Display substrate and display device

Abstract

The display substrate includes a backplane, an anode layer, a first auxiliary layer, a first light-emitting layer, a second auxiliary layer, a plurality of second light-emitting layers of at least two different colors, a third auxiliary layer, and a cathode layer. The first auxiliary layer includes a film layers stacked in sequence, and the optical thickness of the a film layers is L1, and L1 satisfies the following formula. 【Equation 1】 TIFF2025522942000052.tif1525 The second auxiliary layer includes b film layers stacked in sequence, and the optical thickness of the b film layers is L2, and L2 satisfies the following formula. 【Equation 2】 TIFF2025522942000053.tif1725 The third auxiliary layer includes c film layers stacked in sequence, and the optical thickness of the c film layers is L3, and L3 satisfies the following formula. 【Equation 3】 TIFF2025522942000054.tif1828 L1, L2, and L3 satisfy the following formula. 【Equation 4】 TIFF2025522942000055.tif1583

Description

Technical Field

[0001] This application claims priority based on a Chinese patent application with application number 202210798416.7 filed on July 8, 2022, and all of its content is incorporated into this application by reference.

[0002] The present disclosure relates to the field of display technologies, and particularly to display substrates and display devices.

Background Art

[0003] An OLED (Organic Light Emitting Diode) display device is a display device manufactured with organic electroluminescence diodes. OLED display devices have excellent characteristics such as not requiring a backlight, having high contrast, being thin, having a wide viewing angle, having a fast response speed, being usable for flexible panels, having a wide operating temperature range, and having a relatively simple structure and process, and are currently widely used.

Summary of the Invention

[0004] Embodiments of the present invention aim to provide a display substrate and a display device for improving the emission luminance and color purity of the display substrate.

[0005] To achieve the above object, embodiments of the present disclosure provide the following technical solutions.

[0006] In one aspect, a display substrate is provided. The display substrate includes a backplane, and an anode layer, a first auxiliary layer, a first light-emitting layer, a second auxiliary layer, a plurality of second light-emitting layers of at least two different colors, a third auxiliary layer, and a cathode layer, which are sequentially stacked on the backplane. A microcavity is formed between the anode layer and the cathode layer. The first light-emitting layer is provided between the first auxiliary layer and the second auxiliary layer. The plurality of second light-emitting layers are provided between the second auxiliary layer and the third auxiliary layer. Here, the first auxiliary layer includes a film layers stacked in sequence, the optical thickness of the a film layers is L1, and L1 satisfies

Number

[0007] The second auxiliary layer includes b film layers stacked in sequence, the optical thickness of the b film layers is L2, and L2 satisfies

Number

[0008] The third auxiliary layer includes c film layers stacked in sequence, the optical thickness of the c film layers is L3, and L3 satisfies

Number

[0009] In the first optical interference period of the blue light, L1, L2, and L3 satisfy the following formula.

Equation

[0010] According to some embodiments of the present disclosure, the display substrate provided can improve the emission luminance of the display substrate by providing a first auxiliary layer, a second auxiliary layer, and a third auxiliary layer such that the first light-emitting layer and the second light-emitting layer form a series light-emitting element. And a microcavity can be formed between the anode layer and the cathode layer of the display substrate, and the light emitted by the first light-emitting layer and the second light-emitting layer can produce a microcavity effect in the microcavity, thereby improving the emission luminance of the emitted light, narrowing the spectrum of the emitted light, and improving the light-emitting efficiency of the light-emitting element. When the optical thickness of the a film layers included in the first auxiliary layer is L1, the optical thickness of the b film layers included in the second auxiliary layer is L2, and the optical thickness of the c film layers included in the third auxiliary layer is L3, by making it satisfy the following formula,

Equation

[0011]

[0012] In some embodiments, the plurality of second light-emitting layers include a plurality of second blue light-emitting layers, a plurality of second red light-emitting layers, and a plurality of second green light-emitting layers. The wavelength of the light emitted by the first light-emitting layer is smaller than the wavelength of the light emitted by at least one color of the second light-emitting layer.In some embodiments, the first light-emitting layer includes a first guest material, and the second light-emitting layer includes a second guest material. The emission spectrum of the first guest material at least partially overlaps with the absorption spectrum of the second guest material in at least one color of the second light-emitting layer.

[0013] In some embodiments, the overlapping range between the emission spectrum of the first guest material and the absorption spectrum of the second guest material is 60% or more of the wavelength range of the emission spectrum of the first guest material.

[0014] In some embodiments, the overlapping range between the emission spectrum of the first guest material and the absorption spectrum of the second guest material is 60% or more of the wavelength range of the absorption spectrum of the second guest material.

[0015] In some embodiments, the peak value of the emission spectrum of the first guest material is less than 600 nm.

[0016] In some embodiments, the first guest material includes at least one light-emitting material. When the first guest material includes two light-emitting materials, the interval between the peak values of the emission spectra of the two light-emitting materials is 30 nm or less.

[0017] In some embodiments, the range of the peak value of the emission spectrum of the first guest material is 465 nm to 475 nm, and the range of the peak value of the absorption spectrum of the second guest material in the second green light-emitting layer is 507 nm to 517 nm.

[0018] In some embodiments, the range of the peak value of the emission spectrum of the first guest material is 525 nm to 535 nm, the range of the peak value of the absorption spectrum of the second guest material in the second green light-emitting layer is 510 nm to 520 nm, and the range of the peak value of the absorption spectrum of the second guest material in the second red light-emitting layer is 595 nm to 605 nm.

[0019] In some embodiments, the first guest material includes at least one luminescent material. When the first guest material includes two luminescent materials, at least one of the two luminescent materials is doped with a boron element, and the doping ratio range of the boron element is 0.5% - 5%.

[0020] In some embodiments, the second guest material of at least one color of the second light-emitting layer includes at least one luminescent material. When the second guest material includes two luminescent materials, the interval between the peak values of the emission spectra of the two luminescent materials is 30 nm or less.

[0021] In some embodiments, the second guest material of at least one color of the second light-emitting layer includes at least one luminescent material. When the second guest material includes two luminescent materials, at least one of the two luminescent materials is doped with a boron element, and the doping ratio range of the boron element is 0.5% - 5%.

[0022] In some embodiments, the first guest material includes at least one of a fluorescent material, a phosphorescent material, and a thermally activated delayed fluorescence material, and / or the second guest material includes at least one of a fluorescent material, a phosphorescent material, or a thermally activated delayed fluorescence material having multiple resonance characteristics.

[0023] In some embodiments, the first light-emitting layer further includes a first host material, and the first host material includes a single host material or a PN hybrid host material.

[0024] In some embodiments, the material of at least one color of the second light-emitting layer further includes a second host material, and the second host material includes a bipolar host material.

[0025] In some embodiments, the second host material includes a single host material or a PN hybrid host material. When the second host material is a PN hybrid host material, the N-type material has thermally activated delayed fluorescence characteristics.

[0026] In some embodiments, the microcavity includes a plurality of sub-microcavities, and the plurality of sub-microcavities include a red sub-microcavity corresponding to the second red light-emitting layer, a green sub-microcavity corresponding to the second green light-emitting layer, and a blue sub-microcavity corresponding to the second blue light-emitting layer. The number of film layers corresponding to any one color of sub-microcavities located between the anode layer and the cathode layer is d, the optical thickness of the d film layers is L, and L satisfies the following formula.

Number

[0027] In the formula, d is a positive integer, n m is the refractive index of the m-th film layer among the d film layers, r m is the thickness of the m-th film layer, k is a natural number, λ is the target spectral peak wavelength, and φ is the phase shift caused after the target light is reflected by the anode layer.

[0028] In some embodiments, the length of the blue sub-microcavity is smaller than the length of the red sub-microcavity. The length of the blue sub-microcavity is smaller than the length of the green sub-microcavity.

[0029] In some embodiments, the thickness range of the first light-emitting layer is 15 nm to 60 nm, and / or the thickness range of the second light-emitting layer is 10 nm to 50 nm.

[0030] In some embodiments, the first auxiliary layer includes a light-transmissive conductive layer, a hole injection layer, a first hole transport layer, and an electron blocking layer, and / or the second auxiliary layer includes a first hole blocking layer, a first electron transport layer, a first charge generation layer, a second charge generation layer, and a microcavity adjustment layer, and / or the third auxiliary layer includes a second hole blocking layer, a second electron transport layer, and an electron injection layer.

[0031] In some embodiments, the microcavity adjustment layer includes a second hole transport layer, a red sub-microcavity adjustment layer provided between the second hole transport layer and the second red light-emitting layer, a green sub-microcavity adjustment layer provided between the second hole transport layer and the second green light-emitting layer, and a blue sub-microcavity adjustment layer provided between the second hole transport layer and the second blue light-emitting layer. Here, the lengths between the red sub-microcavity adjustment layer and the blue sub-microcavity adjustment layer are different, and the lengths between the green sub-microcavity adjustment layer and the blue sub-microcavity adjustment layer are different.

[0032] In some embodiments, the red sub-microcavity adjustment layer includes a red hole transport layer and a red electron blocking layer sequentially stacked and arranged in a direction away from the back plate, and the green sub-microcavity adjustment layer includes a green hole transport layer and a green electron blocking layer sequentially stacked and arranged in a direction away from the back plate. Here, the red hole transport layer and the green hole transport layer are each used to adjust the length of the corresponding color sub-microcavity.

[0033] In some embodiments, the thickness of the light-transmissive conductive layer is 10 nm or less, and / or the thickness of the hole injection layer is 10 nm or less, and / or the thickness of the electron blocking layer is 10 nm or less, and / or the thickness of the first hole blocking layer is 10 nm or less, and / or the thickness range of the first electron transport layer is 15 nm to 50 nm, and / or the thickness of the first charge generation layer is 10 nm or less, and / or the thickness of the second charge generation layer is 10 nm or less, and / or the thickness of the second hole blocking layer is 10 nm or less, and / or the thickness range of the second electron transport layer is 15 nm to 50 nm.

[0034] In some embodiments, the number of the first light-emitting layers is plural, the second auxiliary layer is provided between any two adjacent first light-emitting layers, and / or the plurality of second light-emitting layers are located in the same layer to form one light-emitting layer group, the number of the light-emitting layer groups is plural, and the third auxiliary layer is provided between any two adjacent light-emitting layer groups.

[0035] In another aspect, a display substrate is provided. The display substrate includes a backplane, an anode layer, a first auxiliary layer, a first light-emitting layer, a second auxiliary layer, a plurality of second light-emitting layers of at least two different colors, a third auxiliary layer, and a cathode layer, which are sequentially stacked on the backplane. A microcavity is formed between the anode layer and the cathode layer. The first light-emitting layer is provided between the first auxiliary layer and the second auxiliary layer. The plurality of second light-emitting layers are provided between the second auxiliary layer and the third auxiliary layer. Here, the first auxiliary layer includes a film layers stacked in sequence, the second auxiliary layer includes b film layers stacked in sequence, the third auxiliary layer includes c film layers stacked in sequence, and a, b, and c are all positive integers. The optical thicknesses of the a film layers, the optical thicknesses of the b film layers, and the optical thicknesses of the c film layers satisfy the following formula.

Number

[0036]

Number

Number

[0037] In yet another aspect, a display substrate is provided. The display substrate includes a backplane, an anode layer, a first auxiliary layer, a first light-emitting layer, a second auxiliary layer, a plurality of second light-emitting layers of at least two different colors, a third auxiliary layer, and a cathode layer, which are sequentially stacked on the backplane. The second auxiliary layer includes a charge generation layer, and a microcavity is formed between the anode layer and the cathode layer. The first light-emitting layer can emit light of at least two different colors. The plurality of second light-emitting layers include a plurality of second blue light-emitting layers, a plurality of second red light-emitting layers, and a plurality of second green light-emitting layers. Here, the first auxiliary layer includes a number a of film layers stacked in sequence, the second auxiliary layer includes a number b of film layers stacked in sequence, the third auxiliary layer includes a number c of film layers stacked in sequence, and a, b, and c are all positive integers. The optical thicknesses of the a film layers, the optical thicknesses of the b film layers, and the optical thicknesses of the c film layers satisfy the following formula.

Number

[0038]

Number

Number

[0039] In yet another aspect, a display device is provided. The display device includes a display substrate described in any of the embodiments of the above aspect, or the display device includes a display substrate described in an embodiment of another aspect, or the display device includes a display substrate described in an embodiment of yet another aspect.

[0040] The display device has the same structure and beneficial technical effects as the display substrate provided in some of the above embodiments, and the description thereof is omitted herein.

Brief Description of the Drawings

[0041] To more clearly illustrate the technical solutions in the present disclosure, the following briefly describes the drawings necessary for the description of some embodiments of the present disclosure. The drawings in the following description are only the drawings of some embodiments of the present disclosure, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings. Furthermore, the drawings in the following description can be regarded as schematic diagrams and do not limit the actual dimensions of the products according to the embodiments of the present disclosure, the actual processes of the methods, the actual sequences of the signals, etc.

[0042]

Figure 1

[0043]

Figure 2

[0044]

Figure 3

[0045]

Figure 4

[0046]

Figure 5

[0047]

Figure 6

[0048]

Figure 7

[0049]

Figure 8

[0050]

Figure 9

[0051]

Figure 10

[0052]

Figure 11

[0053]

Figure 12

[0054]

Figure 13

Embodiments for Carrying out the Invention

[0055] The following will clearly and completely describe the technical solutions of some embodiments of the present disclosure with reference to the drawings. However, it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, not all of them. Based on the embodiments provided by the present disclosure, all other embodiments obtained by those skilled in the art shall fall within the protection scope of the present disclosure.

[0056] In this specification and the claims, the term "comprise" and its other forms, such as the third-person singular form "comprises" and the present participle form "comprising", should be construed in an open, inclusive sense, i.e., "including but not limited to", unless the context requires a different interpretation. In the description of this specification, terms such as "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example", or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic related to the embodiment or example is included in at least one embodiment or example of the present disclosure. The schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be included in any one or more embodiments or examples in any appropriate manner.

[0057] Hereinafter, the terms "first" and "second" are used only for the purpose of explanation and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features shown. Therefore, the features defined by "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the embodiments of the present disclosure, unless otherwise specified, "a plurality" means two or more.

[0058] When describing some embodiments, the terms "connection" and its derived expressions may be used. For example, when describing some embodiments, the term "connection" may be used to indicate that two or more components have direct physical or electrical contact with each other. The embodiments disclosed herein are not necessarily limited to the content of this specification.

[0059] "At least one of A, B, and C" has the same meaning as "at least one of A, B, or C", and both include combinations of A only, B only, C only, combinations of A and B, combinations of A and C, combinations of B and C, and combinations of A, B, and C.

[0060] "A and / or B" includes three combinations: A only, B only, and the combination of A and B.

[0061] The use of "is arranged as" in this specification means open and inclusive language and does not exclude an apparatus that is applied or arranged to perform additional tasks or steps.

[0062] Also, the use of "based on" means open and inclusive because a process, step, calculation, or other operation performed "based on" one or more described conditions or values may actually be based on additional conditions or may exceed the described values.

[0063] As used herein, "about" includes the stated value and the average value within an acceptable deviation range of the specific value, where the acceptable deviation range is determined considering the errors associated with the measurements and the measurements of the specific quantity being considered by those of ordinary skill in the art (i.e., the limitations of the measurement system).

[0064] When a layer or element is referred to as being on another layer or substrate, it is understood that the layer or element may be directly located on the other layer or substrate, or there may be an intermediate layer between the layer or element and the other layer or substrate.

[0065] In this specification, exemplary embodiments are described with reference to cross-sectional views and / or plan views which are idealized exemplary drawings. In the drawings, the thicknesses of layers and regions are enlarged for clarity. Thus, variations in shape with respect to the drawings, for example due to manufacturing techniques and / or tolerances, can be assumed. Accordingly, exemplary embodiments should not be construed as being limited to the shapes of the regions illustrated herein, but should include shape deviations resulting from manufacturing and the like. For example, an etching region shown as rectangular typically has curved features. Thus, the regions shown in the drawings are essentially exemplary, and their shapes are not intended to represent the actual shape of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0066] Some embodiments of the present invention provide a display substrate and a display device. Hereinafter, the display substrate 100 and the display device 1000 will be described with reference to the drawings respectively.

[0067] As shown in FIG. 1, some embodiments of the present disclosure provide a display device 1000. The display device 1000 can be any device that displays whether it is moving (e.g., video) or stationary (e.g., still image), whether it is text or an image. More specifically, it is expected that the described embodiments may be implemented in various electronic devices or may be associated with various electronic devices, and the various electronic devices include, for example, mobile phones, wireless devices, personal data assistants (PDAs), handheld computers or portable computers, GPS receivers / navigators, cameras, MP4 video players, video cameras, game consoles, wristwatches, clocks, calculators, television monitors, flat panel displays, computer monitors, car displays (e.g., odometer displays, etc.), navigation, cockpit controllers and / or displays, camera view displays (e.g., rear view camera displays in vehicles), electrophotography, electronic billboards or signs, projectors, architectural structures, packaging, and aesthetic structures (e.g., displays for images of jewels), etc., but are not limited thereto.

[0068] In some examples, the display device 1000 includes a frame, a display substrate 100 provided within the frame, a circuit board, a data driver IC (Integrated Circuit), and other electronic components.

[0069] The display substrate 100 may be, for example, an organic light-emitting diode display substrate, a quantum dot light-emitting diode (QLED) display substrate, a micro light-emitting diode (Micro LED) display substrate, or a mini light-emitting diode (Mini LED) display substrate, etc., but the present disclosure is not particularly limited thereto.

[0070] Hereinafter, taking the substrate 100 being an OLED display substrate as an example, some embodiments of the present disclosure will be schematically described.

[0071] In some embodiments, as shown in FIG. 2, the display substrate 100 includes a backplane 1.

[0072] In some examples, the backplane 1 includes a substrate 11 and a plurality of pixel driving circuits 12 provided on the substrate 11.

[0073] The types of the substrate 11 include various ones and can be selected and installed according to actual needs.

[0074] Exemplarily, the substrate 11 may be a rigid substrate. The material of the rigid substrate may include, for example, glass, quartz, or plastic, etc.

[0075] Exemplarily, the substrate 11 may be a flexible substrate. The material of the flexible substrate may include, for example, PET (Polyethylene terephthalate), PEN (Polyethylene naphthalate two formic acid glycol ester), or PI (Polyimide).

[0076] In some examples, the plurality of pixel driving circuits 12 are arranged, for example, in an array.

[0077] The structure of the pixel driving circuit 12 includes various types and can be selected and installed according to actual needs. For example, the structure of the pixel driving circuit 12 may include structures such as "3T1C", "4T1C", "6T1C", "7T1C", "6T2C", "7T2C", or "8T2C". Here, "T" represents a transistor, the number before "T" represents the number of transistors, "C" represents a storage capacitor, and the number before "C" represents the number of storage capacitors.

[0078] Exemplarily, in FIG. 3, the pixel driving circuit 12 is represented by one transistor 121.

[0079] In some embodiments, as shown in FIG. 3, the display substrate 100 further includes a light-emitting element layer 2.

[0080] In some examples, as shown in FIG. 3, the light-emitting element layer 2 includes a plurality of light-emitting elements 2a. As shown in FIG. 2, the plurality of light-emitting elements 2a are arranged, for example, in an array. Here, the light-emitting element 2a is, for example, an OLED.

[0081] The pixel driving circuit 12 and the light-emitting element 2a are electrically connected. Here, the electrical connection relationship between the two includes various types and can be specifically selected and installed according to actual needs, and the present disclosure does not limit this.

[0082] For example, the pixel driving circuit 12 and the light emitting element 2a may be electrically connected in a one-to-one correspondence. Also, for example, one pixel driving circuit 12 may be electrically connected to a plurality of light emitting elements 2a. Further, for example, a plurality of pixel driving circuits 12 may be electrically connected to one light emitting element 2a.

[0083] Hereinafter, taking as an example the case where the pixel driving circuit 12 and the light emitting element 2a can be electrically connected in a one-to-one correspondence, the structure of the display substrate 100 will be schematically described.

[0084] It is understood that the pixel driving circuit 12 can generate a driving signal, transmit the driving signal to the corresponding light emitting element 2a, and control the light emitting state of the light emitting element 2a. The light emitting state includes, for example, whether the light emitting element 2a is emitting light or not, and the emission luminance of the light emitting element 2a. By commonly controlling the light emitting states of the plurality of light emitting elements 2a by the plurality of pixel driving circuits 12, a screen display can be realized on the display substrate 100.

[0085] Here, each pixel driving circuit 12 and the light emitting element 2a electrically connected thereto can be called a sub-pixel.

[0086] Note that there are mainly two methods for the display substrate to achieve full-color display. For example, one method is to provide a full-color display solution by R / G / B individual light emitting units, and the other method is to provide a full-color solution by a color conversion or color filtering method.

[0087] In one embodiment, providing a full-color display solution by R / G / B individual light-emitting units means that the light-emitting element mainly includes an anode, a light-emitting layer, and a cathode sequentially stacked in a direction away from the substrate. Here, the light-emitting layer may be a red light-emitting layer, a green light-emitting layer, or a blue light-emitting layer. Correspondingly, the light-emitting element may be a red light-emitting element, a green light-emitting element, or a blue light-emitting element. The red light-emitting element can emit red light under the control of the corresponding pixel driving circuit, the green light-emitting element can emit green light under the control of the corresponding pixel driving circuit, and the blue light-emitting element can emit blue light under the control of the corresponding pixel driving circuit. By the interlocking of a plurality of light-emitting elements, full-color display can be realized. However, in this solution, the light-emitting efficiency and light-emitting luminance of the light-emitting element are relatively low.

[0088] In other embodiments, the methods of providing a full-color solution by color conversion or color filtering mainly include two.

[0089] As shown in FIG. 4, in the first method, the light-emitting element 2a' is a light-emitting element with in-line bottom emission, and the light-emitting element is used to emit white light. The display substrate further includes a color filter CF provided on the side away from the light-emitting element 2a' of the substrate 11'. The white light emitted by the light-emitting element 2a' is converted into red light, green light, or blue light after passing through the color filter CF. Thereby, full-color display is realized. However, due to its structure, it is relatively difficult to improve the luminance at the front viewing angle for the bottom-emission light-emitting element. Furthermore, when using a top-emission light-emitting element, the complexity of the process increases, and there is also a problem that the light loss in a specific wavelength band is too large.

[0090] As shown in FIG. 5, in the second method, the light-emitting element 2a' is a light-emitting element of in-line top emission, and the light-emitting element 2a' is used to emit blue light. The display substrate further includes a red quantum dot conversion layer R-CC and a green quantum dot conversion layer G-CC provided on the side away from the substrate 11' of the light-emitting element 2a'. The blue light passing through the red quantum dot conversion layer R-CC is converted into red light, and the blue light passing through the green quantum dot conversion layer G-CC is converted into green light. Thereby, full-color display is realized. However, due to the influence of the light conversion rate of the red quantum dot conversion layer R-CC and the green quantum dot conversion layer G-CC themselves, the color purity of the converted red light and green light is relatively low. Therefore, it is necessary to match the corresponding filter. For example, a red filter R-CF is provided on the side away from the substrate 11' of the red quantum dot conversion layer R-CC, and a green filter G-CF is further provided on the side away from the substrate 11' of the green quantum dot conversion layer G-CC. This is necessary to improve the color purity. In this way, the complexity of the process of the display substrate is increased, and the power consumption of the display substrate is improved.

[0091] Based on this, as shown in FIG. 3, in some embodiments of the present disclosure, the light-emitting element layer 2 includes an anode layer 21, a first auxiliary layer 22, a first light-emitting layer 23, a second auxiliary layer 24, a plurality of second light-emitting layers 25, a third auxiliary layer 26, and a cathode layer 27 provided on the backplane 1.

[0092] In some examples, as shown in FIG. 3, the anode layer 21 includes a plurality of anodes 211, and the plurality of anodes 211 are arranged in an array, for example. Here, one anode 211 corresponds to one light-emitting element 2a, and each light-emitting element 2a is electrically connected to a corresponding pixel driving circuit 12 through the anode 211, for example. The anode 211 receives a driving signal of the corresponding pixel driving circuit 12, and can realize individual control of the light-emitting element 2a in conjunction with the corresponding pixel driving circuit 12.

[0093] Exemplarily, the material of the anode layer 21 includes a conductive material having a relatively high work function. The structure of the anode layer 21 may be, for example, a single-layer structure, or may be, for example, a structure in which multiple film layers are sequentially laminated.

[0094] Exemplarily, when the structure of the anode layer 21 is a single-layer structure, the single-layer structure has relatively good light reflection performance and can reflect the light radiated to the anode layer 21.

[0095] Exemplarily, when the structure of the anode layer 21 is a structure in which multiple film layers are sequentially laminated, the film layer away from the backplate 1 among the multiple film layers is a film layer with relatively good light reflection performance and can reflect the light radiated to the anode layer 21. The material of the film layer with relatively good light reflection performance may include, for example, at least one of Al (aluminum), Ag (silver), or Mg (magnesium). The film layer close to the backplate 1 among the multiple film layers may be, for example, a film layer with relatively good light transmittance. The material of the film layer with relatively good light transmittance may include, for example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), etc.

[0096] Exemplarily, the method for forming the anode 211 includes forming a conductive thin film (the conductive thin film is a single-layer structure or a structure in which multiple thin films are sequentially laminated) on the backplane 1 (for example, using a sputtering process), and then patterning the conductive film (for example, etching the conductive thin film using a photolithography process) to obtain a plurality of anodes 211 independent of each other.

[0097] In addition, the display substrate 100 may further include a pixel definition layer provided on the side of the anode layer 21 away from the substrate 11. The pixel definition layer has a plurality of openings, and the plurality of openings and the plurality of anodes 211 are arranged in a one-to-one correspondence. Each opening exposes a part of the corresponding anode 211 to facilitate contact between the anode 211 and a film layer located on the side away from the substrate 11 thereof and form an electrical connection.

[0098] In some examples, as shown in FIG. 3, the first auxiliary layer 22 is provided on the side of the anode layer 21 away from the substrate 11. Optionally, the first auxiliary layer 22 is located on the side of the pixel definition layer away from the substrate 11.

[0099] Exemplarily, the first auxiliary layer 22 can contact the anode 211 through the opening of the pixel definition layer to form an electrical connection.

[0100] Exemplarily, the first auxiliary layer 22 includes a film layers stacked in sequence, where a is a positive integer. For example, the number of film layers included in the first auxiliary layer 22 is 1, 2, 3, 4, etc.

[0101] Optionally, when the first auxiliary layer 22 includes one film layer, the first auxiliary layer 22 covers the anode layer 21. That is, different light-emitting elements 2a share the first auxiliary layer 22.

[0102] Optionally, when the first auxiliary layer 22 includes at least two film layers, at least one film layer covers the anode layer 21. That is, different light-emitting elements 2a share the at least one film layer.

[0103] Exemplarily, the present disclosure can use a vapor deposition process to form the first auxiliary layer 22.

[0104] By sharing the film layer of the first auxiliary layer 22 among different light-emitting elements 2a, patterning of the first auxiliary layer 22 can be avoided, which is advantageous for simplifying the manufacturing processes of the first auxiliary layer 22 and the display substrate 100.

[0105] In some examples, as shown in FIG. 3, the first light-emitting layer 23 is provided on a side away from the substrate 11 of the first auxiliary layer 22.

[0106] Exemplarily, the first light-emitting layer 23 is disposed, for example, throughout the layer, and different light-emitting elements 2a share the first light-emitting layer 23.

[0107] Note that the first auxiliary layer 22 is located between the anode layer 21 and the first light-emitting layer 23. The first auxiliary layer 22 is mainly used to increase the hole mobility, reduce the hole injection barrier, increase the amount of holes migrating to the first light-emitting layer 23, increase the recombination rate of holes and electrons migrating to the first light-emitting layer 23, and improve the light-emitting efficiency of the first light-emitting layer 23.

[0108] In some examples, as shown in FIG. 3, the second auxiliary layer 24 is provided on a side away from the substrate 11 of the first light-emitting layer 23. That is, the plurality of first light-emitting layers 23 are provided between the first auxiliary layer 22 and the second auxiliary layer 24. Here, the second auxiliary layer 24 is in contact with the first light-emitting layer 23 to form an electrical connection.

[0109] Exemplarily, the second auxiliary layer 24 includes b film layers stacked in sequence, where b is a positive integer. For example, the number of film layers included in the second auxiliary layer 24 is 1, 2, 3, 4, or the like.

[0110] Exemplarily, different light-emitting elements 2a share the second auxiliary layer 24.

[0111] Exemplarily, the present disclosure can use a vapor deposition process to form the second auxiliary layer 24.

[0112] By sharing the film layer of the second auxiliary layer 24 among different light-emitting elements 2a, patterning of the second auxiliary layer 24 can be avoided, which is advantageous for simplifying the manufacturing processes of the second auxiliary layer 24 and the display substrate 100.

[0113] In some examples, as shown in FIG. 3, the plurality of second light-emitting layers 25 are provided on the side of the second auxiliary layer 24 away from the substrate 11. For example, the plurality of second light-emitting layers 25 are located in the same layer, and each second light-emitting layer 25 is in contact with the second auxiliary layer 24 to form an electrical connection. Of course, at least two second light-emitting layers 25 may be stacked. In the present disclosure, the case where the plurality of second light-emitting layers 25 are located in the same layer will be described as an example.

[0114] Exemplarily, the plurality of second light-emitting layers 25 have at least two different colors.

[0115] For example, the plurality of second light-emitting layers 25 have two different colors. Optionally, the plurality of second light-emitting layers 25 include a plurality of second blue light-emitting layers 25B and a plurality of second red light-emitting layers 25R. Alternatively, the plurality of second light-emitting layers 25 include a plurality of second blue light-emitting layers 25B and a plurality of second green light-emitting layers 25G. Alternatively, the plurality of second light-emitting layers 25 include a plurality of second red light-emitting layers 25R and a plurality of second green light-emitting layers 25G.

[0116] Also, for example, the plurality of second light-emitting layers 25 have three different colors. Optionally, the plurality of second light-emitting layers 25 include a plurality of second blue light-emitting layers 25B, a plurality of second red light-emitting layers 25R, and a plurality of second green light-emitting layers 25G.

[0117] Since the plurality of second light-emitting layers 25 have two different colors, the plurality of second light-emitting layers 25 need to be formed by manufacturing in different processes, where one color of the second light-emitting layer 25 can correspond to one process. For example, the plurality of second light-emitting layers 25 are formed using a vapor deposition process. At this time, one color of the second light-emitting layer 25 can be vapor-deposited and formed in one process, and then the second light-emitting layer 25 of another color can be vapor-deposited and formed in another process.

[0118] Note that the second auxiliary layer 24 is located between the plurality of first light-emitting layers 23 and the plurality of second light-emitting layers 25, and the second auxiliary layer 24 is mainly used to connect the first light-emitting layer 23 and the second light-emitting layer 25 in series to form a series light-emitting element.

[0119] In some examples, as shown in FIG. 3, the third auxiliary layer 26 is provided on the side of the plurality of second light-emitting layers 25 away from the substrate 11. That is, the plurality of second light-emitting layers 25 are provided between the second auxiliary layer 24 and the third auxiliary layer 26. Here, the third auxiliary layer 26 contacts each second light-emitting layer 25 to form an electrical connection.

[0120] Exemplarily, the third auxiliary layer 26 includes c film layers stacked in sequence, where c is a positive integer. For example, the number of film layers included in the third auxiliary layer 26 is 1, 2, or 3, etc.

[0121] Optionally, different light-emitting devices 2a share the third auxiliary layer 26.

[0122] Exemplarily, the present disclosure can use a vapor deposition process to form the third auxiliary layer 26.

[0123] By sharing the third auxiliary layer 26 among different light-emitting elements 2a, patterning of the third auxiliary layer 26 can be avoided, which is advantageous for simplifying the manufacturing process of the third auxiliary layer 26 and the display substrate 100.

[0124] In some examples, as shown in FIG. 3, the cathode layer 27 is provided on the side of the third auxiliary layer 26 away from the substrate 11 and contacts the third auxiliary layer 26 to form an electrical connection.

[0125] Exemplarily, different light-emitting elements 2a share the cathode layer 27. That is, the cathode layer 27 has a whole-layer structure.

[0126] Exemplarily, the present disclosure can use a vapor deposition process to form the cathode layer 27.

[0127] By sharing the cathode layer 27 among different light-emitting elements 2a, patterning of the cathode layer 27 can be avoided, which is advantageous for simplifying the manufacturing processes of the cathode layer 27 and the display substrate 100.

[0128] Note that the third auxiliary layer 26 is located between the plurality of second light-emitting layers 25 and the cathode layer 27. The third auxiliary layer 26 mainly increases the electron mobility, increases the amount of holes migrating to the first light-emitting layer 23, increases the recombination rate of holes and electrons migrating to the first light-emitting layer 23, avoids the leakage of excitons formed by the recombination of holes or holes and electrons from the second light-emitting layer 25, and is used to improve the light-emitting efficiency of the first light-emitting layer 23.

[0129] In some examples, the anode layer 21 has a relatively high reflectivity, and the cathode layer 27 is a film layer having semi-transmissive and semi-reflective characteristics. Here, "semi-transmissive and semi-reflective" means that the cathode layer 27 can transmit light and reflect light, and the specific transmittance and reflectivity are not limited. This means that the light-emitting element 2a in the embodiment of the present disclosure is a top-emission light-emitting element.

[0130] Exemplarily, the reflectivity of the anode layer 21 is 80% or more.

[0131] Exemplarily, the thickness range of the cathode layer 27 is 10 nm to 20 nm. Thereby, while ensuring the conductive performance of the cathode layer 27, the transmittance of the cathode layer 27 to light can be improved, and the light-emitting efficiency of the display substrate 100 can be improved.

[0132] For example, the thickness of the cathode layer 27 may be 10 nm, 12 nm, 14 nm, 17 nm, or 20 nm, etc.

[0133] Exemplarily, the transmittance range of the cathode layer 27 for light with a wavelength of 530 nm is 45% to 60%.

[0134] For example, the transmittance may be 45%, 50%, 53%, 57%, or 60%, etc.

[0135] As shown in FIG. 6, it is understood that a microcavity A can be formed between the anode layer 21 and the cathode layer 27 based on the characteristics of the anode layer 21 and the cathode layer 27. Thereby, the light emitted from the first light-emitting layer 23 and the second light-emitting layer 25 can be reflected, interfered, etc. within the microcavity A, resulting in a microcavity effect, improving the emission luminance of the emitted light, narrowing the spectrum of the emitted light, and improving the luminous efficiency of the light-emitting element 2a. For example, the emission luminance of blue light can be improved and the spectrum of blue light can be narrowed.

[0136] In some examples, the optical thickness of the a film layers included in the first auxiliary layer 22 is L1, and L1 satisfies the following formula.

Number

[0137] In the formula, n h is the refractive index of the h-th film layer among the a film layers, and r h is the thickness of the h-th film layer.

[0138] The optical thickness of the b film layers included in the second auxiliary layer 24 is L2, and L2 satisfies the following formula.

Number

[0139] In the formula, n i is the refractive index of the i-th film layer among the b film layers, and r i is the thickness of the i-th film layer.

[0140] The optical thickness of the c film layers included in the third auxiliary layer 26 is L3, and L3 satisfies the following formula.

Number

[0141] n j is the refractive index of the j-th film layer among the above c film layers, r j is the thickness of the j-th film layer.

[0142] L1, L2, L3 satisfy the following formula.

Number

[0143] Exemplarily,

Number

[0144] By the above installation, the color purity of the light emitted by the light-emitting element 2a in the display substrate 100 can be improved. Therefore, in the display substrate 100 of the present disclosure, the installation of the filter can be reduced. As a result, the blocking of the light emitted by the light-emitting element 2a by the filter can be reduced, and the light-emitting efficiency in the display substrate 100 of the present disclosure is improved. Furthermore, the present disclosure can realize the same luminance as that in the above-described first embodiment and second embodiment while reducing the driving voltage of the pixel driving circuit 12 in the display substrate 100. As a result, the power consumption of the display substrate 100 can be reduced, and the light-emitting life of the light-emitting element 2a can be improved.

[0145] Note that the refractive index ranges of the h-th film layer, the i-th film layer, and the j-th film layer for light with a wavelength of 460 nm are all 1.7 to 2.0.

[0146] Exemplarily, the refractive indices of the h-th film layer, the i-th film layer, and the j-th film layer for light with a wavelength of 460 nm may be the same or different.

[0147] For example, the refractive indices of the h-th film layer, the i-th film layer, and the j-th film layer with respect to light having a wavelength of 460 nm are 1.7, 1.75, 1.8, 1.9, and 2.0.

[0148] In some embodiments, as shown in FIG. 3, the plurality of second light-emitting layers 25 include a plurality of second blue light-emitting layers 25B, a plurality of second red light-emitting layers 25R, and a plurality of second green light-emitting layers 25G. The wavelength of the light emitted by the first light-emitting layer 23 is smaller than the wavelength of the light emitted by at least one of the second light-emitting layers 25.

[0149] Exemplarily, the wavelength of the light emitted by the first light-emitting layer 23 is smaller than the wavelength of the light emitted by the second blue light-emitting layer 25B, or the wavelength of the light emitted by the first light-emitting layer 23 is smaller than the wavelength of the light emitted by the second red light-emitting layer 25R, or the wavelength of the light emitted by the first light-emitting layer 23 is smaller than the wavelength of the light emitted by the second green light-emitting layer 25G. Alternatively, the wavelength of the light emitted by the first light-emitting layer 23 is smaller than the wavelength of the light emitted by the second red light-emitting layer 25R and smaller than the wavelength of the light emitted by the second green light-emitting layer 25G, but the present disclosure is not limited thereto.

[0150] Exemplarily, the first light-emitting layer 23 can emit blue light, yellow light, or the like.

[0151] By making the wavelength of the light emitted by the first light-emitting layer 23 smaller than the wavelength of the light emitted by at least one of the second light-emitting layers 25, when the light emitted by the first light-emitting layer 23 is radiated to the plurality of second light-emitting layers 25, at least one of at least the second red light-emitting layer 25R, the second green light-emitting layer 25G, and the second blue light-emitting layer 25B can be excited to emit light of a corresponding color. Thereby, the light emission luminance and the light emission efficiency of the display substrate 100 are improved. Further, as shown in FIG. 5, the light emitted by the first light-emitting layer 23 can be reflected a plurality of times within the microcavity A. Thereby, the light emitted by the first light-emitting layer 23 can be radiated to the plurality of second light-emitting layers 25 a plurality of times, further improving the excitation effect of the light emitted by the first light-emitting layer 23 on at least one of the plurality of second light-emitting layers 25, and further improving the light emission luminance and the light emission efficiency of the display substrate 100.

[0152] When a plurality of second light-emitting layers 25 include a plurality of second blue light-emitting layers 25B, a plurality of second red light-emitting layers 25R, and a plurality of second green light-emitting layers 25G, the above n h is the refractive index of the h-th film layer among the above a film layers with respect to the central wavelength of red light, green light, or blue light, and the above n i is the refractive index of the i-th film layer among the above b film layers with respect to the central wavelength of red light, green light, or blue light.

[0153] Exemplarily, the wavelength range of red light is 615 nm to 630 nm, the wavelength range of green light is 515 nm to 535 nm, and the wavelength range of blue light is 460 nm to 475 nm.

[0154] In some embodiments, the first light-emitting layer 23 includes a first guest material, and the second light-emitting layer 25 includes a second guest material. The emission spectrum of the first guest material at least partially overlaps with the absorption spectrum of the second guest material of at least one color of the second light-emitting layer 25.

[0155] Note that the materials of the first light-emitting layer 23 and the second light-emitting layer 25 include a host material and a guest material doped in the host material. The host material itself has good film-forming properties and can be used in mixture with other materials having excellent light-emitting performance. The guest material itself has excellent light-emitting performance. Thus, when the first light-emitting layer 23 or the second light-emitting layer 25 is commonly formed using the host material and the guest material doped therein, the host material includes molecules in a high-excitation energy state, and the molecules in the high-excitation energy state can transfer their energy to the guest material. Therefore, the wavelength of the light emitted by the first light-emitting layer 23 or the second light-emitting layer 25 can be changed, and at the same time, the light-emitting efficiency of the first light-emitting layer 23 or the second light-emitting layer 25 can be improved.

[0156] Exemplarily, the first guest material is a material mainly used for light emission in the first light-emitting layer 23, and the second guest material is a material mainly used for light emission in the second light-emitting layer 25.

[0157] The above-mentioned "at least partially overlapping" means that the emission spectrum of the first guest material at least partially overlaps with the absorption spectrum of the second guest material in at least one color of the second light-emitting layer 25, or the emission spectrum of the first guest material entirely overlaps with the absorption spectrum of the second guest material in at least one color of the second light-emitting layer 25.

[0158] Exemplarily, the emission spectrum of the first guest material in the first light-emitting layer 23 and the absorption spectrum of the second guest material in the second red light-emitting layer 25R at least partially overlap, or the emission spectrum of the first guest material in the first light-emitting layer 23 and the absorption spectrum of the second guest material in the second green light-emitting layer 25G at least partially overlap. Or, the emission spectrum of the first guest material in the first light-emitting layer 23 and the absorption spectrum of the second guest material in the second blue light-emitting layer 25B at least partially overlap, or the emission spectrum of the first guest material in the first light-emitting layer 23 not only at least partially overlaps with the absorption spectrum of the second guest material in the second red light-emitting layer 25R, but also at least partially overlaps with the absorption spectrum of the second guest material in the second green light-emitting layer 25G. The present disclosure is not limited thereto.

[0159] By at least partially overlapping the emission spectrum of the first guest material in the first light-emitting layer 23 with the absorption spectrum of the second guest material in at least one color of the second light-emitting layer 25, a part of the light emitted by the first guest material in the first light-emitting layer 23 is absorbed by the second guest material in at least one color of the second light-emitting layer 25. As a result, the second guest material in at least one color of the second light-emitting layer 25 emits light under the excitation of the light emitted by the first guest material, so that the luminous efficiency of the second guest material in the second light-emitting layer 25 can be improved. Here, another part of the light emitted by the first guest material in the first light-emitting layer 23 is emitted through the cathode layer 27, and forms a series light-emitting element with the light emitted by the second light-emitting layer 25, so that the light-emitting luminance of the display substrate 100 can be improved.

[0160] In addition, when the light emitted by the first light-emitting layer 23 in the display substrate 100 is radiated to the second light-emitting layer 25, the second light-emitting layer 25 can absorb the light emitted by the first light-emitting layer 23 and excite the light of the corresponding color. Further, the first light-emitting layer 23 and the second light-emitting layer 25 themselves can also form a series light-emitting assembly. By the cooperation of the above two light-emitting mechanisms, the display substrate 100 can obtain higher luminous efficiency.

[0161] The more the overlapping portion between the emission spectrum of the first guest material and the absorption spectrum of the second guest material of the second light-emitting layer 25, the more the light emitted by the first guest material can excite the second guest material to emit more light, and it is understood that the luminous efficiency of the second guest material of the second light-emitting layer 25 also increases.

[0162] In some embodiments, the overlapping range between the emission spectrum of the first guest material of the first light-emitting layer 23 and the absorption spectrum of the second guest material of the second light-emitting layer 25 is 60% or more of the wavelength range of the emission spectrum of the first guest material.

[0163] For example, the overlapping range between the emission spectrum of the first guest material and the absorption spectrum of the second guest material may be 60%, 70%, 80%, 90%, or 99% of the wavelength range of the emission spectrum of the first guest material.

[0164] By this arrangement, more than 60% of all the light emitted by the first guest material can be absorbed by the second guest material, and the utilization rate of the light emitted by the first guest material by the second guest material can be improved.

[0165] In some embodiments, the overlapping range between the emission spectrum of the first guest material of the first light-emitting layer 23 and the absorption spectrum of the second guest material of the second light-emitting layer 25 is 60% or more of the wavelength range of the absorption spectrum of the second guest material.

[0166] For example, the overlapping range between the emission spectrum of the first guest material and the absorption spectrum of the second guest material may be 60%, 70%, 80%, 90%, or 99% of the wavelength range of the absorption spectrum of the second guest material.

[0167] By this arrangement, more light emitted by the first guest material can be absorbed by the second guest material, and the utilization rate of the light emitted by the first guest material by the second guest material can be improved.

[0168] In some embodiments, the peak value of the emission spectrum of the first guest material in the first light-emitting layer 23 is less than 600 nm.

[0169] Exemplarily, the peak value of the emission spectrum of the first guest material in the first light-emitting layer 23 may be 465 nm, 500 nm, 515 nm, 560 nm, or 595 nm, etc.

[0170] As described above, the shorter the wavelength of light, the higher the energy of the light. With the above arrangement, it can be ensured that the light emitted by the first light-emitting layer 23 has relatively high energy. Thereby, the second guest material in the second light-emitting layer 25 can be better excited to emit light.

[0171] In some embodiments, the first guest material in the first light-emitting layer 23 includes at least one light-emitting material. When the first guest material includes two light-emitting materials, the interval between the peak values of the emission spectra of the two light-emitting materials is 30 nm or less.

[0172] Exemplarily, the type of the light-emitting material included in the first guest material may be one or two, but the present disclosure is not limited thereto.

[0173] It is understood that different light-emitting materials can emit light of different colors. When the first guest material in the first light-emitting layer 23 includes one light-emitting material, the first light-emitting layer 23 can emit light of one color. When the first guest material in the first light-emitting layer 23 includes two light-emitting materials, the first light-emitting layer 23 can emit light of two colors.

[0174] Exemplarily, when the first guest material of the first light-emitting layer 23 includes two light-emitting materials, the interval between the peak values of the emission spectra of the two light-emitting materials may be 1 nm, 10 nm, 19 nm, 25 nm, or 30 nm, etc.

[0175] By setting the interval between the peak values of the emission spectra of the two light-emitting materials of the first guest material to 30 nm or less, the colors of the light emitted by the two light-emitting materials of the first guest material can be made more similar, and the color purity of the light emitted by the first light-emitting layer 23 can be improved.

[0176] In some embodiments, the emission spectrum of the first guest material of the first light-emitting layer 23 and the absorption spectrum of the second guest material of the second green light-emitting layer 25G have an overlap.

[0177] Exemplarily, the light emitted by the first guest material is blue light.

[0178] Exemplarily, the range of the peak value of the emission spectrum of the first guest material is 465 nm to 475 nm, and the range of the peak value of the absorption spectrum of the second guest material of the second green light-emitting layer 25G is 507 nm to 517 nm.

[0179] Exemplarily, the peak value of the emission spectrum of the first guest material may be 465 nm, 467 nm, 469 nm, 471 nm, or 475 nm, etc. The peak value of the absorption spectrum of the second guest material of the second green light-emitting layer 25G may be 507 nm, 509 nm, 512 nm, 514 nm, or 517 nm, etc.

[0180] With this arrangement, the emission spectrum of the first guest material and the absorption spectrum of the second guest material can have a larger overlapping range, so that the emission efficiency of the second guest material of the second light-emitting layer 25 can be improved.

[0181] In some embodiments, the emission spectrum of the first guest material in the first light-emitting layer 23 and the absorption spectrum of the second guest material in the two-color second light-emitting layer 25 have an overlap.

[0182] Exemplarily, the light emitted by the first guest material is green light.

[0183] Exemplarily, the range of the peak value of the emission spectrum of the first guest material is 525 nm to 535 nm, the range of the peak value of the absorption spectrum of the second guest material in the second green light-emitting layer 25G is 510 nm to 520 nm, and the range of the peak value of the absorption spectrum of the second guest material in the second red light-emitting layer 25R is 595 nm to 605 nm.

[0184] Exemplarily, the peak value of the emission spectrum of the first guest material may be 525 nm, 527 nm, 529 nm, 531 nm, or 535 nm, etc. The peak value of the absorption spectrum of the second guest material in the second green light-emitting layer 25G may be 510 nm, 514 nm, 516 nm, 518 nm, or 520 nm, etc. The peak value of the absorption spectrum of the second guest material in the second red light-emitting layer 25R may be 595 nm, 597 nm, 600 nm, 602 nm, or 605 nm, etc.

[0185] By this arrangement, the emission spectrum of the first guest material in the first light-emitting layer 23 and the absorption spectra of the second guest materials in the plurality of second light-emitting layers 25 can have a larger overlapping range, so that the luminous efficiency of the second guest material in the second light-emitting layer 25 can be improved.

[0186] In some embodiments, when the first guest material in the first light-emitting layer 23 includes two kinds of light-emitting materials, at least one of the two kinds of light-emitting materials is doped with a boron element, and the range of the doping ratio of the boron element is 0.5% to 5%.

[0187] Exemplarily, the doping ratio of the boron element may be 0.5%, 1.5%, 3.5%, 4%, or 5%, etc.

[0188] In some embodiments, the first guest material of the first light-emitting layer 23 includes at least one of a fluorescent material, a phosphorescent material, and a thermally activated delayed fluorescence material.

[0189] Exemplarily, the fluorescent materials include pyrene-based, condensed carbazole-based, and boron-containing materials. The phosphorescent materials include iridium (Ir) and platinum (Pt) complexes. The thermally activated delayed fluorescence materials generally have a D-A structure, and the thermally activated delayed fluorescence materials have S1-T1 < 0.3 eV, where S1 represents the energy level of the excited singlet state of the material and T1 represents the energy level of the triplet electron excitation of the material.

[0190] In some embodiments, the first light-emitting layer 23 further includes a first host material. The first host material of the first light-emitting layer 23 includes a single host material or a PN hybrid host material.

[0191] Exemplarily, the first host material includes at least one of anthracene-based materials, fluorene-based materials, pyrene-based materials, and carbazole-based derivative materials. In some embodiments, the thickness range of the first light-emitting layer 23 is 15 nm to 60 nm.

[0192] Exemplarily, the thickness of the first light-emitting layer 23 may be 15 nm, 20 nm, 35 nm, 45 nm, or 60 nm, etc.

[0193] In some embodiments, the second guest material of the at least one-color second light-emitting layer 25 includes at least one light-emitting material. When the second guest material includes two light-emitting materials, the interval between the peak values of the emission spectra of the two light-emitting materials is 30 nm or less.

[0194] Optionally, the second red light-emitting layer may include at least one light-emitting material, or the second green light-emitting layer may include at least one light-emitting material, or the second blue light-emitting layer may include at least one light-emitting material. Optionally, both the second red light-emitting layer and the second green light-emitting layer may include at least one light-emitting material.

[0195] Exemplarily, the type of the luminescent material included in the second guest material may be one or two types. The present disclosure is not limited thereto.

[0196] Different luminescent materials can emit lights of different colors. When the second guest material of the second light-emitting layer 25 includes one type of luminescent material, the second light-emitting layer 25 can emit light of one color. When the second guest material of the second light-emitting layer 25 includes two types of luminescent materials, it is understood that the second light-emitting layer 25 can emit lights of two colors.

[0197] Exemplarily, when the second guest material of the second light-emitting layer 25 includes two types of luminescent materials, the emission spectrum of one of the two types of luminescent materials has an overlapping range with the absorption spectrum of the other luminescent material. By this arrangement, the luminous efficiency of the two types of luminescent materials can be improved.

[0198] Exemplarily, when the second guest material of the second light-emitting layer 25 includes two types of luminescent materials, the interval between the peak values of the emission spectra of the two types of luminescent materials may be 1 nm, 10 nm, 19 nm, 25 nm, or 30 nm, etc.

[0199] By setting the interval between the peak values of the emission spectra of the two types of luminescent materials in the second guest material of the second light-emitting layer 25 to 30 nm or less, the colors of the lights emitted by the two types of luminescent materials in the second guest material can be made more approximate, and the color purity of the light emitted by the second light-emitting layer 25 can be improved.

[0200] In some embodiments, when the second guest material of at least one color of the second light-emitting layer 25 includes two types of luminescent materials, at least one of the two types of luminescent materials is doped with a boron element, and the doping ratio range of the boron element is 0.5% to 5%.

[0201] Exemplarily, the doping ratio of the boron element may be 0.5%, 1.5%, 3.5%, 4%, or 5%, etc.

[0202] In some embodiments, the second guest material includes at least one of a fluorescent material, a phosphorescent material, and a thermally activated delayed fluorescent material having multiple resonance characteristics.

[0203] In some embodiments, at least one color of the second light-emitting layer 25 further includes a second host material. The second host material includes a bipolar host material.

[0204] In some embodiments, the second host material is a single host material or a PN hybrid host material.

[0205] In some examples, when the second host material is a PN hybrid host material, the N-type component has thermally activated delayed fluorescence characteristics.

[0206] In addition, when the N-type component has thermally activated delayed fluorescence characteristics, the luminous efficiency of the second guest material in the second light-emitting layer 25 can be improved.

[0207] In some embodiments, the thickness range of the second light-emitting layer 25 is 10 nm to 50 nm.

[0208] Exemplarily, the thickness of the second light-emitting layer 25 may be 10 nm, 20 nm, 28 nm, 38 nm, or 50 nm, etc.

[0209] In some embodiments, as shown in FIG. 6, the microcavity A includes a plurality of sub-microcavities A1. The plurality of sub-microcavities A1 include a red sub-microcavity A1-R corresponding to the second red light-emitting layer 25R, a green sub-microcavity A1-G corresponding to the second green light-emitting layer 25G, and a blue sub-microcavity A1-B corresponding to the second blue light-emitting layer 25B. The number of film layers corresponding to any one color of the sub-microcavities A1 located between the anode layer 21 and the cathode layer 27 is d, and the optical thickness of the d film layers is L, and L satisfies the following formula.

Equation

[0210] In the formula, d is a positive integer, n m is the refractive index of the m-th film layer among the above d film layers, r m is the thickness of the m-th film layer, k is a natural number, λ is the target spectral peak wavelength, and φ is the phase shift caused after the target light is reflected by the anode layer 21.

[0211] In addition, when a plurality of second light-emitting layers 25 include a plurality of second blue light-emitting layers 25B, a plurality of second red light-emitting layers 25R, and a plurality of second green light-emitting layers 25G, the above n m is the refractive index of the m-th film layer among the above d film layers with respect to the central wavelength of red light, green light, or blue light.

[0212] Exemplarily, when necessary for the interference of blue light, the above λ is the wavelength of blue light; when necessary for the interference of red light, the above λ is the wavelength of red light; and when necessary for the interference of green light, the above λ is the wavelength of green light.

[0213] Exemplarily, when the L of the red sub-microcavity A1-R satisfies the above formula, the red light emitted by the second red light-emitting layer 25R can cause a microcavity effect within the red sub-microcavity A1-R. Thereby, the luminance of the red light can be increased, and the color purity of the red light can be increased.

[0214] Similarly, the green light emitted by the second green light-emitting layer 25G and the blue light emitted by the second blue light-emitting layer 25B also cause a microcavity effect within the corresponding sub-microcavity A1. Thereby, the luminance of the green light and the blue light can be increased, and the color purity of the green light and the blue light can be increased.

[0215] In some embodiments, the length of the blue sub-microcavity A1-B is smaller than the length of the red sub-microcavity A1-R. The length of the blue sub-microcavity A1-B is smaller than the length of the green sub-microcavity A1-G.

[0216] Exemplarily, the wavelength range of red light is 615 nm to 630 nm, the wavelength range of green light is 515 nm to 535 nm, and the wavelength range of blue light is 460 nm to 475 nm. Therefore, when red light, green light, and blue light can all cause the microcavity effect, the length of the blue sub-microcavity A1-B is the smallest.

[0217] Note that any one of the first auxiliary layer 22, the second auxiliary layer 24, and the third auxiliary layer 26 may include one film layer or a plurality of film layers stacked in sequence. When any one of the first auxiliary layer 22, the second auxiliary layer 24, and the third auxiliary layer 26 includes a plurality of film layers, each film layer can have different functions. Thereby, a plurality of functions can be imparted to the first auxiliary layer 22, the second auxiliary layer 24, and the third auxiliary layer 26.

[0218] In some examples, as shown in FIG. 7, the first auxiliary layer 22 includes a light-transmissive conductive layer 221, a hole injection layer 222, a first hole transport layer 223, and an electron blocking layer 224.

[0219] The light-transmissive conductive layer 221 has good light transmissivity and conductivity. When light irradiates the light-transmissive conductive layer 221, the light can pass through the light-transmissive conductive layer 221 and irradiate the anode layer 21. Since the light reflection performance of the anode layer 21 is relatively good, the light can be reflected by the anode layer 21 and the light-transmissive conductive layer 221.

[0220] Exemplarily, the material of the light-transmissive conductive layer 221 may include, for example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), and the like.

[0221] Exemplarily, the thickness of the light-transmissive conductive layer 221 is 10 nm or less. Optionally, the thickness range of the light-transmissive conductive layer 221 is 5 nm to 10 nm.

[0222] For example, the thickness of the light-transmissive conductive layer 221 may be 5 nm, 6.5 nm, 8 nm, 9 nm, or 10 nm, etc.

[0223] Exemplarily, the hole injection layer 222 can be formed by doping the material of the first hole transport layer 223 with a P-type dopant (e.g., MnO3, F4TCNQ, etc.). The doping ratio of the P-type dopant is 5% or less, and the thickness of the hole injection layer 222 is 10 nm or less.

[0224] For example, the doping ratio of the P-type dopant in the material of the first hole transport layer 223 may be 1%, 2%, 3%, 4%, or 5%, etc. The thickness of the hole injection layer 222 may be 1 nm, 3 nm, 5 nm, 8 nm, or 10 nm, etc.

[0225] Exemplarily, the material of the first hole transport layer 223 includes a carbazole-based material with a relatively high hole mobility. The first hole transport layer 223 can be manufactured and formed by a vapor deposition process.

[0226] Exemplarily, the thickness of the electron blocking layer 224 is 10 nm or less. For example, the thickness of the electron blocking layer 224 may be 1 nm, 3 nm, 5 nm, 8 nm, or 10 nm, etc.

[0227] Exemplarily, the HOMO (Highest Occupied Molecular Orbital) energy levels of the materials of the hole injection layer 222, the first hole transport layer 223, and the electron blocking layer 224 increase sequentially. By this arrangement, the injection barrier of holes can be reduced, the hole mobility can be increased, which is advantageous for holes to be injected from the anode layer 21 and sequentially transported into the first light-emitting layer 23. Thereby, the accumulation amount of holes in the first light-emitting layer 23 can be improved, and the light-emitting efficiency and light-emitting lifetime of the first light-emitting layer 23 can be improved.

[0228] Exemplarily, the range of the HOMO energy level of the material of the first hole transport layer 223 is -5.2 eV to -5.6 eV. For example, the HOMO energy level of the material of the first hole transport layer 223 may be -5.2 eV, -5.3 eV, -5.4 eV, -5.5 eV, or -5.6 eV, etc.

[0229] Exemplarily, the range of the HOMO energy level of the material of the electron blocking layer 224 is -5.5 eV to -5.9 eV. For example, the HOMO energy level of the material of the electron blocking layer 224 includes -5.5 eV, -5.6 eV, -5.7 eV, -5.8 eV, -5.9 eV, etc.

[0230] Exemplarily, T1 of the material of the electron blocking layer 224 is greater than T1 of the luminescent material in the first light-emitting layer 23. Thereby, it is possible to prevent electrons and / or excitons from leaking from the first light-emitting layer 23, maintain the concentration of electrons and / or excitons in the first light-emitting layer 23, and ensure the luminous efficiency of the first light-emitting layer 23.

[0231] For example, T1 of the material of the electron blocking layer 224 is at least 0.2 eV higher than T1 of the luminescent material in the first light-emitting layer 23.

[0232] In some examples, as shown in FIG. 7, the second auxiliary layer 24 includes a first hole blocking layer 241, a first electron transport layer 242, a first charge generation layer 243, a second charge generation layer 244, and a microcavity adjustment layer 245.

[0233] Exemplarily, the absolute value of the HOMO energy level of the material of the first hole blocking layer 241 is greater than the absolute value of the HOMO energy level of the material of the first light-emitting layer 23. The first hole blocking layer 241 is used to prevent holes and / or excitons from leaking from the first light-emitting layer 23.

[0234] For example, the absolute value of the HOMO energy level of the material of the first hole blocking layer 241 is at least 0.2 eV greater than the absolute value of the HOMO energy level of the material of the first light-emitting layer 23.

[0235] Exemplarily, T1 of the material of the first hole blocking layer 241 is higher than T1 of the light emitting material contained in the first light emitting layer 23.

[0236] For example, T1 of the material of the first hole blocking layer 241 is at least 0.2 eV higher than T1 of the light emitting material contained in the first light emitting layer 23.

[0237] Exemplarily, the material of the first hole blocking layer 241 includes a triazine-based material or the like.

[0238] Exemplarily, the thickness of the first hole blocking layer 241 is 10 nm or less. For example, the thickness of the first hole blocking layer 241 is 1 nm, 3 nm, 5 nm, 8 nm, or 10 nm or the like.

[0239] Exemplarily, the material of the first electron transport layer 242 includes at least one material among a thiophene-based material, an imidazole-based material, an azine-based derivative material, and lithium quinolate. The first electron transport layer 242 can be obtained by blending a thiophene-based, imidazole-based, or azine derivative or the like with lithium quinolate, where the mass ratio range of lithium quinolate is 30% to 70%.

[0240] For example, the mass ratio of the above lithium quinolate is 30%, 40%, 50%, 60%, or 70% or the like.

[0241] Exemplarily, the thickness range of the first electron transport layer 242 is 15 nm to 50 nm. For example, the thickness of the first electron transport layer 242 is 15 nm, 23 nm, 35 nm, 40 nm, or 50 nm or the like.

[0242] Exemplarily, the first charge generation layer 243 and the second charge generation layer 244 are used to improve the overall light emission luminance of the display substrate 100 by forming the first light emitting layer 23 and the second light emitting layer 25 in the light emitting element layer 2 in series light emission.

[0243] Exemplarily, the first charge generation layer 243 can be formed by doping the material of the first electron transport layer 242 with a low work function metal (such as lithium (Li), ytterbium (Yb), calcium (Ca), etc.), and the doping ratio is 5% or less. The thickness of the first charge generation layer 243 is 10 nm or less.

[0244] For example, the doping ratio of the low work function metal may be 1%, 2%, 3%, 4%, or 5%, etc. The thickness of the first charge generation layer 243 may be 1 nm, 3 nm, 5 nm, 8 nm, or 10 nm, etc.

[0245] Exemplarily, the second charge generation layer 244 can be formed by doping the material of the second hole transport layer 245 described later with a P-type dopant (for example, MnO3 or F4TCNQ, etc.), and the doping ratio is 5% or less. The thickness of the first charge generation layer 243 is 10 nm or less.

[0246] For example, the doping ratio of the P-type dopant may be 1%, 2%, 3%, 4%, or 5%, etc. The thickness of the second charge generation layer 244 may be 1 nm, 3 nm, 5 nm, 8 nm, or 10 nm, etc.

[0247] Optionally, the first charge generation layer 243 may also be referred to as an N-type charge generation layer (N-CGL), and the second charge generation layer 244 may also be referred to as a P-type charge generation layer (P-CGL).

[0248] Exemplarily, the thickness of the microcavity adjustment layer 245 is adjustable, and by adjusting the thickness of the microcavity adjustment layer 245, the lengths of the plurality of sub-microcavities A1 can be adjusted, and all the light corresponding to the plurality of sub-microcavities A1 can be made to generate a microcavity effect.

[0249] In some embodiments, as shown in FIG. 6, the microcavity adjustment layer 245 includes a second hole transport layer 2451, a red sub-microcavity adjustment layer 245R provided between the second hole transport layer 2451 and the second red light-emitting layer 25R, a green sub-microcavity adjustment layer 245G provided between the second hole transport layer 2451 and the second green light-emitting layer 25G, and a blue sub-microcavity adjustment layer 245B provided between the second hole transport layer 2451 and the second blue light-emitting layer 25B. Here, the thickness between the red sub-microcavity adjustment layer 245R and the blue sub-microcavity adjustment layer 245B is different, and the thickness between the green sub-microcavity adjustment layer 245G and the blue sub-microcavity adjustment layer 245B is different.

[0250] Exemplarily, the material of the second hole transport layer 245 includes a carbazole-based material with a relatively high hole mobility. The second hole transport layer 245 can be manufactured and formed by a vapor deposition process.

[0251] Exemplarily, the second hole transport layer 245 is used to reduce the hole injection barrier and increase the hole mobility, which is advantageous for transporting holes into the second light-emitting layer 25. Thereby, the accumulation amount of holes in the second light-emitting layer 25 can be improved, and the light-emitting efficiency and light-emitting lifetime of the second light-emitting layer 25 can be improved.

[0252] For example, the range of the HOMO energy level of the material of the second hole transport layer 245 is -5.2 eV to -5.6 eV. For example, the HOMO energy level of the material of the second hole transport layer 245 includes -5.2 eV, -5.3 eV, -5.4 eV, -5.5 eV, -5.6 eV, etc.

[0253] Exemplarily, the T1 of the materials of the red sub-microcavity adjustment layer 245R, the green sub-microcavity adjustment layer 245G, and the blue sub-microcavity adjustment layer 245B is higher than the T1 of the light-emitting material of the second light-emitting layer 25.

[0254] For example, T1 of the materials of the red sub-microcavity adjustment layer 245R, the green sub-microcavity adjustment layer 245G, and the blue sub-microcavity adjustment layer 245B is at least 0.2 eV higher than T1 of the light-emitting material of the second light-emitting layer 25.

[0255] Exemplarily, the thickness of the blue sub-microcavity adjustment layer 245B is 10 nm or less.

[0256] For example, the thickness of the blue sub-microcavity adjustment layer 245B may be 1 nm, 3 nm, 5 nm, 7 nm, or 10 nm, etc.

[0257] Exemplarily, the thickness of the second hole transport layer 2451, the thickness of the red sub-microcavity adjustment layer 245R, the thickness of the green sub-microcavity adjustment layer 245G, and the thickness of the blue sub-microcavity adjustment layer 245B can all be adjusted individually. By adjusting the thickness of the second hole transport layer 2451, the thickness of the red sub-microcavity adjustment layer 245R, the thickness of the green sub-microcavity adjustment layer 245G, and the thickness of the blue sub-microcavity adjustment layer 245B, the lengths of the plurality of sub-microcavities A1 can be adjusted, and the light corresponding to the plurality of sub-microcavities A1 can all be made to generate a microcavity effect.

[0258] As described above, the wavelengths of red light, green light, and blue light are different. When red light, green light, and blue light can all generate the microcavity effect, the length between the red light sub-microcavity A1-R and the blue light sub-microcavity A1-B is different, and the length between the green light sub-microcavity A1-G and the blue light sub-microcavity A1-B is different. As shown in FIG. 6, the plurality of sub-microcavities A1 share a part of the film layers in the first auxiliary layer 22, the first light-emitting layer 23, the second auxiliary layer 24, and the third auxiliary layer 26. By making the thicknesses different between the red sub-microcavity adjustment layer 245R and the blue sub-microcavity adjustment layer 245B in the second auxiliary layer 24, and making the thicknesses different between the green sub-microcavity adjustment layer 245G and the blue sub-microcavity adjustment layer 245B in the second auxiliary layer 24, only by adjusting the thicknesses of the red sub-microcavity adjustment layer 245R, the green sub-microcavity adjustment layer 245G, and the blue sub-microcavity adjustment layer 245B, the plurality of sub-microcavities A1 can be made to satisfy the desired length, and the above-mentioned shared film layers (for example, the first auxiliary layer 22, the first light-emitting layer 23, and the third auxiliary layer 26, etc.) in the blue sub-microcavity A1-B, the red sub-microcavity A1-R, and the green sub-microcavity A1-G can also be made to have the same thickness. Thereby, the manufacturing process of the above-mentioned shared film layer can be simplified, and correspondingly, the manufacturing process of the display substrate 100 can be simplified.

[0259] Note that the thicknesses of the second hole transport layer 2451, the red sub-microcavity adjustment layer 245R, the green sub-microcavity adjustment layer 245G, and the blue sub-microcavity adjustment layer 245B have a relatively small influence on the electrical performance of the light-emitting element layer 2 in the display substrate 100. By adjusting the thicknesses of the second hole transport layer 2451, the red sub-microcavity adjustment layer 245R, the green sub-microcavity adjustment layer 245G, and the blue sub-microcavity adjustment layer 245B, the length of the plurality of sub-microcavities A1 can be adjusted, and the influence on the electrical performance of the light-emitting element layer 2 in the display substrate 100 can be reduced.

[0260] Any one of the red sub-micro cavity adjustment layer 245R, the green sub-micro cavity adjustment layer 245G, and the blue sub-micro cavity adjustment layer 245B may include one film layer, or any one of the red sub-micro cavity adjustment layer 245R, the green sub-micro cavity adjustment layer 245G, and the blue sub-micro cavity adjustment layer 245B may include a plurality of film layers stacked in sequence.

[0261] In some embodiments, as shown in FIG. 3, the red sub-micro cavity adjustment layer 245R includes a red hole transport layer 245R-1 and a red electron blocking layer 245R-2 stacked in sequence in a direction away from the back plate 1, and the green sub-micro cavity adjustment layer 245G includes a green hole transport layer 245G-1 and a green electron blocking layer 245G-2 stacked in sequence in a direction away from the back plate 1.

[0262] Exemplarily, the red hole transport layer 245R-1 can reduce the hole injection barrier, which is beneficial for holes to be injected from the second auxiliary layer 24 and transported into the second red light-emitting layer 25G. Thereby, the accumulation amount of holes in the second red light-emitting layer 25G can be improved, and the light-emitting efficiency and light-emitting lifetime of the second red light-emitting layer 25G can be improved. The green hole transport layer 245G-1 can reduce the hole injection barrier, which is beneficial for holes to be injected from the second auxiliary layer 24 and transported into the second green light-emitting layer 25G. Thereby, the accumulation amount of holes in the second green light-emitting layer 25G can be improved, and the light-emitting efficiency and light-emitting lifetime of the second green light-emitting layer 25G can be improved.

[0263] Exemplarily, the red electron blocking layer 245R-2 is used to block electrons and / or excitons from overflowing from the second red light-emitting layer 25G, and can confine the electrons and / or excitons within the second red light-emitting layer 25G. Thereby, in order to improve the concentration of electrons and / or excitons in the second red light-emitting layer 25G, the light-emitting luminance and light-emitting efficiency of the second red light-emitting layer 25G are improved. The green electron blocking layer 245G-2 is used to block electrons and / or excitons from overflowing from the second green light-emitting layer 25G, and can confine the electrons and / or excitons within the second green light-emitting layer 25G. Thereby, in order to improve the concentration of electrons and / or excitons in the second green light-emitting layer 25G, the light-emitting luminance and light-emitting efficiency of the second green light-emitting layer 25G are improved.

[0264] In some examples, the red hole transport layer 245R-1 and the green hole transport layer 245G-1 are respectively used to adjust the length of the sub-microcavity A1.

[0265] When the thicknesses of other film layers (for example, the first auxiliary layer 22, the first light-emitting layer 23, etc.) are not changed, it is understood that by changing the thicknesses of the red hole transport layer 245R-1 and the green hole transport layer 245R-1, the lengths of the corresponding red sub-microcavity A1-R and green sub-microcavity A1-G can be changed.

[0266] Exemplarily, by changing the thickness of the red hole transport layer 245R-1, the length of the red sub-microcavity A1-R can be changed. Thereby, red light can generate a microcavity effect in the red sub-microcavity A1-R, and the luminance and color purity of the red light can be improved. Furthermore, the wavelength of light capable of generating a microcavity effect within the red sub-microcavity A1-R can also be changed. Thereby, the color of the light emitted from the red sub-microcavity A1-R can be adjusted. By changing the thickness of the green hole transport layer 245R-1, the length of the green sub-microcavity A1-G can be changed. Thereby, green light can generate a microcavity effect in the green sub-microcavity A1-G, and the luminance and color purity of the green light can be improved. Furthermore, the wavelength of light capable of generating a microcavity effect within the green sub-microcavity A1-G can also be changed. Thereby, the color of the light emitted from the green sub-microcavity A1-G can be adjusted.

[0267] In some examples, as shown in FIG. 7, the third auxiliary layer 26 includes a second hole blocking layer 261, a second electron transport layer 262, and an electron injection layer 263.

[0268] Exemplarily, the absolute value of the HOMO energy level of the material of the second hole blocking layer 261 is greater than the absolute value of the HOMO energy level of the material of the second light emitting layer 25. The second hole blocking layer 261 is used to prevent holes and / or excitons from leaking from the second light emitting layer 25.

[0269] For example, the absolute value of the HOMO energy level of the material of the second hole blocking layer 261 is at least 0.2 eV greater than the absolute value of the HOMO energy level of the material of the second light emitting layer 25.

[0270] Exemplarily, the T1 of the material of the second hole blocking layer 261 is higher than the T1 of the light emitting material included in the second light emitting layer 25.

[0271] For example, T1 of the material of the second hole blocking layer 261 is at least 0.2 eV higher than T1 of the light-emitting material included in the second light-emitting layer 25.

[0272] Exemplarily, the material of the second hole blocking layer 261 includes a triazine-based material or the like.

[0273] Exemplarily, the thickness of the second hole blocking layer 261 is 10 nm or less. For example, the thickness of the second hole blocking layer 261 may be 1 nm, 3 nm, 5 nm, 8 nm, or 10 nm, etc.

[0274] Exemplarily, the material of the second electron transport layer 262 includes at least one of a thiophene-based material, an imidazole-based material, an azine-based derivative material, and lithium quinolate. The second electron transport layer 262 can be obtained by blending a thiophene-based material, an imidazole-based material, or an azine derivative material with lithium quinolate, where the mass ratio range of lithium quinolate is 30% to 70%.

[0275] For example, the mass ratio of the above lithium quinolate may be 30%, 40%, 50%, 60%, or 70%, etc.

[0276] Exemplarily, the thickness range of the second electron transport layer 262 is 15 nm to 50 nm. For example, the thickness of the second electron transport layer 262 may be 15 nm, 23 nm, 35 nm, 40 nm, or 50 nm, etc.

[0277] Exemplarily, the electron injection layer 263 is used to reduce the electron injection barrier, which is advantageous for electrons to be injected from the cathode layer 27 and transported into the second light-emitting layer 25. Thereby, the accumulation amount of electrons in the second light-emitting layer 25 can be improved, and the light-emitting efficiency and light-emitting lifetime of the second light-emitting layer 25 can be improved.

[0278] Exemplarily, the material of the electron injection layer 263 includes lithium fluoride (LiF), ytterbium (Yb), calcium (Ca), etc. The electron injection layer 263 can be manufactured and formed by a vapor deposition process.

[0279] Exemplarily, the thickness range of the electron injection layer 263 is 0.5 nm to 2 nm. For example, the thickness of the electron injection layer 263 may be 0.5 nm, 0.8 nm, 1.2 nm, 1.7 nm, or 2 nm, etc.

[0280] In some examples, as shown in FIG. 7, the display substrate 100 further includes an optical coating layer 3 and / or a sealing layer 4 sequentially stacked on the cathode layer 27.

[0281] Exemplarily, the material of the optical coating layer 3 includes a high refractive index organic material. For example, the refractive index of the optical coating layer 3 for light with a wavelength of 530 nm is greater than 1.9.

[0282] Exemplarily, the thickness of the optical coating layer 3 is 100 nm or less. For example, the thickness of the optical coating layer 3 may be 10 nm, 30 nm, 50 nm, 80 nm, or 100 nm, etc.

[0283] Exemplarily, the sealing layer 4 can prevent the film layers (e.g., the first light emitting layer 23, the second light emitting layer 25, etc.) in the display substrate 100 from contacting moisture and oxygen in the air, reduce the aging rate of the film layers, and extend the service life of the display substrate 100.

[0284] Exemplarily, the sealing type of the sealing layer 4 includes sealant sealing or film sealing, etc.

[0285] Note that the plurality of second light emitting layers 25 are located in the same layer and constitute one light emitting layer group. The present disclosure does not limit the number of the first light emitting layers 23 and the number of the light emitting layer groups, that is, the number of the first light emitting layers 23 and the number of the light emitting layer groups may be one or more.

[0286] In some examples, as shown in FIG. 8, the number of the first light-emitting layers 23 is plural, a second auxiliary layer 24 is provided between any two adjacent first light-emitting layers 23, and / or, as shown in FIG. 9, the number of the light-emitting layer groups is plural, and a third auxiliary layer 26 is provided between any two adjacent light-emitting layer groups.

[0287] Exemplarily, the number of the first light-emitting layers 23 is, for example, 2, 3, 4, 5, or 6.

[0288] By providing a plurality of the first light-emitting layers 23, the total intensity of the light that the first light-emitting layers 23 can emit can be increased, so that the intensity of the excitation light of the second light-emitting layer 25 can be increased, and the light-emitting luminance of the display substrate 100 can be increased.

[0289] By providing a plurality of light-emitting layer groups, the total intensity of the light that the light-emitting layer groups can emit can be increased. Thereby, the absorption of the light emitted by the first light-emitting layers 23 by the light-emitting layer groups can be increased, so that the intensity of the excitation light of the light-emitting layer groups can be increased, and the light-emitting luminance of the display substrate 100 can be increased.

[0290] By providing the second auxiliary layer 24 between any two adjacent first light-emitting layers 23 and providing the third auxiliary layer 26 between any two adjacent light-emitting layer groups, it is ensured that holes and electrons can be transported to the plurality of first light-emitting layers 23 and the light-emitting layer groups to generate excitons, so that the first light-emitting layers 23 and the light-emitting layer groups can emit light.

[0291] The inventor of the present disclosure verified the color purity and light-emitting efficiency of the display substrate 100 of the present disclosure.

[0292] Verification Example 1: It includes Comparative Example 1 and Example 1.

[0293] One display substrate in Comparative Example 1 has a red light-emitting element, a green light-emitting element, and a blue light-emitting element, and the other display substrate has a first blue light-emitting element. Both of the two display substrates include an anode layer, a light-transmissive conductive layer, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer (e.g., a red light-emitting layer, a green light-emitting layer, or a blue light-emitting layer), a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode layer that are sequentially stacked.

[0294] In Comparative Example 1 above, the red light-emitting layer in the red light-emitting element includes a red host material and a red phosphorescent material, and the mass ratio of the red phosphorescent material is 5%. The green light-emitting layer in the green light-emitting element includes a green host material and a green phosphorescent material having multiple resonance characteristics, and the mass ratio of the green phosphorescent material is 5%. The blue light-emitting layer in the blue light-emitting element includes a blue host material and a dark blue fluorescent material (the peak value of the emission spectrum is 460 nm), and the mass ratio of the dark blue fluorescent material is 5%. The blue light-emitting layer of the first blue light-emitting element includes a normal P-type blue host material, a blue light-emitting material having thermally activated delayed fluorescence characteristics (the peak value of the emission spectrum is 500 nm), and a boron-containing blue fluorescent material having multiple resonance characteristics (the peak value of the emission spectrum is 470 nm), and the mass ratios of the above three materials are 79%, 20%, and 1% respectively.

[0295] The thicknesses of the respective film layers corresponding to the light-emitting elements in each display substrate of Comparative Example 1 are shown in Table 1 below.

Table 1

[0296] The display substrate 100 of Example 1 has a red light-emitting element, a green light-emitting element, and a blue light-emitting element. The display substrate 100 includes an anode layer, a light-transmissive conductive layer, a hole injection layer, a first hole transport layer, an electron blocking layer, a first light-emitting layer, a first hole blocking layer, a first electron transport layer, a first charge generation layer, a second charge generation layer, a second hole transport layer, a color microcavity adjustment layer for each color, a second light-emitting layer for each color, a second hole blocking layer, a second electron transport layer, an electron injection layer, and a cathode layer.

[0297] In Example 1, the material of the first light-emitting layer 23 is the same as the light-emitting layer material of the first blue light-emitting element in Comparative Example 1, and includes a normal P-type blue host material, a blue light-emitting material having thermally activated delayed fluorescence characteristics (the peak value of the emission spectrum is 500 nm), and a boron-containing blue fluorescent material having multi-resonance characteristics (the peak value of the emission spectrum is 470 nm), and the mass ratios of the above three materials are 79%, 20%, and 1% respectively.

[0298] In Example 1, the second light-emitting layer 25 in the red light-emitting element includes a red host material and a red phosphorescent material, and the mass ratio of the red phosphorescent material is 5%. The second light-emitting layer 25 in the green light-emitting element includes a green host material and a green phosphorescent material having multi-resonance characteristics, and the mass ratio of the green phosphorescent material is 5%. The second light-emitting layer 25 in the blue light-emitting element includes a blue host material and a dark blue fluorescent material (the peak value of the emission spectrum is 460 nm), and the mass ratio of the dark blue fluorescent material is 5%.

[0299] The thicknesses of the respective film layers corresponding to the respective light-emitting elements in the display substrate 100 of Example 1 are shown in Table 2 below.

Table 2

[0300] Here, in Comparative Example 1 and Example 1, the P-type doping ratio of the hole injection layer is 3%. The material of the cathode layer is a magnesium-silver alloy, and the mass ratio of magnesium to silver in the magnesium-silver alloy is 1:9. The material of the electron transport layer is lithium (8-hydroxyquinoline).

[0301] As shown in FIG. 10, the horizontal axis of the graph is wavelength, with the unit being nm, and the vertical axis is the relative intensity of the spectrum. The emission spectra p1 of the emission layer of the first blue light-emitting element in Comparative Example 1 and the first emission layer 23 of the blue light-emitting element in Example 1 clearly have double-peak characteristics. The above double-peak characteristics are due to the superposition of the emission spectra of a blue light-emitting material having thermally activated delayed fluorescence characteristics (the peak value of the emission spectrum is 500 nm) and a boron-containing blue fluorescent material having multi-resonance characteristics (the peak value of the emission spectrum is 470 nm) in the material of the first emission layer 23. The absorption spectrum p2 of the red phosphorescent material of the second emission layer 25 of the red light-emitting element in Example 1 and the emission spectrum p1 of the first emission layer 23 of the blue light-emitting element have an overlap. Table 3 shows the comparison relationships of each related quantity in Comparative Example 1 and Example 1 with the first blue light-emitting element.

[0302] Here, the driving voltage of the first blue light-emitting element is 4.5 V, the emission luminance is 1000, the color coordinates are (0.17, 0.32), and the luminous efficiency is 38 cd / A.

Table 3

[0303] As can be seen from the above results, after combining the first emission layer 23 and the second emission layer 25 in series in the light-emitting element in Example 1, compared with Comparative Example 1, both the blue light-emitting element and the green light-emitting element showed several times improvement in efficiency and several times improvement in lifespan at the same luminance. Since the red light-emitting element of the second emission layer 25 does not contain a light-emitting material that can be excited by the light emitted by the first emission layer 23, the red light-emitting element of the second emission layer 25 maintains the original efficiency level, and the color purity of the red light emitted by the red emission layer is also not affected by the adjustment of the microcavity. Although the lifespan of the red emission layer decreases, it still maintains a relatively high level.

[0304] Verification Example 2: It includes Comparative Example 2 and Example 2.

[0305] One display substrate in Comparative Example 2 has a red light-emitting element, a green light-emitting element, and a blue light-emitting element, and the other display substrate has a first green light-emitting element. The film layers included in the two display substrates are the same as the film layers included in the display substrate in Comparative Example 1.

[0306] In Comparative Example 2, the light-emitting layer in the red light-emitting element includes a P-type red host material, an N-type red host material having thermally activated delayed fluorescence characteristics, and a red fluorescent light-emitting material, and the mass ratios of the above three materials are 69%, 30%, and 1% respectively. The light-emitting layer in the green light-emitting element includes a green host material and a green light-emitting material having multiple resonance characteristics, and the mass ratio of the green light-emitting material is 1%. The light-emitting layer in the blue light-emitting element includes a blue host material and a dark blue fluorescent material (the peak value of the emission spectrum is 460 nm), and the mass ratio of the dark blue fluorescent material is 5%.

[0307] The thicknesses of the respective film layers corresponding to the respective light-emitting elements in the display substrate of Comparative Example 2 are shown in Table 4 below.

Table 4

[0308] The structure of the display substrate 100 in Example 2 is the same as the structure of the display substrate 100 in Example 1.

[0309] In Example 2, the material of the first light-emitting layer 23 is the same as the material of the light-emitting layer of the first green light-emitting element in Comparative Example 2, and includes a normal P-type green host material and a green light-emitting material having thermally activated delayed fluorescence characteristics (the peak value of the emission spectrum is 460 nm), and the mass ratio of the green light-emitting material having the above thermally activated delayed fluorescence characteristics is 30%.

[0310] In Example 2, the second light-emitting layer 25 in the red light-emitting element includes a P-type red host material, an N-type red host material having thermally activated delayed fluorescence characteristics, and a red fluorescent light-emitting material, and the mass ratios of the above three materials in the material of the second light-emitting layer 25 are 69%, 30%, and 1% respectively. The second light-emitting layer 25 in the green light-emitting element includes a green host material and a green fluorescent light-emitting material having multiple resonance characteristics, and the mass ratio of the green fluorescent light-emitting material is 1%. The second light-emitting layer 25 in the blue light-emitting element includes a blue host material and a dark blue fluorescent material (the peak value of the emission spectrum is 460 nm), and the mass ratio of the dark blue fluorescent material in the material of the second light-emitting layer 25 is 5%.

[0311] The thicknesses of the respective film layers corresponding to the respective light-emitting elements in the display substrate 100 of Example 2 are shown in Table 5 below.

Table 5

[0312] Here, the P-type doping ratio of the hole injection layer is 3%. The material of the cathode layer is a magnesium-silver alloy, and the mass ratio of magnesium to silver in the magnesium-silver alloy is 1:9. The material of the electron transport layer is lithium (8-hydroxyquinoline).

[0313] As shown in FIG. 11, the horizontal axis of the graph is wavelength, the unit is nm, the vertical axis is the relative intensity of the spectrum, and the emission spectra p3 of the first green light-emitting element of Comparative Example 2 and the first light-emitting layer 23 of Example 2 clearly have single-peak characteristics and overlap with the absorption spectrum p4 of the second light-emitting layer 25 of the red light-emitting element and the absorption spectrum p5 of the second light-emitting layer 25 of the green light-emitting element of Example 2. Table 6 shows the comparison relationships of the relevant quantities in Comparative Example 2 and Example 2 with the first green light-emitting element.

[0314] Here, in Comparative Example 2, the driving voltage of the first green light-emitting element is 3.6 V, the emission luminance is 10,000, the color coordinates are (0.34, 0.60), and the luminous efficiency is 53 cd / A.

Table 6

[0315] As can be seen from the above results, in Example 2, after connecting the first light-emitting layer 23 and the second light-emitting layer 25 in series, compared with Comparative Example 2, both the red light-emitting element and the green light-emitting element showed higher efficiency and better lifetime levels at the same luminance. The second light-emitting layer 25 of the blue light-emitting element could not obtain additional gain from the first light-emitting layer 23 and maintained the same efficiency and lifetime levels as the blue light-emitting element of Comparative Example 1.

[0316] Verification Example 3: Including Example 3-1 and Example 3-2.

[0317] The display substrate 100 of Example 3-1 and Example 3-2 has a red light-emitting element, a green light-emitting element, and a blue light-emitting element. The display substrates 100 of Embodiment 3-1 and Embodiment 3-2 both include an anode layer, a light-transmissive conductive layer, a hole injection layer, a first hole transport layer, an electron blocking layer, a first light-emitting layer, a first hole blocking layer, a first electron transport layer, a first charge generation layer, a second charge generation layer, a second hole transport layer, a color microcavity adjustment layer for each color, a second light-emitting layer for each color, a second hole blocking layer, a second electron transport layer, an electron injection layer, a cathode layer, and an optical coating layer, which are sequentially stacked and arranged.

[0318] The thicknesses of the respective film layers in the display substrate 100 of Example 3-1 are shown in Table 7 below.

Table 7

[0319] The thicknesses of the respective film layers in the display substrate 100 of Example 3-2 are shown in Table 8 below.

Table 8

[0320] Here, the P-type doping ratio of the hole injection layer in Example 3-1 and Example 3-2 is 3%. The material of the cathode layer is a magnesium-silver alloy, and the mass ratio of magnesium to silver in the magnesium-silver alloy is 1:9. The material of the electron transport layer is lithium (8-hydroxyquinoline).

[0321] Compared with Example 3-1, in Example 3-2, the optical thickness L1 can be adjusted by adjusting the thickness of the first hole transport layer close to the anode layer 21, and at the same time, the length of each sub-micro cavity A1 can be corrected by adjusting the thickness of the second hole transport layer away from the anode layer 21. That is, the thickness of the first hole transport layer close to the anode layer 21 in Example 3-2 is 40 nm - 25 nm = 15 nm thicker than the thickness of the first hole transport layer close to the anode layer 21 in Example 3-1, and the thickness of the second hole transport layer away from the anode layer 21 in Example 3-2 is 15 nm smaller than the thickness of the second hole transport layer away from the anode layer 21 in Example 3-1.

[0322] The results of the luminous purity and luminous efficiency of Example 3-1 with respect to Example 3-2 are shown in Table 9.

Table 9

[0323] As can be seen from the above results, the blue light-emitting element in Example 3-2 has low luminous efficiency and low color purity. The main reason is that the above L1, L2, and L3 corresponding to the blue light-emitting element deviate too much from the optimized size and do not satisfy the following formula.

Equation

[0324] Some other embodiments of the present disclosure further provide a display substrate 100. As shown in FIG. 12, the display substrate 100 includes a backplane 1 and a light-emitting element layer 2.

[0325] In some examples, as shown in FIG. 12, the light-emitting element layer 2 includes an anode layer 21, a first auxiliary layer 22, a first light-emitting layer 23, a second auxiliary layer 24, a plurality of second light-emitting layers 25, a third auxiliary layer 26, and a cathode layer 27 provided on the back plate 1. A microcavity A is formed between the anode layer 21 and the cathode layer 27.

[0326] In some examples, the plurality of second light-emitting layers 25 include a plurality of second blue light-emitting layers 25B, a plurality of second red light-emitting layers 25R, and a plurality of second green light-emitting layers 25G.

[0327] The first auxiliary layer includes a film layers stacked in sequence, the second auxiliary layer includes b film layers stacked in sequence, and the third auxiliary layer includes c film layers stacked in sequence. Here, a, b, and c are all positive integers.

[0328] The optical thickness of the a film layers, the optical thickness of the b film layers, and the optical thickness of the c film layers satisfy the following formula.

Number

[0329]

Number

Number

[0330] Exemplarily,

Number

[0331] Note that the above average refractive index is obtained by dividing the sum of the optical thicknesses of the film layers located between the anode layer 21 and the cathode layer 27 by the sum of the actual thicknesses of the film layers located between the anode layer 21 and the cathode layer 27. Alternatively, the average refractive index of the film layers between the anode layer 21 and the cathode layer 27 can be directly measured by a refractive index testing device (for example, a refractometer or an ellipsometer).

[0332] Exemplarily,

Number

[0333] In some examples, in the display substrate 100 provided by the above embodiments, the difference between the refractive indices of any two film layers located between the anode layer 21 and the cathode layer 27 is 0.32 or less. By this arrangement, the refractive indices of any two of the film layers located between the anode layer 21 and the cathode layer 27 are made relatively close to each other, so that the difference between the refractive indices of any two of the film layers located between the anode layer 21 and the cathode layer 27 can be made relatively small, the abrupt change in the refractive index between the film layers can be reduced, the light-emitting element 2a can have good light-emitting efficiency, and the dispersion of the light emitted by the light-emitting element 2a can be reduced.

[0334] Note that the structure of the display substrate 100 in this embodiment is the same as the structure of the display substrate 100 in the above several embodiments. Optionally, the backplane 1 in this embodiment has the same features as the backplane in the above several embodiments, and the light-emitting element layer 2 in this embodiment has the same features as the light-emitting element layer 2 in the above several embodiments. For details, reference can be made to the above description, and the description is omitted here.

[0335] Some other embodiments of the present disclosure further provide a display substrate 100. As shown in FIG. 13, the display substrate 100 includes a backplane 1 and a light-emitting element layer 2.

[0336] In some examples, as shown in FIG. 13, the light-emitting element layer 2 includes an anode layer 21, a first auxiliary layer 22, a first light-emitting layer 23, a second auxiliary layer 24, a plurality of second light-emitting layers 25, a third auxiliary layer 26, and a cathode layer 27 provided on the backplane 1. A microcavity A is formed between the anode layer 21 and the cathode layer 27.

[0337] In some examples, the second auxiliary layer 24 includes a charge generation layer 247.

[0338] Exemplarily, the charge generation layer 247 can include an N-type charge generation layer (N-CGL) and a P-type charge generation layer (P-CGL).

[0339] In some examples, the first light-emitting layer 23 can emit light of at least two different colors.

[0340] For example, the first light-emitting layer 23 can emit red light and blue light, or the first light-emitting layer 23 can emit green light and blue light, or the first light-emitting layer 23 can emit red light, green light, and blue light.

[0341] Since the first light-emitting layer 23 has two different colors, the first light-emitting layer 23 needs to be formed by different processes. Here, one color of the first light-emitting layer 23 can correspond to one process. For example, the first light-emitting layer 23 is formed by using a vapor deposition process. At this time, one color of the first light-emitting layer 23 is vapor-deposited and formed in one process, and then the first light-emitting layer 23 of other colors is vapor-deposited and formed in other processes.

[0342] In some examples, the plurality of second light-emitting layers 25 includes a plurality of second blue light-emitting layers 25B, a plurality of second red light-emitting layers 25R, and a plurality of second green light-emitting layers 25G.

[0343] The first auxiliary layer 22 includes a film layers stacked in sequence, the second auxiliary layer 24 includes b film layers stacked in sequence, the third auxiliary layer 26 includes c film layers stacked in sequence, and a, b, and c are all positive integers.

[0344] The optical thickness of the a film layers, the optical thickness of the b film layers, and the optical thickness of the c film layers satisfy the following formula.

Equation

[0345]

Equation

Equation

[0346] Exemplarily,

Equation

[0347] The average refractive index is obtained by dividing the sum of the optical thicknesses of the film layers located between the anode layer 21 and the cathode layer 27 by the sum of the actual thicknesses of the film layers located between the anode layer 21 and the cathode layer 27. Alternatively, the average refractive index of the film layers between the anode layer 21 and the cathode layer 27 can be directly measured by a refractive index testing device (for example, a refractometer or an ellipsometer).

[0348] Exemplarily, [Number] The value of is, for example, 1.7, 1.75, 1.8, 1.9, or 2.0, etc.

[0349] In some examples, in the display substrate 100 provided by each of the above embodiments, the difference between the refractive indices of any two film layers located between the anode layer 21 and the cathode layer 27 is 0.32 or less. By this arrangement, the refractive indices of any two of the film layers located between the anode layer 21 and the cathode layer 27 can be made relatively close to each other, and the difference between the refractive indices of any two of the film layers located between the anode layer 21 and the cathode layer 27 can be made relatively small. The abrupt change in the refractive index between the film layers can be reduced, the light emitting element 2a can have good light emission efficiency, and the dispersion of the light emitted by the light emitting element 2a can be reduced.

[0350] Note that the structure of the display substrate 100 in this embodiment is the same as the structure of the display substrate 100 in some of the above embodiments. Optionally, the backplane 1 in this embodiment has the same features as the backplane in some of the above embodiments, and the light emitting element layer 2 in this embodiment has the same features as the light emitting element layer 2 in some of the above embodiments. For details, reference can be made to the above description, and the description is omitted here.

[0351] In some examples, in the display substrate 100 provided by each of the above embodiments, the material types of the film layers between the anode layer 21 and the cathode layer 27 and the refractive indices of each film layer with respect to blue light with a wavelength of 460 nm are shown in Table 10 below.

Table 10

[0352] As can be seen from Table 10, the difference in refractive index between any two of the film layers located between the anode layer 21 and the cathode layer 27 is 0.32 or less, which means that the refractive indices of any two of the film layers located between the anode layer 21 and the cathode layer 27 are closer. By selecting the materials and refractive indices of each film layer located between the anode layer 21 and the cathode layer 27, the difference between the refractive indices of any two of the film layers located between the anode layer 21 and the cathode layer 27 can be further reduced, the abrupt change in refractive index between each film layer can be further reduced, the light-emitting element 2a can have good light-emitting efficiency, and the dispersion of the light emitted by the light-emitting element 2a can be reduced.

[0353] The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by any person skilled in the art within the technical scope of the present disclosure are all included within the technical scope of the present disclosure. Therefore, the protection scope of the present disclosure should follow the protection scope of the claims.

Claims

1. A backplane, an anode layer, a first auxiliary layer, a second auxiliary layer, a third auxiliary layer, and a cathode layer sequentially stacked on the backplane, wherein a microcavity is formed between the anode layer and the cathode layer, the anode layer, the first auxiliary layer, the second auxiliary layer, the third auxiliary layer, and the cathode layer, a first light-emitting layer provided between the first auxiliary layer and the second auxiliary layer, and at least two types of different-color multiple second light-emitting layers provided between the second auxiliary layer and the third auxiliary layer, The first auxiliary layer includes a film layers sequentially stacked, and the optical thickness of the a film layers is L １ wherein L １ satisfies the following formula 【Number 1】 a is a positive integer, n ｈ is the refractive index of the h-th film layer among the a film layers, r ｈ is the thickness of the h-th film layer, and The second auxiliary layer includes b film layers laminated sequentially, and the optical thickness of the b film layers is L ２ where L ２ satisfies the following formula 【Number 2】 b is a positive integer, n ｉ is the refractive index of the i-th film layer among the b film layers, r ｉ is the thickness of the i-th film layer, and The third auxiliary layer includes c film layers sequentially stacked, and the optical thickness of the c film layers is L ３ where L ３ satisfies the following formula 【Number 3】 c is a positive integer, n ｊ is the refractive index of the j-th film layer among the c film layers, r ｊ is the thickness of the j-th film layer, and L １ 、 L ２ 、 L ３ satisfy the following formula: [Number 4] a display substrate.

2. The multiple second light-emitting layers include multiple second blue light-emitting layers, multiple second red light-emitting layers, and multiple second green light-emitting layers, and the wavelength of the light emitted by the first light-emitting layer is smaller than the wavelength of the light emitted by at least one color of the second light-emitting layer, The display substrate according to Claim 1.

3. The first light-emitting layer includes a first guest material, and the second light-emitting layer includes a second guest material, and the emission spectrum of the first guest material at least partially overlaps with the absorption spectrum of the second guest material of at least one color of the second light-emitting layer, The display substrate according to Claim 2.

4. The overlapping range between the emission spectrum of the first guest material and the absorption spectrum of the second guest material is 60% or more of the wavelength range of the emission spectrum of the first guest material, The display substrate according to Claim 3.

5. The overlapping range between the emission spectrum of the first guest material and the absorption spectrum of the second guest material is 60% or more of the wavelength range of the absorption spectrum of the second guest material, The display substrate according to Claim 3.

6. The peak value of the emission spectrum of the first guest material is less than 600 nm, The display substrate according to any one of Claims 3 to 5.

7. The first guest material includes at least one light-emitting material, when the first guest material includes two light-emitting materials, the interval between the peak values of the emission spectra of the two light-emitting materials is 30 nm or less, The display substrate according to any one of Claims 3 to 6.

8. The range of the peak value of the emission spectrum of the first guest material is 465 nm to 475 nm, and the range of the peak value of the absorption spectrum of the second guest material of the second green light-emitting layer is 507 nm to 517 nm, The display substrate according to any one of Claims 3 to 7.

9. The range of the peak value of the emission spectrum of the first guest material is 525 nm to 535 nm, the range of the peak value of the absorption spectrum of the second guest material of the second green light-emitting layer is 510 nm to 520 nm, and the range of the peak value of the absorption spectrum of the second guest material of the second red light-emitting layer is 595 nm to 605 nm. The display substrate according to any one of claims 3 to 7.

10. The first guest material includes at least one light-emitting material. When the first guest material includes two light-emitting materials, at least one of the two light-emitting materials is doped with a boron element, and the range of the doping ratio of the boron element is 0.5% to 5%. The display substrate according to any one of claims 3 to 9.

11. The second guest material of at least one color of the second light-emitting layer includes at least one light-emitting material. When the second guest material includes two light-emitting materials, the interval between the peak values of the emission spectra of the two light-emitting materials is 30 nm or less. The display substrate according to any one of claims 3 to 10.

12. The second guest material of at least one color of the second light-emitting layer includes at least one light-emitting material. When the second guest material includes two light-emitting materials, at least one of the two light-emitting materials is doped with a boron element, and the range of the doping ratio of the boron element is 0.5% to 5%. The display substrate according to any one of claims 3 to 11.

13. The first guest material includes at least one of a fluorescent material, a phosphorescent material, and a thermally activated delayed fluorescence material, and / or The second guest material includes at least one of a fluorescent material, a phosphorescent material, or a thermally activated delayed fluorescence material having multiple resonance characteristics. The display substrate according to claim 11 or 12.

14. The first light-emitting layer further includes a first host material, and the first host material includes a single host material or a PN mixed-type host material. The display substrate according to any one of claims 3 to 13.

15. The material of at least one color of the second light-emitting layer further includes a second host material, and the second host material includes a bipolar host material. The display substrate according to any one of claims 3 to 14.

16. The second host material includes a single host material or a PN mixed-type host material. When the second host material is a PN hybrid host material, the N-type material has thermally activated delayed fluorescence characteristics. The display substrate according to claim 15.

17. The microcavity includes a plurality of sub-microcavities, and the plurality of sub-microcavities include a red sub-microcavity corresponding to the second red light-emitting layer, a green sub-microcavity corresponding to the second green light-emitting layer, and a blue sub-microcavity corresponding to the second blue light-emitting layer. The number of film layers corresponding to any one color of sub-microcavities located between the anode layer and the cathode layer is d, the optical thickness of the d film layers is L, and L satisfies the following formula. 【Number 5】 where d is a positive integer, n ｍ is the refractive index of the m-th film layer among the d film layers, r ｍ is the thickness of the m-th film layer, k is a natural number, λ is the target spectral peak wavelength, and φ is the phase shift caused after the target light is reflected by the anode layer. The display substrate according to any one of claims 2 to 16.

18. The length of the blue sub-microcavity is smaller than the length of the red sub-microcavity. The length of the blue sub-microcavity is smaller than the length of the green sub-microcavity. The display substrate according to claim 17.

19. The thickness range of the first light-emitting layer is 15 nm to 60 nm, and / or The thickness range of the second light-emitting layer is 10 nm to 50 nm. The display substrate according to any one of claims 1 to 18.

20. The first auxiliary layer includes a light-transmissive conductive layer, a hole injection layer, a first hole transport layer, and an electron blocking layer. And / or The second auxiliary layer includes a first hole blocking layer, a first electron transport layer, a first charge generation layer, a second charge generation layer, and a microcavity adjustment layer. And / or The third auxiliary layer includes a second hole blocking layer, a second electron transport layer, and an electron injection layer. The display substrate according to any one of claims 2 to 19.

21. The microcavity adjustment layer A second hole transport layer A red sub-microcavity adjustment layer provided between the second hole transport layer and the second red light-emitting layer A green sub-microcavity adjustment layer provided between the second hole transport layer and the second green light-emitting layer A blue sub-microcavity adjustment layer provided between the second hole transport layer and the second blue light-emitting layer, and The length between the red sub-microcavity adjustment layer and the blue sub-microcavity adjustment layer is different, and the length between the green sub-microcavity adjustment layer and the blue sub-microcavity adjustment layer is different. The display substrate according to claim 20.

22. The red sub-microcavity adjustment layer includes a red hole transport layer and a red electron blocking layer that are sequentially stacked in a direction away from the backplate, and the green sub-microcavity adjustment layer includes a green hole transport layer and a green electron blocking layer that are sequentially stacked in a direction away from the backplate. The red hole transport layer and the green hole transport layer are each used to adjust the length of the sub-microcavity of the corresponding color. The display substrate according to claim 21.

23. The thickness of the light-transmissive conductive layer is 10 nm or less, and / or The thickness of the hole injection layer is 10 nm or less, and / or The thickness of the electron blocking layer is 10 nm or less, and / or The thickness of the first hole blocking layer is 10 nm or less, and / or The thickness range of the first electron transport layer is 15 nm to 50 nm, and / or The thickness of the first charge generation layer is 10 nm or less, and / or The thickness of the second charge generation layer is 10 nm or less, and / or The thickness of the second hole blocking layer is 10 nm or less, and / or The thickness range of the second electron transport layer is 15 nm to 50 nm. The display substrate according to any one of claims 20 to 22.

24. The number of the first light-emitting layers is plural, and the second auxiliary layer is provided between any two adjacent first light-emitting layers. and / or The plurality of second light-emitting layers are located in the same layer to form one light-emitting layer group, the number of the light-emitting layer groups is plural, and the third auxiliary layer is provided between any two adjacent light-emitting layer groups. The display substrate according to any one of claims 1 to 23.

25. A backplane, An anode layer, a first auxiliary layer, a second auxiliary layer, a third auxiliary layer, and a cathode layer that are sequentially stacked on the backplane, wherein a microcavity is formed between the anode layer and the cathode layer, the anode layer, the first auxiliary layer, the second auxiliary layer, the third auxiliary layer, and the cathode layer, A first light-emitting layer provided between the first auxiliary layer and the second auxiliary layer, And a plurality of second light-emitting layers of at least two different colors provided between the second auxiliary layer and the third auxiliary layer. The first auxiliary layer includes a film layers stacked in sequence, the second auxiliary layer includes b film layers stacked in sequence, the third auxiliary layer includes c film layers stacked in sequence, and a, b, and c are all positive integers. The optical thicknesses of the a film layers, the optical thicknesses of the b film layers, and the optical thicknesses of the c film layers satisfy the following formula, 【Number 6】 【Number 7】 is the average refractive index of the film layers between the anode layer and the cathode layer, 【Number 8】 The range of is 1.7 to 2.0, r ｈ is the thickness of the h-th film layer among the a film layers, r ｉ is the thickness of the i-th film layer among the b film layers, r ｊ is the thickness of the j-th film layer among the c film layers. Display substrate.

26. A backplane, An anode layer, a first auxiliary layer, a second auxiliary layer, a third auxiliary layer, and a cathode layer sequentially stacked on the backplane, wherein the second auxiliary layer includes a charge generation layer, and a microcavity is formed between the anode layer and the cathode layer, an anode layer, a first auxiliary layer, a second auxiliary layer, a third auxiliary layer, and a cathode layer; A first light-emitting layer provided between the first auxiliary layer and the second auxiliary layer and capable of emitting light of at least two different colors; A plurality of second light-emitting layers provided between the second auxiliary layer and the third auxiliary layer, the plurality of second light-emitting layers including a plurality of second blue light-emitting layers, a plurality of second red light-emitting layers, and a plurality of second green light-emitting layers, a plurality of second light-emitting layers; The first auxiliary layer includes a film layers stacked in sequence, the second auxiliary layer includes b film layers stacked in sequence, the third auxiliary layer includes c film layers stacked in sequence, and a, b, and c are all positive integers. The optical thicknesses of the a film layers, the optical thicknesses of the b film layers, and the optical thicknesses of the c film layers satisfy the following formula, 【Number 9】 【Number 10】 is the average refractive index of the film layers between the anode layer and the cathode layer, 【Number 11】 The range of is 1.7 to 2.0, r ｈ is the thickness of the h-th film layer among the a film layers, r ｉ is the thickness of the i-th film layer among the b film layers, r ｊ is the thickness of the j-th film layer among the c film layers Display substrate.

27. Comprising the display substrate according to any one of claims 1 to 24, or Comprising the display substrate according to claim 25, or Comprising the display substrate according to claim 26, Display device.

Images