Light-emitting device and display device

Abstract

The invention provides a light-emitting device and a display device, the light-emitting device comprises at least two light-emitting diodes emitting light of different colors, each light-emitting diode is provided with an optical microcavity, and each light-emitting diode comprises an anode layer, a light-emitting layer and a cathode layer which are stacked in sequence; wherein the optical path order of the optical microcavity corresponding to at least one light emitting diode is 1; and / or, an optical path adjusting layer is arranged in the optical microcavity corresponding to at least one light emitting diode, and the optical path adjusting layer is located in the film layer stacking structure of at least one of the anode layer and the cathode layer. The light-emitting device and the display device provided by the invention can meet higher requirements on the light-emitting device.

Description

Technical Field

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

[0002] Organic light emitting diode (OLED) display devices are widely used in various consumer electronic products such as mobile phones, televisions, personal digital assistants, digital cameras, laptops, desktop computers, etc., and have become the mainstream of display devices due to their advantages of being all solid, ultra-thin, no viewing angle limitation, fast response, room temperature operation, and easy to achieve flexible display and 3D display. With the continuous development of OLED technology, higher requirements are put forward for display device technology, such as how to reduce preparation cost, reduce film thickness, reduce power consumption, and improve device quality. Summary of the invention

[0003] The embodiments of the present disclosure provide a light-emitting device and a display apparatus, which can meet higher requirements for light-emitting devices.

[0004] The technical solutions provided by the embodiments of the present disclosure are as follows:

[0005] In a first aspect, an embodiment of the present disclosure provides a light-emitting device, comprising at least two light-emitting diodes emitting light of different colors, each of the light-emitting diodes having an optical microcavity, and each of the light-emitting diodes comprising an anode layer, a light-emitting layer, and a cathode layer stacked in sequence; wherein,

[0006] The optical path order of the optical microcavity corresponding to at least one of the light-emitting diodes is 1; and / or,

[0007] An optical path adjustment layer is provided in the optical microcavity corresponding to at least one of the light emitting diodes, and the optical path adjustment layer is located in the film layer stacking structure of at least one of the anode layer and the cathode layer.

[0008] Exemplarily, at least two of the light-emitting diodes include a first light-emitting diode and a second light-emitting diode, the light-emitting wavelength of the first light-emitting diode is λ1, the light-emitting wavelength of the second light-emitting diode is λ2, the optical path order of the first light-emitting diode is n1, and the optical path order of the second light-emitting diode is n2; wherein, λ1>λ2, n1=1, n2≥1.

[0009] Exemplarily, at least two of the light emitting diodes further include a third light emitting diode, the light emission wavelength of the third light emitting diode is λ3, and the optical path order of the third light emitting diode is n3; wherein λ1>λ3, n3≥2.

[0010] Exemplarily, the thickness of the light-emitting layer corresponding to the first light-emitting diode is H1, the thickness of the light-emitting layer corresponding to the second light-emitting diode is H2, and the thickness of the light-emitting layer corresponding to the third light-emitting diode is H3, wherein H2>H1, and H2>H3.

[0011] Exemplarily, λ2>λ3, and n2=n3≥2 or, n2=1 and n3≥2.

[0012] Exemplarily, each of the light emitting diodes at least includes:

[0013] A hole transport unit layer, located between the light-emitting layer and the anode layer;

[0014] An electron transport unit layer, located between the light-emitting layer and the cathode layer;

[0015] Wherein, in at least one of the light-emitting diodes, at least one buffer layer is arranged between the light-emitting layer and the hole transport unit layer.

[0016] Exemplarily, each of the light-emitting diodes includes only one corresponding light-emitting layer; wherein,

[0017] One buffer layer is disposed between the corresponding light-emitting layer and the hole transport unit layer in each light-emitting diode; or two buffer layers are disposed between the corresponding light-emitting layer and the hole transport unit layer in at least one light-emitting diode.

[0018] Exemplarily, only one buffer layer is provided between the light-emitting layer and the hole transport unit layer corresponding to the first light-emitting diode and the third light-emitting diode, respectively; two buffer layers are provided between the light-emitting layer and the hole transport unit layer corresponding to the second light-emitting diode, and the two buffer layers are a first buffer layer and a second buffer layer, respectively, the second buffer layer is located on a side of the first buffer layer close to the light-emitting layer, and the HOMO energy level of the second buffer layer is higher than the HOMO energy level of the first buffer layer, and the LUMO energy level of the second buffer layer is higher than the LUMO energy level of the first buffer layer.

[0019] Exemplarily, the light-emitting layer in each of the light-emitting diodes includes: a first light-emitting layer; and a second light-emitting layer located on a side of the first light-emitting layer close to the anode layer; wherein each of the light-emitting diodes includes:

[0020] A first hole transport unit layer, located between the second light-emitting layer and the anode layer;

[0021] A first electron transport unit layer, located between the first light-emitting layer and the cathode layer; and

[0022] The charge generation unit layer is located between the first light-emitting layer and the second light-emitting layer, and the first light-emitting layer and the second light-emitting layer are connected through the charge generation unit layer.

[0023] Exemplarily, at least one buffer layer is disposed between the first light-emitting layer and the charge generation unit layer, and at least one buffer layer is disposed between the second light-emitting layer and the first hole transport unit layer.

[0024] Exemplarily, each of the light-emitting diodes further includes a second hole transport unit layer and a second electron transport unit layer, wherein the second hole transport unit layer is located between the charge generation unit layer and the first light-emitting layer, and the second electron transport unit layer is located between the charge generation unit layer and the second light-emitting layer.

[0025] Exemplarily, each of the light-emitting diodes includes a first anode layer, a first hole transport unit layer, a first light-emitting layer, a first electron transport unit layer, a first cathode layer, a covering layer, a second cathode layer, a second electron transport unit layer, a second light-emitting layer, a second hole transport unit layer and a second anode layer stacked in sequence; wherein the first anode layer, the first hole transport unit layer, the first light-emitting layer, the first electron transport unit layer and the first cathode layer form a first light-emitting element, the second anode layer, the second hole transport unit layer, the second light-emitting layer, the second electron transport unit layer and the second cathode layer form a second light-emitting element, the first anode layer is coupled to the first drive signal input terminal, the second anode layer is coupled to the second drive signal input terminal, and the first cathode layer is coupled to the second cathode layer, so that the first light-emitting element and the second light-emitting element are arranged in parallel.

[0026] Exemplarily, in at least one of the light-emitting diodes, at least one buffer layer is further provided between the first light-emitting layer and the first hole transport unit layer; and at least one buffer layer is further provided between the second light-emitting layer and the second hole transport unit layer. 14. The light-emitting device according to claim 2, characterized in that the anode layer is a reflective electrode layer, and the cathode layer is a semi-transmissive and semi-reflective electrode layer; the light-emitting diode further comprises a covering layer, and the covering layer is located on the side of the cathode layer away from the anode layer; wherein the film thickness of the light-emitting layer corresponding to the first light-emitting diode is H1, and the film thickness of the light-emitting layer corresponding to the second light-emitting diode is H2, and H2>H1, the film thickness of the covering layer corresponding to the first light-emitting diode is h1, and the film thickness of the covering layer corresponding to the second light-emitting diode is h2, and h1>h2.

[0027] Exemplarily, the anode layer is a reflective electrode layer, and the cathode layer is a semi-transparent and semi-reflective electrode layer; wherein, in at least one of the light-emitting diodes, the anode layer includes at least one transparent conductive layer and at least one reflective conductive layer stacked together, wherein the optical path adjustment layer is arranged in the anode layer and is located between at least one transparent conductive layer and at least one reflective conductive layer.

[0028] Exemplarily, in at least one of the light-emitting diodes, the anode layer includes a first transparent conductive layer, a reflective conductive layer, and a second light-transmitting conductive layer stacked in sequence along a direction from the cathode layer to the anode layer, and at least one layer of the optical path adjustment layer is provided between the first transparent conductive layer and the reflective conductive layer.

[0029] Exemplarily, the optical path adjustment layer is a semi-transmissive and semi-reflective film layer, and the film thickness of the optical path adjustment layer is 10 to 300 nm.

[0030] Exemplarily, the optical path adjustment layer is a single film layer structure formed by at least one material selected from the group consisting of metals, metal oxides, or metal alloys; or, the optical path adjustment layer includes at least two film layer structures formed by stacking film layers formed by one or more materials selected from the group consisting of metals, metal oxides, and metal alloys in sequence.

[0031] Exemplarily, at least two of the light-emitting diodes include a first light-emitting diode, a second light-emitting diode and a third light-emitting diode, the first light-emitting diode is a red light-emitting diode, the second light-emitting diode is a green light-emitting diode, the third light-emitting diode is a blue light-emitting diode, and the film thickness of the first light-emitting diode is The film thickness of the second light emitting diode is The film thickness of the third light emitting diode is

[0032] In a second aspect, an embodiment of the present disclosure further provides a display device, which includes the light-emitting device as described above.

[0033] The beneficial effects brought by the embodiments of the present disclosure are as follows:

[0034] The light-emitting device and display device provided by the embodiments of the present disclosure include at least two light-emitting diodes, each of which has a corresponding optical microcavity. In the optical microcavity, when the wavelength of the optical microcavity and the light wave are at the same order of magnitude, light of a specific complementary wavelength will be selected and enhanced to achieve spectrum narrowing, that is, to produce a microcavity effect. The microcavity optical path of the light-emitting diode is n times the corresponding light emission wavelength, that is, an n-order microcavity effect can be achieved in a light-emitting diode with a microcavity structure.

[0035] In the above scheme, by configuring the optical path order of the optical microcavity corresponding to at least one light-emitting diode to 1, that is, the optical microcavity of at least one of the light-emitting diodes uses the first optical path mode (fundamental mode), a first-order microcavity effect is achieved. In this way, compared with the scheme of using a higher-order optical path mode to achieve spectrum narrowing in the related art, the thickness of the organic film layer in at least one light-emitting diode can be reduced while achieving spectrum narrowing, for example, the film thickness of the light-emitting layer is reduced, and then the overall thickness of the organic film layer in the light-emitting device is reduced, thereby effectively reducing material costs and device power consumption, reducing lateral leakage, and improving product quality; and / or, by providing an optical path adjustment layer in the optical microcavity of at least one light-emitting diode, and the optical path adjustment layer can be located in the electrode layer of the light-emitting diode, in this way, it is helpful to reduce the thickness of other film layers in the corresponding light-emitting diode, for example, reducing the film thickness of the light-emitting layer, and then reducing the overall thickness of the organic film layer in the light-emitting device, thereby effectively reducing material costs and device power consumption, reducing lateral leakage, and improving product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram showing the structure of a light-emitting device provided by some embodiments of the present disclosure;

[0037] Figure 2 A schematic diagram showing the structure of a light emitting device provided in some other embodiments of the present disclosure;

[0038] Figure 3 A schematic diagram showing the structure of a light emitting device provided in some other embodiments of the present disclosure;

[0039] Figure 4 A schematic diagram showing the structure of a light emitting device provided in some other embodiments of the present disclosure;

[0040] Figure 5 A schematic diagram showing the structure of a light emitting device provided in some other embodiments of the present disclosure;

[0041] Figure 6 A schematic diagram showing the structure of a light emitting device provided in some other embodiments of the present disclosure;

[0042] Figure 7 A schematic diagram showing the structure of a light emitting device provided in some other embodiments of the present disclosure;

[0043] Figure 8 Indicates the T95 life test results of the light emitting device in the test example;

[0044] Fig. 9 It represents the T95 life test result of the light emitting device in the control example;

[0045] Fig.10 Indicates the L-decay test result of the light emitting device in the test example;

[0046] Fig.11 represents the L-decay test result of the light emitting device in the control example;

[0047] Fig.12 A schematic diagram showing the structure of a light emitting device provided in some other embodiments of the present disclosure;

[0048] Fig.13 A schematic diagram showing the structure of a light emitting device provided in some other embodiments of the present disclosure;

[0049] Fig.14 A schematic diagram showing the structure of a light-emitting device provided in some other embodiments of the present disclosure. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0051] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0052] The features such as "parallel", "perpendicular", and "same" used in the embodiments of the present disclosure include the features such as "parallel", "perpendicular", and "same" in a strict sense, as well as the cases where "approximately parallel", "approximately perpendicular", "approximately the same", etc. include certain tolerances, taking into account the tolerances associated with the measurement of specific quantities (e.g., the limitations of the measurement system), and represent the acceptable deviation range for a specific value determined by ordinary technicians in the field. For example, "approximately" can mean within one or more standard deviations, or within 3% or 5% of the value.

[0053] In addition, in this document, unless otherwise defined, the terms "substantially", "substantially", "approximately" and "about" are used to describe and explain small changes. When used with an event or situation, these terms can cover situations where the event or situation occurs exactly, and can also cover situations where the event or situation occurs approximately. For example, when used with a numerical value, these terms can include a range of variation of less than or equal to 10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, less than or equal to ±0.05%. The term "substantially coplanar" can refer to two surfaces being arranged along the same plane in the micrometer range, for example, arranged along the same plane within 40μm, 30μm, 20μm, 10μm or 1μm.

[0054] It should be understood that in the exemplary embodiments of the present disclosure, when a layer or an element is referred to as being on another layer or substrate, the layer or element may be directly on the other layer or substrate, or there may be an intermediate layer between the layer or element and the other layer or substrate. "A and B are arranged on the same layer" means that after A and B adopt the same film forming process to form a film layer for forming a specific pattern, a layer structure is formed by a single patterning process using the same mask.

[0055] The embodiment of the present disclosure provides a light-emitting device, including at least two light-emitting diodes that emit light of different colors. Each of the light-emitting diodes can be: a monochromatic organic light-emitting diode; or a white light organic light-emitting diode provided with a filter, and the type of the filter can be selected according to the wavelength of the required emitted light, such as a red filter, a green filter, or a blue filter, that is, at least two light-emitting diodes in the light-emitting device can mix at least two different colors of light together to achieve full-color display.

[0056] like Figure 1As shown, each of the light-emitting diodes comprises an anode layer 100, a light-emitting layer 200 and a cathode layer 300 stacked in sequence. Each of the light-emitting diodes has an optical microcavity. In the optical microcavity, when the wavelength of the optical microcavity and the wavelength of the light wave are at the same order of magnitude, light of a specific complementary wavelength will be selected and enhanced to achieve spectrum narrowing, that is, to produce a microcavity effect.

[0057] The microcavity optical path of the light-emitting diode is n times the corresponding light emission wavelength, that is, the optical path order of the optical microcavity corresponding to at least one light-emitting diode is configured to n, that is, the optical microcavity of at least one of the light-emitting diodes uses the nth optical path mode, and the nth order microcavity effect can be realized in the light-emitting diode with a microcavity structure.

[0058] The light emitting device includes m light emitting diodes, and the microcavity optical path L of the light emitting diode and the corresponding light emitting wavelength λ of the light emitting diode satisfy the following relationship: i =n i λ i , where n i is a positive integer, and m≥i≥1, i and m are positive integers.

[0059] For example, the microcavity optical path L may refer to the distance traveled by the light emitted from the light emitting layer 200 during the process of being reflected by the anode layer 100 and then reflected by the cathode layer 300 and returning to the starting position, as well as the equivalent distance caused by the reflection phase shift of the anode layer 100 and the cathode layer 300.

[0060] In some embodiments, the optical path order of the optical microcavity corresponding to at least one of the light-emitting diodes is 1.

[0061] In this way, by configuring the optical path order of the optical microcavity corresponding to at least one light-emitting diode to 1, that is, using the first optical path mode (fundamental mode) of the optical microcavity of at least one light-emitting diode to achieve a first-order microcavity effect, compared with the solution of using the second-order or higher-order optical path mode in the related art to achieve spectrum narrowing, the use of the first optical path mode can achieve spectrum narrowing while reducing the thickness of some functional film layers in at least one light-emitting diode. For light-emitting diodes, the light-emitting layer 200 is made of organic light-emitting materials. When the film thickness of the light-emitting layer 200 is thick, the following problems will occur: high material cost, high device power consumption, and easy to cause lateral leakage. Therefore, by using the first optical path mode of the optical microcavity of at least one light-emitting diode, the optical path thickness of the light-emitting layer 200 corresponding to the light-emitting diode can be reduced accordingly, thereby effectively reducing the material cost and device power consumption, and the thinning of the light-emitting layer 200 can also reduce the risk of lateral leakage and improve product quality.

[0062] In other embodiments, Figure 2As shown, an optical path adjustment layer 400 is provided in the optical microcavity corresponding to at least one of the light-emitting diodes, and the optical path adjustment layer 400 is located in the film layer stacking structure of at least one of the anode layer 100 and the cathode layer 300. That is, the optical path adjustment layer 400 is provided in the optical microcavity of at least one light-emitting diode, and the optical path adjustment layer 400 can be located in the electrode layer of the light-emitting diode.

[0063] In the above scheme, since the optical path adjustment layer 400 is set in at least one electrode layer of the light-emitting diode, the optical path adjustment layer 400 can increase the film thickness of the corresponding electrode layer, which helps to reduce the thickness of other film layers in the corresponding light-emitting diode. For the light-emitting diode, the light-emitting layer 200 uses an organic film layer. When the film thickness of the light-emitting layer 200 is thick, the following problems will occur: high material cost, high device power consumption, and easy lateral leakage. Therefore, the total optical path of the optical microcavity is composed of organic materials and inorganic materials in the light-emitting diode. By setting the optical path adjustment layer 400, the proportion of the electrode layer in the entire microcavity optical path is relatively increased, that is, the proportion of the optical path of the inorganic material is increased, so that the optical path of the organic material can be reduced accordingly, for example, the film thickness of the light-emitting layer 200 in the light-emitting diode is reduced, and then the overall thickness of the organic film layer in the light-emitting device is reduced, effectively reducing the cost of organic light-emitting materials and device power consumption, and the film thickness of the light-emitting layer 200 is reduced, which can also reduce the risk of lateral leakage, thereby improving product quality.

[0064] In other embodiments, Figure 3 As shown, the optical path order of the optical microcavity corresponding to at least one of the light-emitting diodes is 1, and at the same time, an optical path adjustment layer 400 is arranged in the optical microcavity corresponding to at least one of the light-emitting diodes, and the optical path adjustment layer 400 is located in the film layer stacking structure of at least one of the anode layer 100 and the cathode layer 300. The optical path adjustment layer 400 is arranged in the optical microcavity of at least one light-emitting diode, and the optical path adjustment layer 400 can be located in the electrode layer of the light-emitting diode.

[0065] In the above solution, the film thickness of the light-emitting layer 200 in the light-emitting diode is reduced by configuring the optical path order of at least one light-emitting diode to be 1 and setting an optical path adjustment layer 400 in the optical microcavity corresponding to at least one light-emitting diode.

[0066] For m light-emitting diodes, n iIn other words, the optical path modes of different light-emitting diodes may be different or the same, that is, the order of microcavity effect in different light-emitting diodes may be the same or different. Specifically, the order of microcavity effect corresponding to different light-emitting diodes may be set according to different properties of the emitted light (such as wavelength, spectrum, etc.), thereby achieving better spectrum narrowing effect and color gamut area while reducing the film thickness of the organic film layer in the corresponding light-emitting diode.

[0067] For example, in some embodiments, the optical path order of the optical microcavity in the light-emitting diode can be configured as the first optical path mode. In other embodiments, the optical path order of the optical microcavity in the light-emitting diode of a part of the color light can be configured as the first optical path mode, and the optical path order of the optical microcavity in the light-emitting diode of another part of the color light can be configured as a second optical path mode or a third optical path mode or other higher-order optical path mode, that is, the light-emitting diode of another part of the color light can realize a 2nd order microcavity, a 3rd order microcavity or a higher order microcavity.

[0068] In the relevant technology, taking the red, green and blue full-color display light-emitting device as an example, the red light wavelength range is 600nm~760nm, the green light wavelength range is 492nm~577nm, and the blue light wavelength range is 435~480nm. The wavelength of red light is greater than that of blue and green light. The red, green and blue primary color light-emitting diodes all use 2nd-order microcavities, 3rd-order microcavities or higher-order microcavities to achieve enhanced luminescence. The total optical path of the optical microcavity in the red light-emitting diode is relatively large. Taking the 2nd-order microcavity as an example, the film thickness of the red light-emitting layer is relatively thick, generally in The thickness of the light-emitting layer of the green-blue light-emitting diode is lower than that of the red light-emitting layer. The thicker the red light-emitting layer is, the more prone to lateral leakage, which causes the light-emitting device to emit a reddish color.

[0069] In order to improve the above problems, Figure 1 As shown, exemplarily, at least two of the light-emitting diodes include a first light-emitting diode T1 and a second light-emitting diode T2, the light-emitting wavelength of the first light-emitting diode T1 is λ1, the light-emitting wavelength of the second light-emitting diode T2 is λ2, the optical path order of the first light-emitting diode T1 is n1, and the optical path order of the second light-emitting diode T2 is n2; wherein, λ1>λ2, n1=1, n2≥1.

[0070] In the above scheme, the light emission wavelength λ1 of the first light emitting diode T1 is greater than the light emission wavelength λ2 of the second light emitting diode T2. By configuring the first light emitting diode T1 as a first-order microcavity, the film thickness of the light emitting layer 200 in the first light emitting diode T1 can be reduced, and the film thickness of the light emitting layer 200 corresponding to the first light emitting diode T1 can be reduced, so as to reduce the lateral leakage phenomenon of the first light emitting diode T1 and improve the color cast phenomenon.

[0071] For example, λ1 is the wavelength of red light, and the wavelength range is 600nm to 760nm, that is, the first light emitting diode T1 is a red light emitting diode; λ2 is the wavelength of green light, and the wavelength range is 492nm to 577nm, that is, the second light emitting diode T2 is a green light emitting diode.

[0072] It should be noted that the second light emitting diode T2 may have the same microcavity order as that of the first light emitting diode T1, or may have a different microcavity order.

[0073] In other exemplary embodiments, at least two of the light-emitting diodes further include a third light-emitting diode T3, the light emission wavelength of the third light-emitting diode T3 is λ3, and the optical path order of the third light-emitting diode T3 is n3; wherein λ1>λ3, n3≥2. For example, λ3 is a blue light wavelength, and the wavelength range is 435~480nm. Since the color coordinates of the blue light-emitting diode itself are closer to the blue light color coordinates of the high color gamut standard, generally speaking, the film thickness of the light-emitting layer 200 in the blue light-emitting diode is already thin, and therefore, the order of the optical microcavity in the blue light-emitting diode can be 2 or a higher order greater than 2. However, this is not limited to this.

[0074] In some exemplary embodiments, λ1>λ2>λ3, and n1=1, n2=n3=2. That is, the optical path order of the optical microcavity of the first light emitting diode T1 is 1, and the optical path order of the optical microcavity of the second light emitting diode T2 and the third light emitting diode T3 is 2.

[0075] In some other exemplary embodiments, λ1>λ2>λ3, and n1=n2=1, n3=2. That is, the optical path order of the optical microcavity of the first light emitting diode T1 and the second light emitting diode T2 is 1, and the optical path order of the optical microcavity of the third light emitting diode T3 is 2.

[0076] However, the above is only an example. In other embodiments, n1=n2=n3=1, that is, the optical path order of all light emitting diodes is 1; or n1=1, n2=n3 or n2≠n3, and n2, n3 are 2, 3, etc.

[0077] In some embodiments, when n1=1, the thickness of the light-emitting layer 200 corresponding to the first light-emitting diode T1 is H1. For example, still taking the first light-emitting diode T1 as a red light-emitting diode as an example, when n1=1, H1 is Compared with the red light emitting layer in the related art For the scheme, the thickness of the light-emitting layer 200 is reduced The risk of lateral leakage of the red light emitting layer is improved, the consumption of organic materials is reduced, and the cost is reduced.

[0078] In some embodiments, the comparison results of the two cases where the optical path order of the red light emitting diode and the green light emitting diode is 1 and 2 are shown in the following Table 1.

[0079] Table 1

[0080]

[0081] From the results in Table 1, it can be seen that when the optical path order of the optical microcavity of the red and green light emitting diodes is 1, compared with the case where the optical path order of the optical microcavity of the red and green light emitting diodes is 2, the film thickness of the light emitting layer 200 is reduced, and the voltage is reduced by 15-20%, thereby reducing the power consumption of the device, and the luminous efficiency of the red light emitting diode can reach 62.7Cd / A, and the efficiency of the green light emitting diode can reach 169Cd / A.

[0082] Therefore, in some embodiments, the optical path order of the optical microcavity of the red light emitting diode can be configured as 1. In addition, the optical path order of the optical microcavity of the green light emitting diode can also be configured as 1 or 2.

[0083] It should be noted that, in some embodiments, according to actual needs, only the optical path order of the optical microcavity of the green light emitting diode may be configured to be 1.

[0084] like Figure 1 As shown, in some exemplary embodiments, when n1=1, the film thickness of the light-emitting layer 200 corresponding to the first light-emitting diode T1 is H1, the film thickness of the light-emitting layer 200 corresponding to the second light-emitting diode T2 is H2, and the film thickness of the light-emitting layer 200 corresponding to the third light-emitting diode T3 is H3, wherein H2>H1, and H2>H3.

[0085] For light-emitting diodes of different colors, the optical path order of each optical microcavity is specifically adjusted so that the thickness of the light-emitting layer 200 of the second light-emitting diode T2 is greater than the thickness of the light-emitting layer 200 of the first light-emitting diode T1 and the thickness of the light-emitting layer 200 of the third light-emitting diode T3. By adjusting the order of the microcavity, the thickness of the corresponding light-emitting layer 200 in each light-emitting diode is adjusted, the consumption of the organic light-emitting material of the light-emitting layer 200 is reduced, the cost is reduced, and the lateral leakage is reduced.

[0086] Taking the first LED T1 corresponding to a red LED, the second LED T2 corresponding to a green LED, and the third LED T3 corresponding to a blue LED as an example, the thickness of the light-emitting layer 200 of the green LED is greater than the thickness of the light-emitting layer 200 of the red LED and the thickness of the light-emitting layer 200 of the blue LED, and the thickness of the light-emitting layer 200 of the red LED is thinner than that in the prior art.

[0087] For example, Figure 5 As shown, the anode layer 100 is a reflective electrode layer, and the cathode layer 300 is a semi-transmissive and semi-reflective electrode layer; the light-emitting diode further includes a cover layer (CPL) 500, and the cover layer 500 is located on the side of the cathode layer 300 away from the anode layer 100, that is, the cover layer 500 is stacked on the light-emitting side of the light-emitting diode. The film thickness of the light-emitting layer 200 corresponding to the first light-emitting diode T1 is H1, and the film thickness of the light-emitting layer 200 corresponding to the second light-emitting diode T2 is H2, and H2>H1, the film thickness of the cover layer 500 corresponding to the first light-emitting diode T1 is h1, and the film thickness of the cover layer 500 corresponding to the second light-emitting diode T2 is h2, and h1>h2.

[0088] In the above scheme, a covering layer 500 is provided on the light-emitting side of the light-emitting diode, and the thickness of the covering layer 500 is positively correlated with the light-emitting efficiency of the corresponding light-emitting diode. Since the light-emitting layer 200 of the first light-emitting diode T1 is the thinnest relative to the second light-emitting diode T2 and the third light-emitting diode T3, the thickness of the covering layer 500 corresponding to the light-emitting diodes of different colors of light can be differentiated and the thickness of the covering layer 500 corresponding to the first light-emitting diode T1 can be increased to further improve the light-emitting efficiency of the first light-emitting diode T1.

[0089] Please refer to Figure 5, the thickness of the cover layer 500 corresponding to the third light emitting diode T3 is h3, wherein h2=h3, or h2≠h3. For example, please refer to Figure 5 As shown, the cover layer 500 may be an integral film layer provided for all light emitting diodes, wherein only the region corresponding to the first light emitting diode T1 is thickened. Specifically, the cover layer 500 is close to the surface of one side of the light emitting layer 200, and the region corresponding to the first light emitting diode T1 is protruded relative to other regions and toward the direction where the light emitting layer 200 is located, so as to thicken the region corresponding to the first light emitting diode T1.

[0090] It should be noted that, taking the third light emitting diode T3 as a blue light emitting diode as an example, its luminous efficiency is relatively low, therefore, the optical path order of the optical microcavity of the third light emitting diode T3 may be greater than or equal to 2.

[0091] It should also be noted that if Figure 1 In the illustrated embodiment, the anode layer 100 is stacked on a side of the cathode layer 300 close to the base substrate 10, the anode layer 100 is a reflective electrode layer, and the cathode layer 300 is a semi-transparent and semi-reflective electrode layer. The light emitted by the light-emitting layer 200 can be reflected by the anode layer 100 and then transmitted from the cathode layer 300. The reflective properties of the anode layer 100 and the semi-reflective and semi-transparent properties of the cathode layer 300 can be used to form an optical microcavity between the anode layer 100 and the cathode layer 300.

[0092] Exemplarily, the light emitting device is a top-emitting light emitting device. The anode layer 100 is an anode, and the cathode layer 300 is a cathode. However, the above is only an example, but is not limited thereto.

[0093] In other embodiments, the light emitting device may also be a bottom emitting light emitting device, that is, the anode layer 100 is stacked on the side of the cathode layer 300 close to the base substrate 10, the anode layer 100 is a semi-transmissive and semi-reflective electrode layer, and the cathode layer 300 is a reflective electrode layer.

[0094] In some other embodiments of the present disclosure, the film thickness of the light-emitting layer 200 is reduced by providing an optical path adjustment layer 400 in the optical microcavity of the light-emitting diode.

[0095] In some exemplary embodiments of the present disclosure, the anode layer 100 is a reflective electrode layer, and the cathode layer 300 is a semi-transparent and semi-reflective electrode layer; wherein, in at least one of the light-emitting diodes, the anode layer 100 includes at least one transparent conductive layer and at least one reflective conductive layer stacked, wherein the optical path adjustment layer 400 is arranged in the anode layer 100 and is located between the at least one transparent conductive layer and the at least one reflective conductive layer.

[0096] In this way, by setting the optical path adjustment layer 400 in the anode layer 100 in the corresponding light-emitting diode, the thickness of the anode layer 100 in the corresponding light-emitting diode is increased, that is, the microcavity optical path of the anode layer 100 is increased, and the film thickness of the light-emitting layer 200 in the corresponding light-emitting diode can be reduced.

[0097] As an exemplary embodiment, Figure 2 As shown, the anode layer 100 includes a first transparent conductive layer 110, a reflective conductive layer 120 and a second light-transmitting conductive layer 130 stacked in sequence along a direction from the cathode layer 300 to the anode layer 100, and at least one layer of the optical path adjustment layer 400 is provided between the first transparent conductive layer 110 and the reflective conductive layer 120.

[0098] In the above scheme, the anode layer 100 is a film layer structure using multiple conductive metal stacks. For the light-emitting diode, the anode layer 100 is a reflective electrode layer, and the cathode layer 300 is a semi-transparent and semi-reflective electrode layer. The light emitted by the light-emitting layer 200 can be reflected by the anode layer 100 and then transmitted from the cathode layer 300. The reflective property of the anode layer 100 and the semi-reflective and semi-transparent property of the cathode layer 300 can be used to form an optical microcavity between the anode layer 100 and the cathode layer 300. Therefore, When the anode layer 100 includes the first transparent conductive layer 110, the reflective conductive layer 120 and the second light-transmitting conductive layer 130, the reflective conductive layer 120 can be regarded as the boundary of the optical microcavity, that is, light is reflected on the surface of the reflective conductive layer 120 on one side close to the first transparent conductive layer 110. Therefore, at least one layer of the optical path adjustment layer 400 can be provided between the first transparent conductive layer 110 and the reflective conductive layer 120 to adjust the optical path proportion of the anode layer 100 in the optical microcavity.

[0099] The material of the first transparent conductive layer 110 may be one or more of indium tin oxide (ITO), aluminum zinc oxide (AZO), tin oxide (SnO2), conductive polymers, carbon-based materials, oxide semiconductors, etc.; the material of the second light-transmitting conductive layer 130 may be one or more of indium tin oxide (ITO), aluminum zinc oxide (AZO), tin oxide (SnO2), conductive polymers, carbon-based materials, oxide semiconductors, etc.; the material of the reflective conductive layer 120 may be one or more of metal materials such as silver (Ag), aluminum (Al) and gold (Au).

[0100] As an exemplary embodiment, the anode layer 100 may be a composite electrode formed of ITO / Ag / ITO, Ag / IZO, CNT / ITO, CNT / IZO, GO / ITO, GO / IZO, etc.

[0101] In other embodiments not shown, the optical path adjustment layer 400 may also be provided on the cathode layer 300 serving as a semi-transmissive and semi-reflective electrode.

[0102] Compared with the solution of disposing the optical path adjustment layer 400 in the anode layer 100 as a reflective electrode, disposing the optical path adjustment layer 400 in the cathode layer 300 as a semi-transmissive and semi-reflective electrode will not reduce the light transmittance and has a higher luminous efficiency.

[0103] It should be noted that if Figure 2In the illustrated embodiment, the anode layer 100 is stacked on the side of the cathode layer 300 close to the base substrate 10, the anode layer 100 is a reflective electrode layer, the cathode layer 300 is a semi-transmissive and semi-reflective electrode layer, and the light emitted by the light-emitting layer 200 can be reflected by the anode layer 100 and then transmitted from the cathode layer 300. Exemplarily, the anode layer 100 is an anode, and the cathode layer 300 is a cathode. In other words, the light-emitting device is a top-emitting light-emitting device.

[0104] However, the above is only an example, but is not limited thereto. In other embodiments, the light emitting device may also be a bottom emitting light emitting device, that is, the anode layer 100 is stacked on the side of the cathode layer 300 close to the base substrate 10, the anode layer 100 is a semi-transmissive and semi-reflective electrode layer, and the cathode layer 300 is a reflective electrode layer.

[0105] Exemplarily, the optical path adjustment layer 400 is a semi-transmissive and semi-reflective film layer, which can make the light emitted by the light-emitting layer 200 partially transmitted and partially reflected, so as to achieve the purpose of adjusting the optical path of the optical microcavity of the corresponding light-emitting diode. Exemplarily, the optical path adjustment layer 400 can be selected from one or more of metal films, oxide films, conductive polymer films, dielectric films, etc.

[0106] Specifically, the optical path adjustment layer 400 may be a single film layer structure formed by at least one material selected from metal, metal oxide or metal alloy; or, the optical path adjustment layer 400 includes at least two film layers structure formed by stacking film layers formed by one or more materials selected from metal, metal oxide and metal alloy in sequence. For example, when the optical adjustment layer uses a metal film, the metal film may be formed by one or more metals selected from silver (Ag), aluminum (Al) and gold (Au) or metal oxides or metal alloys. Alternatively, the optical path adjustment layer 400 may be a single layer or multiple layers of oxide films selected from one or more oxide materials selected from indium tin oxide (ITO), zinc oxide (ZnO) and the like; or, the optical path adjustment layer 400 may be a dielectric material selected from different dielectric materials (such as silicon oxide SiO2, silicon nitride Si3N 4、 Alternatively, the optical path adjustment layer 400 may be formed by any combination of the above metal film, oxide film, conductive polymer film, dielectric film, etc. The refractive index of the optical path adjustment layer 400 may be 1.2 to 1.5.

[0107] As an exemplary embodiment, the optical path adjustment layer 400 is a film structure of at least two layers, which includes a first adjustment film layer, at least one intermediate adjustment film layer and a second adjustment film layer stacked in sequence along the direction from the anode layer 100 to the cathode layer 300, wherein the first adjustment film layer is formed of one or more metals, metal oxides or metal alloy materials selected from Ag, Au and AL; the intermediate adjustment film layer is one or more film layers selected from one or more materials selected from silicon oxide, silicon nitride or titanium oxide; and the second adjustment film layer is formed from one or more metals, metal oxides or metal alloy materials selected from Ag, Au and AL. The total film thickness of the optical path adjustment layer 400 is less than or equal to 300 nm.

[0108] In some embodiments, the film thickness of the optical path adjustment layer 400 may be 10 to 300 nm. Further, the film thickness of the optical path adjustment layer 400 may be 10 to 80 nm. The optical path adjustment layer 400 may be disposed only in the light emitting diodes corresponding to one or several colors of light, or may be disposed in all light emitting diodes at the same time.

[0109] For example, in some embodiments, if the problem of reddish color of the light emitting device in the related art is to be improved, the optical path adjustment layer 400 may be provided only in the red light emitting diode to reduce the film thickness of the light emitting layer 200 in the red light emitting diode. The optical field adjustment layer may not be provided in the green light emitting diode and the blue light emitting diode.

[0110] For other embodiments, see Figure 2 As shown, at least two light emitting diodes are both provided with an optical path adjustment layer 400, and the optical path adjustment layers 400 corresponding to at least two light emitting diodes are provided in the same layer. In other words, at least two light emitting diodes share the same optical path adjustment layer 400. Figure 2 In the figure, all the light emitting diodes share the same optical path adjustment layer 400 as an example. Compared with the solution in the related art in which the light emitting diode is not provided with the optical path adjustment layer 400, the light emitting layer 200 in all the light emitting diodes can be designed with a thin film thickness.

[0111] It should be understood that, in other embodiments not shown, when the optical path adjustment layer 400 is provided in at least two light-emitting diodes, the corresponding optical path adjustment layers 400 in different light-emitting diodes may be provided in the same layer or in different layers.

[0112] For example, the optical path adjustment layer 400 corresponding to the red light emitting diode can be arranged between the first transparent conductive layer of the anode layer 100 and the reflective conductive layer 120, and can be a single film layer or a multi-layer structure; the optical path adjustment layer 400 corresponding to at least one of the green light emitting diode and the blue light emitting diode can be arranged in the cathode layer 300, or between the reflective conductive layer 120 and the second transparent conductive layer, and can be a single film layer or a multi-layer structure.

[0113] As shown in the figure, in this embodiment, exemplarily, when the optical path adjustment layer 400 is provided in at least one of the light-emitting diodes, the optical microcavities of the first light-emitting diode T1, the second light-emitting diode T2 and the third light-emitting diode T3 can be configured as high-order microcavities with optical path orders greater than or equal to 2, so as to increase the color gamut area by enhancing the microcavity effect. At this time, see Figure 2 As shown, in some embodiments, the film thickness of the light-emitting layer 200 corresponding to the first light-emitting diode T1 is H1, the film thickness of the light-emitting layer 200 corresponding to the second light-emitting diode T2 is H2, and the film thickness of the light-emitting layer 200 corresponding to the third light-emitting diode T3 is H3, wherein H1>H2>H3.

[0114] In some other exemplary embodiments, when the optical path adjustment layer 400 is provided in at least one of the light emitting diodes, the optical microcavities of the first light emitting diode T1, the second light emitting diode T2 and the third light emitting diode T3 may be configured as follows: n1=1, n2≥1, n 3 ≥2. That is, the optical path order of the first light emitting diode T1 is 1, the optical path order of the second light emitting diode T2 is greater than or equal to 1, and the optical path order of the third light emitting diode T3 is a high-order microcavity greater than or equal to 2. Specifically, for example, n1=1, n2=1, n 3 =2; or, n1 = 1, n2 = 2, n 3 =2; etc. In other words, the above scheme can configure the optical path order of at least one light emitting diode (such as the first light emitting diode T1) to 1, and at the same time, the optical path adjustment layer 400 is provided in the optical microcavity of the light emitting diode to further achieve the purpose of thinning the light emitting layer 200 of at least one light emitting diode.

[0115] In an exemplary embodiment, the optical path order of the first light emitting diode T1 is configured as 1, and the optical path adjustment layer 400 is provided in the optical microcavity of the first light emitting diode T1. Further, the optical path adjustment layer 400 is provided in the anode layer of the first light emitting diode T1. For example, the first light emitting diode T1 is a red light emitting diode.

[0116] Since the optical microcavity of the first light-emitting diode T1 uses the first optical path mode and has a shorter optical path, its leakage probability is greater than that of a light-emitting diode using the second optical path mode or a higher-order optical path. In the above scheme, by further providing the optical path adjustment layer 400 in the anode layer of the first light-emitting diode T1 and thickening the anode layer, leakage can be prevented and the optical path thickness of the organic light-emitting material can be further reduced.

[0117] Please refer to Figure 3 As shown, taking n1=1, n2≥1, n3≥2, and setting an optical path adjustment layer 400 in the optical microcavity of each light-emitting diode as an example, at this time, in some embodiments, please refer to the figure, the film thickness of the light-emitting layer 200 corresponding to the first light-emitting diode T1 is H1, the film thickness of the light-emitting layer 200 corresponding to the second light-emitting diode T2 is H2, and the film thickness of the light-emitting layer 200 corresponding to the third light-emitting diode T3 is H3, wherein H2>H1, and H2>H3.

[0118] Exemplarily, the anode layer 100 is a reflective electrode layer, and the cathode layer 300 is a semi-transmissive and semi-reflective electrode layer; the light-emitting diode further includes a cover layer (CPL) 500, and the cover layer 500 is located on the side of the cathode layer 300 away from the anode layer 100, that is, the cover layer 500 is stacked on the light-emitting side of the light-emitting diode. Figure 5 As shown, the film thickness of the light-emitting layer 200 corresponding to the first light-emitting diode T1 is H1, the film thickness of the light-emitting layer 200 corresponding to the second light-emitting diode T2 is H2, and H2>H1, the film thickness of the covering layer 500 corresponding to the first light-emitting diode T1 is h1, the film thickness of the covering layer 500 corresponding to the second light-emitting diode T2 is h2, and h1>h2.

[0119] In the above scheme, a covering layer 500 is provided on the light-emitting side of the light-emitting diode, and the thickness of the covering layer 500 is positively correlated with the light-emitting efficiency of the corresponding light-emitting diode. Since the light-emitting layer 200 of the first light-emitting diode T1 is the thinnest relative to the second light-emitting diode T2 and the third light-emitting diode T3, the thickness of the covering layer 500 corresponding to the light-emitting diodes of different colors of light can be differentiated and the thickness of the covering layer 500 corresponding to the first light-emitting diode T1 can be increased to further improve the light-emitting efficiency of the first light-emitting diode T1.

[0120] See also Figure 5 As shown, the thickness of the cover layer 500 corresponding to the third light emitting diode T3 is h3, wherein h2=h3, or h2≠h3. For example, see Figure 5As shown, the cover layer 500 may be an integral film layer provided for all light emitting diodes, wherein only the region corresponding to the first light emitting diode T1 is thickened. Specifically, the cover layer 500 is close to the surface of one side of the light emitting layer 200, and the region corresponding to the first light emitting diode T1 is protruded relative to other regions and toward the direction where the light emitting layer 200 is located, so as to thicken the region corresponding to the first light emitting diode T1.

[0121] In some embodiments, at least two of the light-emitting diodes include a first light-emitting diode T1, a second light-emitting diode T2, and a third light-emitting diode T3, wherein the first light-emitting diode T1 is a red light-emitting diode, the second light-emitting diode T2 is a green light-emitting diode, and the third light-emitting diode T3 is a blue light-emitting diode. Based on the light-emitting device in the embodiment of the present disclosure, by reasonably configuring the optical path order of the light-emitting diodes, and / or by setting an optical path adjustment layer 400 in the optical microcavity of at least one of the light-emitting diodes, the film thickness H1 of the first light-emitting diode T1 can be reduced to The film thickness H2 of the second light emitting diode T2 can be reduced to The film thickness H3 of the third light emitting diode T3 can be reduced to

[0122] Compared with the related technology, the optical path thickness of the three organic light-emitting materials of red, green and blue is thinned As an exemplary embodiment, the thickness of the red organic light emitting material is reduced to about The thickness of the blue light organic light emitting material is reduced to about The thickness of green organic light emitting material is reduced to about At the same time, the thickness of the organic light-emitting materials for blue and green light is also reduced. At the same time, the overall thickness of the light-emitting layer in the light-emitting device is reduced, which can reduce the occurrence of lateral leakage.

[0123] In addition, as an optional embodiment, the light-emitting diode further includes a hole transport unit layer 800 and an electron transport unit layer 900, wherein the hole transport unit layer 800 may include at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL), and the electron transport unit layer 900 may include at least one of a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL). The hole transport unit layer 800 may be disposed between the light-emitting layer 200 and the anode layer 100, and the electron transport unit layer 900 may be disposed between the light-emitting layer 200 and the cathode layer 300.

[0124] Thus, while increasing the color gamut area, the carrier transmission efficiency is improved, thereby improving the luminous efficiency of the light-emitting diode. One, two or more layers of the above film layers can be provided according to actual needs, with strong flexibility and selectivity.

[0125] In some exemplary embodiments, in at least one of the light-emitting diodes, at least one buffer layer (Prime) 600 is disposed between the light-emitting layer 200 and the hole transport unit layer 800. That is, the light-emitting layer 200 is disposed on a side of the buffer layer 600 away from the anode layer.

[0126] For ease of description, the buffer layer 600 in the blue light-emitting diode, the green light-emitting diode, and the red light-emitting diode is hereinafter referred to as B Prime (or B'), G Prime (or G'), R Prime or (R'). The light-emitting layer 200 in the blue light-emitting diode, the green light-emitting diode, and the red light-emitting diode is hereinafter referred to as B EML, G EML, and R EML. As an exemplary embodiment, at least one of the hole injection layer (HIL), the hole transport layer (HTL), the electron blocking layer (EBL), the hole blocking layer (HBL), the electron transport layer (ETL), and the electron injection layer (EIL) is shared by all the light-emitting diodes.

[0127] As some exemplary embodiments, in the light-emitting diode, the light-emitting layer 200 may be provided with one or at least two layers, and one or at least two buffer layers 600 may be provided between each light-emitting layer 200 and the hole transport unit layer 800. For ease of description, the structure in which one buffer layer 600 may be provided between each light-emitting layer 200 and the hole transport unit layer 800 is referred to as a single buffer layer structure; the structure in which two buffer layers 600 may be provided between each light-emitting layer 200 and the hole transport unit layer 800 is referred to as a double buffer layer structure.

[0128] In the light-emitting device provided in the present disclosure, the light-emitting layer 200 in each light-emitting diode may have one layer or at least two layers. That is, the light-emitting device may be a Single device or a Tandem device. A Single device refers to a light-emitting diode composed of a single light-emitting layer 200. A Tandem device refers to a light-emitting diode composed of multiple light-emitting layers 200 connected in series or in parallel.

[0129] The structure of the light emitting device provided by the present disclosure is exemplarily described below.

[0130] See also Figure 6As shown, in some exemplary embodiments, each of the light-emitting diodes includes only a corresponding layer of the light-emitting layer 200 , and a buffer layer 600 is provided between the corresponding light-emitting layer 200 in each of the light-emitting diodes and the hole transport unit layer 800 .

[0131] That is to say, only one light-emitting layer 200 is disposed in each of the light-emitting diodes, and each of the light-emitting diodes has a single buffer layer 600 structure.

[0132] As an exemplary embodiment, Figure 6 As shown, the hole transport unit layer 800 may include a hole injection layer (HIL) and a hole transport layer (HTL). The electron transport unit layer 900 may include a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL).

[0133] In addition, for example, Figure 6 As shown, the light emitting device further includes a capping layer (CPL) 500. The capping layer 500 is disposed above the cathode layer 300, which can significantly improve the electron injection efficiency, optimize the charge balance, enhance the light emitting efficiency, and improve the stability of the device.

[0134] In this embodiment, the hole injection layer (HIL) can be a non-doped hole injection material or a doped hole injection layer, and the thickness of the hole injection layer (HIL) is between 5 and 20 nm. When the hole injection layer (HIL) adopts a single organic material, HATCN and the like can be selected. When the hole injection layer (HIL) adopts an inorganic material, a p-type inorganic oxide material such as MoO3 can be selected. If a doped hole injection material is used: the p-type doped material can be selected from F4TCNQ and the like, the doping concentration of the p-type material is between 0.1% and 50%, and the vacuum energy level of the P-type organic hole injection material is <-5.2eV. The Tg (glass transition temperature) of the material is greater than 90 degrees Celsius.

[0135] The material of the hole transport layer (HTL) can be selected from sp3 hybridized N heterocyclic compounds, such as NPB materials, the HOMO energy level of the material is between -5.5 and -4.5 eV, and the mobility of the material of the hole transport layer is between 10 -5 cm 2 / Vs~10 - 4 cm 2 / Vs. The Tg (glass transition temperature) of the material is greater than 90 degrees Celsius, and the refractive index of the material is between 1.4 and 1.8.

[0136] The material of R prime is a heterocyclic compound of N, O, and S. The HOMO energy level of the material is between -5.2 and -4.3 eV, the LUMO energy level is between -2.8 and 3.5 eV, and the hole mobility is 10 -6 cm 2 / Vs—10 -4 cm 2 / Vs. The triplet energy level of R prime is greater than 2.2eV, and the Tg (glass transition temperature) of the material is greater than 90 degrees Celsius. The refractive index of the material is between 1.4 and 1.8.

[0137] The material of G prime is N, S, O heterocyclic compound. The HOMO energy level of the material is between -5.3 and -4.5 eV, the LUMO energy level is between -2.8 and 3.5 eV, and the hole mobility is 10 -6 cm 2 / Vs~10 -5 cm 2 / Vs. The triplet energy level of R prime is greater than 2.4eV, and the Tg (glass transition temperature) of the material is greater than 90 degrees Celsius. The refractive index of the material is between 1.4-1.8.

[0138] The material of B Prime is N, S, O heterocyclic compound. The HOMO energy level of the material is between -5.3 and -4.5 eV, the LUMO energy level is between -2.8 and 3.5 eV, and the hole mobility is 10 -7 cm 2 / Vs~10 -5 cm 2 / Vs, the Tg (glass transition temperature) of the material is greater than 90 degrees Celsius. The refractive index of the material is between 1.4 and 1.8.

[0139] The cover layer 500 may be made of a material that can improve the luminous efficiency and service life of the device, and may be a hole-type material or an electron-type material. For example, the cover layer 500 is made of an organic heterocyclic compound, the refractive index of the material is greater than 1.7, and the thickness is about 50-90 nm.

[0140] The doping material (B dopant) in the blue light-emitting diode can be a B (boron) compound, and the main luminescence peak of the material is between 455 and 465 nm. The doping material (G dopant) in the green light-emitting diode can be a phosphorescent material containing a complex such as Ir (iridium) and Pt (platinum), and the ligand is a heterocyclic compound substituted with deuterium / tritium, and the main luminescence peak of the material is between 520 and 540 nm. The doping material (R dopant) in the green light-emitting diode is a phosphorescent material containing a complex such as Ir (iridium) and Pt (platinum), and the ligand is a heterocyclic compound substituted with deuterium / tritium, and the main luminescence peak of the material is between 618 and 640 nm.

[0141] The blue host material (Blue Host) in the blue light emitting diode is a conjugated ring compound with anthracene and other structures. The Tg (glass transition temperature) of the material is greater than 90 degrees Celsius. The refractive index of the material is between 1.4 and 1.8.

[0142] The green host material (Green Host) in the green light-emitting diode is an n-type / p-type mixed compound with a mixing ratio of 6:4 to 4:6. The hole mobility of the Green Host material is about 10 -7 cm 2 / Vs~10 -5 cm 2 / Vs, the electron mobility is about 10 -7 cm 2 / Vs~10 -5 cm 2 / Vs. The triplet energy level of the material is greater than 2.4eV. The Tg (glass transition temperature) of the material is greater than 90 degrees Celsius. The refractive index of the material is between 1.4 and 1.8.

[0143] The red host material (Red Host) in the red light-emitting diode is an n-type / p-type mixed compound with a mixing ratio of 6:4 to 4:6. The hole mobility of the red host material is about 10 -7 cm 2 / Vs~10 -5 cm 2 / Vs, the electron mobility is about 10 -7 cm 2 / Vs~10 -5 cm 2 / Vs. The triplet energy level of the material is greater than 2.2eV. The Tg (glass transition temperature) of the material is greater than 90 degrees Celsius. The refractive index of the material is between 1.4 and 1.8.

[0144] The material of the hole blocking layer (HBL) is an SP2 hybrid N-containing compound, including pyridine, triazine, 1,10-phenanthroline and other compounds. The electron mobility is about 10 -7 cm 2 / Vs~10 -4 cm 2 / Vs. The triplet energy level of the material is greater than 2.4eV. The Tg (glass transition temperature) of the material is greater than 90 degrees Celsius. The refractive index of the material is between 1.4 and 1.8.

[0145] The material of the electron transport layer (ETL) is an SP2 hybrid N-containing compound, including pyridine, triazine, 1,10-phenanthroline and other compounds. The electron mobility is about 10 -6 cm 2 / Vs~10 -4 cm 2 / Vs. The Tg (glass transition temperature) of the material is greater than 90 degrees Celsius. The refractive index of the material is between 1.4 and 1.8.

[0146] The cathode layer 300 is made of a material with a low work function so as to easily inject electrons into the organic layer, and has good light transmittance and electrical conductivity. Such as metals, metal oxides, metal alloys, 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), lithium calcium magnesium alloy (Li:Ca:Mg), etc.; and laminated materials, 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.

[0147] Exemplarily, the thickness of the hole injection layer (HIL) is about 5-20 nm; the thickness of the hole blocking layer is about 3-10 nm; the thickness of the electron transport layer (ETL) is about 20-35 nm, wherein the electron transport layer is an N-type material such as Liq doped with an electron transport material; the thickness of the electron injection layer (EIL) is 0.5-2 nm; the thickness of the cap layer 500 is 50-90 nm; the thickness of the cathode layer (CTD) is 10-20 nm; the thickness of the light-emitting layer 200 (B EML) in the blue light-emitting diode is 15-25 nm, and the thickness of the light-emitting layer 200 (R EML) in the red light-emitting diode is 35-50 nm; the thickness of the light-emitting layer 200 (G EML) in the blue light-emitting diode is 25-40 nm; the thickness of B Prime is 3-7 nm; the thickness of R Prime is 15-30 nm; The thickness of the prime film is 9 to 15 nm.

[0148] Exemplarily, the optical path order n1 of the first light emitting diode T1 may be 1, the optical path order n2 of the second light emitting diode T2 may be 1 or 2, and the optical path order n3 of the third light emitting diode T3 may be 2. That is, the optical path of the blue light emitting diode is configured as the second optical path, the optical path of the red light emitting diode is configured as the first optical path, and the optical path of the green light emitting diode is configured as the first optical path or the second optical path.

[0149] In addition, in some embodiments, the hole transport layers in the red light-emitting diode, the green light-emitting diode and the blue light-emitting diode can also be set separately, or the hole transport layers in the red light-emitting diode and the green light-emitting diode are shared, while the hole transport layer in the blue light-emitting diode is set separately.

[0150] When the optical path order n1 of the first light emitting diode T1 is 1, the optical path order n2 of the second light emitting diode T2 is 1, and the optical path order n3 of the third light emitting diode T3 is 2, the first light emitting diode T1 is a red light emitting diode, the second light emitting diode T2 is a green light emitting diode, and the third light emitting diode T3 is a blue light emitting diode. Figure 6 As shown in the example, the hole transport layer (HTL) in the red light-emitting diode and the green light-emitting diode is shared, while the hole transport layer (HTL) in the blue light-emitting diode is separately provided, the film thickness of the hole transport layer (HTL) in the blue light-emitting diode can be 90 to 110 nm, and the film thickness of the hole transport layer shared by the red light-emitting diode and the green light-emitting diode can be 6 nm.

[0151] In the above embodiments, since the hole transport layer in the blue light emitting diode is separately provided, a separate mask is required for patterning process, which increases the mass production cost. Therefore, in order to reduce the cost, in other embodiments, such as Fig.14 As shown, the hole transport layer in the red light emitting diode, the green light emitting diode and the blue light emitting diode can be shared. In order to meet the optical path of the blue light emitting diode, the optical path adjustment layer in the anode layer can be used to adjust the optical path. For example, Fig.14 As shown, the optical path adjustment layer 400 can be only provided in the blue light emitting diode, and the film thickness of the optical path adjustment layer 400 can be 50-80nm. In one embodiment, the film thickness of the hole injection layer (HIL) is about 5-20nm; the film thickness of the hole transport layer (HTL) is about 6-25nm; the film thickness of the hole blocking layer (HBL) is 3-10nm; the film thickness of the electron transport layer is 20-35nm; the film thickness of the electron injection layer (EIL) is 0.5-2nm; the film thickness of the cathode layer is 10-20nm; the thickness of the capping layer 500 is 50-70nm; the film thickness of the BEML is 15-25nm, the film thickness of the REML is 35-50nm; the film thickness of the GEML is 25-40nm; the film thickness of the B Prime is 3-7nm; the film thickness of the R Prime is 15-30nm, and the film thickness of the G prime is 9-15nm.

[0152] In other exemplary embodiments, Figure 7 As shown, each of the light-emitting diodes includes only one corresponding light-emitting layer 200 , and two buffer layers 600 are disposed between the corresponding light-emitting layer 200 and the hole transport unit layer 800 in at least one of the light-emitting diodes.

[0153] by Figure 7Taking the embodiment shown as an example, only one buffer layer 600 is provided between the light-emitting layer 200 and the hole transport unit layer 800 corresponding to the first light-emitting diode T1 and the third light-emitting diode T3; two buffer layers 600 are provided between the light-emitting layer 200 and the hole transport unit layer 800 corresponding to the second light-emitting diode T2, and the two buffer layers 600 are respectively a first buffer layer 610 and a second buffer layer 620, the second buffer layer 620 is located on the side of the first buffer layer 610 close to the light-emitting layer 200, and the HOMO energy level of the second buffer layer 620 is higher than the HOMO energy level of the first buffer layer 610, and the LUMO energy level of the second buffer layer 620 is higher than the LUMO energy level of the first buffer layer 610. In the above embodiment, the buffer layer 600 of the second light-emitting diode adopts a double buffer layer 600 structure, for example, the second light-emitting diode T2 is a green light-emitting diode, and G prime is a double buffer layer 600 structure. The refractive index of the material of the buffer layer 600 can be between 1.4 and 1.8.

[0154] The optical paths of the red light emitting diode and the green light emitting diode in the light emitting device in some embodiments of the present disclosure are configured as the first optical path, and the optical path of the blue light emitting diode is configured as the second optical path, as a test example, and the optical paths of the red light emitting diode, the green light emitting diode, and the blue light emitting diode are all configured as the second optical path as a control example, and the performance of the light emitting device of the test example and the control example is tested. The test results of the test example are shown in Table 2 below, and the test results of the control example are shown in Table 3 below.

[0155] Table 2

[0156]

[0157]

[0158] Table 3

[0159]

[0160] It can be seen from Table 2 and Table 3 that when the optical path of the red light emitting diode and the green light emitting diode of the light emitting device in the test example is the first optical path, the voltage is reduced by 1.6V and 1.2V respectively compared with the light emitting device in the control example, which can significantly improve the power consumption of the product.

[0161] also, Figure 8 Shown is the T95 life test result of the light emitting device in the test example; Fig. 9The figure shows the T95 life test results of the light emitting device in the control example. T95 life refers to the time required for the brightness of the OLED device to decay to 95% of its initial brightness under normal working conditions. In other words, T95 life refers to the total working time required for the brightness of the device to decrease to 95% of the initial value during use.

[0162] from Figure 8 and Fig. 9 It can be seen that when the red LED uses the first optical path and the second optical path, the T95 life is basically the same, and when the green LED uses the first optical path, the T95 life is increased by about 40% compared with the second optical path.

[0163] Fig.10 Shown is the L-decay test result of the light emitting device in the test example; Fig.11 The figure shows the L-decay test result of the light emitting device in the control example. The L-decay test result refers to the brightness decay characteristics of the OLED device. Fig.10 and Fig.11 It can be seen that at 45 degrees, the L-decay of the red LED in the test example decays 62% slower than that of the control example, and the L-decay of the green LED in the test example decays 37% slower than that of the control example.

[0164] Table 4 shows the power consumption performance test results of the light emitting devices in the display products in the test examples and the control examples.

[0165] Table 4

[0166]

[0167] It can be seen from Table 5 that the power consumption of the light emitting device in the test example in the display product is reduced by about 8% compared with the power consumption of the existing mass production solution.

[0168] In addition, the above embodiments illustrate the structure of the light emitting diode using a Single device, and the following illustrates the structure of the light emitting diode using a Tandem device.

[0169] In some embodiments, see Fig.12As shown, the light-emitting layer 200 in each of the light-emitting diodes includes: a first light-emitting layer 200A; and a second light-emitting layer 200B located on a side of the first light-emitting layer 200A close to the anode layer 100; wherein each of the light-emitting diodes includes: a first hole transport unit layer 800A located between the second light-emitting layer 200B and the anode layer 100; a first electron transport unit layer 900A located between the first light-emitting layer 200A and the cathode layer 300; and a charge generation unit layer 700 located between the first light-emitting layer 200A and the second light-emitting layer 200B, and the first light-emitting layer 200A and the second light-emitting layer 200B are connected through the charge generation unit layer 700.

[0170] The light-emitting diode adopts the structure of a Tandem device. By increasing the number of light-emitting layers 200200, the microcavity intensity can be increased, the color gamut area can be increased, and the high color gamut of the light-emitting device as a whole can be ensured. In addition, the luminous flux can be effectively increased, and the luminous efficiency and luminous effect of the light-emitting diode can be improved.

[0171] At least one buffer layer 600 may be disposed between the first light-emitting layer 200A and the charge generation unit layer 700 , and at least one buffer layer 600 may be disposed between the second light-emitting layer 200B and the first hole transport unit layer 800A.

[0172] by Fig.12 As shown in the example, only one buffer layer 600 is disposed between the first light-emitting layer 200A and the charge generation unit layer 700 , and one buffer layer 600 may be disposed between the second light-emitting layer 200B and the first hole transport unit layer 800A.

[0173] In other embodiments not shown, two buffer layers 600 may be provided between the first light-emitting layer 200A and the charge generation unit layer 700, and two buffer layers 600 may be provided between the second light-emitting layer 200B and the first hole transport unit layer 800A.

[0174] In addition, the charge generation unit layer 700 is located between the first light emitting layer 200A and the second light emitting layer 200B, and is used to connect the first light emitting layer 200A and the second light emitting layer 200B. In some implementations, the charge generation unit layer 700 may include an N-type doped charge generation layer (N CGL) and a P-type doped charge generation layer (P CGL), that is, the direction from the anode layer 100 to the cathode layer 300 is the N-type doped charge generation layer and the P-type doped charge generation layer.

[0175] In some embodiments, only the charge generation unit layer 700 may be disposed in the first light emitting layer 200A and the second light emitting layer 200B.

[0176] In other embodiments, Fig.12 As shown, each of the light-emitting diodes further includes a second hole transport unit layer 800B and a second electron transport unit layer 900B, wherein the second hole transport unit layer 800B is located between the charge generation unit layer 700 and the first light-emitting layer 200A, and the second electron transport unit layer 900B is located between the charge generation unit layer 700 and the second light-emitting layer 200B.

[0177] For example, see Fig.12 As shown, the first hole transport unit layer 800A may include a hole injection layer (HIL) and a hole transport layer (HTL), and the second hole transport unit layer 800B may include a hole transport layer (HTL). The first electron transport unit layer 900A may include a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL). The second electron transport unit layer 900B may include an electron transport layer (ETL) and a hole blocking layer (HBL). However, it is not limited thereto.

[0178] Exemplarily, the hole transport layer (HTL), the electron transport layer (ETL), the hole blocking layer (HBL), the hole injection layer (HIL), the charge generation unit layer 700, the capping layer 500 and the cathode layer 300 are all common film layers.

[0179] Exemplarily, the hole injection layer (HIL) has a thickness of about 5 to 15 nm.

[0180] For example, the N-type doped charge generation layer can be made of p-type materials such as Yb, Li, and LiF doped with electron transport materials, and the charges are separated in the N-type doped charge generation layer to generate electrons. The thickness of the N-type doped charge generation layer is about 5 to 20 nm.

[0181] Exemplarily, the film thickness of the P-type doped charge generation layer is between 5 and 20 nm. The P-type doped charge generation layer can be made of organic materials, such as HATCN, etc., or inorganic materials, such as P-type inorganic semiconductor materials such as MoO3, etc., or p-type doped materials, such as F4TCNQ, etc., and the doping concentration of the p-type material is between 0.1% and 50%.

[0182] Exemplarily, the thickness of the hole blocking layer (HBL) is between 1 nm and 10 nm.

[0183] Exemplarily, the film thickness of the electron transport layer (ETL) in the first electron transport unit layer 900A is about 5 to 15 nm; the thickness of the electron transport layer (ETL) in the second electron transport unit layer 900B is about 5 to 25 nm. The electron transport layer in the first electron transport unit layer 900A and the electron transport layer in the second electron transport unit layer 900B can both be a binary doping structure, and the host materials used can be the same or different.

[0184] For example, the thickness of the electron injection layer (EIL) is about 0.5-2 nm.

[0185] Exemplarily, the film thickness of the capping layer (CPL) is 50-90 nm; the film thickness of the cathode layer 300 is 10-20 nm.

[0186] Exemplarily, the film thickness of B prime is about 2-7 nm; the film thickness of B EML is about 10-25 nm. The film thickness of Gprime is 5-15 nm, and the film thickness of G EML is about 20-40 nm. GPrime can use double G prime or single G prime. The film thickness of R prime is 10-25 nm, and the film thickness of R EML is about 20-50 nm.

[0187] Exemplarily, the red light emitting diode and the green light emitting diode use the first optical path, and the blue light emitting diode uses the second optical path.

[0188] In the above embodiment, the light emitting device adopts a tandem device structure, which can further increase the life of the device and improve the performance of the device compared to a single device.

[0189] In some other embodiments of the present disclosure, the light-emitting device adopts a parallel Tandem device structure.

[0190] Specifically, see Fig.13As shown, each of the light-emitting diodes includes a first anode layer 100A, a first hole transport unit layer 800A, a first light-emitting layer 200A, a first electron transport unit layer 900A, a first cathode layer 300A, a covering layer 500, a second cathode layer 300B, a second electron transport unit layer 900B, a second light-emitting layer 200B, a second hole transport unit layer 800B and a second anode layer 100B stacked in sequence; wherein the first anode layer 100A, the first hole transport unit layer 800A, the first light-emitting layer 200A, the first electron transport unit layer 900A 00A and the first cathode layer 300A form a first light-emitting element, the second anode layer 100B, the second hole transport unit layer 800B, the second light-emitting layer 200B, the second electron transport unit layer 900B and the second cathode layer 300B form a second light-emitting element, the first anode layer 100A is coupled to the first drive signal input terminal, the second anode layer 100B is coupled to the second drive signal input terminal, the first cathode layer 300A is coupled to the second cathode layer 300B, so that the first light-emitting element and the second light-emitting element are arranged in parallel.

[0191] In this embodiment, the first light-emitting layer 200A in the first light-emitting element can realize the light-emitting function under the joint action of the first anode layer 100A and the first cathode layer 300A. The second light-emitting layer 200B in the second light-emitting element can realize the light-emitting function under the joint action of the second anode layer 100B and the second cathode layer 300B.

[0192] Exemplarily, the material of the second anode layer 100B may be a P-type oxide such as MoO 3 .

[0193] In this embodiment, illustratively, the optical paths of the first light-emitting layer 200A and the second light-emitting layer 200B in the first light-emitting diode T1 can both be the first optical path, the optical paths of the first light-emitting layer 200A and the second light-emitting layer 200B in the second light-emitting diode T2 can both be the first optical path or the second optical path, and the optical paths of the first light-emitting layer 200A and the second light-emitting layer 200B in the third light-emitting diode T3 can both be the second optical path.

[0194] The parallel tandem device structure can further reduce power consumption and increase device life compared to the series tandem device structure.

[0195] In addition, in this embodiment, exemplarily, as shown in the figure, in at least one of the light-emitting diodes, at least one buffer layer 600 is further arranged between the first light-emitting layer 200A and the first hole transport unit layer 800A; at least one buffer layer 600 is further arranged between the second light-emitting layer 200B and the second hole transport unit layer 800B.

[0196] In addition, the embodiments of the present disclosure further provide a display device, which includes the light-emitting device provided in the embodiments of the present disclosure. The display device includes but is not limited to devices with display functions such as smart phones, displays, laptops, tablet computers, electronic photo frames, driving recorders, smart wearable devices, etc. Other essential components of the display device (such as driver chips) should be understood by ordinary technicians in the field, and will not be described in detail here, nor should they be used as limitations on the present disclosure. Since the principle of solving the problem by the display device is similar to the principle of solving the problem by the above-mentioned light-emitting device, the embodiment of the display device provided in the embodiments of the present disclosure can refer to the embodiment of the above-mentioned light-emitting device provided in the embodiments of the present disclosure, and will not be described in detail here.

[0197] There are a few points to note:

[0198] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure, and other structures may refer to the general design.

[0199] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element or there may be intermediate elements.

[0200] (3) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to obtain new embodiments.

[0201] The above are only specific implementations of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and the protection scope of the present disclosure shall be based on the protection scope of the claims.

Claims

1. A light emitting device, characterized in that: It comprises at least two light emitting diodes emitting light of different colors, each of the light emitting diodes has an optical microcavity, and each of the light emitting diodes comprises an anode layer, a light emitting layer and a cathode layer stacked in sequence; wherein, The optical path order of the optical microcavity corresponding to at least one of the light-emitting diodes is 1; and / or, An optical path adjustment layer is provided in the optical microcavity corresponding to at least one of the light emitting diodes, and the optical path adjustment layer is located in the film layer stacking structure of at least one of the anode layer and the cathode layer.

2. The light emitting device according to claim 1, characterized in that: At least two of the light-emitting diodes include a first light-emitting diode and a second light-emitting diode, the light-emitting wavelength of the first light-emitting diode is λ1, the light-emitting wavelength of the second light-emitting diode is λ2, the optical path order of the first light-emitting diode is n1, and the optical path order of the second light-emitting diode is n2; wherein λ1>λ2, n1=1, n2≥1.

3. The light emitting device according to claim 2, characterized in that: At least two of the light emitting diodes further include a third light emitting diode, the light emission wavelength of the third light emitting diode is λ3, and the optical path order of the third light emitting diode is n3; wherein λ1>λ3, n3≥2.

4. The light emitting device according to claim 3, characterized in that: The thickness of the light-emitting layer corresponding to the first light-emitting diode is H1, the thickness of the light-emitting layer corresponding to the second light-emitting diode is H2, and the thickness of the light-emitting layer corresponding to the third light-emitting diode is H3, wherein H2>H1, and H2>H3.

5. The light emitting device according to claim 3, characterized in that: λ2>λ3, and n2=n3≥2 or, n2=n1=1 and n3≥2.

6. The light emitting device according to claim 5, characterized in that: Each of the light emitting diodes at least comprises: A hole transport unit layer, located between the light-emitting layer and the anode layer; An electron transport unit layer, located between the light-emitting layer and the cathode layer; Wherein, in at least one of the light-emitting diodes, at least one buffer layer is arranged between the light-emitting layer and the hole transport unit layer.

7. The light emitting device according to claim 6, characterized in that: Each of the light-emitting diodes includes only one corresponding light-emitting layer; wherein, One buffer layer is disposed between the corresponding light-emitting layer and the hole transport unit layer in each light-emitting diode; or two buffer layers are disposed between the corresponding light-emitting layer and the hole transport unit layer in at least one light-emitting diode.

8. The light emitting device according to claim 7, characterized in that: Only one buffer layer is arranged between the light-emitting layer and the hole transport unit layer corresponding to the first light-emitting diode and the third light-emitting diode, respectively; two buffer layers are arranged between the light-emitting layer and the hole transport unit layer corresponding to the second light-emitting diode, and the two buffer layers are respectively a first buffer layer and a second buffer layer, the second buffer layer is located on a side of the first buffer layer close to the light-emitting layer, and the HOMO energy level of the second buffer layer is higher than the HOMO energy level of the first buffer layer, and the LUMO energy level of the second buffer layer is higher than the LUMO energy level of the first buffer layer.

9. The light emitting device according to claim 5, characterized in that: The light-emitting layer in each of the light-emitting diodes comprises: a first light-emitting layer; and a second light-emitting layer located on a side of the first light-emitting layer close to the anode layer; wherein each of the light-emitting diodes comprises: A first hole transport unit layer, located between the second light-emitting layer and the anode layer; A first electron transport unit layer, located between the first light-emitting layer and the cathode layer; and The charge generation unit layer is located between the first light-emitting layer and the second light-emitting layer, and the first light-emitting layer and the second light-emitting layer are connected through the charge generation unit layer.

10. The light emitting device according to claim 9, characterized in that: At least one buffer layer is disposed between the first light-emitting layer and the charge generation unit layer, and at least one buffer layer is disposed between the second light-emitting layer and the first hole transport unit layer.

11. The light emitting device according to claim 9, characterized in that: Each of the light-emitting diodes further includes a second hole transport unit layer and a second electron transport unit layer, wherein the second hole transport unit layer is located between the charge generation unit layer and the first light-emitting layer, and the second electron transport unit layer is located between the charge generation unit layer and the second light-emitting layer.

12. The light emitting device according to claim 5, characterized in that: Each of the light-emitting diodes includes a first anode layer, a first hole transport unit layer, a first light-emitting layer, a first electron transport unit layer, a first cathode layer, a covering layer, a second cathode layer, a second electron transport unit layer, a second light-emitting layer, a second hole transport unit layer and a second anode layer stacked in sequence; wherein the first anode layer, the first hole transport unit layer, the first light-emitting layer, the first electron transport unit layer and the first cathode layer form a first light-emitting element, the second anode layer, the second hole transport unit layer, the second light-emitting layer, the second electron transport unit layer and the second cathode layer form a second light-emitting element, the first anode layer is coupled to a first drive signal input terminal, the second anode layer is coupled to a second drive signal input terminal, and the first cathode layer is coupled to the second cathode layer, so that the first light-emitting element and the second light-emitting element are arranged in parallel.

13. The light emitting device according to claim 12, characterized in that: In at least one of the light-emitting diodes, at least one buffer layer is disposed between the first light-emitting layer and the first hole transport unit layer; and at least one buffer layer is disposed between the second light-emitting layer and the second hole transport unit layer.

14. The light emitting device according to claim 2, characterized in that: The anode layer is a reflective electrode layer, and the cathode layer is a semi-transparent and semi-reflective electrode layer; the light-emitting diode also includes a covering layer, and the covering layer is located on the side of the cathode layer away from the anode layer; wherein the film thickness of the light-emitting layer corresponding to the first light-emitting diode is H1, and the film thickness of the light-emitting layer corresponding to the second light-emitting diode is H2, and H2>H1, the film thickness of the covering layer corresponding to the first light-emitting diode is h1, and the film thickness of the covering layer corresponding to the second light-emitting diode is h2, wherein h1>h2.

15. The light emitting device according to claim 1, characterized in that: The anode layer is a reflective electrode layer, and the cathode layer is a semi-transparent and semi-reflective electrode layer; wherein, in at least one of the light-emitting diodes, the anode layer includes at least one transparent conductive layer and at least one reflective conductive layer stacked, wherein the optical path adjustment layer is arranged in the anode layer and is located between at least one transparent conductive layer and at least one reflective conductive layer.

16. The light emitting device according to claim 15, characterized in that: In at least one of the light-emitting diodes, the anode layer includes a first transparent conductive layer, a reflective conductive layer, and a second light-transmitting conductive layer stacked in sequence along a direction from the cathode layer to the anode layer, and at least one layer of the optical path adjustment layer is provided between the first transparent conductive layer and the reflective conductive layer.

17. The light emitting device according to claim 1, characterized in that: The optical path adjustment layer is a semi-transmissive and semi-reflective film layer, and the film thickness of the optical path adjustment layer is 10-300 nm.

18. The light emitting device according to claim 17, characterized in that: The optical path adjustment layer is a single film layer structure formed by at least one material selected from metal, metal oxide or metal alloy; or, the optical path adjustment layer includes at least two film layer structures formed by stacking film layers formed by one or more materials selected from metal, metal oxide and metal alloy in sequence.

19. The light emitting device according to claim 1, characterized in that: At least two of the light emitting diodes include a first light emitting diode, a second light emitting diode and a third light emitting diode, wherein the first light emitting diode is a red light emitting diode, the second light emitting diode is a green light emitting diode, the third light emitting diode is a blue light emitting diode, and the film thickness of the first light emitting diode is The film thickness of the second light emitting diode is The film thickness of the third light emitting diode is 20. A display device, characterized in that: The light emitting device comprises the light emitting device as claimed in any one of claims 1 to 19.

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