Light-emitting device, display panel and display device

Abstract

The embodiment of the invention provides a light-emitting device, a display panel and a display device, relates to the technical field of display, and aims to solve the problem of color cast under a large viewing angle. The light emitting device includes a first light emitting device, a second light emitting device, and a third light emitting device. Each of the first light emitting device, the second light emitting device, and the third light emitting device includes a first electrode, a second electrode, at least one light emitting layer, and at least one first functional unit. The thickness of the first function unit of the first light-emitting device, the thickness of the first function unit of the second light-emitting device and the thickness of the first function unit of the third light-emitting device are different. Based on the same light-emitting area of the light-emitting device, the light-emitting device has a first color cast value under a first preset view angle and has a second color cast value under a second preset view angle. The absolute value of the difference between the first color cast value and the second color cast value is smaller than or equal to 2. The light-emitting device is used for displaying images.

Description

TECHNICAL FIELD

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

[0002] Organic Light Emitting Diode (OLED) has been widely used in the display field due to its advantages of self-illumination, low driving voltage, high luminous efficiency, fast response speed and flexible display.

[0003] In some implementations, the OLED light-emitting device has a more obvious color deviation problem at a large viewing angle. SUMMARY

[0004] Embodiments of the present disclosure aim to provide a light-emitting device, a display panel and a display device to improve the color deviation problem at a large viewing angle.

[0005] To achieve the above-mentioned purpose, embodiments of the present disclosure provide the following technical solutions:

[0006] In one aspect, a light-emitting device is provided. The light-emitting device includes a first light-emitting device, a second light-emitting device and a third light-emitting device. The light-emitting wavelength of the first light-emitting device, the light-emitting wavelength of the second light-emitting device and the light-emitting wavelength of the third light-emitting device are all different. Each of the first light-emitting device, the second light-emitting device and the third light-emitting device includes a first electrode, a second electrode, at least one light-emitting layer and at least one first functional unit. The first electrode and the second electrode are oppositely arranged, and the first electrode can reflect light. The at least one light-emitting layer is located between the first electrode and the second electrode. The first functional unit is arranged on the side of the light-emitting layer close to the first electrode. The thickness of the first functional unit of the first light-emitting device, the first functional unit of the second light-emitting device and the first functional unit of the third light-emitting device are all different. Based on the same light-emitting area of the light-emitting device, the light-emitting device has a first color deviation value at a first preset viewing angle, and the light-emitting device has a second color deviation value at a second preset viewing angle. The absolute value of the difference between the first color deviation value and the second color deviation value is less than or equal to 2. The difference between the first preset viewing angle and the second preset viewing angle is less than or equal to 15°.

[0007] In the aforementioned light-emitting devices, the thicknesses of the first functional units of the first light-emitting device, the second light-emitting device, and the third light-emitting device are all different. This serves two purposes: first, it allows the first, second, and third light-emitting devices to have different optical cavity thicknesses, enabling them to be matched with light of different wavelengths and increasing the emission of light from all three devices due to the microcavity effect; second, it allows the first functional unit to adjust the distance between the light-emitting layer and the first electrode, thus increasing the light emission of the light-emitting layers of the first, second, and third devices. Each layer is located within its corresponding microcavity enhancement region, enabling constructive interference between the light emitted by each light-emitting layer and the light propagating towards the light-emitting side and then reflected by the first electrode. This allows the luminous efficiency of the first, second, and third light-emitting devices to be at a high level, ensuring consistent efficiency decay at wide viewing angles. This improves color shift at wide viewing angles, ensuring the absolute value of the difference between the first and second color shift values ​​is less than or equal to 2, thus optimizing the performance of the light-emitting devices and achieving high-quality display.

[0008] In some embodiments, the thicknesses of the first functional units of the first light-emitting device, the first functional units of the second light-emitting device, and the first functional units of the third light-emitting device, which are located at corresponding positions, are all different.

[0009] In some embodiments, based on the same emitting area of ​​the light-emitting device, the absolute value of the difference between the color deviation value of the light-emitting device at a 15° viewing angle and the color deviation value of the light-emitting device at a 0° viewing angle is less than or equal to 1; and / or, based on the same emitting area of ​​the light-emitting device, the absolute value of the difference between the color deviation value of the light-emitting device at a 30° viewing angle and the color deviation value of the light-emitting device at a 15° viewing angle is less than or equal to 2; and / or, based on the same emitting area of ​​the light-emitting device, the absolute value of the difference between the color deviation value of the light-emitting device at a 45° viewing angle and the color deviation value of the light-emitting device at a 30° viewing angle is less than or equal to 1.

[0010] In some embodiments, based on the same emitting area of ​​the light-emitting device, the absolute value of the difference between the color deviation value of the light-emitting device at a 60° viewing angle and the color deviation value of the light-emitting device at a 45° viewing angle is less than or equal to 1; and / or, based on the same emitting area of ​​the light-emitting device, the absolute value of the difference between the color deviation value of the light-emitting device at a 75° viewing angle and the color deviation value of the light-emitting device at a 60° viewing angle is less than or equal to 1.

[0011] In some embodiments, the brightness attenuation ratio of the light-emitting device at a 30° viewing angle is less than or equal to 30%; and / or, the brightness attenuation ratio of the light-emitting device at a 45° viewing angle is less than or equal to 60%.

[0012] In some embodiments, within a viewing angle range of -75° to 75°, the chromaticity coordinates CIEx of the light emitted by the light-emitting device range from 0.280 to 0.305; and / or, within a viewing angle range of -75° to 75°, the chromaticity coordinates CIEy of the light emitted by the light-emitting device range from 0.290 to 0.320.

[0013] In some embodiments, the ratio of the distance between the surface of the selected light-emitting layer furthest from the first electrode and the light-reflecting surface of the first electrode, and the selected wavelength, is greater than or equal to (2n+1) / 4a and less than or equal to (2n+3) / 4a, where n is a positive integer and a ranges from 1.7 to 1.8. The selected light-emitting layer is any one of at least one light-emitting layer of a first light-emitting device, at least one light-emitting layer of a second light-emitting device, and at least one light-emitting layer of a third light-emitting device. The selected wavelength is the emission wavelength of the selected light-emitting layer.

[0014] In some embodiments, the light-reflecting surface of the first electrode is the surface of the first electrode near the selected light-emitting layer; or, the first electrode includes a second sub-layer and a first sub-layer stacked in a direction away from the selected light-emitting layer; the first sub-layer is capable of reflecting light; the second sub-layer is capable of transmitting light; and the light-reflecting surface of the first electrode is the surface of the first sub-layer near the second sub-layer.

[0015] In some embodiments, the thickness of the light-emitting layer of the first light-emitting device is less than the thickness of the light-emitting layer of the second light-emitting device; and / or, the thickness of the light-emitting layer of the first light-emitting device is less than the thickness of the light-emitting layer of the third light-emitting device.

[0016] In some embodiments, the thickness of the light-emitting layer of the first light-emitting device ranges from 18 nm to 22 nm; and / or, the thickness of the light-emitting layer of the second light-emitting device ranges from 30 nm to 50 nm; and / or, the thickness of the light-emitting layer of the third light-emitting device ranges from 30 nm to 50 nm.

[0017] In some embodiments, at least one first functional unit includes a first hole transport unit and a second hole transport unit, wherein the first hole transport unit is closer to the first electrode than the second hole transport unit. The thickness of the first hole transport unit of the second light-emitting device is greater than the thickness of the first hole transport unit of the first light-emitting device and less than the thickness of the first hole transport unit of the third light-emitting device; and / or, the thickness of the second hole transport unit of the second light-emitting device is greater than the thickness of the second hole transport unit of the first light-emitting device and less than the thickness of the second hole transport unit of the third light-emitting device.

[0018] In some embodiments, the first hole transport unit includes a hole injection layer, a first hole transport layer, and a first electron blocking layer. The second hole transport unit includes a second hole transport layer and a second electron blocking layer. The hole injection layers of the first, second, and third light-emitting devices are all of equal thickness. The first, second, and third hole transport layers of the first, second, and third light-emitting devices are all of equal thickness. The second, third, and fourth hole transport layers of the first, second, and third light-emitting devices are all of equal thickness. The first electron blocking layer of the second light-emitting device is thicker than the first electron blocking layer of the first light-emitting device and thinner than the first electron blocking layer of the third light-emitting device; and / or, the second electron blocking layer of the second light-emitting device is thicker than the second electron blocking layer of the first light-emitting device and thinner than the second electron blocking layer of the third light-emitting device.

[0019] In some embodiments, the thickness of the first electron blocking layer of the first light-emitting device ranges from 5 nm to 10 nm. The thickness of the first electron blocking layer of the second light-emitting device ranges from 40 nm to 45 nm. The thickness of the first electron blocking layer of the third light-emitting device ranges from 80 nm to 95 nm.

[0020] In some embodiments, the thickness of the second electron blocking layer of the first light-emitting device ranges from 5 nm to 10 nm. The thickness of the second electron blocking layer of the second light-emitting device ranges from 15 nm to 20 nm. The thickness of the second electron blocking layer of the third light-emitting device ranges from 25 nm to 35 nm.

[0021] In some embodiments, the thickness of the hole injection layer of the first light-emitting device ranges from 5 nm to 15 nm. The thickness of the first hole transport layer of the first light-emitting device ranges from 95 nm to 105 nm. The thickness of the second hole transport layer of the first light-emitting device ranges from 50 nm to 60 nm.

[0022] In some embodiments, at least one light-emitting layer includes two light-emitting layers, namely a first light-emitting layer and a second light-emitting layer, wherein the first light-emitting layer is closer to the first electrode than the second light-emitting layer. Each of the first light-emitting device, the second light-emitting device, and the third light-emitting device further includes a first charge-generating layer and a second charge-generating layer. The first charge-generating layer and the second charge-generating layer are located between the first light-emitting layer and the second hole transport unit; the first charge-generating layer is closer to the first light-emitting layer than the second charge-generating layer. The thickness of the first charge-generating layer of the first light-emitting device, the first charge-generating layer of the second light-emitting device, and the first charge-generating layer of the third light-emitting device are all fourth thicknesses, ranging from 80 nm to 100 nm. The thickness of the second charge-generating layer of the first light-emitting device, the second charge-generating layer of the second light-emitting device, and the second charge-generating layer of the third light-emitting device are all fifth thicknesses, ranging from 160 nm to 200 nm.

[0023] In some embodiments, each of the first, second, and third light-emitting devices further includes a first hole-blocking layer and a second electron transport unit. The first hole-blocking layer is located between the first light-emitting layer and the first charge-generating layer. The second electron transport unit is located between the second light-emitting layer and the second electrode. The second electron transport unit includes a second hole-blocking layer and a second electron transport layer stacked in a direction away from the second light-emitting layer. The thickness of the first hole-blocking layer of the first light-emitting device, the first hole-blocking layer of the second light-emitting device, and the first hole-blocking layer of the third light-emitting device is a sixth thickness, ranging from 5 nm to 10 nm. The thickness of the second hole-blocking layer of the first light-emitting device, the second hole-blocking layer of the second light-emitting device, and the second hole-blocking layer of the third light-emitting device is a seventh thickness, ranging from 5 nm to 10 nm. The thickness of the second electron transport layer of the first light-emitting device, the second electron transport layer of the second light-emitting device, and the second electron transport layer of the third light-emitting device is an eighth thickness, ranging from 30 nm to 40 nm.

[0024] In some embodiments, the peak wavelength of the emission spectrum of the material of the light-emitting layer of the first light-emitting device is greater than or equal to 400 nm and less than or equal to 500 nm. The peak wavelength of the emission spectrum of the material of the light-emitting layer of the second light-emitting device is greater than or equal to 510 nm and less than or equal to 540 nm. The peak wavelength of the emission spectrum of the material of the light-emitting layer of the third light-emitting device is greater than or equal to 600 nm.

[0025] On the other hand, a display panel is provided. The display panel includes a substrate and a light-emitting device as described in any of the above embodiments. The light-emitting device is disposed on the substrate.

[0026] The above-described display panel has the same structure and beneficial technical effects as the light-emitting devices provided in some of the above embodiments, and will not be described again here.

[0027] In another aspect, a display device is provided. The display device includes: a driver chip and a display panel as described in any of the above embodiments. The driver chip is used to drive the display panel to perform display.

[0028] The above-described display device has the same structure and beneficial technical effects as the display panel provided in some of the above embodiments, and will not be described again here. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual process of the method, etc. involved in the embodiments of this disclosure.

[0030] Figure 1 This is a structural diagram of a display device according to some embodiments;

[0031] Figure 2 This is a structural diagram of a display panel according to some embodiments;

[0032] Figure 3 This is a structural diagram of a display panel according to some other embodiments;

[0033] Figure 4 This is a structural diagram of a display panel according to some other embodiments;

[0034] Figure 5 This is a structural diagram of a light-emitting device according to some embodiments;

[0035] Figure 6 This is a structural diagram of a light-emitting device according to some other embodiments;

[0036] Figure 7 This is a structural diagram of a display panel according to some other embodiments;

[0037] Figure 8 This is a structural diagram of a light-emitting device located within a pixel opening according to some embodiments;

[0038] Figure 9 This is a structural diagram of a display panel according to some other embodiments;

[0039] Figure 10 This is a structural diagram of a light-emitting device located within a pixel opening according to some other embodiments;

[0040] Figure 11 A graph showing the color shift value of a light-emitting device as a function of viewing angle according to some embodiments;

[0041] Figure 12 A graph showing the color shift value of a light-emitting device as a function of viewing angle according to some other embodiments;

[0042] Figure 13 CIE trajectory diagram of a light-emitting device according to some embodiments;

[0043] Figure 14 A CIE trajectory diagram of a light-emitting device according to some other embodiments;

[0044] Figure 15 This is a CIE trajectory diagram of a display panel according to some other embodiments. Detailed Implementation

[0045] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0046] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0047] Hereinafter, 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0048] "At least one of A, B and C" has the same meaning as "at least one of A, B or C", both including the following combinations of A, B and C: only A, only B, only C, combinations of A and B, combinations of A and C, combinations of B and C, and combinations of A, B and C.

[0049] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0050] The use of “applies to” or “configured to” in this article implies an open and inclusive language that does not preclude applicability to or configuration to devices that perform additional tasks or steps.

[0051] In addition, the use of “based on” implies openness and inclusivity, because processes, steps, calculations or other actions “based on” one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0052] As used herein, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).

[0053] As used herein, “parallel,” “perpendicular,” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable range of deviation for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable range of deviation for approximate perpendicularity may also be, for example, within 5°; “equal” includes absolute equality and approximate equality, where an acceptable range of deviation for approximate equality may be, for example, a difference between the two equals being less than or equal to 5% of either one.

[0054] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0055] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as being limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched areas shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0056] It should be noted that, for example, 11 to 1 in the accompanying drawings of this disclosure indicate that component 11 belongs to component 1. Figure 2 In the figures, 100C-100 indicates that the third light-emitting device 100C belongs to the light-emitting device 100, and other similar reference numerals appearing in the figures also follow the above description. For example, 1 / 2 in the figures of this disclosure indicates that both component 1 and component 2 can refer to that component, for example, in the attached figure... Figure 3 In the figure, 130D / 130 indicates that both the light-emitting layer 130D and the light-emitting layer 130 of the second light-emitting device can be represented by this component. Other similar reference numerals appearing in the figures also follow the above explanation.

[0057] It should be noted that the thickness mentioned in the embodiments of this disclosure refers to the dimension along the first direction X. For example, the thickness of the first functional unit 190 refers to the dimension of the first functional unit 190 along the first direction X. Here, the first direction X is the thickness direction of the substrate 210. Other thicknesses appearing in the embodiments also follow the above description.

[0058] like Figure 1 As shown, some embodiments of this disclosure provide a display device 300, such as an OLED display device 300. The display device 300 includes a display panel 200.

[0059] For example, such as Figure 1 As shown, the display device 300 also includes a driver chip 310. The driver chip 310 is used to drive the display panel 200 for display.

[0060] In addition, the display device 300 may also include an under-display camera and an under-display fingerprint sensor, enabling the display device 300 to perform various functions such as taking photos, recording videos, fingerprint recognition, or facial recognition.

[0061] The aforementioned display device 300 can be any display device that displays either moving (e.g., video) or stationary (e.g., still image) text or images. More specifically, the display device 300 of the described embodiment is contemplated for implementation in or associated with a variety of electronic devices, such as (but not limited to) mobile phones, wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, camcorders, game consoles, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controllers and / or displays, displays of camera views (e.g., displays of rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging and aesthetic structures (e.g., displays of images of a piece of jewelry), etc.

[0062] In some embodiments, such as Figures 2-4 As shown, the display panel 200 includes a substrate 210 and a light-emitting device 100 disposed on the substrate 210.

[0063] For example, the material of the substrate 210 can be a transparent rigid material, such as glass, to achieve a rigid panel display; or the material of the substrate 210 can also be a transparent flexible material, such as polyimide (PI), to achieve a flexible panel display.

[0064] For example, the material of substrate 210 may include inorganic materials, such as soda-lime glass, quartz glass, or sapphire glass. Alternatively, the material of substrate 210 may also include organic materials, such as one or any combination of polymethyl methacrylate, polyvinyl alcohol, polyvinylphenol, polyethersulfone, polyimide, polyamide, polyacetal, polycarbonate, polyethylene terephthalate, and polyethylene naphthalate. Or, the material of substrate 210 may include both organic and inorganic materials.

[0065] In some embodiments, such as Figures 2-4 As shown, the display panel 200 also includes a pixel defining layer 220, which has a plurality of pixel openings Q, and the light-emitting device 100 is disposed within the plurality of pixel openings Q.

[0066] For example, such as Figures 2-4 As shown, multiple pixel openings Q can be arranged along the second direction Y, which is, for example, a direction parallel to the plane where the substrate 210 is located.

[0067] The pixel defining layer 220 can be configured to form a pixel opening Q (the pixel opening Q can correspond to a macroscopic sub-pixel), which is used to define the light-emitting area of ​​the light-emitting device 100. In this way, the light emitted by the light-emitting device 100 can be emitted from the preset sub-pixel area of ​​the display panel 200, thus avoiding color crosstalk.

[0068] In some embodiments, such as Figure 3 and Figure 4 As shown, the light-emitting device 100 includes a first light-emitting device 100A, a second light-emitting device 100D, and a third light-emitting device 100C. The light-emitting wavelengths of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C are all different.

[0069] It should be understood that the number of first light-emitting devices 100A included in the light-emitting device 100 can be multiple, and the number of second light-emitting devices 100D included in the light-emitting device 100 can be multiple. Moreover, the arrangement of the multiple first light-emitting devices 100A, multiple second light-emitting devices 100D, and multiple third light-emitting devices 100C can be, for example, an array arrangement.

[0070] For example, such as Figures 2-4 As shown, when the display panel 200 includes a pixel defining layer 220, each of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C is disposed within a pixel opening Q.

[0071] It should be understood that when the emission wavelengths of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C are all different, the brightness (grayscale) of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can be adjusted respectively. Through color combination and superposition, multiple colors can be displayed, thereby realizing the full-color display of the display panel 200.

[0072] In some examples, such as Figure 2As shown, the display panel 200 also includes a driving circuit layer 230 disposed between the substrate 210 and the light-emitting device 100. The driving circuit layer 230 includes, for example, a plurality of pixel driving circuits 231 arranged in an array. Each pixel driving circuit 231 can generate a driving signal when receiving at least one of a scan signal, a data signal, and a power signal. The driving signal can drive one of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C to be electrically connected, so that the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can emit light independently, so that the selected sub-pixel area emits light and displays an image.

[0073] In some examples, depending on the driving type of the pixel driving circuit 231, the driving circuit layer 230 can be divided into a passive matrix driving circuit layer and an active matrix driving circuit layer (e.g., ...). Figure 2 (As shown). Among them, the pixel driving circuit 231 in the active matrix driving circuit layer 230 includes a capacitor and a plurality of thin film transistors (TFTs); the plurality of thin film transistors include, for example, a switching TFT and a driving TFT.

[0074] In some examples, such as Figure 2 As shown, the display panel 200 also includes an encapsulation layer 240; at this time, the driving circuit layer 230, the pixel defining layer 220 and the encapsulation layer 240 are stacked on the substrate 210, and the driving circuit layer 230, the pixel defining layer 220 and the encapsulation layer 240 are arranged sequentially in a direction away from the substrate 210.

[0075] For example, the display panel 200 can be an OLED display panel 200. In this case, the encapsulation layer 240 covers the light-emitting device 100 and encapsulates the light-emitting device 100 to prevent moisture and oxygen from the external environment from entering the display panel 200 and damaging the organic materials in the light-emitting device 100, thereby shortening the lifespan of the OLED display panel 200.

[0076] In some embodiments, such as Figure 7 As shown, in the display panel 200, a cover layer 250 (also called a light extraction layer or capping layer) is provided between the encapsulation layer 240 and the light-emitting device 100. The material forming the cover layer 250 is, for example, an organic small molecule material. By providing the cover layer 250 and adjusting the refractive index of the material of the cover layer 250, for example, making the material of the cover layer 250 have high refractive properties, the light extraction efficiency of the light-emitting device 100 is improved, and the brightness of the light-emitting device 100 when lit can be increased.

[0077] For example, the thickness of the cover layer 250 can be in the range of 50nm to 80nm, such as 50nm, 55nm, 60nm, 65nm, 70nm, 75nm or 80nm.

[0078] For example, the material of the capping layer 250 has a refractive index greater than or equal to 1.8 at a wavelength of 460 nm, such as 1.8, 2.0, 2.2, 2.5, 3.0, etc.

[0079] In some examples, based on the direction of light emission, the display panel 200 can be classified as a top-emitting display panel (also known as a top-emitting display panel), a bottom-emitting display panel (also known as a bottom-emitting display panel), and a double-sided emitting display panel (also known as a double-emitting display panel).

[0080] In the bottom-emitting display panel, the light emitted by the light-emitting device 100 is emitted from the substrate 210 side. At this time, the one that is relatively closer to the substrate 210 can be a light-transmitting electrode (such as a transparent electrode or a semi-transparent electrode), and the one that is relatively farther away from the substrate 210 can be a reflective electrode.

[0081] In a top-emitting display panel, the light emitted by the light-emitting device 100 is emitted from the side away from the substrate 210. At this time, the one that is relatively closer to the substrate 210 can be a reflective electrode, and the one that is relatively farther away from the substrate 210 can be a transparent electrode or a semi-transparent electrode.

[0082] In a double-sided emitting display panel, the light emitted by the light-emitting device 100 can exit from both the side away from the substrate 210 and the side of the substrate 210, enabling the display panel to have a double-sided display function. Since the light needs to exit in two directions, both the first electrode 110 and the second electrode 120 need to be configured as light-transmitting electrodes.

[0083] In some embodiments, such as Figures 3-6 As shown, each of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C includes a first electrode 110, a second electrode 120, and at least one light-emitting layer 130. The first electrode 110 and the second electrode 120 are disposed opposite to each other. At least one light-emitting layer 130 is located between the first electrode 110 and the second electrode 120.

[0084] In some embodiments, such as Figure 3 As shown, the first electrode 110 is closer to the substrate 210 than the second electrode 120. In some other examples, such as Figure 4 As shown, the second electrode 120 is closer to the substrate 210 than the first electrode 110.

[0085] In some embodiments, such as Figure 4 and Figure 5As shown, the first electrode 110 is the anode and the second electrode 120 is the cathode. In some other examples, the second electrode 120 is the anode and the first electrode 110 is the cathode.

[0086] For example, such as Figures 2-4 As shown, the first electrode 110 and the second electrode 120 are disposed opposite to each other along the first direction X, which is the thickness direction of the substrate 210.

[0087] For example, the first electrode 110 or the second electrode 120 is electrically connected to the pixel driving circuit 231.

[0088] Based on the above structure, the light-emitting principle of the light-emitting device 100 is as follows: Through a circuit connecting the anode and cathode (e.g., pixel driving circuit 231), holes are injected into the light-emitting layer 130 by the anode, and electrons are injected into the light-emitting layer 130 by the cathode. The injected electrons and holes form excitons (i.e., electron-hole pairs) in the light-emitting layer 130. The excitons then undergo radiative transitions back to the ground state, emitting photons. It is evident that efficient charge generation, effective charge injection, and rapid charge transport are all indispensable processes in the light-emitting process of the light-emitting device 100. The aforementioned charges are holes or electrons. In some examples, electrons and holes recombine in the light-emitting layer 130, generating singlet and triplet excitons with a probability of 25:75.

[0089] For example, to ensure that the light-emitting device 100 can emit light effectively, the anode can be made of a material with a high work function. This allows holes in the anode to migrate effectively to the light-emitting layer 130 under the drive of the electric field, thereby recombineing with electrons from the cathode to emit light. The anode material can be a transparent conductive metal oxide material, such as indium tin oxide (ITO) or indium zinc oxide (IZO). Alternatively, the anode can be a composite electrode containing multiple materials, such as ITO / Ag / ITO, Ag / IZO, CNT / ITO, CNT / IZO, GO / ITO, or GO / IZO, where Ag is silver, CNT is carbon nanotube, and GO is graphene oxide.

[0090] In some examples, the cathode can be made of a material with a low work function, which makes it easier for electrons from the cathode to be injected into the target film layer (e.g., the electron injection layer 183 described in detail below). This allows electrons in the cathode to migrate effectively to the light-emitting layer 130 under the drive of an electric field, thereby recombineing with holes in the anode to emit light. Furthermore, the cathode must also possess good light transmittance and conductivity. The cathode material can be a metal, metal oxide, or metal alloy, such as aluminum (Al), silver (Ag), gold (Au), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium (Li), potassium (K), sodium (Na), tin (Sn), titanium (Ti), lead (Pb), samarium (Sm), yttrium (Y), indium tin oxide (ITO), magnesium-silver alloy (Mg:Ag), ytterbium-gold alloy (Yb:Au), ytterbium-silver alloy (Yb:Ag), lithium-aluminum alloy (Li:Al), or lithium-calcium-magnesium alloy (Li:Ca:Al), etc.; or, the cathode material can be a multilayer structure, such as magnesium / aluminum (Mg / Al), magnesium / silver (Mg / Ag), aluminum / silver (Al / Ag), aluminum / gold (Al / Au), ytterbium / gold (Yb / Au), ytterbium / silver (Yb / Ag), calcium / magnesium (Ca / Mg), calcium / silver (Ca / Ag), barium / silver (Ba / Ag), etc. Among them, magnesium / aluminum (Mg / Al) means that the cathode includes two thin films, and the materials of the two thin films are magnesium (Mg) and aluminum (Al) respectively.

[0091] In some embodiments, such as Figure 3 , Figure 5 and Figure 6 As shown, the first electrode 110 of the light-emitting device 100 is a patterned electrode, and the second electrode 120 of the light-emitting device 100 can be a structure with the entire layer connected, that is, the second electrode 120 can be a common electrode shared by the first light-emitting device 100A, the second light-emitting device 100D and the third light-emitting device 100C.

[0092] In some examples, such as Figure 3 and Figure 4 As shown, each of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C includes a light-emitting layer 130. In this case, the light-emitting device 100 is a single-layer light-emitting device, with the first electrode 110, the light-emitting layer 130, and the second electrode 120 stacked along a first direction X. In some other examples, such as... Figure 5 and Figure 6As shown, each of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C includes multiple (e.g., two) stacked light-emitting layers 130. In this case, the light-emitting device 100 is a stacked light-emitting device (also referred to as a Tandem OLED light-emitting device or a series OLED light-emitting device). The first electrode 110, the multiple light-emitting layers 130, and the second electrode 120 are stacked along a first direction X. Stacked OLED light-emitting devices have advantages such as higher efficiency and higher brightness, leading to their wider application.

[0093] In some embodiments, the material of the light-emitting layer 130 includes a host material and a guest material.

[0094] For example, the host material can be configured to: transport holes or electrons, and / or, recombine electrons with holes to form excitons and transfer exciton energy to the guest material.

[0095] For example, the guest material can be configured to: emit photons using exciton energy transferred from the host material, and / or, recombine electrons and holes to form excitons and emit photons.

[0096] In some examples, the guest material is a fluorescent material, which can emit light using singlet excitons; in other examples, the guest material is a phosphorescent material or a delayed fluorescence material, which can emit light using triplet excitons.

[0097] In some examples, the host material may include one material, while in other examples, the host material may include two or more materials. For example, the host material may include a first host material and a second host material, wherein the first host material is a hole-type material and the second host material is an electronic-type material.

[0098] For example, when the light-emitting device 100 includes a blue light-emitting device for emitting blue light, the host material of the light-emitting layer 130 of the blue light-emitting device can be a carbazole derivative, such as 1,3-bis(N-carbazolyl)benzene (mCP), 2-amino-4-(2-amino-4-methoxyphenyl)-5-methyl-2H-carbazole (UGH2), or bis(p-tolyl)carbazole oxide (DCPPO); the guest material can be a metal complex or metal coordination compound, such as bis(4,6-difluorophenylpyridine-C 2 ,N)(pyridinecarboxylate)iridium(III)(FIrpic), etc.

[0099] For example, when the light-emitting device 100 includes a green light-emitting device for emitting green light, the main material of the light-emitting layer 130 of the green light-emitting device can be a coumarin dye, a quinacridone copper derivative, a polycyclic aromatic hydrocarbon, a diamine anthracene derivative, or a carbazole derivative, such as N,N'-dimethylquinacridone (DMQA), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyldiamine (BA-NPB), or tris(8-hydroxyquinoline)aluminum (Alq3). The guest material can be a metal complex, such as tris(2-phenylpyridine)iridium (Ir(ppy)3) or di(2-phenylpyridine)-acetylacetone iridium (Ir(ppy)2(acac)).

[0100] In some examples, where the light-emitting device 100 includes a red light-emitting device for emitting red light, the main material of the light-emitting layer 130 of the red light-emitting device can be a 4-(dicyanomethyl)-2-methyl-6-(p-dimethylaminophenyl)-H-pyran (DCM) series material, such as 4-(dicyanomethyl)-2-methyl-6-(p-dimethylaminophenyl)-H-pyran (DCM), 4-(dicyanomethyl)-2-methyl-6-(p- Dimethylaminophenyl)-H-pyran (DCJTB) or 4-(dicyanomethyl)-2-methyl-6-(p-dimethoxyphenyl)-H-pyran (DCJTI), etc., the guest material can be a metal complex, such as bis(3-phenylpyridine)bis(propanedione)iridium (Ir(piq)2(acac)), platinum octaethylporphyrin (PtOEP) or bis(8-tripropyl)bis(pyridocarbazoline)iridium (Ir(btp)2(acac)), etc.

[0101] In the field of organic semiconductors, OLED light-emitting devices have the advantage of self-illumination. Compared to Liquid Crystal Display (LCD) devices, OLED displays offer better viewing angles and contrast. Furthermore, OLED displays do not require a separate backlight, allowing them to be lighter, thinner, and cheaper to manufacture. Compared to LCD devices or other flat panel displays, OLED displays consume less power, enabling them to be driven with low DC current and offering faster response times.

[0102] In some implementations, the light-emitting device 100 exhibits noticeable color shift at wide viewing angles. For example, when a stacked OLED light-emitting device is used in a top-emitting display panel, noticeable color shift occurs at wide viewing angles. In some cases, when the half-width at half maximum (WWHM) of the light-emitting device 100 is narrow, the color shift problem becomes more pronounced as the viewing angle increases. Simply put, more light is emitted from the front, and less light is emitted from the side. When the efficiency of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C decreases at different rates as the viewing angle increases, the color changes at different viewing angles, causing color shift.

[0103] Based on this, some embodiments of this disclosure provide a light-emitting device 100, which can be applied to the display panel 200 in the above embodiments as a light-emitting device 100 in the display panel 200.

[0104] like Figure 3 and Figure 4 As shown, the first electrode 110 is capable of reflecting light. Each of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C further includes at least one first functional unit 190. The first functional unit 190 is disposed on the side of the light-emitting layer 130 near the first electrode 110. The thicknesses of the first functional unit 190A of the first light-emitting device 100A, the first functional unit 190D of the second light-emitting device 100D, and the first functional unit 190C of the third light-emitting device 100C are all different. Based on the same light-emitting area of ​​the light-emitting device 100, the light-emitting device 100 has a first color bias value E@θ1 at a first preset viewing angle θ1 and a second color bias value E@θ2 at a second preset viewing angle θ2. The absolute value of the difference between the first color bias value E@θ1 and the second color bias value E@θ2 is less than or equal to 2. The difference between the first preset viewing angle θ1 and the second preset viewing angle θ2 is less than or equal to 15°.

[0105] That is, based on the same light-emitting area of ​​the light-emitting device 100, |E@θ1-E@θ2|≤2, and θ1-θ2≤15°.

[0106] For example, the difference between the first preset viewing angle θ1 and the second preset viewing angle θ2 can be 0°, 3°, 6°, 9°, 12° or 15°, etc.

[0107] It should be noted that, as Figure 3 and Figure 4As shown, the direction perpendicular to the light-emitting layer 130 is the reference direction X. The viewing angle refers to the angle between the line of sight and the reference direction X when an observer views the light-emitting device 100 from its light-emitting side W. For example, a 0° viewing angle means that the angle between the line of sight and the reference direction X is 0° when the observer views the light-emitting device 100 from its light-emitting side W; a 15° viewing angle means that the angle between the line of sight and the reference direction X is 15° when the observer views the light-emitting device 100 from its light-emitting side W. The reference direction X is, for example, the thickness direction of the substrate 210.

[0108] Color deviation is an important indicator for measuring the color accuracy of a screen, also known as color offset rate. This indicator directly affects the user's visual experience. Specifically, color deviation refers to the distance between the "measured color" and the "accurate color" displayed on the screen within a preset color space. Therefore, the smaller the color deviation, the higher the color accuracy of the screen. Here, the preset color space is, for example, the CIE 1931 color space.

[0109] In some embodiments, the color difference that the human eye can just perceive is JNCD (Just Noticeable Color Difference). In other words, the smallest unit of color change that the human eye can distinguish is 1 JNCD, where 1 JNCD = 0.0040.

[0110] It should be noted that the color deviation value of the light-emitting device 100 refers to the distance between the "measured color" and the "accurate color" displayed by the light-emitting device 100 in the preset color space. The following example illustrates the calculation method of the color deviation value of the light-emitting device 100 based on a selected area and the first color deviation value E@θ1 at the first preset viewing angle θ1.

[0111] When the light-emitting device 100 is lit, the chromaticity value of the measured color of the selected area under the first preset viewing angle θ1 in the preset color space is (u1′, v1′), and the chromaticity value of the accurate color of the selected area under the first preset viewing angle θ1 in the preset color space is (u2′, v2′). Then, the formula for calculating the first color deviation value E@θ1 is as follows:

[0112]

[0113] The state in which the light-emitting device 100 is lit refers to the state in which the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C included in the light-emitting device 100 are all lit.

[0114] It should be noted that the selected area can be any light-emitting area of ​​the light-emitting device 100.

[0115] In some examples, the first light-emitting device 100A is one of a blue light-emitting device, a green light-emitting device, and a red light-emitting device; the second light-emitting device 100D is another one of a blue light-emitting device, a green light-emitting device, and a red light-emitting device; and the third light-emitting device 100C is yet another one of a blue light-emitting device, a green light-emitting device, and a red light-emitting device. In this case, when the light-emitting device 100 is lit, the light emitted by the light-emitting device 100 is white light, and the color deviation value of the light-emitting device 100 can also be called the white light color deviation value.

[0116] It should be understood that when the first electrode 110 is capable of reflecting light, the light-emitting area of ​​the light-emitting device 100 (e.g., the area where the light-emitting layer 130 is located) is located within an optical cavity formed by a reflective film (i.e., the first electrode 110) and a semi-reflective film (i.e., the second electrode 120). For a given cavity length, light of a given wavelength will resonate due to multiple reflections from the walls of the optical cavity (e.g., the first electrode 110 and the second electrode 120), thus selectively enhancing the light of that wavelength. The increase in emission at a given wavelength caused by resonance within the optical cavity can be referred to as the microcavity effect.

[0117] Here, the light-emitting device 100 includes at least one first functional unit 190. For example, such as Figure 3 As shown, the light-emitting device 100 includes a light-emitting layer 130 and a first functional unit 190, the first functional unit 190 being located on the side of the light-emitting layer 130 near the first electrode 110. For example, as... Figure 5 and Figure 6 As shown, the light-emitting device 100 includes two light-emitting layers 130 and two first functional units 190. The first first functional unit 190 is located on the side of the first light-emitting layer 130 near the first electrode 110, and the second first functional unit 190 is located on the side of the second light-emitting layer 130 near the first electrode 110. The two first functional units 190 can be arranged in a direction from the first electrode 110 to the second electrode 120.

[0118] In some examples, such as Figure 5 and Figure 6 As shown, the first electrode 110 is the anode, and the first functional unit 190 is a structural unit with hole transport function (e.g., the first hole transport unit 140 and / or the second hole transport unit 150 described in detail below).

[0119] In some other examples, the first electrode 110 is a cathode, and the first functional unit 190 is a structural unit with electron transport function (e.g., the first electron transport unit 170 and / or the second electron transport unit 180, which are described in detail below).

[0120] In some embodiments, the thicknesses of the first functional unit 190A of the first light-emitting device 100A, the first functional unit 190D of the second light-emitting device 100D, and the first functional unit 190C of the third light-emitting device 100C, which are located at corresponding positions, are all different.

[0121] Here, the thicknesses of the first functional unit 190A of the first light-emitting device 100A, the first functional unit 190D of the second light-emitting device 100D, and the first functional unit 190C of the third light-emitting device 100C are all different, meaning that the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C each include N first functional units 190 (see [reference]). Figure 3 N ≥ 1 and N is an integer; the thickness of any two of the i-th first functional unit 190A of the first light-emitting device 100A, the i-th first functional unit 190D of the second light-emitting device 100D, and the i-th first functional unit 190C of the third light-emitting device 100C are different, i = 1 to N. The sorting direction of the N first functional units 190 can be from the first electrode 110 to the second electrode 120.

[0122] For example, such as Figure 5 and Figure 6 As shown, the first functional unit 190A, the first functional unit 190D and the third light-emitting device 100C are located on the lower side and are in corresponding positions, while the first functional unit 190A, the first functional unit 190D and the third light-emitting device 100C are located on the upper side and are in corresponding positions.

[0123] Understandably, by setting the first functional unit 190A of the first light-emitting device 100A, the first functional unit 190D of the second light-emitting device 100D, and the first functional unit 190C of the third light-emitting device 100C to have different thicknesses, firstly, the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can have different optical cavity thicknesses, which can be matched with light of different wavelengths, so that the light emitted by the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can all have increased light emission due to the microcavity effect; secondly, the first functional unit 190 can be used to adjust the distance between the light-emitting layer 130 and the first electrode 110, so that the light-emitting layer 130A of the first light-emitting device 100A and the light-emitting layer 130C of the second light-emitting device 100D can be adjusted. The light-emitting layer 130C of both the first light-emitting device 100A and the second light-emitting device 100D are located in the corresponding microcavity enhancement region. This allows the light emitted by each light-emitting layer 130 to form a constructive interference effect between the light propagating towards the light-emitting side and the light propagating towards the first electrode 110 and reflected by the first electrode 110. In this way, the luminous efficiency of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can all be at a high level. This also makes the efficiency attenuation of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C more consistent at a wide viewing angle. This can improve the color shift problem at a wide viewing angle, and make the absolute value of the difference between the first color shift value E@θ1 and the second color shift value E@θ2 less than or equal to 2. This can optimize the performance of the light-emitting device 100 and achieve high-quality display of the light-emitting device 100.

[0124] In some embodiments, such as Figure 5 As shown, based on the same light-emitting area of ​​the light-emitting device 100, the absolute value of the difference between the color deviation value E@15° of the light-emitting device 100 at a 15° viewing angle and the color deviation value E@0° of the light-emitting device 100 at a 0° viewing angle is less than or equal to 1.

[0125] That is, based on the same light-emitting area of ​​the light-emitting device 100, |E@15°-E@0°|≤1.

[0126] For example, based on the same light-emitting area of ​​the light-emitting device 100, the absolute value of the difference between the color deviation value E@15° of the light-emitting device 100 at a 15° viewing angle and the color deviation value E@0° of the light-emitting device 100 at a 0° viewing angle can be 0.01, 0.05, 0.1, 0.3, 0.5, 0.7, 0.9 or 1.0, etc.

[0127] When |E@15°-E@0°|≤1 for the same light-emitting area of ​​the light-emitting device 100, the efficiency attenuation of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C is relatively consistent within the viewing angle range of 0° to 15°, and the color shift of the light-emitting device 100 is relatively small within the viewing angle range of 0° to 15°.

[0128] In some embodiments, such as Figure 5 As shown, based on the same light-emitting area of ​​the light-emitting device 100, the absolute value of the difference between the color deviation value E@30° of the light-emitting device 100 at a 30° viewing angle and the color deviation value E@15° of the light-emitting device 100 at a 15° viewing angle is less than or equal to 2.

[0129] That is, based on the same light-emitting area of ​​the light-emitting device 100, |E@30°-E@15°|≤2.

[0130] For example, based on the same light-emitting area of ​​the light-emitting device 100, the absolute value of the difference between the color deviation value E@30° of the light-emitting device 100 at a 30° viewing angle and the color deviation value E@15° of the light-emitting device 100 at a 15° viewing angle can be 0.01, 0.05, 0.1, 0.4, 0.7, 1.0, 1.3, 1.6, 1.8 or 2.0, etc.

[0131] When |E@30°-E@15°|≤2 for the same light-emitting area of ​​the light-emitting device 100, the efficiency attenuation of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C is relatively consistent within the viewing angle range of 15° to 30°, and the color shift of the light-emitting device 100 is relatively small within the viewing angle range of 15° to 30°.

[0132] In some embodiments, such as Figure 5 As shown, based on the same light-emitting area of ​​the light-emitting device 100, the absolute value of the difference between the color deviation value E@45° of the light-emitting device 100 at a 45° viewing angle and the color deviation value E@30° of the light-emitting device 100 at a 30° viewing angle is less than or equal to 1.

[0133] That is, based on the same light-emitting area of ​​the light-emitting device 100, |E@45°-E@30°|≤1.

[0134] For example, based on the same light-emitting area of ​​the light-emitting device 100, the absolute value of the difference between the color deviation value E@45° of the light-emitting device 100 at a 45° viewing angle and the color deviation value E@30° of the light-emitting device 100 at a 30° viewing angle can be 0.01, 0.05, 0.15, 0.3, 0.5, 0.7, 0.9 or 1.0, etc.

[0135] When |E@45°-E@30°|≤1 for the same light-emitting area of ​​the light-emitting device 100, the efficiency attenuation of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C is relatively consistent within the viewing angle range of 30° to 45°, and the color shift of the light-emitting device 100 is relatively small within the viewing angle range of 30° to 45°.

[0136] In some embodiments, such as Figure 5 As shown, based on the same light-emitting area of ​​the light-emitting device 100, the absolute value of the difference between the color deviation value E@60° of the light-emitting device 100 at a 60° viewing angle and the color deviation value E@45° of the light-emitting device 100 at a 45° viewing angle is less than or equal to 1.

[0137] That is, based on the same light-emitting area of ​​the light-emitting device 100, |E@60°-E@45°|≤1.

[0138] For example, based on the same light-emitting area of ​​the light-emitting device 100, the absolute value of the difference between the color deviation value E@60° of the light-emitting device 100 at a 60° viewing angle and the color deviation value E@45° of the light-emitting device 100 at a 45° viewing angle can be 0.01, 0.05, 0.15, 0.2, 0.4, 0.6, 0.8 or 1.0, etc.

[0139] When |E@60°-E@45°|≤1 for the same light-emitting area of ​​the light-emitting device 100, the efficiency attenuation of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C is relatively consistent within the viewing angle range of 45° to 60°, and the color shift of the light-emitting device 100 is relatively small within the viewing angle range of 45° to 60°.

[0140] In some embodiments, such as Figure 5 As shown, based on the same light-emitting area of ​​the light-emitting device 100, the absolute value of the difference between the color deviation value E@75° of the light-emitting device 100 at a 75° viewing angle and the color deviation value E@60° of the light-emitting device 100 at a 60° viewing angle is less than or equal to 1.

[0141] That is, based on the same light-emitting area of ​​the light-emitting device 100, |E@75°-E@60°|≤1.

[0142] For example, based on the same light-emitting area of ​​the light-emitting device 100, the absolute value of the difference between the color deviation value E@75° of the light-emitting device 100 at a 75° viewing angle and the color deviation value E@60° of the light-emitting device 100 at a 60° viewing angle can be 0.01, 0.05, 0.10, 0.2, 0.4, 0.6, 0.8 or 1.0, etc.

[0143] When |E@75°-E@60°|≤1 for the same light-emitting area of ​​the light-emitting device 100, the efficiency attenuation of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C is relatively consistent within the viewing angle range of 60° to 75°, and the color shift of the light-emitting device 100 is relatively small within the viewing angle range of 60° to 75°.

[0144] In some other implementations, the light-emitting device 100 suffers from significant brightness decay at wide viewing angles. For example, when a stacked OLED light-emitting device is used in a top-emitting display panel, it exhibits significant brightness decay at wide viewing angles.

[0145] By setting the thicknesses of the first functional unit 190A of the first light-emitting device 100A, the first functional unit 190D of the second light-emitting device 100D, and the first functional unit 190C of the third light-emitting device 100C to be different, as mentioned above, the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can all achieve a strong microcavity effect, so that the brightness of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C is at a high level, which can improve the problem of brightness error under a large viewing angle.

[0146] For example, by setting the thicknesses of the first functional unit 190A of the first light-emitting device 100A, the first functional unit 190D of the second light-emitting device 100D, and the first functional unit 190C of the third light-emitting device 100C to be different, when the stacked OLED light-emitting devices are applied to the top-emitting display panel, the brightness of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can all be at a high level, which can improve the problem of brightness error under a wide viewing angle.

[0147] In some embodiments, such as Figure 5 As shown, the brightness attenuation ratio of the light-emitting device 100 at a 30° viewing angle is less than or equal to 30%.

[0148] It should be noted that the brightness attenuation ratio of the light-emitting device 100 at a 30° viewing angle refers to the fact that, based on the same light-emitting area of ​​the light-emitting device 100, the brightness at a 0° viewing angle is L1 and the brightness at a 30° viewing angle is L2. Therefore, the brightness attenuation ratio of the light-emitting device 100 at a 30° viewing angle is equal to (L1-L2) / L1×100%.

[0149] For example, the brightness attenuation ratio of the light-emitting device 100 at a 30° viewing angle can be 0%, 5%, 10%, 15%, 20%, 25%, or 30%, etc.

[0150] When the brightness attenuation ratio of the light-emitting device 100 at a 30° viewing angle is less than or equal to 30%, the brightness attenuation of the light-emitting device 100 in the viewing angle range of 0° to 30° is less, which can optimize the performance of the light-emitting device 100 and achieve high-quality display of the light-emitting device 100.

[0151] In some embodiments, such as Figure 5 As shown, the brightness attenuation ratio of the light-emitting device 100 at a 45° viewing angle is less than or equal to 60%.

[0152] For an understanding of the brightness attenuation ratio of the light-emitting device 100 at a 45° viewing angle, please refer to the description of the brightness attenuation ratio of the light-emitting device 100 at a 30° viewing angle in the previous section, which will not be repeated here.

[0153] For example, the brightness attenuation ratio of the light-emitting device 100 at a 45° viewing angle can be 0%, 10%, 20%, 30%, 40%, 50%, or 60%, etc.

[0154] When the brightness attenuation ratio of the light-emitting device 100 at a 45° viewing angle is less than or equal to 60%, the brightness attenuation of the light-emitting device 100 in the viewing angle range of 0° to 45° is less, which can optimize the performance of the light-emitting device 100 in a larger viewing angle range and achieve high-quality display of the light-emitting device 100.

[0155] In some embodiments, within a viewing angle range of -75° to 75°, the chromaticity coordinates CIEx of the light emitted by the light-emitting device 100 range from 0.280 to 0.305.

[0156] It should be noted that the -75° viewing angle and the 75° viewing angle are relative concepts. They can be understood as two 75° viewing angles within the same plane perpendicular to the light-emitting layer 130. If one 75° viewing angle is defined as the positive viewing angle, then the other 75° viewing angle is the negative viewing angle. Here, the plane perpendicular to the light-emitting layer 130 can be any plane perpendicular to the light-emitting layer 130.

[0157] For example, within a viewing angle range of -75° to 75°, the color coordinates CIEx of the light emitted by the light-emitting device 100 can be 0.280, 0.285, 0.290, 0.295, 0.300, or 0.305, etc.

[0158] In some embodiments, within a viewing angle range of -75° to 75°, the chromaticity coordinates (CIEy) of the light emitted by the light-emitting device 100 range from 0.290 to 0.320.

[0159] For example, within a viewing angle range of -75° to 75°, the color coordinates CIEy of the light emitted by the light-emitting device 100 can be 0.290, 0.95, 0.300, 0.305, 0.310, 0.315, or 0.320, etc.

[0160] Here, the light emitted by the light-emitting device 100 refers to the light emitted by any area of ​​the light-emitting device 100 when the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C included in the light-emitting device 100 are all lit.

[0161] For example, the light emitted by the light-emitting device 100 can be white light.

[0162] For example, the color coordinates CIEx and CIEy of the light emitted by the light-emitting device 100 refer to the color coordinates of the light in a preset color space, such as the CIE1931 color space.

[0163] When the color coordinates CIEx of the light emitted by the light-emitting device are in the range of 0.280 to 0.305 within a viewing angle range of 0 to 75°; and / or the color coordinates CIEy of the light emitted by the light-emitting device are in the range of 0.290 to 0.320, the color deviation of the light-emitting device 100 within a viewing angle range of 0° to 75° is small, and the color accuracy of the light-emitting device 100 within a viewing angle range of 0° to 75° is high.

[0164] In related technologies, the total optical path K of the microcavity of the first light-emitting device 100A, the second light-emitting device 100D, or the third light-emitting device 100C can be calculated using the following formula.

[0165]

[0166] in, It is the sum of the phase shifts of light at the reflecting surfaces of the first electrode 110 and the second electrode 120, respectively. i d is the refractive index of the i-th transparent film layer along the direction from the first electrode 110 to the second electrode 120. i Let be the thickness of the i-th light-transmitting film layer along the direction from the first electrode 110 to the second electrode 120. This light-transmitting film layer includes an organic layer located between the first electrode 110 and the second electrode 120, and may also include a portion of the first electrode 110 and the second electrode 120 located on the reflective surface near the light-emitting layer 130 that is transmissible to light. m is the order of the mode, and λ... m The wavelength of the emitted light.

[0167] As can be seen from the above formula, changing the total optical path K of the microcavity can change the position of the mode m of the optical cavity, thereby changing the emission wavelength λ of the microcavity device.m .

[0168] In some embodiments, such as Figure 5 and Figure 6 As shown, the ratio of the distance H1 between the surface 130Xa of the selected light-emitting layer 130X, which is away from the first electrode 110, and the light-reflecting surface 110a of the first electrode 110, to the selected wavelength λ is greater than or equal to (2n+1) / 4a and less than or equal to (2n+3) / 4a, where n is a positive integer and a ranges from 1.7 to 1.8. The selected light-emitting layer 130X is any one of at least one light-emitting layer 130A of the first light-emitting device 100A, at least one light-emitting layer 130D of the second light-emitting device 100D, and at least one light-emitting layer 130D of the third light-emitting device 100C. The selected wavelength λ is the emission wavelength of the selected light-emitting layer 130X.

[0169] That is: 1.7≤a≤1.8, where n is a positive integer.

[0170] In some examples, the 130X light-emitting layer is selected as a blue light-emitting layer, and the wavelength λ is selected as the wavelength of blue light; in other examples, the 130X light-emitting layer is selected as a green light-emitting layer, and the wavelength λ is selected as the wavelength of green light; in still other examples, the 130X light-emitting layer is selected as a red light-emitting layer, and the wavelength λ is selected as the wavelength of red light.

[0171] Understandably, the light emitted by the selected light-emitting layer 130X includes light propagating towards the first electrode 110 (hereinafter referred to as the first light) and light propagating towards the second electrode 120 (hereinafter referred to as the second light). Moreover, if the first electrode 110 can reflect light, the first light can be reflected by the first electrode 110. Through the above arrangement, the ratio between the distance H1 between the surface 130Xa of the selected light-emitting layer 130X away from the first electrode 110 and the light-reflecting surface 110a of the first electrode 110 and the selected wavelength λ can be within a suitable range, so that the interference between the second light and the first light reflected by the first electrode 110 is enhanced. In other words, constructive interference can be generated between the second light and the first light reflected by the first electrode 110, and the constructive interference wavelength is close to the selected wavelength. Thus, the luminous efficiency of the light-emitting device 100 can be improved, and the luminous color purity of the light-emitting device 100 can be improved, thereby enhancing the luminous performance of the light-emitting device 100.

[0172] It should be understood that the light-reflecting surface 110a of the first electrode 110 refers to the surface capable of reflecting the first light ray. It should be noted that the light-reflecting surface 110a of the first electrode 110 can be one side surface of the first electrode 110, or it can be the interface between different material films located within the first electrode 110.

[0173] In some embodiments, such as Figure 5 As shown, the light reflecting surface 110a of the first electrode 110 is the surface of the first electrode 110 that is close to the selected light-emitting layer 130X.

[0174] For example, the material of the first electrode 110 includes only materials capable of reflecting light (e.g., metal), and in this case, the light reflecting surface 110a of the first electrode 110 is the surface of the first electrode 110 near the selected light-emitting layer 130X.

[0175] For example, in the material of the first electrode 110, the sub-film layer capable of reflecting light (e.g., its material is metal) is closer to the selected light-emitting layer 130X than other sub-film layers (e.g., its material is transparent conductive metal oxide). For example, the material of the first electrode 110 includes a silver sub-film layer and an ITO sub-film layer, with the silver sub-film layer being closer to the selected light-emitting layer 130X than the ITO sub-film layer. In this case, the light-reflecting surface 110a of the first electrode 110 is the surface of the first electrode 110 that is closer to the selected light-emitting layer 130X.

[0176] In some embodiments, such as Figure 6 As shown, the first electrode 110 includes a second sub-layer 112 and a first sub-layer 111 stacked along a direction away from the selected light-emitting layer 130X; the first sub-layer 111 is capable of reflecting light; the second sub-layer 112 is capable of transmitting light; the light-reflecting surface 110a of the first electrode 110 is the surface of the first sub-layer 111 near the second sub-layer 112.

[0177] It should be understood that when the first sublayer 111 can reflect light and the second sublayer 112 can transmit light, the thickness of the second sublayer 112 can form part of the cavity length of the optical cavity, and the first light emitted by the selected light-emitting layer 130X can pass through the second sublayer 112 and be reflected at the surface of the first sublayer 111 near the second sublayer 112.

[0178] For example, the material of the second sublayer 112 can be a transparent conductive metal oxide, such as ITO or IZO.

[0179] For example, the material of the first sublayer 111 can be a metal, such as silver.

[0180] In some embodiments, such as Figure 5 and Figure 6 As shown, the peak wavelength of the emission spectrum of the material of the light-emitting layer 130A of the first light-emitting device 100A is greater than or equal to 400nm and less than or equal to 500nm.

[0181] For example, the peak wavelength of the emission spectrum of the material of the light-emitting layer 130A of the first light-emitting device 100A can be 400nm, 420nm, 430nm, 440nm, 450nm, 460nm, 480nm or 500nm, etc.

[0182] In some embodiments, such as Figure 5 and Figure 6 As shown, the peak wavelength of the emission spectrum of the material of the light-emitting layer 130D of the second light-emitting device 100D is greater than or equal to 510nm and less than or equal to 540nm.

[0183] For example, the peak wavelength of the emission spectrum of the material of the light-emitting layer 130D of the second light-emitting device 100D can be 510nm, 516nm, 520nm, 522nm, 528nm, 530nm, 535nm or 540nm, etc.

[0184] In some embodiments, such as Figure 5 and Figure 6 As shown, the peak wavelength of the emission spectrum of the material of the light-emitting layer 130C of the third light-emitting device 100C is greater than or equal to 600nm.

[0185] For example, the peak wavelength of the emission spectrum of the material of the light-emitting layer 130C of the third light-emitting device 100C can be 600nm, 610nm, 620nm, 630nm, 640nm or 650nm, etc.

[0186] When the peak wavelength of the emission spectrum of the material of the light-emitting layer 130A of the first light-emitting device 100A is greater than or equal to 400nm and less than or equal to 500nm, the first light-emitting device 100A is a blue light-emitting device; when the peak wavelength of the emission spectrum of the material of the light-emitting layer 130D of the second light-emitting device 100D is greater than or equal to 510nm and less than or equal to 540nm, the second light-emitting device 100D is a green light-emitting device; when the peak wavelength of the emission spectrum of the material of the light-emitting layer 130C of the third light-emitting device 100C is greater than or equal to 600nm, the third light-emitting device 100C is a red light-emitting device. In this way, the light-emitting device 100 can achieve full-color display, and at the same time, the color purity of the light emitted by the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can be improved.

[0187] In some examples, the exciton recombination region of the third light-emitting device 100C (e.g., a red light-emitting device) is more prone to shifting from the light-emitting layer compared to the first light-emitting device 100A (e.g., a blue light-emitting device) and the second light-emitting device 100D (e.g., a green light-emitting device).

[0188] In some examples, the material type of the light-emitting layer of the first light-emitting device 100A (e.g., a blue light-emitting device) is different from the material type of the light-emitting layers of the second light-emitting device 100D (e.g., a green light-emitting device) and the third light-emitting device 100C (e.g., a red light-emitting device). The material types of the light-emitting layers of the second light-emitting device 100D (e.g., a green light-emitting device) and the third light-emitting device 100C (e.g., a red light-emitting device) are more consistent.

[0189] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness D1 of the light-emitting layer 130A of the first light-emitting device 100A is less than the thickness D2 of the light-emitting layer 130D of the second light-emitting device 100D.

[0190] For example, when both the first light-emitting device 100A and the second light-emitting device 100D include multiple light-emitting layers 130, the thickness of any light-emitting layer 130A of the first light-emitting device 100A is less than the thickness of any light-emitting layer 130B of the second light-emitting device 100D.

[0191] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness D1 of the light-emitting layer 130A of the first light-emitting device 100A is less than the thickness D3 of the light-emitting layer 130C of the third light-emitting device 100C.

[0192] For example, when both the first light-emitting device 100A and the third light-emitting device 100C include multiple light-emitting layers 130, the thickness of any light-emitting layer 130A of the first light-emitting device 100A is less than the thickness of any light-emitting layer 130B of the third light-emitting device 100C.

[0193] Understandably, firstly, through the above-mentioned configuration, the thickness of the light-emitting layer 130C of the third light-emitting device 100C can be relatively large, forming a thicker light-emitting buffer zone. This prevents the recombination region of holes and electrons in the third light-emitting device 100C from shifting away from the light-emitting layer 130C, thus preventing excitons from accumulating in areas other than the light-emitting layer 130C and improving the lifetime of the third light-emitting device 100C. Secondly, through the above-mentioned configuration, the thickness of the light-emitting layer 130A of the first light-emitting device 100A can be relatively small. This allows the thickness of the light-emitting layer 130A of the first light-emitting device 100A to match its material properties, improving the consistency of luminous efficiency, lifetime, and brightness decay among the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C. Thirdly, the microcavity length of the first light-emitting device 100A can be better matched with its emission wavelength, the microcavity length of the second light-emitting device 100D can be better matched with its emission wavelength, and the microcavity length of the third light-emitting device 100C can be better matched with its emission wavelength. This can create a microcavity effect in the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C, thereby improving the luminous efficiency of the light-emitting device 100.

[0194] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness D1 of the light-emitting layer 130A of the first light-emitting device 100A ranges from 18nm to 22nm.

[0195] For example, the thickness D1 of the light-emitting layer 130A of the first light-emitting device 100A can be 18nm, 19nm, 20nm, 21.5nm or 22nm, etc.

[0196] In some examples, the first light-emitting device 100A includes multiple (e.g., two) light-emitting layers 130A, where the thickness of each light-emitting layer 130A ranges from 18nm to 22nm, and the thicknesses of the multiple light-emitting layers 130A may be equal or unequal.

[0197] It should be understood that when the thickness D1 of the light-emitting layer 130A of the first light-emitting device 100A is large, it may lead to an increase in the turn-on voltage of the first light-emitting device 100A, resulting in higher energy consumption, and may also cause a shift in the exciton recombination region. When the thickness D1 of the light-emitting layer 130A of the first light-emitting device 100A is small, the exciton recombination region is relatively small, which may result in lower luminous efficiency of the first light-emitting device 100A. Therefore, through the above settings, the thickness D1 of the light-emitting layer 130A of the first light-emitting device 100A can be kept within a suitable range. This ensures that the turn-on voltage of the first light-emitting device 100A is low and the luminous efficiency is high, while also making the thickness D1 of the light-emitting layer 130A of the first light-emitting device 100A relatively small, so that the thickness D1 of the light-emitting layer 130A of the first light-emitting device 100A is matched with the material properties of the light-emitting layer of the first light-emitting device 100A.

[0198] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness D2 of the light-emitting layer 130D of the second light-emitting device 100D ranges from 30nm to 50nm.

[0199] For example, the thickness D2 of the light-emitting layer 130D of the second light-emitting device 100D can be 30nm, 37nm, 40nm, 45nm or 50nm, etc.

[0200] In some examples, the second light-emitting device 100D includes multiple (e.g., two) light-emitting layers 130D, in which case the thickness of each light-emitting layer 130D is in the range of 30nm to 50nm, and the thickness of the multiple light-emitting layers 130D may be equal or unequal.

[0201] Similarly, through the above settings, the thickness D2 of the light-emitting layer 130D of the second light-emitting device 100D can be kept within a suitable range. While ensuring a low start-up voltage and high luminous efficiency of the second light-emitting device 100D, firstly, the thickness D2 of the light-emitting layer 130D of the second light-emitting device 100D can be better matched with the material properties of the light-emitting layer 130D of the second light-emitting device 100D; secondly, the thickness D2 of the light-emitting layer 130D of the second light-emitting device 100D can be larger, forming a light-emitting buffer of a certain thickness, which can prevent the recombination region of holes and electrons in the second light-emitting device 100D from shifting to the light-emitting layer 130D.

[0202] In some embodiments, such as Figure 3 and Figure 5 As shown, the thickness D3 of the light-emitting layer 130C of the third light-emitting device 100C ranges from 30nm to 50nm.

[0203] For example, the thickness D3 of the light-emitting layer 130C of the third light-emitting device 100C can be 30nm, 35nm, 41nm, 45nm or 50nm, etc.

[0204] In some examples, the third light-emitting device 100C includes multiple (e.g., two) light-emitting layers 130C, in which case the thickness of each light-emitting layer 130C is in the range of 30nm to 50nm, and the thickness of the multiple light-emitting layers 130C may be equal or unequal.

[0205] Similarly, through the above settings, the thickness D3 of the light-emitting layer 130C of the third light-emitting device 100C can be kept within a suitable range. While ensuring a low start-up voltage and high luminous efficiency of the third light-emitting device 100C, firstly, the thickness D3 of the light-emitting layer 130C of the third light-emitting device 100C can be better matched with the material properties of the light-emitting layer 130C of the third light-emitting device 100C; secondly, the thickness D3 of the light-emitting layer 130C of the third light-emitting device 100C can be larger, which can form a thicker light-emitting buffer zone and prevent the recombination region of holes and electrons in the third light-emitting device 100C from shifting to the light-emitting layer 130C.

[0206] The above is an exemplary description of the light-emitting layer 130 of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C.

[0207] As mentioned above, the first functional unit 190 (see also...) Figure 6 This can be a structural unit with hole transport capability or a structural unit with electron transport capability. The following will use the first functional unit 190 as an example, which is a structural unit with hole transport capability. Figure 5 and Figure 6 As shown, an example is given in which the thicknesses of the first functional unit 190A of the first light-emitting device 100A, the first functional unit 190D of the second light-emitting device 100D, and the first functional unit 190C of the third light-emitting device 100C are all different.

[0208] In some embodiments, such as Figure 5 and Figure 6 As shown, at least one first functional unit 190 includes a first hole transmission unit 140 and a second hole transmission unit 150, wherein the first hole transmission unit 140 is closer to the first electrode 110 than the second hole transmission unit 150.

[0209] In this case, each of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C includes two light-emitting layers 130, with the first hole transport unit 140 disposed on the side of the light-emitting layer 130 that is relatively close to the first electrode 110, and the second hole transport unit 150 disposed on the side of the light-emitting layer 130 that is relatively far from the first electrode 110.

[0210] For example, the first hole transport unit 140 and / or the second hole transport unit 150 may be configured to transport holes and / or block electrons and excitons generated within the light-emitting layer 130.

[0211] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness D5 of the first hole transmission unit 140D of the second light-emitting device 100D is greater than the thickness D4 of the first hole transmission unit 140A of the first light-emitting device 100A, and less than the thickness of the first hole transmission unit 140C of the third light-emitting device 100C.

[0212] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness D8 of the second hole transmission unit 150D of the second light-emitting device 100D is greater than the thickness D7 of the second hole transmission unit 150A of the first light-emitting device 100A, and less than the thickness D9 of the second hole transmission unit 150C of the third light-emitting device 100C.

[0213] With the above settings, the thickness of the first functional unit 190A of the first light-emitting device 100A can be matched with the emission wavelength of the first light-emitting device 100A, the thickness of the first functional unit 190D of the second light-emitting device 100D can be matched with the emission wavelength of the second light-emitting device 100D, and the thickness of the first functional unit 190C of the third light-emitting device 100C can be matched with the emission wavelength of the third light-emitting device 100C. Thus, as mentioned above, the luminous efficiency of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can all be at a high level.

[0214] In some embodiments, such as Figure 3 and Figure 5 As shown, the first hole transport unit 140 includes a hole injection layer 141, a first hole transport layer 142, and a first electron blocking layer 143. The second hole transport unit 150 includes a second hole transport layer 151 and a second electron blocking layer 152.

[0215] Exemplarily, the hole injection layer 141 can be configured to reduce the hole injection barrier and improve the hole injection efficiency. The first hole transport layer 142 and / or the second hole transport layer 151 can be configured to transport holes. The first electron blocking layer 143 and / or the second electron blocking layer 152 can be configured to transport holes, block electrons, and serve as the light-emitting layer 130 (see [reference]). Figure 6 Excitons generated within the body.

[0216] For example, the hole injection layer 141 can be made of inorganic oxides, such as molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, manganese oxide, etc.; or, the hole injection layer 141 can be a dopant of a strong electron-withdrawing system, such as tetrafluorotetracyanoquinolinequinone dimethyl ether (F4TCNQ), hexaazaheptaphenyltriphenylhexanitrile (HATCN), etc.; or, the hole injection layer 141 can also be obtained by p-type doping of the hole transport material (e.g., by co-evaporation to form the hole injection layer). For example, the thickness of the hole injection layer 141 can range from 5 nm to 20 nm.

[0217] For example, the first hole transport layer 142 and / or the second hole transport layer 151 have good hole transport characteristics, and their materials can be aromatic amines or carbazole materials, such as N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB), N,N'-di(naphthyl)-N,N'-diphenylphenyldiamine (TPD), bis(2-(2-hydroxyphenyl)benzoxazole) (BAFLP) or 2,8-difluoro-5,11-bis(tri-tert-butylsilylethynyl)benzo[3,8]phenanthroline (DFLDPBi), etc.

[0218] For example, the first electron blocking layer 143 and / or the second electron blocking layer 152 (also referred to as the prime layer or the light-emitting auxiliary layer) have good hole transport characteristics. The materials of the first electron blocking layer 143 and / or the second electron blocking layer 152 can be aromatic amine materials or carbazole materials, such as biphenylbenzoxazole (CBP), polycarbazole phthaloline (PCzPA), etc.

[0219] In some embodiments, such as Figure 5 and Figure 6As shown, the hole injection layer 141 of the first light-emitting device 100A, the hole injection layer 141 of the second light-emitting device 100D, and the hole injection layer 141 of the third light-emitting device 100C all have the same thickness. The first hole transport layer 142 of the first light-emitting device 100A, the first hole transport layer 142 of the second light-emitting device 100D, and the first hole transport layer 142 of the third light-emitting device 100C all have the same thickness. The second hole transport layer 151 of the first light-emitting device 100A, the second hole transport layer 151 of the second light-emitting device 100D, and the second hole transport layer 151 of the third light-emitting device 100C all have the same thickness.

[0220] For example, the hole injection layer 141 of the first light-emitting device 100A, the hole injection layer 141 of the second light-emitting device 100D, and the hole injection layer 141 of the third light-emitting device 100C are all made of the same material.

[0221] For example, the first hole transport layer 142 of the first light-emitting device 100A, the first hole transport layer 142 of the second light-emitting device 100D, and the first hole transport layer 142 of the third light-emitting device 100C are all made of the same material.

[0222] For example, the second hole transport layer 151 of the first light-emitting device 100A, the second hole transport layer 151 of the second light-emitting device 100D, and the second hole transport layer 151 of the third light-emitting device 100C are all made of the same material.

[0223] With the above configuration, the hole injection layer 141 of the first light-emitting device 100A, the hole injection layer 141 of the second light-emitting device 100D, and the hole injection layer 141 of the third light-emitting device 100C can be formed in the same step. The first hole transport layer 142 of the first light-emitting device 100A, the first hole transport layer 142 of the second light-emitting device 100D, and the first hole transport layer 142 of the third light-emitting device 100C can be formed in the same step. The second hole transport layer 151 of the first light-emitting device 100A, the second hole transport layer 142 of the second light-emitting device 100D, and the second hole transport layer 151 of the third light-emitting device 100C can be formed in the same step. Thus, the hole injection layer 141, the first hole transport layer 142, and the second hole transport layer 151 can be a common film layer shared by the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C, which simplifies the fabrication process of the light-emitting device 100.

[0224] In some embodiments, such as Figure 5 and Figure 6As shown, the thickness D11 of the first electron blocking layer 143 of the second light-emitting device 100D is greater than the thickness D10 of the first electron blocking layer 143 of the first light-emitting device 100A, and less than the thickness D12 of the first electron blocking layer 143 of the third light-emitting device 100C.

[0225] For example, the materials of the first electron blocking layer 143 of the first light-emitting device 100A, the first electron blocking layer 143 of the second light-emitting device 100D, and the first electron blocking layer 143 of the third light-emitting device 100C can be the same or different. For instance, the materials of the first electron blocking layer 143 of the first light-emitting device 100A, the first electron blocking layer 143 of the second light-emitting device 100D, and the first electron blocking layer 143 of the third light-emitting device 100C can all be different to match the performance of the light-emitting layer 130 material.

[0226] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness D14 of the second electron blocking layer 152 of the second light-emitting device 100D is greater than the thickness D13 of the second electron blocking layer 152 of the first light-emitting device 100A, and less than the thickness D15 of the second electron blocking layer 152 of the third light-emitting device 100C.

[0227] For example, the materials of the second electron blocking layer 152 of the first light-emitting device 100A, the second electron blocking layer 152 of the second light-emitting device 100D, and the second electron blocking layer 152 of the third light-emitting device 100C can be the same or different. For instance, the materials of the second electron blocking layer 152 of the first light-emitting device 100A, the second electron blocking layer 152 of the second light-emitting device 100D, and the second electron blocking layer 152 of the third light-emitting device 100C can all be different to match the performance of the light-emitting layer 130 material.

[0228] Through the above settings, the thickness of the first hole transmission unit 140 and / or the second hole transmission unit 150 of the first light-emitting device 100A can be matched with the emission wavelength of the first light-emitting device 100A, the thickness of the first hole transmission unit 140 and / or the second hole transmission unit 150 of the second light-emitting device 100D can be matched with the emission wavelength of the second light-emitting device 100D, and the thickness of the first hole transmission unit 140 and / or the second hole transmission unit 150 of the third light-emitting device 100C can be matched with the emission wavelength of the third light-emitting device 100C. Thus, as mentioned above, the luminous efficiency of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can all be at a high level.

[0229] Furthermore, through the above arrangement, the first electron blocking layer 143 and / or the second electron blocking layer 152 of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can be independently configured. In this way, the materials of the first electron blocking layer 143 and / or the second electron blocking layer 152 with matching performance can be selected as needed according to the performance of the light-emitting layer 130 materials of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C, so as to improve the hole transport effect and electron blocking effect of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C.

[0230] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness D10 of the first electron blocking layer 143 of the first light-emitting device 100A ranges from 5 nm to 10 nm. The thickness D11 of the first electron blocking layer 143 of the second light-emitting device 100D ranges from 40 nm to 45 nm. The thickness D12 of the first electron blocking layer 143 of the third light-emitting device 100C ranges from 80 nm to 95 nm.

[0231] For example, the thickness D10 of the first electron blocking layer 143 of the first light-emitting device 100A can be 5nm, 6nm, 7nm, 8nm, 9nm or 10nm, etc.

[0232] For example, the thickness D11 of the first electron blocking layer 143 of the second light-emitting device 100D can be 40nm, 41nm, 42nm, 43nm, 44nm or 45nm, etc.

[0233] For example, the thickness D12 of the first electron blocking layer 143 of the third light-emitting device 100C can be 80nm, 83nm, 86nm, 89nm, 92nm or 95nm, etc.

[0234] With the above configuration, the thickness D11 of the first electron blocking layer 143 of the second light-emitting device 100D can be greater than the thickness D10 of the first electron blocking layer 143 of the first light-emitting device 100A, and less than the thickness D12 of the first electron blocking layer 143 of the third light-emitting device 100C. Thus, as mentioned above, the luminous efficiency of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can all be at a high level. Furthermore, with the above configuration, the thickness D10 of the first electron blocking layer 143 of the first light-emitting device 100A, the thickness D11 of the first electron blocking layer 143 of the second light-emitting device 100D, and the thickness D12 of the first electron blocking layer 143 of the third light-emitting device 100C can be within a suitable range, which is beneficial for improving the hole transport effect and electron blocking effect of the light-emitting device 100.

[0235] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness D13 of the second electron blocking layer 152 of the first light-emitting device 100A ranges from 5 nm to 10 nm. The thickness D14 of the second electron blocking layer 152 of the second light-emitting device 100D ranges from 15 nm to 20 nm. The thickness D15 of the second electron blocking layer 152 of the third light-emitting device 100C ranges from 25 nm to 35 nm.

[0236] For example, the thickness D13 of the second electron blocking layer 152 of the first light-emitting device 100A can be 5nm, 6nm, 7nm, 8nm, 9nm or 10nm, etc.

[0237] For example, the thickness D14 of the second electron blocking layer 152 of the second light-emitting device 100D can be 15nm, 16nm, 17nm, 18nm, 19nm or 20nm, etc.

[0238] For example, the thickness D15 of the second electron blocking layer 152 of the third light-emitting device 100C can be 25nm, 27nm, 29nm, 31nm, 33nm or 35nm, etc.

[0239] With the above configuration, the thickness D14 of the second electron blocking layer 152 of the second light-emitting device 100D can be greater than the thickness D13 of the second electron blocking layer 152 of the first light-emitting device 100A, and less than the thickness D15 of the second electron blocking layer 152 of the third light-emitting device 100C. Thus, as mentioned above, the luminous efficiency of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C can all be at a high level. Furthermore, with the above configuration, the thickness D13 of the second electron blocking layer 152 of the first light-emitting device 100A, the thickness D14 of the second electron blocking layer 152 of the second light-emitting device 100D, and the thickness D15 of the second electron blocking layer 152 of the third light-emitting device 100C can be within a suitable range, which is beneficial for improving the hole transport effect and electron blocking effect of the light-emitting device 100.

[0240] In some embodiments, such as Figure 5 and Figure 6 As shown, the hole injection layer 141 of the first light-emitting device 100A, the hole injection layer 141 of the second light-emitting device 100D, and the hole injection layer 141 of the third light-emitting device 100C all have a first thickness D16, and the first thickness D16 ranges from 5nm to 15nm.

[0241] For example, the first thickness D16 can be 5nm, 7nm, 9nm, 11nm, 13nm or 15nm, etc.

[0242] With the above settings, the thickness of the hole injection layer 141 is within a suitable range, which can improve the hole injection effect of the light-emitting device 100.

[0243] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness of the first hole transport layer 142 of the first light-emitting device 100A, the first hole transport layer 142 of the second light-emitting device 100D, and the first hole transport layer 142 of the third light-emitting device 100C is the second thickness D17, and the second thickness D17 ranges from 95nm to 105nm.

[0244] For example, the second thickness D17 can be 95nm, 97nm, 99nm, 101nm, 103nm or 105nm, etc.

[0245] With the above settings, the thickness of the first hole transport layer 142 is within a suitable range, which can improve the hole transport effect of the light-emitting device 100.

[0246] In some embodiments, such as Figure 5 and Figure 5 As shown, the thickness of the second hole transport layer 151 of the first light-emitting device 100A, the second hole transport layer 151 of the second light-emitting device 100D, and the second hole transport layer 151 of the third light-emitting device 100C is a third thickness D18, and the third thickness D18 ranges from 50nm to 60nm.

[0247] For example, the third thickness D18 can be 50nm, 52nm, 54nm, 56nm, 58nm or 60nm, etc.

[0248] With the above settings, the thickness of the second hole transport layer 151 is within a suitable range, which can improve the hole transport effect of the light-emitting device 100.

[0249] In some embodiments, such as Figure 5 and Figure 6 As shown, at least one light-emitting layer 130 includes two light-emitting layers 130, namely a first light-emitting layer 131 and a second light-emitting layer 132, wherein the first light-emitting layer 131 is closer to the first electrode 110 than the second light-emitting layer 132. Each of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C further includes a first charge-generating layer 161 and a second charge-generating layer 162. The first charge-generating layer 161 and the second charge-generating layer 162 are located between the first light-emitting layer 131 and the second hole transport unit 150; the first charge-generating layer 161 is closer to the first light-emitting layer 131 than the second charge-generating layer 162.

[0250] For example, the first charge generation layer 161 can also be called the N-type charge generation layer NCGL, and the second charge generation layer 162 can also be called the P-type charge generation layer PCGL. The N-type charge generation layer NCGL and the P-type charge generation layer PCGL can be in contact to form a PN junction charge generation unit.

[0251] Exemplarily, the material of the first charge generation layer 161 includes a first matrix material and an N-type dopant. The first matrix material can be an organic material, such as one or any combination of three-8-hydroxyquinoline aluminum, triazine, hydroxyquinoline derivatives, indole derivatives, and thiophene derivatives. The N-type dopant can be an alkali metal, alkali metal compound, alkaline earth metal, or alkaline earth metal compound, such as one or any combination of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), magnesium (Mg), calcium (Ga), strontium (Sr), barium (Ba), lanthanum (La), cerium (Ce), samarium (Sm), europium (Eu), terbium (Tb), dysprosium (Dy), and ytterbium (Yb).

[0252] Exemplarily, the material of the second charge-generating layer 162 includes a second matrix material and a P-type dopant. The second matrix material can be an organic material, such as one or any combination of N,N′-di(naphthyl-1-yl)-N,N′-diphenyl-benzidine (NPB), N,N′-diphenyl-N,N′-bis(3-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine (TPD), and N,N,N′,N′-tetranaphthylbenzidine (TNB). The P-type dopant can be a metal or an organic material. When the P-type dopant is a metal, the metal can be selected from one or any combination of aluminum (Al), copper (Cu), iron (Fe), lead (Pb), zinc (Zn), gold (Au), platinum (Pt), tungsten (W), indium (In), molybdenum (Mo), nickel (Ni), and titanium (Ti). When the P-type dopant is an organic material, the P-type dopant can be one or any combination of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-quinone dimethyl ether (F4-TFNQ) and 7,7,8,8-tetracyano-p-quinone dimethyl ether (TFNQ) derivatives.

[0253] With the above configuration, the first light-emitting layer 131 and the second light-emitting layer 132 can be sequentially connected in the vertical direction (e.g., the first direction X) of the light-emitting surface. Furthermore, the first charge-generating layer 161 and the second charge-generating layer 162 in the stacked OLED light-emitting device 100 not only serve to connect the light-emitting layers 130, but also generate charges and / or separate holes and electrons. This allows charges (holes or electrons) to be injected into the adjacent light-emitting layer 130. For example, the first charge-generating layer 161 can inject charges into the light-emitting layer adjacent to the first electrode 110 (e.g., the first charge-generating layer 131).Figure 5 The second light-emitting layer 132, located on the lower side, supplies electrons; the second charge-generating layer 162 can supply electrons to the light-emitting layer adjacent to the second electrode 120 (e.g., a second charge-generating layer 162). Figure 6 The first light-emitting layer 131, located on the upper side, supplies holes; thus, firstly, it is beneficial to improve the generation efficiency of charge (holes or electrons), which can improve the luminous efficiency of the light-emitting device 100; secondly, it can reduce the driving voltage of the light-emitting device 100.

[0254] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness of the first charge generation layer 161 of the first light-emitting device 100A, the first charge generation layer 161 of the second light-emitting device 100D, and the first charge generation layer 161 of the third light-emitting device 100C is a fourth thickness D19, and the fourth thickness D19 ranges from 80nm to 100nm.

[0255] For example, the fourth thickness D19 can be 80nm, 84nm, 88nm, 92nm, 96nm or 100nm, etc.

[0256] For example, the first charge generation layer 161 of the first light-emitting device 100A, the first charge generation layer 161 of the second light-emitting device 100D, and the first charge generation layer 161 of the third light-emitting device 100C are all made of the same material.

[0257] With the above configuration, the first charge generation layer 161 of the first light-emitting device 100A, the first charge generation layer 161 of the second light-emitting device 100D, and the first charge generation layer 161 of the third light-emitting device 100C can be formed in the same step. Thus, the first charge generation layer 161 can be a common film layer shared by the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C, which can simplify the fabrication process of the light-emitting device 100. Moreover, the thickness of the first charge generation layer 161 can be kept within a suitable range, which can improve the electron supply effect of the first charge generation layer 161 to the first light-emitting layer 131.

[0258] In some embodiments, such as Figure 4 and Figure 5 As shown, the thickness of the second charge generation layer 162 of the first light-emitting device 100A, the second charge generation layer 162 of the second light-emitting device 100D, and the second charge generation layer 162 of the third light-emitting device 100C is a fifth thickness D20, and the fifth thickness D20 ranges from 160nm to 200nm.

[0259] For example, the fifth thickness D20 can be 80nm, 84nm, 88nm, 92nm, 96nm or 100nm, etc.

[0260] For example, the second charge generation layer 162 of the first light-emitting device 100A, the second charge generation layer 162 of the second light-emitting device 100D, and the second charge generation layer 162 of the third light-emitting device 100C are all made of the same material.

[0261] With the above configuration, the second charge generation layer 162 of the first light-emitting device 100A, the second charge generation layer 162 of the second light-emitting device 100D, and the second charge generation layer 162 of the third light-emitting device 100C can be formed in the same step. Thus, the second charge generation layer 162 can be a common film layer shared by the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C, which can simplify the fabrication process of the light-emitting device 100. Moreover, the thickness of the second charge generation layer 162 can be kept within a suitable range, which can improve the hole supply effect of the second charge generation layer 162 to the second light-emitting layer 132.

[0262] In some embodiments, such as Figure 5 and Figure 6 As shown, each of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C further includes a first hole-blocking layer 171 and a second electron transport unit 180. The first hole-blocking layer 171 is located between the first light-emitting layer 131 and the first charge-generating layer 161. The second electron transport unit 180 is located between the second light-emitting layer 132 and the second electrode 120. The second electron transport unit 180 includes a second hole-blocking layer 181 and a second electron transport layer 182 stacked in a direction away from the second light-emitting layer 132.

[0263] In some examples, such as Figure 5 and Figure 6 As shown, each of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C further includes a first electron transport layer 172 located between the first hole blocking layer 171 and the first charge generating layer 161. In this case, the first hole blocking layer 171 and the first electron transport layer 172 can constitute a first electron transport unit 170.

[0264] For example, the first electron transport unit 170 and / or the second electron transport unit 180 may be configured to transport electrons and / or block holes and excitons generated within the light-emitting layer 130.

[0265] For example, the materials of the first hole blocking layer 171, the first electron transport layer 172, the second hole blocking layer 181, or the second electron transport layer 182 can be aromatic heterocyclic compounds, such as imidazole derivatives, pyrimidine derivatives, azine derivatives, compounds containing a nitrogen-containing six-membered ring structure, or compounds containing phosphine oxide substituents on the heterocycle. Among them, the imidazole derivatives are, for example, benzimidazole derivatives, imidazopyridine derivatives, or benzimidazolephenanthridine derivatives; the azine derivatives are, for example, triazine derivatives; and the compounds containing a nitrogen-containing six-membered ring structure are, for example, quinoline derivatives, isoquinoline derivatives, or phenanthreneroline derivatives. The materials of the first hole blocking layer 171, the first electron transport layer 172, the second hole blocking layer 181, or the second electron transport layer 182 are, for example, oxadiazole-7 (OXD-7), 1,3,4-thiadiazole (TAZ), p-ethyltrithiophene (p-EtTAZ), 2,9-diphenyl-1,10-phenanthroline (BPhen), or 2,9-diphenyl-4,7-dinitro-1,10-phenanthroline (BCP), etc.

[0266] In some examples, such as Figure 5 and Figure 6 As shown, the second electron transport unit 180 includes an electron injection layer 183 located between the second electron transport layer 182 and the second electrode 120.

[0267] For example, the material of the electron injection layer 183 can be a material with the ability to transport electrons, having the effect of injecting electrons from the cathode 12, and having excellent thin film forming ability. It is generally an alkali metal or a metal, such as lithium fluoride (LiF), ytterbium (Yb), magnesium (Mg), calcium (Ca), or compounds of ytterbium, compounds of magnesium, compounds of calcium, etc.

[0268] In some embodiments, such as Figure 5 and Figure 6 As shown, the thickness of the first hole blocking layer 171 of the first light-emitting device 100A, the first hole blocking layer 171 of the second light-emitting device 100D, and the first hole blocking layer 171 of the third light-emitting device 100C is a sixth thickness D21, and the sixth thickness D21 ranges from 5nm to 10nm.

[0269] For example, the sixth thickness D21 can be 5nm, 6nm, 7nm, 8nm, 9nm or 10nm, etc.

[0270] For example, the first hole blocking layer 171 of the first light-emitting device 100A, the first hole blocking layer 171 of the second light-emitting device 100D, and the first hole blocking layer 171 of the third light-emitting device 100C are all made of the same material.

[0271] With the above configuration, the first hole blocking layer 171 of the first light-emitting device 100A, the first hole blocking layer 171 of the second light-emitting device 100D, and the first hole blocking layer 171 of the third light-emitting device 100C can be formed in the same step. Thus, the first hole blocking layer 171 can be a common film layer shared by the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C, which can simplify the fabrication process of the light-emitting device 100. Moreover, the thickness of the first hole blocking layer 171 can be kept within a suitable range, which can improve the hole blocking effect of the portion of the light-emitting device 100 near the first electrode 210.

[0272] In some embodiments, such as Figure 7 and Figure 8 As shown, the thickness of the second hole blocking layer 181 of the first light-emitting device 100A, the second hole blocking layer 181 of the second light-emitting device 100D, and the second hole blocking layer 181 of the third light-emitting device 100C is a seventh thickness D22, and the seventh thickness D22 ranges from 5nm to 10nm.

[0273] For example, the seventh thickness D22 can be 5nm, 6nm, 7nm, 8nm, 9nm or 10nm, etc.

[0274] For example, the second hole blocking layer 181 of the first light-emitting device 100A, the second hole blocking layer 181 of the second light-emitting device 100D, and the second hole blocking layer 181 of the third light-emitting device 100C are all made of the same material.

[0275] With the above configuration, the second hole blocking layer 181 of the first light-emitting device 100A, the second hole blocking layer 181 of the second light-emitting device 100D, and the second hole blocking layer 181 of the third light-emitting device 100C can be formed in the same step. Thus, the second hole blocking layer 181 can be a common film layer shared by the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C, which can simplify the fabrication process of the light-emitting device 100. Moreover, the thickness of the second hole blocking layer 181 can be kept within a suitable range, which can improve the hole blocking effect of the portion of the light-emitting device 100 away from the first electrode 210.

[0276] In some embodiments, such as Figure 9 and Figure 10 As shown, the thickness of the second electron transport layer 182 of the first light-emitting device 100A, the second electron transport layer 182 of the second light-emitting device 100D, and the second electron transport layer 182 of the third light-emitting device 100C is an eighth thickness D23, and the eighth thickness D23 ranges from 30nm to 40nm.

[0277] For example, the eighth thickness D23 can be 30nm, 32nm, 34nm, 36nm, 38nm or 40nm, etc.

[0278] For example, the second electron transport layer 182 of the first light-emitting device 100A, the second electron transport layer 182 of the second light-emitting device 100D, and the second electron transport layer 182 of the third light-emitting device 100C are all made of the same material.

[0279] With the above configuration, the second electron transport layer 182 of the first light-emitting device 100A, the second electron transport layer 182 of the second light-emitting device 100D, and the second electron transport layer 182 of the third light-emitting device 100C can be formed in the same step. Thus, the second electron transport layer 182 can be a common film layer shared by the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C, which can simplify the fabrication process of the light-emitting device 100. Moreover, the thickness of the second electron transport layer 182 can be kept within a suitable range, which can improve the electron transport effect of the portion of the light-emitting device 100 away from the first electrode 210.

[0280] The technical solutions provided in this disclosure will be described in detail and by way of the following experimental examples and comparative examples.

[0281] The following Examples 1 and 2 respectively fabricated display panels 200. The thickness of a portion of the film layer in the display panels 200 of Examples 1 and 2 differs; specific thickness parameters are described below and will not be repeated here. The structure of the display panel 200 is as follows: Figure 7 As shown, the display panel 200 includes a light-emitting device 100, which includes a first light-emitting device 100A, a second light-emitting device 100D, and a third light-emitting device 100C. The structure of the first light-emitting device 100A, the second light-emitting device 100D, or the third light-emitting device 100C in the light-emitting device 100 is as follows: Figure 9 As shown. The following Example 3 describes the fabrication of a display panel 200. The structure of the display panel 200 is as follows. Figure 7 As shown, the display panel 200 includes a light-emitting device 100, which includes a first light-emitting device 100A, a second light-emitting device 100D, and a third light-emitting device 100C. The structure of the first light-emitting device 100A, the second light-emitting device 100D, or the third light-emitting device 100C in the light-emitting device 100 is as follows: Figure 9 As shown. It should be noted that, Figure 11 and Figure 12 This is a simplified schematic diagram of the display panel 200 after removing all film layers except those related to the light-emitting device 100.

[0282] Exemplary examples, in Embodiments 1 and 2, the method for fabricating the display panel 200 comprising a first light-emitting device 100A, a second light-emitting device 100D, and a third light-emitting device 100C is as follows: a substrate 210 (glass substrate) with a patterned first electrode 110 (ITO electrode) is used as a back plate, and the back plate is placed in the vacuum chamber of a vacuum evaporation apparatus, and the vacuum is evacuated to 1×10⁻⁶. -5 Pa ~ 1×10 -6 After Pa, the materials of hole injection layer 141, first hole transport layer 142, first electron blocking layer 143, first light-emitting layer 131, first hole blocking layer 171, first charge generation layer 161, second charge generation layer 162, second hole transport layer 151, second electron blocking layer 152, second light-emitting layer 132, second hole blocking layer 181, second electron transport layer 182, and electron injection layer 183 are utilized. The materials of the second electrode 120 and the capping layer 250 are sequentially formed on the back plate as follows: hole injection layer 141, first hole transport layer 142, first electron blocking layer 143, first light-emitting layer 131, first hole blocking layer 171, first charge generation layer 161, second charge generation layer 162, second hole transport layer 151, second electron blocking layer 152, second light-emitting layer 132, second hole blocking layer 181, second electron transport layer 182, electron injection layer 183, second electrode 120, and capping layer 250.

[0283] For example, in Embodiment 3, the method for fabricating the display panel 200 comprising a first light-emitting device 100A, a second light-emitting device 100D, and a third light-emitting device 100C is as follows: a substrate 210 (glass substrate) with a patterned first electrode 110 (ITO electrode) is used as a back plate, and the back plate is placed in the vacuum chamber of a vacuum evaporation apparatus, and the vacuum is evacuated to 1×10⁻⁶. - 5 Pa ~ 1×10 -6 After Pa, using the materials of hole injection layer 101, hole transport layer 102, electron blocking layer 103, light emitting layer 130, hole blocking layer 104, electron transport layer 105, electron injection layer 106, second electrode 120 and capping layer 250, hole injection layer 101, hole transport layer 102, electron blocking layer 103, light emitting layer 130, hole blocking layer 104, electron transport layer 105, electron injection layer 106, second electrode 120 and capping layer 250 are sequentially formed on the backplate.

[0284] In Examples 1 to 3, before use, the backplate is ultrasonically treated in a cleaning agent and rinsed in deionized water. Then, it is ultrasonically treated sequentially in acetone and isopropanol solvents to remove oil. Finally, it is baked in a clean environment until all moisture is removed, and then baked with an ultraviolet lamp to remove residual organic matter from the backplate surface. In Examples 1 to 3, the first light-emitting layer 131, the second light-emitting layer 132, and the light-emitting layer 130 all include a light-emitting layer for a first light-emitting device 100A, a light-emitting layer for a second light-emitting device 100D, and a light-emitting layer for a third light-emitting device 100C. The material of the light-emitting layer of the first light-emitting device 100A is deposited in the area corresponding to the first light-emitting device 100A; the material of the light-emitting layer of the second light-emitting device 100D is deposited in the area corresponding to the second light-emitting device 100D; and the material of the light-emitting layer of the third light-emitting device 100C is deposited in the area corresponding to the third light-emitting device 100C.

[0285] It should be noted that in the following Embodiments 1 and 2, the materials used for the hole injection layer 141, the first hole transport layer 142, the first electron blocking layer 143, the first hole blocking layer 171, the first charge generation layer 161, the second charge generation layer 162, the second hole transport layer 151, the second electron blocking layer 152, the second hole blocking layer 181, the second electron transport layer 182, the electron injection layer 183, the second electrode 120, and the capping layer 250 in the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C are all the same. In Example 3, the hole injection layer 101, hole transport layer 102, electron blocking layer 103, hole blocking layer 104, electron transport layer 105, and electron injection layer 106 are all made of the same materials as the hole injection layer 141, first hole transport layer 142, first electron blocking layer 143, second hole blocking layer 181, second electron transport layer 182, and electron injection layer 183 in Example 1. For example, the material of the hole injection layer 141 in Example 1 is the same as the material of the hole injection layer 141 in Example 2, and also the same as the material of the hole injection layer 141 in Example 3.

[0286] The hole injection layer 141 is made of a hole transport material with the structure shown in formula (NPB) and a hole injection material with the structure shown in formula (HATCN), with a mass ratio of 99:1. The materials of the first hole transport layer 142 and the second hole transport layer 151 have the structures shown in formula (NPB). The materials of the first electron blocking layer 143 and the second electron blocking layer 152 have the structures shown in formula (TCTA). The materials of the first hole blocking layer 171 and the second hole blocking layer 181 have the structures shown in formula (PPF). The material of the first charge generation layer 161 includes a first material with the structure shown in formula (BCP) and lithium (Li). The materials of the second charge generation layer 162 include a hole transport material with the structure shown in formula (NPB) and a hole injection material with the structure shown in formula (HATCN), and the mass ratio of the two is 99.5:0.5; the materials of the second charge generation layer 162 include an electron transport material with the structure shown in formula (TmPypB) and Liq (the two materials vaporize at the same rate when forming the second electron transport layer 182), and the mass ratio of the two is 1:1; the material of the electron injection layer 183 is ytterbium; the material of the second electrode 120 is a magnesium-silver alloy; the structure of the material of the capping layer 250 is shown in formula (CPL).

[0287]

[0288] In the following Examples 1, 2, and 3, the materials used for the light-emitting layers in the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C are different. Specifically, the light-emitting layer 130 of the first light-emitting device 100A (including the first light-emitting layer 131, the second light-emitting layer 132, and the light-emitting layer 130) comprises a host material with the structure shown in formula (mCP) and a guest material with the structure shown in formula (Flrpic), with a mass ratio of 99:1. The light-emitting layer 130 of the second light-emitting device 100D (including the first light-emitting layer 131, the second light-emitting layer 132, and the light-emitting layer 130) comprises a host material with the structure shown in formula (CBP) and a guest material with the structure shown in formula (Ir(ppy)3), with a mass ratio of 92:8. The light-emitting layer 130 of the third light-emitting device 100C (including the first light-emitting layer 131, the second light-emitting layer 132 and the light-emitting layer 130) includes a host material with the structure shown in the following formula (DCzDBT) and a guest material with the structure shown in the following formula (Ir(piq)2(acac)), and the mass ratio of the two is 98:2.

[0289]

[0290] In Examples 1 and 2 below, the thickness of the first light-emitting layer 131 is the same as the thickness of the second light-emitting layer 132 in each of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C. The film layer thicknesses in Examples 1 and 2 are shown in Tables 1 and 2, respectively. The film layer thicknesses in Example 3 are shown in Table 3.

[0291] Table 1

[0292]

[0293] Table 2

[0294]

[0295] Table 3

[0296]

[0297] It should be noted that the meanings of D16, D17, D10, D11, D12, D1, D2, D3, D21, D19, D20, D18, D13, D14, D15, D22, and D23 in Tables 1 and 2 can be found in the reference table. Figure 13 The meanings of a1, a2, a31, a32, a33, a41, a42, a43, a5, and a6 in Table 3 can be found in the reference table. Figure 14 Furthermore, the units for thickness shown in Tables 1 through 3 are all in nm.

[0298] Based on the above settings, the brightness L, color coordinates CIEx, color coordinates CIEy, chromaticity value u′, chromaticity value v′, and color deviation value E of the display panels of Embodiments 1, 2, and 3 were tested at different viewing angles. The test results for Embodiment 1 are shown in Table 4, the test results for Embodiment 2 are shown in Table 5, and the test results for Embodiment 3 are shown in Table 6. Furthermore, curves showing the color deviation value of the light-emitting device 100 as a function of viewing angle in Embodiments 1 and 2 were plotted, as shown below. Figure 15 As shown, the color shift value of the light-emitting device 100 in Example 3 as a function of viewing angle is plotted, as shown in the figure. Viewing angle (°) As shown. A CIE trajectory diagram of the light-emitting device 100 in Example 1 is plotted, as follows. CIE x As shown. A CIE trajectory diagram of the light-emitting device 100 in Example 2 is plotted, as follows. CIE y As shown. A CIE trajectory diagram of the light-emitting device 100 in Example 3 is plotted, as follows. CIE u' As shown.

[0299] It should be noted that the above tests were conducted when all three light-emitting devices included in the display panel 200—the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C—were lit. Furthermore, the same test data for the same display panel 200 was measured based on the same light-emitting area of ​​the light-emitting device 100. The test data includes any one of the following: luminance L, color coordinates CIEx, color coordinates CIEy, chromaticity value u′, chromaticity value v′, and color deviation value E.

[0300] Table 4

[0301] CIE v' [ L (cd / m 2 )]]> Viewing angle (°) CIE x CIE y CIE u' E -75 68.548 0.2894 0.3094 0.1887 0.4539 4.25 -60 117.21 0.2858 0.3043 0.1881 0.4504 5.1 -45 215.7 0.2836 0.2987 0.1886 0.4468 5.85 -30 378.78 0.2878 0.3004 0.191 0.4484 5.25 -15 491.41 0.2984 0.3063 0.1964 0.4535 3.725 0 518.53 0.303 0.3109 0.1979 0.4568 2.875 15 495.81 0.2991 0.3072 0.1965 0.4541 3.575 30 393.19 0.2892 0.3029 0.191 0.4501 4.85 45 229.5 0.2842 0.3038 0.187 0.4499 5.325 60 124.77 0.2858 0.3087 0.1864 0.453 4.775 75 70.898 0.2892 0.3133 0.1871 0.4562 4.05

[0302] Table 5

[0303]

[0304]

[0305] Table 6

[0306] CIE v' [ L (cd / m 2 )]]> Figure 7 Figure 9 ​ ​ E -75 54.96 0.2901 0.3279 0.1826 0.4644 3.78 -60 109.2 0.2905 0.3207 0.1854 0.4605 3.00 -45 197.7 0.2966 0.3165 0.1912 0.4591 1.65 -30 339.4 0.296 0.3121 0.1924 0.4565 1.75 -15 459.9 0.3019 0.314 0.1959 0.4584 0.85 0 495.6 0.3062 0.3182 0.1974 0.4614 0.00 15 467.2 0.3026 0.3156 0.1958 0.4595 0.63 30 354.6 0.2967 0.3162 0.1914 0.4589 1.63 45 210.3 0.2957 0.3235 0.188 0.4629 2.38 60 115.8 0.2961 0.3284 0.1865 0.4656 2.93 75 57.64 0.2997 0.3327 0.1875 0.4684 3.03

[0307] In Examples 1 to 3, please refer to Tables 4 to 6. The absolute value of the difference between the first color deviation value E@θ1 and the second color deviation value E@θ2 is less than or equal to 2. The difference between the first preset viewing angle θ1 and the second preset viewing angle θ2 is 15°, indicating that the color deviation problem has been improved. This is because in Examples 1 to 3, among the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C, the first functional unit 190A of the first light-emitting device 100A (i.e., the first hole transmission unit 140A, the second hole transmission unit 150A, or the hole transmission unit 107A, see...) is located in the first functional unit 190A (i.e., the first hole transmission unit 140A, the second hole transmission unit 150A, or the hole transmission unit 107A, see...) in the third functional unit 100A. ​ and ​ The thicknesses of the first functional unit 190D of the second light-emitting device 100D and the first functional unit 190C of the third light-emitting device 100C are different. This has two advantages: first, it allows the light emitted by the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C to be increased due to the microcavity effect; second, it allows the light-emitting layers 130A, 130A, and 130C of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C to be located in their respective micro-intensity enhancement regions, resulting in higher luminous efficiency for all three devices. This also ensures that the efficiency attenuation of the first light-emitting device 100A, the second light-emitting device 100D, and the third light-emitting device 100C is more consistent at large viewing angles, which can improve the color shift problem at large viewing angles.

[0308] Moreover, compared to Embodiment 3, the absolute values ​​of the difference between the first color deviation value E@θ1 and the second color deviation value E@θ2 in Embodiments 1 and 2 are smaller, and the color deviation problem can be greatly improved. This shows that by setting the thicknesses of the first functional unit 190A of the first light-emitting device 100A, the first functional unit 190D of the second light-emitting device 100D, and the first functional unit 190C of the third light-emitting device 100C to be different, the color deviation problem of the stacked light-emitting device 100 under a large viewing angle can be greatly improved.

[0309] Furthermore, in Embodiments 1 and 2, the brightness attenuation ratio of the light-emitting device 100 at a 30° viewing angle is less than or equal to 30%, and the brightness attenuation ratio of the light-emitting device 100 at a 45° viewing angle is less than or equal to 60%. This indicates that by setting the thicknesses of the first functional unit 190A of the first light-emitting device 100A, the first functional unit 190D of the second light-emitting device 100D, and the first functional unit 190C of the third light-emitting device 100C to be different, the brightness attenuation of the light-emitting device 100 can be reduced in the viewing angle range of 0° to 45° and the viewing angle range of 0° to 60°. In Examples 1 and 2, within a viewing angle range of 0 to 75°, the chromaticity coordinates CIEx of the light emitted by the light-emitting device 100 range from 0.280 to 0.305, and the chromaticity coordinates CIEy range from 0.290 to 0.320. This demonstrates that by setting the thicknesses of the first functional unit 190A of the first light-emitting device 100A, the first functional unit 190D of the second light-emitting device 100D, and the first functional unit 190C of the third light-emitting device 100C to be different, the color accuracy of the light-emitting device 100 within the 0° to 75° range can be improved.

[0310] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A light-emitting device, characterized in that, It includes a first light-emitting device, a second light-emitting device, and a third light-emitting device; the emission wavelengths of the first light-emitting device, the second light-emitting device, and the third light-emitting device are all different; each of the first light-emitting device, the second light-emitting device, and the third light-emitting device includes: The first electrode is capable of reflecting light when it is positioned opposite to the second electrode. At least one light-emitting layer is located between the first electrode and the second electrode; and, At least one first functional unit, wherein the first functional unit is disposed on the side of the light-emitting layer near the first electrode; The thicknesses of the first functional unit of the first light-emitting device, the first functional unit of the second light-emitting device, and the first functional unit of the third light-emitting device are all different. Based on the same light-emitting area of ​​the light-emitting device, the light-emitting device has a first color deviation value under a first preset viewing angle, and the light-emitting device has a second color deviation value under a second preset viewing angle. The absolute value of the difference between the first color deviation value and the second color deviation value is less than or equal to 2. The difference between the first preset viewing angle and the second preset viewing angle is less than or equal to 15°.

2. The light-emitting device according to claim 1, characterized in that, The thicknesses of the first functional units of the first light-emitting device, the first functional units of the second light-emitting device, and the first functional units of the third light-emitting device, which are located at corresponding positions, are all different.

3. The light-emitting device according to claim 1, characterized in that, Based on the same light-emitting area of ​​the light-emitting device, the absolute value of the difference between the color deviation value of the light-emitting device at a 15° viewing angle and the color deviation value of the light-emitting device at a 0° viewing angle is less than or equal to 1. And / or, Based on the same emitting area of ​​the light-emitting device, the absolute value of the difference between the color shift value of the light-emitting device at a 30° viewing angle and the color shift value of the light-emitting device at a 15° viewing angle is less than or equal to 2; and / or, Based on the same light-emitting area of ​​the light-emitting device, the absolute value of the difference between the color deviation value of the light-emitting device at a 45° viewing angle and the color deviation value of the light-emitting device at a 30° viewing angle is less than or equal to 1.

4. The light-emitting device according to claim 1, characterized in that, Based on the same light-emitting area of ​​the light-emitting device, the absolute value of the difference between the color deviation value of the light-emitting device at a 60° viewing angle and the color deviation value of the light-emitting device at a 45° viewing angle is less than or equal to 1. And / or, Based on the same light-emitting area of ​​the light-emitting device, the absolute value of the difference between the color deviation value of the light-emitting device at a 75° viewing angle and the color deviation value of the light-emitting device at a 60° viewing angle is less than or equal to 1.

5. The light-emitting device according to claim 1, characterized in that, The brightness attenuation ratio of the light-emitting device at a 30° viewing angle is less than or equal to 30%; and / or, The brightness attenuation ratio of the light-emitting device at a 45° viewing angle is less than or equal to 60%.

6. The light-emitting device according to claim 1, characterized in that, Within a viewing angle range of -75° to 75°, the chromaticity coordinates (CIEx) of the light emitted by the light-emitting device range from 0.280 to 0.305; and / or, Within a viewing angle range of -75° to 75°, the chromaticity coordinates (CIEy) of the light emitted by the light-emitting device range from 0.290 to 0.

320.

7. The light-emitting device according to claim 1, characterized in that, The ratio between the distance between the surface of the selected light-emitting layer furthest from the first electrode and the light-reflecting surface of the first electrode, and the selected wavelength, is greater than or equal to (2n+1) / 4a and less than or equal to (2n+3) / 4a, where n is a positive integer and a ranges from 1.7 to 1.

8. Wherein, the selected light-emitting layer is any one of at least one light-emitting layer of the first light-emitting device, at least one light-emitting layer of the second light-emitting device, and at least one light-emitting layer of the third light-emitting device; the selected wavelength is the emission wavelength of the selected light-emitting layer.

8. The light-emitting device according to claim 7, characterized in that, The light-reflecting surface of the first electrode is the surface of the first electrode closest to the selected light-emitting layer; or, The first electrode includes a second sub-layer and a first sub-layer stacked along a direction away from the selected light-emitting layer; the first sub-layer is capable of reflecting light; the second sub-layer is capable of transmitting light; the light-reflecting surface of the first electrode is the surface of the first sub-layer close to the second sub-layer.

9. The light-emitting device according to any one of claims 1 to 8, characterized in that, The thickness of the light-emitting layer of the first light-emitting device is less than the thickness of the light-emitting layer of the second light-emitting device; and / or, The thickness of the light-emitting layer of the first light-emitting device is less than the thickness of the light-emitting layer of the third light-emitting device.

10. The light-emitting device according to any one of claims 1 to 8, characterized in that, The thickness of the light-emitting layer of the first light-emitting device ranges from 18 nm to 22 nm; and / or, The thickness of the light-emitting layer of the second light-emitting device ranges from 30 nm to 50 nm; and / or, The thickness of the light-emitting layer of the third light-emitting device ranges from 30 nm to 50 nm.

11. The light-emitting device according to any one of claims 1 to 8, characterized in that, The at least one first functional unit includes a first hole transport unit and a second hole transport unit, wherein the first hole transport unit is closer to the first electrode than the second hole transport unit. Wherein, the thickness of the first hole transport unit of the second light-emitting device is greater than the thickness of the first hole transport unit of the first light-emitting device, and less than the thickness of the first hole transport unit of the third light-emitting device; and / or, The thickness of the second hole transmission unit of the second light-emitting device is greater than the thickness of the second hole transmission unit of the first light-emitting device, and less than the thickness of the second hole transmission unit of the third light-emitting device.

12. The light-emitting device according to claim 11, characterized in that, The first hole transport unit includes a hole injection layer, a first hole transport layer, and a first electron blocking layer; The second hole transport unit includes a second hole transport layer and a second electron blocking layer; The hole injection layer of the first light-emitting device, the hole injection layer of the second light-emitting device, and the hole injection layer of the third light-emitting device all have the same thickness. The thicknesses of the first hole transport layer of the first light-emitting device, the first hole transport layer of the second light-emitting device, and the first hole transport layer of the third light-emitting device are all equal. The second hole transport layer of the first light-emitting device, the second hole transport layer of the second light-emitting device, and the second hole transport layer of the third light-emitting device all have the same thickness; The thickness of the first electron blocking layer of the second light-emitting device is greater than the thickness of the first electron blocking layer of the first light-emitting device, and less than the thickness of the first electron blocking layer of the third light-emitting device; and / or, The thickness of the second electron blocking layer of the second light-emitting device is greater than the thickness of the second electron blocking layer of the first light-emitting device, and less than the thickness of the second electron blocking layer of the third light-emitting device.

13. The light-emitting device according to claim 12, characterized in that, The thickness of the first electron blocking layer of the first light-emitting device ranges from 5 nm to 10 nm; The thickness of the first electron blocking layer of the second light-emitting device ranges from 40 nm to 45 nm; The thickness of the first electron blocking layer of the third light-emitting device ranges from 80 nm to 95 nm.

14. The light-emitting device according to claim 12, characterized in that, The thickness of the second electron blocking layer of the first light-emitting device ranges from 5 nm to 10 nm; The thickness of the second electron blocking layer of the second light-emitting device ranges from 15 nm to 20 nm; The thickness of the second electron blocking layer of the third light-emitting device ranges from 25 nm to 35 nm.

15. The light-emitting device according to claim 12, characterized in that, The thickness of the hole injection layer of the first light-emitting device ranges from 5 nm to 15 nm; The thickness of the first hole transport layer of the first light-emitting device ranges from 95 nm to 105 nm; The thickness of the second hole transport layer of the first light-emitting device ranges from 50 nm to 60 nm.

16. The light-emitting device according to claim 12, characterized in that, The at least one light-emitting layer includes two light-emitting layers, which are a first light-emitting layer and a second light-emitting layer, wherein the first light-emitting layer is closer to the first electrode than the second light-emitting layer. Each of the first light-emitting device, the second light-emitting device, and the third light-emitting device further includes: A first charge generation layer and a second charge generation layer are located between the first light-emitting layer and the second hole transport unit; the first charge generation layer is closer to the first light-emitting layer than the second charge generation layer. The thickness of the first charge generation layer of the first light-emitting device, the first charge generation layer of the second light-emitting device, and the first charge generation layer of the third light-emitting device are all fourth thicknesses, and the fourth thickness ranges from 80nm to 100nm. The thickness of the second charge generation layer of the first light-emitting device, the second charge generation layer of the second light-emitting device, and the second charge generation layer of the third light-emitting device are all fifth thicknesses, and the fifth thickness ranges from 160nm to 200nm.

17. The light-emitting device according to claim 16, characterized in that, Each of the first light-emitting device, the second light-emitting device, and the third light-emitting device further includes: A first hole-blocking layer is located between the first light-emitting layer and the first charge-generating layer; and The second electron transport unit is located between the second light-emitting layer and the second electrode; the second electron transport unit includes a second hole blocking layer and a second electron transport layer stacked in a direction away from the second light-emitting layer. Wherein, the thickness of the first hole blocking layer of the first light-emitting device, the first hole blocking layer of the second light-emitting device, and the first hole blocking layer of the third light-emitting device are all sixth thicknesses, and the sixth thickness ranges from 5nm to 10nm; The second hole blocking layer of the first light-emitting device, the second hole blocking layer of the second light-emitting device, and the second hole blocking layer of the third light-emitting device all have a seventh thickness, which ranges from 5 nm to 10 nm. The thickness of the second electron transport layer of the first light-emitting device, the second electron transport layer of the second light-emitting device, and the second electron transport layer of the third light-emitting device are all eighth thicknesses, and the eighth thickness ranges from 30nm to 40nm.

18. The light-emitting device according to claim 11, characterized in that, The peak wavelength of the emission spectrum of the material of the light-emitting layer of the first light-emitting device is greater than or equal to 400 nm and less than or equal to 500 nm. The peak wavelength of the emission spectrum of the material of the light-emitting layer of the second light-emitting device is greater than or equal to 510 nm and less than or equal to 540 nm; The peak wavelength of the emission spectrum of the material of the light-emitting layer of the third light-emitting device is greater than or equal to 600 nm.

19. A display panel, characterized in that, include: The light-emitting device as described in any one of claims 1 to 18; The light-emitting device is disposed on the substrate.

20. A display device, characterized in that, include: The display panel as described in claim 19; A driver chip, which is used to drive the display panel to display.

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