The thickness of the first light-emitting unit located in the second area is less than or equal to the thickness of the first light-emitting unit located in the first area; The thickness of the first light emitting unit located in the second area of ​​the substrate is greater than the thickness of the second light emitting unit located in the second area of ​​the substrate.

18. The light emitting device according to claim 3, wherein The thickness of the yellow light-emitting layer in the first light-emitting layer is 0.1 nm-5 nm.

19. A display panel, wherein: The light emitting device comprises the light emitting device according to any one of claims 1 to 18.

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