Display substrate and display device

Abstract

The display substrate (100) comprises a back plate (1), an anode layer (21), a first auxiliary layer (22), a plurality of first light-emitting layers (23), a second auxiliary layer (24), a plurality of second light-emitting layers (25), a third auxiliary layer (26) and a cathode layer (27). The first auxiliary layer (22), the second auxiliary layer (24) and the third auxiliary layer (26) are arranged to form series light-emitting devices with the first light-emitting layers and the second light-emitting layers, thereby increasing the light-emitting brightness.

Description

[0001] This application claims priority to Chinese Patent Application No. 202210798479.2, filed on July 8, 2022, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to the technical field of display, and in particular, to a display substrate and a display device. BACKGROUND

[0003] Organic Light Emitting Diode (OLED) display technology is a technology that uses light-emitting materials to emit light under the drive of current to realize display. OLED display has the advantages of ultra-light, ultra-thin, high brightness, large viewing angle, low voltage, low power consumption, fast response, high definition, shock resistance, bendable, low cost, simple process, less use of raw materials, high luminous efficiency, and wide temperature range. SUMMARY

[0004] Embodiments of the present disclosure aim to provide a display substrate and a display device for improving the luminous brightness and color purity of the display substrate.

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

[0006] In one aspect, a display substrate is provided. The display substrate includes a back plate, an anode layer, a first auxiliary layer, a second auxiliary layer, a third auxiliary layer, and a cathode layer which are sequentially stacked on the back plate, a plurality of first light-emitting layers of at least two different colors which are disposed between the first auxiliary layer and the second auxiliary layer, and a plurality of second light-emitting layers of at least two different colors which are disposed between the second auxiliary layer and the third auxiliary layer. The back plate includes a substrate and a plurality of pixel driving circuits disposed on the substrate; a pixel driving circuit includes a plurality of transistors and at least one storage capacitor. A microcavity is formed between the anode layer and the cathode layer. The plurality of first light-emitting layers includes at least a plurality of first blue light-emitting layers. The plurality of second light-emitting layers includes at least a plurality of second blue light-emitting layers. The first auxiliary layer includes a plurality of film layers which are sequentially stacked, and the optical thickness of the portion of the plurality of film layers which is opposite to the first blue light-emitting layer is L1, L1 satisfies:

[0007]

[0008] a is a positive integer, n h is the refractive index of the hth film layer in the plurality of film layers, r h is the thickness of the hth film layer.

[0009] The third auxiliary layer comprises b film layers stacked in sequence, and an optical thickness of a portion of the b film layers opposite to the first blue light-emitting layer is L2, L2 satisfies:

[0010]

[0011] b is a positive integer, n i ni is a refractive index of an i-th film layer of the b film layers, ri i is a thickness of the i-th film layer.

[0012] L1 and L2 satisfy a formula:

[0013]

[0014] ni is an average refractive index of the film layers between the first auxiliary layer and the third auxiliary layer and opposite to the first blue light-emitting layer for a central wavelength of blue light, λ B is a target spectral peak wavelength of blue light, and k is a positive integer.

[0015] The display substrate provided by some embodiments of the present disclosure can increase the luminous brightness of the display substrate by arranging the first auxiliary layer, the second auxiliary layer and the third auxiliary layer to form the series light-emitting device of the first light-emitting layer and the second light-emitting layer. In addition, 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 generate microcavity effect in the microcavity, thereby enhancing the luminous intensity of the outgoing light, narrowing the spectrum of the outgoing light, and improving the luminous efficiency of the light-emitting device. The optical thickness L1 of the a film layers included in the first auxiliary layer and the optical thickness L2 of the b film layers included in the third auxiliary layer satisfy a formula:

[0016]

[0017] The color purity of the light emitted by the light-emitting device in the display substrate can be improved. Therefore, the display substrate of the present disclosure can reduce the arrangement of the optical filter and improve the luminous efficiency. Further, the display substrate can also reduce power consumption and increase the luminous life of the light-emitting device under the condition of high luminous brightness.

[0018] In some embodiments, the ranges from 1.7 to 2.0.

[0019] In some embodiments, the plurality of first light-emitting layers further comprise a plurality of first red light-emitting layers and a plurality of first green light-emitting layers. The thickness of the first red light-emitting layer is different from that of the first blue light-emitting layer, and / or the thickness of the first green light-emitting layer is different from that of the first blue light-emitting layer.

[0020] In some embodiments, the plurality of second light-emitting layers further comprises a plurality of second red light-emitting layers and a plurality of second green light-emitting layers. The thickness of the second red light-emitting layers is different from the thickness of the second blue light-emitting layers, and / or the thickness of the second green light-emitting layers is different from the thickness of the second blue light-emitting layers.

[0021] In some embodiments, the second auxiliary layer comprises a first microcavity adjustment layer. The thickness of the portion of the first microcavity adjustment layer opposite to the second red light-emitting layers is different from the thickness of the portion of the first microcavity adjustment layer opposite to the second blue light-emitting layers, and / or the thickness of the portion of the first microcavity adjustment layer opposite to the second green light-emitting layers is different from the thickness of the portion of the first microcavity adjustment layer opposite to the second blue light-emitting layers.

[0022] In some embodiments, the first microcavity adjustment layer comprises a second hole transport layer, a first red sub-microcavity adjustment layer, a first green sub-microcavity adjustment layer, and a first blue sub-microcavity adjustment layer. The first red sub-microcavity adjustment layer is disposed between the second hole transport layer and the second red light-emitting layers, the first green sub-microcavity adjustment layer is disposed between the second hole transport layer and the second green light-emitting layers, and the first blue sub-microcavity adjustment layer is disposed between the second hole transport layer and the second blue light-emitting layers. The thickness between the first red sub-microcavity adjustment layer and the first blue sub-microcavity adjustment layer is different, and / or the thickness between the first green sub-microcavity adjustment layer and the first blue sub-microcavity adjustment layer is different.

[0023] In some embodiments, the first red sub-microcavity adjustment layer comprises a red hole transport layer and a red electron blocking layer stacked in sequence in a direction away from the backplane, and the first green sub-microcavity adjustment layer comprises a green hole transport layer and a green electron blocking layer stacked in sequence in a direction away from the backplane. The red hole transport layer and the green hole transport layer are respectively used to adjust the microcavity length.

[0024] In some embodiments, the wavelength of the light emitted by the first light-emitting layer of at least one color is less than the wavelength of the light emitted by the second light-emitting layer of the corresponding color.

[0025] In some embodiments, the first light-emitting layer comprises a first guest material, and the second light-emitting layer comprises a second guest material. The emission spectrum of the first guest material of the first light-emitting layer of at least one color at least partially overlaps with the absorption spectrum of the second guest material of the second light-emitting layer of the corresponding color.

[0026] In some embodiments, the overlap range of the emission spectrum of the first guest material and the absorption spectrum of the second guest material is greater than or equal to 60% of the wavelength range of the emission spectrum of the first guest material.

[0027] In some embodiments, the overlap range of the emission spectrum of the first guest material and the absorption spectrum of the second guest material is greater than or equal to 60% of the wavelength range of the absorption spectrum of the second guest material.

[0028] In some embodiments, the peak of the emission spectrum of the first guest material of the first red light-emitting layer ranges from 560 nm to 570 nm, and the peak of the absorption spectrum of the second guest material of the second red light-emitting layer ranges from 595 nm to 605 nm.

[0029] In some embodiments, the peak of the emission spectrum of the first guest material of the first green light-emitting layer ranges from 500 nm to 510 nm, and the peak of the absorption spectrum of the second guest material of the second green light-emitting layer ranges from 515 nm to 525 nm.

[0030] In some embodiments, the first guest material of the first light-emitting layer of at least one color comprises at least one light-emitting material. In the case where the first guest material comprises two light-emitting materials, the interval between the emission spectrum peaks of the two light-emitting materials is less than or equal to 30 nm.

[0031] In some embodiments, the first guest material comprises two light-emitting materials. Among the two light-emitting materials, at least one light-emitting material is doped with boron elements, and the doping proportion of the boron elements ranges from 0.5% to 5%.

[0032] In some embodiments, the second guest material of the second light-emitting layer of at least one color comprises at least one light-emitting material. In the case where the second guest material comprises two light-emitting materials, the interval between the emission spectrum peaks of the two light-emitting materials is less than or equal to 30 nm.

[0033] In some embodiments, the second guest material comprises two light-emitting materials. Among the two light-emitting materials, at least one light-emitting material is doped with boron elements, and the doping proportion of the boron elements ranges from 0.5% to 5%.

[0034] In some embodiments, the first guest material comprises at least one of a fluorescent material, a phosphorescent material, and a thermally activated delayed fluorescence material; and / or, the second guest material comprises at least one of a fluorescent material, a phosphorescent material, and a thermally activated delayed fluorescence material with multi-resonance characteristics.

[0035] In some embodiments, the first light-emitting layer further comprises a first host material, and the first host material is a single host material or a PN hybrid host material. The second light-emitting layer further comprises a second host material, and the second host material comprises a bipolar host material.

[0036] In some embodiments, the second host material is a single host material or a PN hybrid host material. In the case where the second host material is a PN hybrid host material, the host material of the N-type component has a thermally activated delayed fluorescence characteristic.

[0037] In some embodiments, the first red light-emitting layer and the second red light-emitting layer are oppositely arranged, the first green light-emitting layer and the second green light-emitting layer are oppositely arranged, and the first blue light-emitting layer and the second blue light-emitting layer are oppositely arranged.

[0038] In some embodiments, the first auxiliary layer comprises, in sequence from the direction away from the back plate, a light-transmitting conductive layer, a hole injection layer, and a second microcavity adjustment layer. The second microcavity adjustment layer comprises a first hole transport layer, a second red microcavity adjustment layer arranged between the first hole transport layer and the first red light-emitting layer, a second green microcavity adjustment layer arranged between the first hole transport layer and the first green light-emitting layer, and a second blue microcavity adjustment layer arranged between the first hole transport layer and the first blue light-emitting layer.

[0039] In some embodiments, the first auxiliary layer comprises, in sequence from the direction away from the back plate, a light-transmitting conductive layer, a hole injection layer, and a second microcavity adjustment layer. The second microcavity adjustment layer comprises a first hole transport layer and an electron blocking layer.

[0040] In some embodiments, the first auxiliary layer comprises, in sequence from the direction away from the back plate, a light-transmitting conductive layer, a hole injection layer, and a second microcavity adjustment layer. The second microcavity adjustment layer comprises a first hole transport layer, a second blue sub-microcavity adjustment layer arranged on the side of the first hole transport layer away from the back plate, a second red sub-microcavity adjustment layer arranged between the second blue sub-microcavity adjustment layer and the first red light-emitting layer, and a second green sub-microcavity adjustment layer arranged between the second blue sub-microcavity adjustment layer and the first green light-emitting layer.

[0041] In some embodiments, the material of the light-transmitting conductive layer comprises indium tin oxide or indium zinc oxide, and / or the thickness of the light-transmitting conductive layer is less than or equal to 10 nm.

[0042] In some embodiments, the material of the first hole transport layer comprises a carbazole-based material; and / or the highest occupied molecular orbital energy level range of the material of the first hole transport layer is -5.2 eV to -5.6 eV; and / or the highest occupied molecular orbital energy level range of the material of the electron blocking layer is -5.5 eV to -5.9 eV.

[0043] In some embodiments, the microcavity comprises a plurality of sub-microcavities, the plurality of sub-microcavities comprising a red sub-microcavity corresponding to the first red light-emitting layer, a green sub-microcavity corresponding to the first green light-emitting layer, and a blue sub-microcavity corresponding to the first blue light-emitting layer. Wherein the number of film layers between the anode layer and the cathode layer and corresponding to any one color of sub-microcavity is c, the optical thickness of the c film layers is L3, L3 satisfies:

[0044]

[0045] c is a positive integer, n j is the refractive index of the jth film layer in the c film layers, r j is the thickness of the jth film layer.

[0046] Any one color of sub-microcavity satisfies:

[0047]

[0048] m is a natural number, λ is an interference wavelength, is the phase shift caused by the anode layer.

[0049] In some embodiments, the length of the blue sub-microcavity is less than the length of the red sub-microcavity. The length of the blue sub-microcavity is less than the length of the green sub-microcavity.

[0050] In some embodiments, the anode layer comprises: an anode layer and a light-transmitting conductive layer which are sequentially stacked in a direction away from the back plate; the optical thickness of the portion of the anode layer opposite to the first blue light-emitting layer is the optical thickness of the portion of the light-transmitting conductive layer opposite to the first blue light-emitting layer.

[0051] In some embodiments, the second auxiliary layer further comprises: a first hole blocking layer, a first electron transport layer and a charge generation layer which are sequentially stacked in a direction away from the back plate on the side of the first microcavity adjustment layer close to the back plate; and / or, the third auxiliary layer comprises: a second hole blocking layer, a second electron transport layer and an electron injection layer which are sequentially stacked in a direction away from the back plate.

[0052] In some embodiments, the thickness of the first hole blocking layer is less than or equal to 10 nm; and / or, the thickness of the first electron transport layer ranges from 15 nm to 50 nm; and / or, the thickness of the first charge generation layer is less than or equal to 10 nm; and / or, the thickness of the second charge generation layer is less than or equal to 10 nm; and / or, the thickness of the second hole blocking layer is less than or equal to 10 nm; and / or, the thickness of the second electron transport layer ranges from 15 nm to 50 nm.

[0053] In some embodiments, the material of the first electron transport layer comprises at least one of a thiophene material, an imidazole material, an azine derivative material, and lithium quinolate; and / or, the material of the second hole blocking layer comprises a triazine material; and / or, the material of the second electron transport layer comprises at least one of a thiophene material, an imidazole material, an azine derivative material, and lithium quinolate.

[0054] In some embodiments, the thickness of the first blue light emitting layer ranges from 15 nm to 60 nm; and / or, the thickness of the second blue light emitting layer ranges from 10 nm to 50 nm.

[0055] In some embodiments, the number of the second auxiliary layers is multiple, and at least two first light emitting layers of different colors or at least two second light emitting layers of different colors are arranged between any two adjacent second auxiliary layers.

[0056] In some embodiments, the anode layer comprises a reflective layer; or, the anode layer comprises a reflective layer and a light-transmitting layer located on the side of the reflective layer close to the back plate.

[0057] In another aspect, a display device is provided. The display device comprises the display substrate according to any one of the above embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the present disclosure, the following will briefly introduce the drawings needed to be used in some embodiments of the present disclosure. Obviously, the drawings described in the following description are only the drawings of some embodiments of the present disclosure, and other drawings can also be obtained by those skilled in the art according to these drawings. In addition, the drawings described in the following description can be regarded as schematic diagrams, and are not limited to the actual size of the products involved in the embodiments of the present disclosure.

[0059] Figure 1 FIG. 1 is a structural diagram of a display device according to some embodiments of the present disclosure;

[0060] Figure 2 FIG. 2 is a structural diagram of a display substrate according to some embodiments of the present disclosure;

[0061] Figure 3 FIG. 3 is a structural diagram of another display substrate according to some embodiments of the present disclosure;

[0062] Figure 4 FIG. 4 is a structural diagram of a display substrate in the first mode according to some embodiments of the present disclosure;

[0063] Figure 5 FIG. 5 is a structural diagram of a display substrate in the second mode according to some embodiments of the present disclosure;

[0064] Figure 6A structural diagram of yet another display substrate according to some embodiments of the present disclosure;

[0065] Figure 7 A structural diagram of yet another display substrate according to some embodiments of the present disclosure;

[0066] Figure 8 A structural diagram of yet another display substrate according to some embodiments of the present disclosure;

[0067] Figure 9 A structural diagram of yet another display substrate according to some embodiments of the present disclosure;

[0068] Figure 10 A structural diagram of yet another display substrate according to some embodiments of the present disclosure;

[0069] Figure 11 A spectral diagram of a part of the light emitting layer in the verification example 1;

[0070] Figure 12 A spectral diagram of another part of the light emitting layer in the verification example 1;

[0071] Figure 13 A spectral diagram of a blue light emitting device in the verification example 2. DETAILED DESCRIPTION

[0072] The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings. It should be apparent that the described embodiments are only a part of the embodiments of the present disclosure, but not all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by those of ordinary skill in the art should belong to the scope of protection of the present disclosure.

[0073] Unless the context clearly requires otherwise, throughout the description and the claims, the term "comprise," and variations thereof (e.g., "comprises" and "comprising"), will be construed to be inclusive, and will be

[0074] Hereinafter, the terms "first", "second", etc. are used only for the purpose of description, and should not be construed as indicating or implying relative importance or implying the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0075] In describing some embodiments, the term "connected" and variations thereof can be used. For example, the term "connected" can be used to describe some embodiments in which two or more components are in direct physical or electrical contact with each other. The embodiments disclosed herein are not necessarily limited to the context.

[0076] "A, B, and C at least one of" has the same meaning as "at least one of A, B, or C", and includes the following combinations of A, B, and C: only A, only B, only C, a combination of A and B, a combination of A and C, a combination of B and C, and a combination of A, B, and C.

[0077] "A and / or B" includes the following three combinations: only A, only B, and a combination of A and B.

[0078] As used herein, the term "if' is, optionally, interpreted as meaning "when" or "while" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [a stated condition or event] is detected" is, optionally, interpreted as meaning "upon being determined" or "in response to determining" or "upon detecting [the stated condition or event]" or "in response to detecting [the stated condition or event]," depending on the context.

[0079] The use of "adapted to" or "configured to" herein means open and inclusive language that is not limited to devices that are adapted to or configured to perform additional tasks or steps.

[0080] Additionally, the use of "based on" means open and inclusive, as the process, step, calculation, or other action based on a stated condition or value can in fact be based on additional condition or values beyond those stated.

[0081] It will be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers can also be present.

[0082] Exemplary embodiments are described herein with reference to cross-sectional and / or plan view illustrations that are idealized examples. In the interest of clarity, not all of the layer and regions are shown in the drawings with the same dimensions. For example, the thickness of layers and regions can be exaggerated in some drawings. Thus, the exemplary embodiments should not be construed as limited to the shapes of regions illustrated in the drawings, which are schematically represented. For example, the etched regions illustrated as rectangular can typically have curved features. The regions illustrated in the drawings are schematic and not intended to be limiting of the actual shape of the regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0083] Some embodiments of the present disclosure provide a display substrate and a display device. The display substrate 100 and the display device 1000 are introduced respectively below in combination with the accompanying drawings.

[0084] As Figure 1As shown, some embodiments of this disclosure provide a display device 1000. The display device 1000 can be any device that displays images, whether moving (e.g., video) or stationary (e.g., still images), and whether text or images. More specifically, the embodiments are contemplated to be implemented in or associated with a variety of electronic devices, such as (but not limited to) mobile phones, wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, camcorders, game consoles, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controllers and / or displays, displays of camera views (e.g., displays of rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging and aesthetic structures (e.g., displays of images of a piece of jewelry), etc.

[0085] In some examples, the display device 1000 described above includes a frame, a display substrate 100 disposed within the frame, a circuit board, a data driver IC (Integrated Circuit), and other electronic components.

[0086] The aforementioned 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., and this disclosure does not specifically limit it.

[0087] The following describes some embodiments of this disclosure using the above-mentioned display substrate 100 as an OLED display substrate as an example.

[0088] In some embodiments, such as Figure 2 As shown, the display substrate 100 includes a back plate 1.

[0089] In some examples, the backplate 1 described above includes a substrate 11 and a plurality of pixel driving circuits 12 disposed on the substrate 11.

[0090] The types of substrate 11 mentioned above include various types, and can be selected and set according to actual needs.

[0091] For example, substrate 11 may be a rigid substrate. The material of the rigid substrate may include, for example, glass, quartz, or plastic.

[0092] Exemplarily, the substrate 11 can be a flexible substrate. The material of the flexible substrate can include, for example, PET (Polyethylene terephthalate), PEN (Polyethylenenaphthalate two formic acid glycol ester), PI (Polyimide), or the like.

[0093] In some examples, the plurality of pixel driving circuits 12 are arranged in an array, for example.

[0094] The structure of the pixel driving circuit 12 can include various structures, which can be selected and arranged as required. For example, the structure of the pixel driving circuit 12 can include a “3T1C”, “4T1C”, “6T1C”, “7T1C”, “6T2C”, “7T2C”, or “8T2C” structure. 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.

[0095] Exemplarily, Figure 3 The pixel driving circuit 12 is represented by a transistor 121.

[0096] In some embodiments, as Figure 3 shown, the display substrate 100 further includes a light emitting device layer 2.

[0097] In some examples, the light emitting device layer 2 includes a plurality of light emitting devices 2a arranged in an array, for example. Here, the light emitting device 2a is an OLED, for example.

[0098] The pixel driving circuit 12 and the light emitting device 2a are electrically connected. The electrical connection relationship between the two can include various types, which can be selected and arranged as required, and the present disclosure does not limit the same.

[0099] For example, the pixel driving circuit 12 and the light emitting device 2a can be electrically connected one-to-one. For another example, one pixel driving circuit 12 can be electrically connected to a plurality of light emitting devices 2a. For another example, a plurality of pixel driving circuits 12 can be electrically connected to one light emitting device 2a.

[0100] In the following, the structure of the display substrate 100 will be described schematically taking the example that the pixel driving circuit 12 and the light emitting device 2a can be electrically connected one-to-one.

[0101] It is understood that the pixel driving circuit 12 can generate a driving signal and transmit the driving signal to the corresponding light-emitting device 2a to control the light-emitting state of the light-emitting device 2a. The light-emitting state includes, for example, whether the light-emitting device 2a emits light, or the brightness of the light-emitting device 2a. Multiple pixel driving circuits 12 jointly control the light-emitting state of the multiple light-emitting devices 2a, thereby enabling the display substrate 100 to display an image.

[0102] Here, each pixel driving circuit 12 and the light-emitting device 2a electrically connected to it can be referred to as a sub-pixel.

[0103] It should be noted that there are two main ways to achieve full-color display on a display substrate. For example, one way is to provide a full-color display solution through separate R / G / B light-emitting units, and the other way is to provide a full-color solution through color conversion or color filtering.

[0104] In one implementation, a full-color display solution using individual R / G / B light-emitting units refers to a light-emitting device primarily comprising an anode, a light-emitting layer, and a cathode sequentially stacked along a direction away from the substrate. The light-emitting layer can be a red, green, or blue light-emitting layer, and correspondingly, the light-emitting device can be a red, green, or blue light-emitting device. The red light-emitting device emits red light under the control of its corresponding pixel driving circuit, the green light-emitting device emits green light under the control of its corresponding pixel driving circuit, and the blue light-emitting device emits blue light under the control of its corresponding pixel driving circuit. Multiple light-emitting devices work together to achieve a full-color display. However, in this solution, the luminous efficiency and brightness of the light-emitting devices are relatively low.

[0105] In another implementation method, there are two main ways to provide a full-color solution through color conversion or color filtering.

[0106] like Figure 4 As shown, in the first method, the first light-emitting device 2a' is a series-connected bottom-emitting light-emitting device, and this first light-emitting device 2a' is used to emit white light. The display substrate also includes a color filter CF disposed on the side of the first substrate 11' away from the first light-emitting device 2a'. The white light emitted by the first light-emitting device 2a' is converted into red, green, or blue light after passing through the color filter CF, thereby realizing full-color display. However, the structure of the bottom-emitting light-emitting device also makes it more difficult to improve the brightness at the front viewing angle; in addition, if a top-emitting light-emitting device is used, the process complexity will increase and the light loss in certain wavelength bands will be too large.

[0107] like Figure 5As shown, in the second mode, the first light emitting device 2a' is a top emission type light emitting device in series, and the first light emitting device 2a' is configured 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 arranged on the side of the first light emitting device 2a' away from the first substrate 11'. Blue light passing through the red quantum dot conversion layer R-CC can be converted into red light, and blue light passing through the green quantum dot conversion layer G-CC can be converted into green light, thereby realizing full-color display. 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 low, and therefore, it is necessary to match the corresponding optical filter, for example, a red optical filter R-CF needs to be arranged on the side of the red quantum dot conversion layer R-CC away from the first substrate 11', and a green optical filter G-CF needs to be arranged on the side of the green quantum dot conversion layer G-CC away from the first substrate 11', so as to improve the color purity. This will increase the process complexity of the display substrate and increase the power consumption of the display substrate.

[0108] Based on this, as Figure 3 shown, in some embodiments of the present disclosure, the light emitting device layer 2 includes an anode layer 21, a first auxiliary layer 22, a plurality of first light emitting layers 23, a second auxiliary layer 24, a plurality of second light emitting layers 25, a third auxiliary layer 26, and a cathode layer 27 arranged on the backplane 1.

[0109] In some examples, as Figure 3 shown, the anode layer 21 includes a plurality of anodes 211, for example, arranged in an array. Among them, one anode 211 corresponds to one light emitting device 2a, and each light emitting device 2a is electrically connected to the corresponding pixel driving circuit 12 through the anode 211, for example. The anode 211 can receive the driving signal of the corresponding pixel driving circuit 12, cooperate with the corresponding pixel driving circuit 12, and realize the individual control of the light emitting device 2a.

[0110] For example, the material of the anode layer 21 includes a conductive material with a high work function. The structure of the anode layer 21 can be, for example, a single-layer structure, or a structure in which a plurality of film layers are sequentially stacked.

[0111] For example, in the case where the structure of the anode layer 21 is a single-layer structure, the anode layer 21 includes a reflective layer, and the single-layer structure (for example, the reflective layer) has good light reflection performance and can reflect light incident on the anode layer 21.

[0112] For example, in the case where the anode layer 21 has a structure in which a plurality of film layers are sequentially stacked, the anode layer 21 includes a reflective layer and a light-transmissive layer located on the side of the reflective layer close to the back plate 1, the film layer far from the back plate 1 in the plurality of film layers is a film layer having a good light-reflecting property (for example, the reflective layer), and the film layer having the good light-reflecting property can include at least one of Al (aluminum), Ag (silver), and Mg (magnesium), for example. The film layer close to the back plate 1 in the plurality of film layers can be a film layer having a good light-transmissive property (for example, the light-transmissive layer), and the film layer having the good light-transmissive property can include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or the like, for example.

[0113] For example, the method of forming the anode 211 includes forming (for example, by a sputtering process) a conductive thin film (the conductive thin film has a single-layer structure or a structure in which a plurality of film layers are sequentially stacked) on the back plate 1, and then performing a patterning process (for example, etching the conductive thin film by a photolithography process) on the conductive thin film to obtain a plurality of anodes 211 that are independent of each other.

[0114] It should be noted that the display substrate 100 can further include a pixel definition layer disposed on the side of the anode layer 21 far from the substrate 11. The pixel definition layer has a plurality of openings, the plurality of openings and the plurality of anodes 211 are disposed one-to-one, and each opening exposes a portion of the corresponding anode 211 to facilitate the anode 211 to contact a film layer located on the side of the anode 211 far from the substrate 11 to form an electrical connection.

[0115] In some examples, as shown in FIG. 1A, the first auxiliary layer 22 is disposed on the side of the anode layer 21 far from the substrate 11. Optionally, the first auxiliary layer 22 is located on the side of the pixel definition layer far from the substrate 11. Figure 3

[0116] For example, the first auxiliary layer 22 can contact the anode 211 through the opening of the pixel definition layer to form an electrical connection.

[0117] For example, the first auxiliary layer 22 includes a plurality of film layers sequentially stacked, and a is a positive integer. For example, the number of the film layers included in the first auxiliary layer 22 is one, two, three, or four, or the like.

[0118] Optionally, in the case where the first auxiliary layer 22 includes one film layer, the first auxiliary layer 22 covers the anode layer 21. That is, different light-emitting devices 2a share the first auxiliary layer 22.

[0119] ​Optionally, in the case that the first auxiliary layer 22 comprises at least two film layers, at least one film layer covers the anode layer 21. That is, different light emitting devices 2a share the at least one film layer.

[0120] For example, the first auxiliary layer 22 can be formed by an evaporation process.

[0121] By making different light emitting devices 2a share the film layer in the first auxiliary layer 22, the first auxiliary layer 22 can be avoided from being patterned, which is conducive to simplifying the manufacturing process of the first auxiliary layer 22 and the display substrate 100.

[0122] In some examples, as shown in FIG. 1, the plurality of first light emitting layers 23 are arranged on the side of the first auxiliary layer 22 away from the substrate 11. For example, the plurality of first light emitting layers 23 can be located in the same layer, and each first light emitting layer 23 is in contact with the first auxiliary layer 22 to form an electrical connection. Of course, at least two first light emitting layers 23 can also be arranged in a stacked manner. The disclosure is described by way of example with the plurality of first light emitting layers 23 located in the same layer. Figure 3

[0123] For example, the plurality of first light emitting layers 23 and the plurality of anodes 211 in the anode layer 21 are arranged one-to-one. Each first light emitting layer 23 is opposite to the corresponding anode 211, that is, the orthographic projection parts of the two on the substrate 11 overlap or coincide.

[0124] For example, the plurality of first light emitting layers 23 have at least two different colors, and at least comprise a plurality of first blue light emitting layers 23B.

[0125] For example, the plurality of first light emitting layers 23 have two different colors. Optionally, the plurality of first light emitting layers 23 comprise a plurality of first blue light emitting layers 23B and a plurality of first red light emitting layers 23R. Alternatively, the plurality of first light emitting layers 23 comprise a plurality of first blue light emitting layers 23B and a plurality of first green light emitting layers 23G.

[0126] For example, the plurality of first light emitting layers 23 have three different colors. Optionally, the plurality of first light emitting layers 23 comprise a plurality of first blue light emitting layers 23B, a plurality of first red light emitting layers 23R, and a plurality of first green light emitting layers 23G.

[0127] Since the plurality of first light emitting layers 23 have two different colors, the plurality of first light emitting layers 23 need to be prepared in different processes, and one color of the first light emitting layer 23 can correspond to one process. For example, the plurality of first light emitting layers 23 are formed by an evaporation process, at which one color of the first light emitting layer 23 can be formed by evaporation in one process, and another color of the first light emitting layer 23 can be formed by evaporation in another process. ​

[0128] It should be noted that the first auxiliary layer 22 is located between the anode layer 21 and the plurality of first light-emitting layers 23, and the first auxiliary layer 22 is mainly used to improve the hole mobility, reduce the injection barrier of the holes, increase the amount of holes migrated to the first light-emitting layer 23, increase the recombination rate of holes and electrons migrated to the first light-emitting layer 23, and improve the light-emitting efficiency of the first light-emitting layer 23.

[0129] In some examples, as shown in FIG. 2, the second auxiliary layer 24 is arranged on the side of the plurality of first light-emitting layers 23 away from the substrate 11. That is, the plurality of first light-emitting layers 23 are arranged between the first auxiliary layer 22 and the second auxiliary layer 24. The second auxiliary layer 24 is in contact with each of the first light-emitting layers 23 to form an electrical connection. Figure 3

[0130] For example, the second auxiliary layer 24 includes a plurality of film layers stacked in sequence, and different light-emitting devices 2a share the second auxiliary layer 24.

[0131] For example, the second auxiliary layer 24 can be formed by a vapor deposition process.

[0132] By making different light-emitting devices 2a share the film layers in the second auxiliary layer 24, the second auxiliary layer 24 can be avoided from being patterned, which is beneficial to simplify the preparation process of the first auxiliary layer 22 and the display substrate 100.

[0133] In some examples, as shown in FIG. 2, the plurality of second light-emitting layers 25 are arranged 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 of the second light-emitting layers 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 can also be stacked. The present disclosure takes the plurality of second light-emitting layers 25 located in the same layer as an example for description. Figure 3

[0134] For example, the plurality of second light-emitting layers 25 and the plurality of first light-emitting layers 23 are arranged one by one. Each second light-emitting layer 25 is opposite to the corresponding first light-emitting layer 23, that is, the orthographic projection parts of the two on the substrate 11 overlap or coincide. In addition, the orthographic projection parts of each second light-emitting layer 25 and the corresponding anode 211 on the substrate 11 overlap or coincide.

[0135] For example, the plurality of second light-emitting layers 25 have at least two different colors, and at least include a plurality of second blue light-emitting layers 25B.

[0136] ​​For example, the plurality of second light-emitting layers 25 described above have two different colors. Optionally, the plurality of second light-emitting layers 25 includes 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 includes a plurality of second blue light-emitting layers 25B and a plurality of second green light-emitting layers 25G.

[0137] For example, the aforementioned plurality of second light-emitting layers 25 may have three different colors. Optionally, the plurality of second light-emitting layers 25 may 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.

[0138] Since the aforementioned plurality of second light-emitting layers 25 have two different colors, these plurality of second light-emitting layers 25 need to be formed in different processes, wherein one color of second light-emitting layer 25 can correspond to one process. For example, the aforementioned plurality of second light-emitting layers 25 are formed by vapor deposition. In this case, one color of second light-emitting layer 25 can be vapor-deposited in one process, and then another color of second light-emitting layer 25 can be vapor-deposited in another process.

[0139] It should be noted that the second auxiliary layer 24 is located between the multiple first light-emitting layers 23 and the multiple second light-emitting layers 25. The second auxiliary layer 24 is mainly used to connect the first light-emitting layers 23 and the second light-emitting layers 25 in series to form a series light-emitting device.

[0140] In some examples, such as Figure 3 As shown, the third auxiliary layer 26 is disposed 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 disposed between the second auxiliary layer 24 and the third auxiliary layer 26. The third auxiliary layer 26 is in contact with each of the second light-emitting layers 25 to form an electrical connection.

[0141] For example, the third auxiliary layer 26 includes b membrane layers stacked sequentially, where b is a positive integer. For instance, the number of membrane layers included in the third auxiliary layer 26 may be one, two, or three, etc.

[0142] Optionally, different light-emitting devices 2a share the third auxiliary layer 26.

[0143] For example, the third auxiliary layer 26 can be formed using a vapor deposition process.

[0144] By allowing different light-emitting devices 2a to share the third auxiliary layer 26, the patterning process of the third auxiliary layer 26 can be avoided, which helps to simplify the fabrication process of the third auxiliary layer 26 and the display substrate 100.

[0145] In some examples, such as Figure 3As shown, the cathode layer 27 is disposed on the third auxiliary layer 26 away from the substrate 11 and in contact with the third auxiliary layer 26, forming an electrical connection.

[0146] Exemplarily, the different light emitting devices 2a share the cathode layer 27. That is, the cathode layer 27 is an integral layer structure.

[0147] Exemplarily, the cathode layer 27 can be formed by a vapor deposition process.

[0148] By making the different light emitting devices 2a share the cathode layer 27, the cathode layer 27 can be avoided from being patterned, which is beneficial to simplify the preparation process of the cathode layer 27 and the display substrate 100.

[0149] It should be noted that the third auxiliary layer 26 is located between the plurality of second light emitting layers 25 and the cathode layer 27, and the third auxiliary layer 26 is mainly used to improve the electron mobility, so as to increase the amount of holes migrated to the first light emitting layer 23, increase the recombination rate of holes and electrons migrated to the first light emitting layer 23, and avoid the leakage of holes or excitons formed by the recombination of holes and electrons from the second light emitting layer 25, thereby improving the light emitting efficiency of the first light emitting layer 23.

[0150] In some examples, the anode layer 21 has a high reflectivity, and the cathode layer 27 is a film layer with semi-transmissive and semi-reflective properties. Here, "semi-transmissive and semi-reflective" means that the cathode layer 27 can both transmit light and reflect light, and the specific transmittance and reflectivity are not limited. This means that the light emitting device 2a in the embodiment of the present disclosure is a top-emitting light emitting device.

[0151] Exemplarily, the reflectivity of the anode layer 21 is greater than or equal to 80%.

[0152] It can be understood that, based on the properties of the anode layer 21 and the cathode layer 27, such as the reflectivity of the anode layer 21 and the transmittance of the cathode layer 27, the light emitting device 2a can be a top-emitting light emitting device or a bottom-emitting light emitting device. Figure 6 As shown, a microcavity A can be formed between the anode layer 21 and the cathode layer 27. In this way, the light emitted by the first light emitting layer 23 and the second light emitting layer 25 can be reflected and interfered in the microcavity, to produce a microcavity effect, enhance the light emitting intensity of the emitted light, narrow the spectrum of the emitted light, and improve the light emitting efficiency of the light emitting device 2a. For example, the light emitting intensity of blue light can be enhanced, and the spectrum of blue light can be narrowed.

[0153] As shown, the optical thickness of the part of the a film layers in the first auxiliary layer 22 opposite to the first blue light emitting layer 23B is L1, and L1 satisfies: Figure 3

[0154]

[0155] a is a positive integer, n h is the refractive index of the hth film layer in the a film layers.​h is the thickness of the i-th film layer of the b film layers.

[0156] The optical thickness of the portion of the b film layers in the third auxiliary layer that is opposite the first blue light-emitting layer 23B is L2, and L2 satisfies:

[0157]

[0158] b is a positive integer, n i is the refractive index of the i-th film layer of the b film layers, r i is the thickness of the i-th film layer.

[0159] L1 and L2 satisfy the formula:

[0160]

[0161] is the average refractive index of the film layers between the first auxiliary layer 22 and the third auxiliary layer 26 and opposite the first blue light-emitting layer 23B, λ B is the blue light target spectrum peak wavelength, and k is a positive integer.

[0162] It should be noted that the optical thickness is the refractive index of the target film layer multiplied by the actual thickness of the target film layer. The average refractive index is the sum of the optical thicknesses of the film layers between the first auxiliary layer 22 and the third auxiliary layer 26 and opposite the first blue light-emitting layer 23B, divided by the sum of the actual thicknesses of the film layers between the first auxiliary layer 22 and the third auxiliary layer 26 and opposite the first blue light-emitting layer 23B. Here, the average refractive index of the film layers between the first auxiliary layer 22 and the third auxiliary layer 26 and opposite the first blue light-emitting layer 23B, for example, can be directly measured by a refractive index testing device (such as a refractometer or an ellipsometer).

[0163] It should be noted that the film layers opposite the first blue light-emitting layer 23B refer to the film layers covering the pixel defining layer openings of the blue sub-pixels.

[0164] For example, the film layers between the first auxiliary layer 22 and the third auxiliary layer 26 and opposite the first blue light-emitting layer 23B include the first blue light-emitting layer, the second auxiliary layer, and the second blue light-emitting layer.

[0165] By satisfying the above formula by L1 and L2, the luminous efficiency and color purity of the blue light emitting device in the display substrate 100 can be improved, thus the display substrate 100 of the present disclosure can reduce the setting of the optical filter, so as to reduce the blocking of the light emitted by the light emitting device 2a by the optical filter, and improve the luminous efficiency in the display substrate 100 of the present disclosure. Further, the present disclosure can achieve the same brightness as in the above-mentioned first and second implementation manners while reducing the driving voltage of the pixel driving circuit 12 in the display substrate 100, and further can reduce the power consumption of the display substrate 100 and increase the light emitting life of the light emitting device 2a.

[0166] Correspondingly, in the case that L1 and L2 of the first light emitting layer 23 of other colors in the relative area satisfy the formula:

[0167] , the luminous efficiency and color purity of the light emitting device of the corresponding color can also be enhanced.

[0168] In some examples, is in the range of 1.7-2.0.

[0169] For example, the value of L1 / L2 may, for example, be 1.7, 1.75, 1.8, 1.9 or 2.0, etc.

[0170] In some embodiments, as shown in Figure 3 , the plurality of first light emitting layers 23 further comprises a plurality of first red light emitting layers 23R and a plurality of first green light emitting layers 23G. Wherein the thickness of the first red light emitting layer 23R and the first blue light emitting layer 23B is different, and / or the thickness of the first green light emitting layer 23G and the first blue light emitting layer 23B is different.

[0171] For example, the plurality of first red light emitting layers 23R, the plurality of first green light emitting layers 23G, and the plurality of first blue light emitting layers 23B can emit light of corresponding colors, so that the display substrate 100 can realize full-color display.

[0172] For example, by making the thickness of the first red light emitting layer 23R and the first blue light emitting layer 23B different, and making the thickness of the first green light emitting layer 23G and the first blue light emitting layer 23B different, the length of the corresponding microcavity of the first light emitting layer 23 of the corresponding color can be adjusted, and thus the luminous efficiency and color purity of the light emitting device of the corresponding color can be enhanced.

[0173] In some embodiments, as shown in Figure 3As shown, the plurality of second light-emitting layers 25 further comprises a plurality of second red light-emitting layers 25R and a plurality of second green light-emitting layers 25G. The thickness of the second red light-emitting layers 25R is different from that of the second blue light-emitting layers 25B, and / or the thickness of the second green light-emitting layers 25G is different from that of the second blue light-emitting layers 25B.

[0174] For example, the plurality of second red light-emitting layers 25R, the plurality of second green light-emitting layers 25G, and the plurality of second blue light-emitting layers 25B can emit light of corresponding colors, so that the display substrate 100 can realize full-color display.

[0175] For example, by making the thickness of the second red light-emitting layers 25R different from that of the second blue light-emitting layers 25B, and making the thickness of the second green light-emitting layers 25G different from that of the second blue light-emitting layers 25B, the length of the microcavity corresponding to the second light-emitting layer 25 of the corresponding color can be adjusted, and thus the light-emitting efficiency and color purity of the light-emitting device of the corresponding color can be enhanced.

[0176] For example, the wavelength of the light emitted by the first light-emitting layer 23 is less 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 less 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 less than the wavelength of the light emitted by the second red light-emitting layer 25R, and less than the wavelength of the light emitted by the second green light-emitting layer 25G, which is not limited in the present disclosure.

[0177] For example, the first light-emitting layer 23 can emit blue light or yellow light, etc.

[0178] By making the wavelength of the light emitted by the first light-emitting layer 23 less than the wavelength of the light emitted by at least one color of the second light-emitting layer 25, the light emitted by the first light-emitting layer 23 can at least excite at least one of the second red light-emitting layer 25R, the second green light-emitting layer 25G, and the second blue light-emitting layer 25B to emit light of the corresponding color when the light emitted by the first light-emitting layer 23 is incident on the plurality of second light-emitting layers 25, thereby increasing the luminous brightness and light-emitting efficiency of the display substrate 100. Moreover, as Figure 6 As shown, the light emitted by the first light-emitting layer 23 can also be reflected multiple times within the microcavity A, so that the light emitted by the first light-emitting layer 23 can be incident on the plurality of second light-emitting layers 25 multiple times, further increasing 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 increasing the luminous brightness and light-emitting efficiency of the display substrate 100.

[0179] It should be noted that the positional relationship between the plurality of first red light-emitting layers 23R, the plurality of first green light-emitting layers 23G, the plurality of first blue light-emitting layers 23B, the plurality of second red light-emitting layers 25R, the plurality of second green light-emitting layers 25G, and the plurality of second blue light-emitting layers 25B includes multiple types, and can be set as needed.

[0180] In some examples, the first light-emitting layers 23 and the second light-emitting layers 25 of the same color are arranged opposite to each other. That is, the first light-emitting layers 23 and the second light-emitting layers 25 of the same color overlap or coincide in the orthographic projection on the substrate 11.

[0181] For example, the plurality of first blue light-emitting layers 23B and the plurality of second blue light-emitting layers 25B are arranged opposite to each other, the plurality of first red light-emitting layers 23R and the plurality of second red light-emitting layers 25R are arranged opposite to each other, and the plurality of first green light-emitting layers 23G and the plurality of second green light-emitting layers 25G are arranged opposite to each other.

[0182] By arranging the first light-emitting layers 23 and the second light-emitting layers 25 of the same color opposite to each other, the light-emitting efficiency of the light-emitting device 2a can be improved, and the color purity of the red light, the green light, or the blue light emitted by the light-emitting device 2a can be improved.

[0183] In some embodiments, the first light-emitting layers 23 include a first guest material, and the second light-emitting layers 25 include 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 the second light-emitting layer 25 of at least one color.

[0184] It should be noted that the materials of the first light-emitting layers 23 and the second light-emitting layers 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 combination with other materials with excellent light-emitting properties; the guest material itself has excellent light-emitting properties. Therefore, when the host material and the guest material doped therein are used to form the first light-emitting layers 23 or the second light-emitting layers 25, because the host material includes molecules with high excitation energy states, and the molecules with high excitation energy states can transfer their energy to the guest material, the wavelength of the light emitted by the first light-emitting layers 23 or the second light-emitting layers 25 can be changed, and the light-emitting efficiency of the first light-emitting layers 23 or the second light-emitting layers 25 can be improved.

[0185] For example, the first guest material is a material mainly used for light emission in the first light-emitting layers 23, and the second guest material is a material mainly used for light emission in the second light-emitting layers 25.

[0186] The "at least partially overlapping" means that the emission spectrum of the first guest material overlaps with the absorption spectrum of the second guest material of the second light-emitting layer 25 of at least one color, or the emission spectrum of the first guest material overlaps with the absorption spectrum of the second guest material of the second light-emitting layer 25 of all colors.

[0187] For example, the emission spectrum of the first guest material of the first light-emitting layer 23 at least partially overlaps with the absorption spectrum of the second guest material of the second red light-emitting layer 25R, or the emission spectrum of the first guest material of the first light-emitting layer 23 at least partially overlaps with the absorption spectrum of the second guest material of the second green light-emitting layer 25G. Or, the emission spectrum of the first guest material of the first light-emitting layer 23 at least partially overlaps with the absorption spectrum of the second guest material of the second blue light-emitting layer 25B, or the emission spectrum of the first guest material of the first light-emitting layer 23 at least partially overlaps with the absorption spectrum of the second guest material of the second red light-emitting layer 25R and the second green light-emitting layer 25G. The present disclosure does not limit this.

[0188] By at least partially overlapping the emission spectrum of the first guest material of the first light-emitting layer 23 with the absorption spectrum of the second guest material of the second light-emitting layer 25 of at least one color, a part of the light emitted by the first guest material of the first light-emitting layer 23 can be absorbed by the second guest material of the second light-emitting layer 25 of at least one color, so that the second guest material of the second light-emitting layer 25 emits light under the excitation of the light emitted by the first guest material, thereby improving the light-emitting efficiency of the second guest material of the second light-emitting layer 25. Another part of the light emitted by the first guest material of the first light-emitting layer 23 can be emitted through the cathode layer 27 to form a series light-emitting device with the light emitted by the second light-emitting layer 25, thereby enhancing the light-emitting brightness of the display substrate 100.

[0189] It should be noted that when the light emitted by the first light-emitting layer 23 in the display substrate 100 is directed 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 light of the corresponding color. Moreover, the first light-emitting layer 23 and the second light-emitting layer 25 can also form a series light-emitting component. The two light-emitting mechanisms work together, and the display substrate 100 will have higher light-emitting efficiency.

[0190] It can be understood that the more the overlapping part of 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 light emitted by the first guest material can excite the second guest material to emit more light, and the higher the light-emitting efficiency of the second guest material of the second light-emitting layer 25.

[0191] In some embodiments, the overlap range of 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 greater than or equal to 60% of the wavelength range of the emission spectrum of the first guest material.

[0192] For example, the overlap range of the emission spectrum of the first guest material and the absorption spectrum of the second guest material can be 60%, 70%, 80%, 90% or 99% of the wavelength range of the emission spectrum of the first guest material, etc.

[0193] In this way, more than or equal to 60% of the light emitted by the first guest material can be absorbed by the second guest material, thereby improving the utilization rate of the light emitted by the first guest material by the second guest material.

[0194] In some embodiments, the overlap range of 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 greater than or equal to 60% of the wavelength range of the absorption spectrum of the second guest material.

[0195] For example, the overlap range of the emission spectrum of the first guest material and the absorption spectrum of the second guest material can be 60%, 70%, 80%, 90% or 99% of the wavelength range of the absorption spectrum of the second guest material, etc.

[0196] In this way, more light emitted by the first guest material can be absorbed by the second guest material, thereby improving the utilization rate of the light emitted by the first guest material by the second guest material.

[0197] In some embodiments, the first guest material of the first light-emitting layer 23 of at least one color comprises at least one light-emitting material. In the case where the above-mentioned first guest material comprises two light-emitting materials, the interval between the emission spectrum peaks of the two light-emitting materials is less than or equal to 30 nm.

[0198] For example, the first guest material of the first red light-emitting layer 23R comprises at least one light-emitting material; or, the first guest material of the first green light-emitting layer 23G comprises at least one light-emitting material; or, the first guest material of the first blue light-emitting layer 23B comprises at least one light-emitting material; or, the first guest material of the first red light-emitting layer 23R and the first guest material of the first green light-emitting layer 23G both comprise at least one light-emitting material; or, other schemes are also possible, which are not limited by the present disclosure.

[0199] For example, the first guest material can comprise one or two types of light-emitting materials, etc., which are not limited by the present disclosure.

[0200] It can be understood that different light-emitting materials can emit different colors of light. In the case that the first guest material of the first light-emitting layer 23 includes one light-emitting material, the first light-emitting layer 23 can emit one color of light; in the case that the first guest material of the first light-emitting layer 23 includes two light-emitting materials, the first light-emitting layer 23 can emit two colors of light.

[0201] For example, in the case that 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 can be 1 nm, 10 nm, 19 nm, 25 nm, 30 nm, etc.

[0202] By making the interval between the peak values of the emission spectra of the two light-emitting materials of the first guest material less than or equal to 30 nm, 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.

[0203] In some embodiments, the emission spectrum of the first guest material of the first red light-emitting layer 23R overlaps with the absorption spectrum of the second guest material of the second red light-emitting layer 25R.

[0204] For example, the peak value of the emission spectrum of the first guest material ranges from 560 nm to 570 nm, and the peak value of the absorption spectrum of the second guest material of the second green light-emitting layer 25G ranges from 595 nm to 605 nm.

[0205] For example, the peak value of the emission spectrum of the first guest material of the first red light-emitting layer 23R can be 560 nm, 562 nm, 566 nm, 568 nm, 570 nm, etc. The peak value of the absorption spectrum of the second guest material of the second green light-emitting layer 25G can be 595 nm, 597 nm, 600 nm, 602 nm, 605 nm, etc.

[0206] In this way, the emission spectrum of the first guest material of the first red light-emitting layer 23R and the absorption spectrum of the second guest material of the second red light-emitting layer 25R can have a larger overlapping range, and the light-emitting efficiency of the second guest material of the second red light-emitting layer 25R can be improved.

[0207] In some embodiments, the emission spectrum of the first guest material of the first green light-emitting layer 23G overlaps with the absorption spectrum of the second guest material of the second green light-emitting layer 25G.

[0208] For example, the peak value of the emission spectrum of the first guest material ranges from 500 nm to 510 nm, and the peak value of the absorption spectrum of the second guest material of the second green light-emitting layer 25G ranges from 515 nm to 525 nm.

[0209] Exemplarily, the peak of the emission spectrum of the first guest material can be 500 nm, 502 nm, 506 nm, 508 nm, or 510 nm, etc. The peak of the absorption spectrum of the second guest material of the second green light-emitting layer 25G can be 515 nm, 518 nm, 520 nm, 522 nm, or 525 nm, etc.

[0210] In this way, the emission spectrum of the first guest material of the first green light-emitting layer 23G and the absorption spectrum of the second guest material of the second green light-emitting layer 25G can have a larger overlapping range, and thus the light-emitting efficiency of the second guest material of the second green light-emitting layer 25G can be improved.

[0211] In some embodiments, in the case where the first guest material of the first light-emitting layer 23 includes two light-emitting materials, at least one of the two light-emitting materials is doped with boron elements, and the doping proportion of the boron elements ranges from 0.5% to 5%.

[0212] Exemplarily, the doping proportion of the boron elements can be 0.5%, 1.5%, 3.5%, 4%, or 5%, etc.

[0213] 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.

[0214] Exemplarily, the fluorescent material includes a pyrene material, a fused carbazole material, and a boron-containing material, etc. The phosphorescent material includes an iridium (Ir) and a platinum (Pt) complex, etc. The thermally activated delayed fluorescence material generally has a D-A structure, and the S1-T1 of the thermally activated delayed fluorescence material is less than 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 electronic excited state of the material.

[0215] 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 is a single host material or a PN hybrid host material.

[0216] Exemplarily, the first host material includes at least one of an anthracene material, a fluorene material, a pyrene material, and a carbazole derivative material.

[0217] In some embodiments, the thickness of the first blue light-emitting layer 23B ranges from 15 nm to 60 nm.

[0218] Exemplarily, the thickness of the first blue light-emitting layer 23B can be 15 nm, 20 nm, 35 nm, 45 nm, or 60 nm, etc.

[0219] In some embodiments, the second guest material of the second light-emitting layer 25 of at least one color comprises at least one light-emitting material. In the case where the above-mentioned second guest material comprises two light-emitting materials, the interval between the peak values of the emission spectra of the two light-emitting materials is less than or equal to 30 nm.

[0220] Optionally, the second red light-emitting layer can comprise at least one light-emitting material, or the second green light-emitting layer can comprise at least one light-emitting material, or the second blue light-emitting layer can comprise at least one light-emitting material. Optionally, both the second red light-emitting layer and the second green light-emitting layer can comprise at least one light-emitting material.

[0221] For example, the above-mentioned second guest material can comprise one or two light-emitting materials. The present disclosure does not limit this.

[0222] It can be understood that different light-emitting materials can emit light of different colors. In the case where the second guest material of the second light-emitting layer 25 comprises one light-emitting material, the above-mentioned second light-emitting layer 25 can emit light of one color. In the case where the second guest material of the second light-emitting layer 25 comprises two light-emitting materials, the above-mentioned second light-emitting layer 25 can emit light of two colors.

[0223] For example, in the case where the second guest material of the second light-emitting layer 25 comprises two light-emitting materials, one of the two light-emitting materials can have an emission spectrum overlapping with the absorption spectrum of the other light-emitting material. In this way, the light-emitting efficiency of the above-mentioned two light-emitting materials can be increased.

[0224] For example, in the case where the second guest material of the second light-emitting layer 25 comprises two light-emitting materials, the interval between the peak values of the emission spectra of the above-mentioned two light-emitting materials can be 1 nm, 10 nm, 19 nm, 25 nm or 30 nm, etc.

[0225] By making the interval between the peak values of the emission spectra of the two light-emitting materials in the second guest material of the second light-emitting layer 25 less than or equal to 30 nm, the colors of the light emitted by the two light-emitting materials of the second guest material can be made more similar, and the color purity of the light emitted by the second light-emitting layer 25 can be improved.

[0226] In some embodiments, in the case where the second guest material of the second light-emitting layer 25 comprises two light-emitting materials, at least one of the two light-emitting materials is doped with boron elements, and the doping proportion of the boron elements ranges from 0.5% to 5%.

[0227] For example, the doping proportion of the boron elements can be 0.5%, 1.5%, 3.5%, 4% or 5%, etc.

[0228] In some embodiments, the second guest material includes at least one of a fluorescent material, a phosphorescent material, and a thermally activated delayed fluorescence material having a multiple resonance characteristic.

[0229] In some embodiments, the second light-emitting layer 25 further includes a second host material. The second host material includes a bipolar host material.

[0230] In some embodiments, the second host material is a single host material or a PN hybrid host material.

[0231] In some examples, in the case where the second host material is a PN hybrid host material, the N-type component has a thermally activated delayed fluorescence characteristic.

[0232] It should be noted that, in the case where the N-type component has a thermally activated delayed fluorescence characteristic, the light-emitting efficiency of the second guest material in the second light-emitting layer 25 can be improved.

[0233] In some embodiments, the thickness of the second blue light-emitting layer 25B ranges from 10 nm to 50 nm.

[0234] For example, the thickness of the second light-emitting layer 25 can be 10 nm, 20 nm, 28 nm, 38 nm, or 50 nm, etc.

[0235] In some embodiments, as shown in FIG. 1B, the microcavity A includes a plurality of sub-microcavities A1, and the plurality of sub-microcavities A1 include a red sub-microcavity A1-R corresponding to the first red light-emitting layer 23R, a green sub-microcavity A1-G corresponding to the first green light-emitting layer 23G, and a blue sub-microcavity A1-B corresponding to the first blue light-emitting layer 23B. Figure 6 The number of film layers between the anode layer 21 and the cathode layer 27 and corresponding to any color of the sub-microcavity A1 is c, and the optical thickness of the c film layers is L3, which satisfies:

[0236]

[0237] where c is a positive integer, n j is the refractive index of the jth film layer in the c film layers, r j is the thickness of the jth film layer.

[0238] Any color of the sub-microcavity A1 satisfies:

[0239]

[0240] m is a natural number, λ is an interference wavelength, is a phase shift caused by the anode layer 21.

[0241] For example, when blue light interference is required, λ is the wavelength of blue light; when red light interference is required, λ is the wavelength of red light; and when green light interference is required, λ is the wavelength of green light.

[0242] For example, when L3 of the red sub-microcavity A1-R satisfies the above formula, the red light emitted by the second red light-emitting layer 25R can generate a microcavity effect in the red sub-microcavity A1-R, thereby increasing the brightness and color purity of the red light.

[0243] 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 can also generate a microcavity effect in the corresponding sub-microcavity A1, thereby increasing the brightness and color purity of the green and blue light.

[0244] In some embodiments, the length of the blue sub-microcavity A1-B is less than the length of the red sub-microcavity A1-R. The length of the blue sub-microcavity A1-B is less than the length of the green sub-microcavity A1-G.

[0245] For example, the wavelength range of red light is 615nm to 630nm, the wavelength range of green light is 515nm to 535nm, and the wavelength range of red light is 460nm to 475nm. Therefore, when red, green, and blue light can all produce microcavity effects, the length of the blue sub-microcavity A1-B is the smallest.

[0246] In some embodiments, such as Figure 6 As shown, the second auxiliary layer 24 includes a first microcavity adjustment layer 241. The thickness of the portion of the first microcavity adjustment layer 241 opposite to the second red light-emitting layer 25R is different from the thickness of the portion of the first microcavity adjustment layer 241 opposite to the second blue light-emitting layer 25B, and / or, the thickness of the portion of the first microcavity adjustment layer 241 opposite to the second green light-emitting layer 25G is different from the thickness of the portion of the first microcavity adjustment layer 241 opposite to the second blue light-emitting layer 25B.

[0247] For example, the first microcavity adjustment layer 241 is used to adjust the length of microcavity A. By adjusting the thickness of the portions of the first microcavity adjustment layer 241 that are opposite to the second red light-emitting layer 25R, the second green light-emitting layer 25G, and the second blue light-emitting layer 25B, the corresponding color light can generate a microcavity effect in the red sub-microcavity A1-R, the green sub-microcavity A1-G, and the blue sub-microcavity A1-B.

[0248] In some embodiments, such as Figure 6As shown, the first microcavity adjustment layer 241 comprises: a second hole transport layer 2411, a first red sub-microcavity adjustment layer 2412R disposed between the second hole transport layer 2411 and the second red light-emitting layer 25R, a first green sub-microcavity adjustment layer 2412G disposed between the second hole transport layer 2411 and the second green light-emitting layer 25G, and a first blue sub-microcavity adjustment layer 2412B disposed between the second hole transport layer 2411 and the second blue light-emitting layer 25B. The thickness between the first red sub-microcavity adjustment layer 2412R and the first blue sub-microcavity adjustment layer 2412B is different, and the thickness between the first green sub-microcavity adjustment layer 2412G and the first blue sub-microcavity adjustment layer 2412B is different.

[0249] In some examples, the second hole transport layer 2411 is disposed as a whole layer and the thickness thereof is adjustable.

[0250] By disposing the second hole transport layer 2411 as a whole layer, the manufacturing process of the display substrate 100 can be simplified.

[0251] By adjusting the thickness of the second hole transport layer 2411, the length of the microcavity A can be adjusted, so that the corresponding color light can generate a microcavity effect in the red sub-microcavity A1-R, the green sub-microcavity A1-G and the blue sub-microcavity A1-B.

[0252] For example, the second hole transport layer 2411 is used to reduce the injection barrier of holes, improve the mobility of holes, and facilitate the transport of holes to the second light-emitting layer 25, thereby improving the accumulation of holes in the second light-emitting layer 25 and improving the light-emitting efficiency and light-emitting life of the second light-emitting layer 25.

[0253] For example, the HOMO energy level of the material of the second hole transport layer 2411 ranges from -5.2 eV to -5.6 eV. For example, the HOMO energy level of the material of the second hole transport layer 2411 includes -5.2 eV, -5.3 eV, -5.4 eV, -5.5 eV, -5.6 eV, and the like.

[0254] For example, the T1 of the material of the first red sub-microcavity adjustment layer 2412R, the first green sub-microcavity adjustment layer 2412G and the first blue sub-microcavity adjustment layer 2412B is higher than the T1 of the light-emitting material of the second light-emitting layer 25.

[0255] For example, the T1 of the material of the first red sub-microcavity adjustment layer 2412R, the first green sub-microcavity adjustment layer 2412G and the first blue sub-microcavity adjustment layer 2412B is at least 0.2 eV higher than the T1 of the light-emitting material of the second light-emitting layer 25.

[0256] For example, the thickness of the first blue sub-microcavity adjustment layer 2412B is less than or equal to 10 nm.

[0257] For example, the thickness of the first blue sub-microcavity modulation layer 2412B can be 1nm, 3nm, 5nm, 7nm or 10nm, etc.

[0258] As mentioned above, red, green, and blue light have different wavelengths. When all three light sources can produce a microcavity effect, the lengths between the red photonic microcavity A1-R and the blue photonic microcavity A1-B are different, as are the lengths between the green photonic microcavity A1-G and the blue photonic microcavity A1-B. For example... Figure 6 As shown, multiple sub-microcavities A1 share a first auxiliary layer 22, a first light-emitting layer 23, a portion of a second auxiliary layer 24, and a third auxiliary layer 26. By making the thicknesses of the first red sub-microcavity adjustment layer 2412R and the first blue sub-microcavity adjustment layer 2412B different, and the thicknesses of the first green sub-microcavity adjustment layer 2412G and the first blue sub-microcavity adjustment layer 2412B different, the multiple sub-microcavities A1 can meet the required length by adjusting only the thicknesses of the first red sub-microcavity adjustment layer 2412R, the first green sub-microcavity adjustment layer 2412G, and the first blue sub-microcavity adjustment layer 2412B. This allows the shared film layers (e.g., the first auxiliary layer 22, the first light-emitting layer 23, a portion of the second auxiliary layer 24, and the third auxiliary layer 26) in the blue sub-microcavities A1-B, red sub-microcavities A1-R, and green sub-microcavities A1-G to have the same thickness. This simplifies the manufacturing process of the shared film layers and, correspondingly, simplifies the manufacturing process of the display substrate 100.

[0259] It should be noted that the thicknesses of the first red sub-microcavity adjustment layer 2412R, the first green sub-microcavity adjustment layer 2412G, and the first blue sub-microcavity adjustment layer 2412B have little impact on the electrical performance of the light-emitting device layer 2 in the display substrate 100. By adjusting the thicknesses of the first red sub-microcavity adjustment layer 2412R, the first green sub-microcavity adjustment layer 2412G, and the first blue sub-microcavity adjustment layer 2412B, and thereby adjusting the length of the multiple sub-microcavities A1, the impact on the electrical performance of the light-emitting device layer 2 in the display substrate 100 can be reduced.

[0260] It is understood that any one of the first red sub-microcavity adjustment layer 2412R, the first green sub-microcavity adjustment layer 2412G, and the first blue sub-microcavity adjustment layer 2412B may include a single film layer, or any one of the first red sub-microcavity adjustment layer 2412R, the first green sub-microcavity adjustment layer 2412G, and the first blue sub-microcavity adjustment layer 2412B may include multiple film layers stacked sequentially.

[0261] In some examples, both the first red sub-microcavity conditioning layer 2412R and the first green sub-microcavity conditioning layer 2412G include a film layer.

[0262] For example, such as Figure 6As shown, the first red sub-microcavity adjusting layer 2412R includes a red hole transport layer 2412R-1, and the first green sub-microcavity adjusting layer 2412G includes a green hole transport layer 2412G-1.

[0263] For example, the red hole transport layer 2412R-1 can reduce the injection barrier of holes, facilitate the injection and transport of holes from the second auxiliary layer 24 into the second red light-emitting layer 25R, thereby increasing the accumulation of holes in the second red light-emitting layer 25R and improving the light-emitting efficiency and lifetime of the second red light-emitting layer 25R. The green hole transport layer 2412G-1 can reduce the injection barrier of holes, facilitate the injection and transport of holes from the second auxiliary layer 24 into the second green light-emitting layer 25G, thereby increasing the accumulation of holes in the second green light-emitting layer 25G and improving the light-emitting efficiency and lifetime of the second green light-emitting layer 25G.

[0264] In other embodiments, as shown in FIG. 24B, the first red sub-microcavity adjusting layer 2412R includes a red hole transport layer 2412R-1 and a red electron blocking layer 2412R-2 stacked in sequence along the direction away from the backplane 1, and the first green sub-microcavity adjusting layer 2412G includes a green hole transport layer 2412G-1 and a green electron blocking layer 2412G-2 stacked in sequence along the direction away from the backplane 1. Figure 3

[0265] For example, the red hole transport layer 2412R-1 can reduce the injection barrier of holes, facilitate the injection and transport of holes from the second auxiliary layer 24 into the second red light-emitting layer 25R, thereby increasing the accumulation of holes in the second red light-emitting layer 25R and improving the light-emitting efficiency and lifetime of the second red light-emitting layer 25R. The green hole transport layer 2412G-1 can reduce the injection barrier of holes, facilitate the injection and transport of holes from the second auxiliary layer 24 into the second green light-emitting layer 25G, thereby increasing the accumulation of holes in the second green light-emitting layer 25G and improving the light-emitting efficiency and lifetime of the second green light-emitting layer 25G.

[0266] For example, the red electron blocking layer 2412R-2 is used to block the overflow of electrons and / or excitons from the second red light-emitting layer 25R, which can limit the electrons and / or excitons in the second red light-emitting layer 25R, thereby increasing the concentration of electrons and / or excitons in the second red light-emitting layer 25R and improving the light-emitting brightness and efficiency of the second red light-emitting layer 25R. The green electron blocking layer 2412G-2 is used to block the overflow of electrons and / or excitons from the second green light-emitting layer 25G, which can limit the electrons and / or excitons in the second green light-emitting layer 25G, thereby increasing the concentration of electrons and / or excitons in the second green light-emitting layer 25G and improving the light-emitting brightness and efficiency of the second green light-emitting layer 25G. ​

[0267] In some examples, the red hole transport layer 2412R-1 and the green hole transport layer 2412G-1 are used to adjust the length of the sub-microcavity A1, respectively.

[0268] It is understandable that, with the thickness of other film layers (such as the first auxiliary layer 22, the first light-emitting layer 23, etc.) remaining unchanged, the lengths of the corresponding red sub-microcavities A1-R and green sub-microcavities A1-G can be changed by altering the thickness of the red hole transport layer 2412R-1 and the green hole transport layer 2412G-1.

[0269] For example, by changing the thickness of the red hole transport layer 2412R-1, the length of the red sub-microcavity A1-R can be changed; thereby, a microcavity effect can be generated in the red sub-microcavity A1-R, increasing the brightness and color purity of the red light. Furthermore, the wavelength of the light capable of generating a microcavity effect in the red sub-microcavity A1-R can be changed, thereby adjusting the color of the light emitted from the red sub-microcavity A1-R. Similarly, by changing the thickness of the green hole transport layer 2412G-1, the length of the green sub-microcavity A1-G can be changed; thereby, a microcavity effect can be generated in the green sub-microcavity A1-G, increasing the brightness and color purity of the green light. Furthermore, the wavelength of the light capable of generating a microcavity effect in the green sub-microcavity A1-G can be changed, thereby adjusting the color of the light emitted from the green sub-microcavity A1-G.

[0270] It should be noted that the first auxiliary layer 22 may include a single membrane layer or multiple membrane layers stacked sequentially. When the first auxiliary layer 22 includes multiple membrane layers, the structure of the multiple membrane layers of the first auxiliary layer 22 can have various schemes, and each membrane layer can have different functions, so that the first auxiliary layer 22 can have multiple functions.

[0271] In some embodiments, such as Figure 7 As shown, the first auxiliary layer 22 includes: a light-transmitting conductive layer 221, a hole injection layer 222, and a second microcavity adjustment layer 223, which are sequentially stacked along the direction away from the back plate 1.

[0272] For example, the light-transmitting conductive layer 221 has good light transmittance and conductivity. When light shines on the light-transmitting conductive layer 221, the light can pass through the light-transmitting conductive layer 221 and shine on the anode layer 21. The anode layer 21 has good light reflection performance, so the light can be reflected by the anode layer 21 and the light-transmitting conductive layer 221.

[0273] For example, the light-transmitting conductive layer 221 can be a single-layer structure, or the light-transmitting conductive layer 221 can include multiple film layers stacked sequentially.

[0274] For example, the material of the transparent conductive layer 221 may include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), etc.

[0275] For example, the thickness of the light-transmitting conductive layer 221 is less than or equal to 10 nm. Optionally, the thickness of the light-transmitting conductive layer 221 ranges from 5 nm to 10 nm.

[0276] For example, the thickness of the transparent conductive layer 221 can be 5nm, 6.5nm, 8nm, 9nm or 10nm, etc.

[0277] For example, the hole injection layer 222 can be formed by doping the material of the first hole transport layer 2231 with a P-type dopant (e.g., MnO3, F4TCNQ, etc.), wherein the doping ratio of the P-type dopant is less than or equal to 5%, and the thickness of the hole injection layer 222 is less than or equal to 10 nm.

[0278] For example, the doping ratio of P-type dopant in the material of the first hole transport layer 2231 can be 1%, 2%, 3%, 4%, or 5%, etc. The thickness of the hole injection layer 222 can be 1nm, 3nm, 5nm, 8nm, or 10nm, etc.

[0279] For example, the second microcavity adjustment layer 223 is used to adjust the length of microcavity A. By adjusting the thickness of the portions of the second microcavity adjustment layer 223 that are opposite to the second red light-emitting layer 25R, the second green light-emitting layer 25G, and the second blue light-emitting layer 25B, the corresponding colored light can generate a microcavity effect in the red sub-microcavity A1-R, the green sub-microcavity A1-G, and the blue sub-microcavity A1-B, thereby improving the color purity and luminous brightness of the light emitted from the sub-microcavity A1.

[0280] In some examples, such as Figure 7 As shown, the second microcavity modulation layer 223 includes: a first hole transport layer 2231, a second red sub-microcavity modulation layer 2232R, a second green sub-microcavity modulation layer 2232G, and a second blue sub-microcavity modulation layer 2232B. The second red sub-microcavity modulation layer 2232R is disposed between the first hole transport layer 2231 and the first red emitting layer 23R. The second green sub-microcavity modulation layer 2232G is disposed between the first hole transport layer 2231 and the first green emitting layer 23G. The second blue sub-microcavity modulation layer 2232B is disposed between the first hole transport layer 2231 and the first blue emitting layer 23B.

[0281] In some examples, the first hole transport layer 2231 is set as a whole and its thickness is adjustable.

[0282] The first hole transport layer 2231 is formed in an integral layer, which simplifies the manufacturing process of the display substrate 100.

[0283] The length of the microcavity A can be adjusted by adjusting the thickness of the first hole transport layer 2231, so that the corresponding color light can generate a microcavity effect in the red sub-microcavity A1-R, the green sub-microcavity A1-G and the blue sub-microcavity A1-B, thereby improving the color purity and luminous brightness of the light emitted by the sub-microcavity A1.

[0284] For example, the HOMO (Highest Occupied Molecular Orbital) energy level of the hole injection layer 222 material, and the HOMO energy level of the first hole transport layer 2231 material are sequentially increased. This arrangement can reduce the injection barrier of holes, improve the mobility of holes, and facilitate the injection and transmission of holes from the anode layer 21 to the first light-emitting layer 23 of the corresponding color, thereby improving the accumulation of holes in the first light-emitting layer 23 and improving the light-emitting efficiency and light-emitting life of the first light-emitting layer 23.

[0285] For example, the HOMO energy level of the first hole transport layer 2231 material ranges from -5.2 eV to -5.6 eV. For example, the HOMO energy level of the first hole transport layer 2231 material can be -5.2 eV, -5.3 eV, -5.4 eV, -5.5 eV or -5.6 eV, etc.

[0286] For example, the material of the first hole transport layer 2231 includes a carbazole material with high hole mobility. The first hole transport layer 2231 can be formed by a vapor deposition process.

[0287] For example, the second red sub-microcavity adjusting layer 2232R is used to reduce the barrier of holes transmitted from the first hole transport layer 2231 to the first red light-emitting layer 23R; the second green sub-microcavity adjusting layer 2232G is used to reduce the barrier of holes transmitted from the first hole transport layer 2231 to the first green light-emitting layer 23G; and the second blue sub-microcavity adjusting layer 2232B is used to reduce the barrier of holes transmitted from the first hole transport layer 2231 to the first blue light-emitting layer 23B. This can increase the mobility of holes transmitted to the first light-emitting layer 23, increase the content of holes in the first light-emitting layer 23, and increase the luminous brightness and light-emitting efficiency of the first light-emitting layer 23.

[0288] For example, the T1 of the material of the second red sub-microcavity adjusting layer 2232R, the second green sub-microcavity adjusting layer 2232G, and the second blue sub-microcavity adjusting layer 2232B is at least 0.2 eV higher than the T1 of the light-emitting material of the first light-emitting layer 23.

[0289] For example, the T1 of the material of the second red sub-microcavity adjusting layer 2232R, the second green sub-microcavity adjusting layer 2232G, and the second blue sub-microcavity adjusting layer 2232B is at least 0.2 eV higher than the T1 of the light-emitting material of the first light-emitting layer 23.

[0290] For example, the thickness of the second red sub-microcavity adjusting layer 2232R, the second green sub-microcavity adjusting layer 2232G, and the second blue sub-microcavity adjusting layer 2232B is individually adjustable. By individually adjusting the thickness of the second red sub-microcavity adjusting layer 2232R, the second green sub-microcavity adjusting layer 2232G, and the second blue sub-microcavity adjusting layer 2232B, the microcavity length of the corresponding red sub-microcavity A1-R, green sub-microcavity A1-G, and blue sub-microcavity A1-B can be adjusted, so that the corresponding color light can generate a microcavity effect in the red sub-microcavity A1-R, green sub-microcavity A1-G, and blue sub-microcavity A1-B, and the color purity and luminous brightness of the light emitted by the sub-microcavity A1 can be improved.

[0291] For example, the thickness of the second blue sub-microcavity adjusting layer 2232B can be 1 nm, 3 nm, 5 nm, 7 nm, or 10 nm, etc.

[0292] For example, the thickness of the second blue sub-microcavity adjusting layer 2232B can be 1 nm, 3 nm, 5 nm, 7 nm, or 10 nm, etc.

[0293] In other embodiments, the first auxiliary layer 22 includes a plurality of film layers different from the above-mentioned film layer structure, such as Figure 8 As shown, the first auxiliary layer 22 includes the above-mentioned light-transmitting conductive layer 221, the above-mentioned hole injection layer 222, and the second microcavity adjusting layer 223. The second microcavity adjusting layer 223 includes the above-mentioned first hole transport layer 2231 and the electron blocking layer 2233.

[0294] For example, the second microcavity adjusting layer 223 is used to adjust the length of the microcavity A. By adjusting the thickness of the part of the second microcavity adjusting layer 223 opposite to the second red light-emitting layer 25R, the second green light-emitting layer 25G, and the second blue light-emitting layer 25B, respectively, the corresponding color light can generate a microcavity effect in the red sub-microcavity A1-R, green sub-microcavity A1-G, and blue sub-microcavity A1-B, and the color purity and luminous brightness of the light emitted by the sub-microcavity A1 can be improved.

[0295] For example, the HOMO (Highest Occupied Molecular Orbital) energy level of the hole injection layer 222 material, the HOMO energy level of the first hole transport layer 2231 material, and the HOMO energy level of the electron blocking layer 2233 material increase sequentially. This arrangement can reduce the hole injection barrier, improve the hole mobility, and facilitate the injection of holes from the anode layer 21 and their sequential transport to the first light-emitting layer 23. This can further increase the accumulation of holes in the first light-emitting layer 23, thereby improving the luminous efficiency and luminous lifetime of the first light-emitting layer 23.

[0296] For example, the HOMO energy level range of the electron blocking layer 2233 material is -5.5 eV to -5.9 eV. For instance, the HOMO energy levels of the electron blocking layer 2233 material include: -5.5 eV, -5.6 eV, -5.7 eV, -5.8 eV, -5.9 eV, etc.

[0297] For example, the T1 of the electron blocking layer 2233 material is greater than the T1 of the light-emitting material in the first light-emitting layer 23. This can 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.

[0298] For example, the T1 of the electron blocking layer 2233 material is at least 0.2 eV higher than the T1 of the luminescent material in the first luminescent layer 23.

[0299] In some examples, in the display substrate 100 provided in the above embodiments, the difference in refractive index between any two films located between the anode layer 21 and the cathode layer 27 is less than or equal to 0.32. This arrangement ensures that the refractive indices of any two films located between the anode layer 21 and the cathode layer 27 are relatively close, resulting in a smaller difference in refractive index between any two films located between the anode layer 21 and the cathode layer 27. This reduces abrupt changes in refractive index between the films, enabling the light-emitting device 2a to have good light extraction efficiency and reducing the dispersion of the light emitted by the light-emitting device 2a.

[0300] For example, such as Figure 8 As shown in Table 1, the types of materials used in the film between the anode layer 21 and the cathode layer 27, as well as the refractive index of each film layer for blue light with a wavelength of 460 nm, are shown in Table 1 below.

[0301] Table 1

[0302] Film layer name Material kind Refractive index Hole injection layer Carbazole doped acetylene 1.74 First hole transport layer Carbazole 1.74 Electron blocking layer Carbazole 1.87 First hole blocking layer Triazine 1.88 First electron transport layer Triazine 2.00 First charge generation layer Phosphorus oxide 1.82 Second charge generation layer Carbazole doped acetylene 1.74 Second hole transport layer Carbazole 1.74 Color sub-cavity adjustment layer Carbazole 1.87 Second hole blocking layer Triazine 1.86 Second electron transport layer Triazine 1.79 Electron injection layer Metal complex 1.68

[0303] As shown in Table 1, the difference between the refractive indexes of any two film layers in the film layers between the anode layer 21 and the cathode layer 27 is less than or equal to 0.32, which means that the refractive indexes of any two film layers in the film layers between the anode layer 21 and the cathode layer 27 are closer. By selecting the materials and the refractive indexes of the film layers between the anode layer 21 and the cathode layer 27, the difference between the refractive indexes of any two film layers in the film layers between the anode layer 21 and the cathode layer 27 can be further reduced, the refractive index mutation between the film layers can be further reduced, the light-emitting device 2a has good light-emitting efficiency, and the dispersion of the light emitted by the light-emitting device 2a is reduced.

[0304] In yet some embodiments, the first auxiliary layer 22 includes a plurality of film layers different from the above two film layer structures, such as Figure 9 As shown, the first auxiliary layer 22 includes the above light-transmitting conductive layer 221, the above hole injection layer 222, and the second microcavity adjusting layer 223 which are sequentially stacked in the direction away from the back plate 1.

[0305] The second microcavity adjusting layer 223 includes the above first hole transport layer 2231, the second blue sub-microcavity adjusting layer 2232B, the second red sub-microcavity adjusting layer 2232R, and the second green sub-microcavity adjusting layer 2232G. The second blue sub-microcavity adjusting layer 2232B is disposed on the side of the first hole transport layer 2231 away from the back plate 1. The second red sub-microcavity adjusting layer 2232R is disposed between the second blue sub-microcavity adjusting layer 2232B and the first red light-emitting layer 23R. The second green sub-microcavity adjusting layer 2232G is disposed between the second blue sub-microcavity adjusting layer 2232B and the first green light-emitting layer 23G.

[0306] For example, the second microcavity adjusting layer 223 is used to adjust the length of the microcavity A. By adjusting the thickness of the portions of the second microcavity adjusting layer 223 opposite to the second red light-emitting layer 25R, the second green light-emitting layer 25G, and the second blue light-emitting layer 25B, the corresponding color light can generate microcavity effect in the red sub-microcavity A1-R, the green sub-microcavity A1-G, and the blue sub-microcavity A1-B, and the color purity and the light-emitting brightness of the light emitted by the sub-microcavity A1 are improved.

[0307] For example, the second blue sub-microcavity adjusting layer 2232B, the second red sub-microcavity adjusting layer 2232R and the second green sub-microcavity adjusting layer 2232G are used to reduce the potential barrier of the holes transmitted from the first hole transport layer 2231 to the first light-emitting layer 23. By disposing the second blue sub-microcavity adjusting layer 2232B as a whole layer, disposing the second red sub-microcavity adjusting layer 2232R on the second blue sub-microcavity adjusting layer 2232B can further reduce the potential barrier of the holes transmitted from the first hole transport layer 2231 to the first red light-emitting layer 23R, and disposing the second green sub-microcavity adjusting layer 2232G on the second blue sub-microcavity adjusting layer 2232B can further reduce the potential barrier of the holes transmitted from the first hole transport layer 2231 to the first green light-emitting layer 23G, thereby further increasing the mobility of the holes and improving the light-emitting brightness and light-emitting efficiency of the first light-emitting layer 23.

[0308] For example, the thickness of the second blue sub-microcavity adjusting layer 2232B, the second red sub-microcavity adjusting layer 2232R and the second green sub-microcavity adjusting layer 2232G is individually adjustable.

[0309] For example, in the case that each color light generates the microcavity effect in the corresponding sub-microcavity A1, the length of the blue sub-microcavity A1-B is the smallest. By disposing the second blue sub-microcavity adjusting layer 2232B as a whole layer, after adjusting the thickness of the second blue sub-microcavity adjusting layer 2232B to make the blue light generate the microcavity effect, as shown in FIG. 23B, the adjustment amount of the thickness of the second red sub-microcavity adjusting layer 2232R and the second green sub-microcavity adjusting layer 2232G can be reduced, and the manufacturing process of the second red sub-microcavity adjusting layer 2232R and the second green sub-microcavity adjusting layer 2232G in the display substrate 100 can be simplified. Figure 9

[0310] It should be noted that the display substrate 100 can also adjust the peak position in the spectrum of the light emitted by the sub-microcavity A1 by adjusting the thickness of the second blue sub-microcavity adjusting layer 2232B, the second red sub-microcavity adjusting layer 2232R and the second green sub-microcavity adjusting layer 2232G, thereby adjusting the color of the light.

[0311] In addition, the thickness of the hole injection layer 222, the first hole transport layer 2231 and the electron blocking layer 2233 in the above-mentioned embodiments is individually adjustable, and the hole injection layer 222, the first hole transport layer 2231 and the electron blocking layer 2233 can be used to adjust the length of the sub-microcavity A1, thereby improving the color purity and light-emitting brightness of the light emitted by the sub-microcavity A1. Further, by adjusting the length of the sub-microcavity A1, the peak position in the spectrum of the light emitted by the sub-microcavity A1 can be adjusted, thereby adjusting the color of the light.

[0312] ​It should be noted that any one of the second auxiliary layer 24 and the third auxiliary layer 26 can include one film layer or a plurality of film layers which are sequentially stacked, and in the case that any one of the second auxiliary layer 24 and the third auxiliary layer 26 includes a plurality of film layers, each film layer can have different functions, so that the second auxiliary layer 24 and the third auxiliary layer 26 can have multiple functions.

[0313] In some examples, as shown in FIG. 1A, the second auxiliary layer 24 further includes a first hole blocking layer 242, a first electron transport layer 243, a first charge generation layer 244 and a second charge generation layer 245 which are sequentially stacked on a side of the first microcavity adjustment layer 241 close to the back plate 1 and away from the back plate 1. Figure 8

[0314] In this case, as shown in FIG. 1A, the film layer between the first auxiliary layer 22 and the third auxiliary layer 26 and opposite to the first blue light emitting layer 23B includes the first blue light emitting layer 23B, the first hole blocking layer 242, the first electron transport layer 243, the first charge generation layer 244, the second charge generation layer 245, the second hole transport layer 2411, the first blue sub-microcavity adjustment layer 2412B and the second blue light emitting layer 25B. The sum of the optical thicknesses of the film layer between the first auxiliary layer 22 and the third auxiliary layer 26 and opposite to the first blue light emitting layer 23B, i.e., the sum of the optical thicknesses of the first blue light emitting layer 23B, the first hole blocking layer 242, the first electron transport layer 243, the first charge generation layer 244, the second charge generation layer 245, the second hole transport layer 2411, the first blue sub-microcavity adjustment layer 2412B and the second blue light emitting layer 25B. The sum of the actual thicknesses of the film layer between the first auxiliary layer 22 and the third auxiliary layer 26 and opposite to the first blue light emitting layer 23B, i.e., the sum of the actual thicknesses of the first blue light emitting layer 23B, the first hole blocking layer 242, the first electron transport layer 243, the first charge generation layer 244, the second charge generation layer 245, the second hole transport layer 2411, the first blue sub-microcavity adjustment layer 2412B and the second blue light emitting layer 25B. Figure 8 For example, the HOMO energy level absolute value of the material of the first hole blocking layer 242 is at least 0.2 eV greater than the HOMO energy level absolute value of the material of the first light emitting layer 23.

[0315] For example, the HOMO energy level absolute value of the material of the first hole blocking layer 242 is at least 0.2 eV greater than the HOMO energy level absolute value of the material of the first light emitting layer 23.

[0316] For example, the HOMO energy level absolute value of the material of the first hole blocking layer 242 is at least 0.2 eV greater than the HOMO energy level absolute value of the material of the first light emitting layer 23.

[0317] ​For example, the material of the first hole blocking layer 242 has a T1 higher than a T1 of a light emitting material contained in the first light emitting layer 23.

[0318] For example, the material of the first hole blocking layer 242 has a T1 at least 0.2 eV higher than a T1 of a light emitting material contained in the first light emitting layer 23.

[0319] For example, the material of the first hole blocking layer 242 includes a triazine material or the like.

[0320] For example, the first hole blocking layer 242 has a thickness of 1 nm, 3 nm, 5 nm, 8 nm, 10 nm, or the like.

[0321] For example, the material of the first electron transport layer 243 includes at least one of a thiophene material, an imidazole material, an azine derivative material, or lithium quinoline. The first electron transport layer 243 can be prepared by blending a thiophene, an imidazole, or an azine derivative with lithium quinoline, with the mass ratio of lithium quinoline being 30% to 70%.

[0322] For example, the mass ratio of the lithium quinoline is 30%, 40%, 50%, 60%, or 70%.

[0323] For example, the first electron transport layer 243 has a thickness of 15 nm, 23 nm, 35 nm, 40 nm, or 50 nm.

[0324] For example, the first charge generation layer 244 and the second charge generation layer 245 are used to make the first light emitting layer 23 and the second light emitting layer 25 in the light emitting device layer 2 form series light emitting, thereby increasing the overall light emitting brightness of the display substrate 100.

[0325] For example, the first charge generation layer 244 can be formed by doping a low-function metal (such as lithium (Li), ytterbium (Yb), calcium (Ca), or the like) in the material of the first electron transport layer 243, and the doping ratio is less than or equal to 5%. The first charge generation layer 244 has a thickness of less than or equal to 10 nm.

[0326] For example, the doping ratio of the low-function metal can be 1%, 2%, 3%, 4%, or 5%. The first charge generation layer 244 has a thickness of 1 nm, 3 nm, 5 nm, 8 nm, or 10 nm.

[0327] For example, the second charge generation layer 245 can be formed by doping a P-type dopant (such as MnO3 or F4TCNQ, etc.) in a material of the second hole transport layer 2411 at a doping ratio less than or equal to 5%. The first charge generation layer 244 has a thickness less than or equal to 10 nm.

[0328] For example, the doping ratio of the P-type dopant can be 1%, 2%, 3%, 4%, or 5%, etc. The second charge generation layer 245 has a thickness of 1 nm, 3 nm, 5 nm, 8 nm, or 10 nm, etc.

[0329] Optionally, the first charge generation layer 244 can also be referred to as an N-type charge generation layer (N-CGL), and the second charge generation layer 245 can also be referred to as a P-type charge generation layer (P-CGL).

[0330] In some examples, as shown in FIG. 1, the third auxiliary layer 26 includes, in sequence from the back plate 1, a second hole blocking layer 261, a second electron transport layer 262, and an electron injection layer 263. Figure 8

[0331] For example, the material of the second hole blocking layer 261 has a HOMO energy level absolute value greater than that of the material of the second light-emitting layer 25. The second hole blocking layer 261 is used to prevent the leakage of holes and / or excitons from the second light-emitting layer 25.

[0332] For example, the HOMO energy level absolute value of the material of the second hole blocking layer 261 is at least 0.2 eV greater than that of the material of the second light-emitting layer 25.

[0333] For example, the T1 of the material of the second hole blocking layer 261 is at least 0.2 eV higher than that of the light-emitting material contained in the second light-emitting layer 25.

[0334] For example, the T1 of the material of the second hole blocking layer 261 is at least 0.2 eV higher than that of the light-emitting material contained in the second light-emitting layer 25.

[0335] For example, the material of the second hole blocking layer 261 includes a triazine material, etc.

[0336] For example, the second hole blocking layer 261 has a thickness less than or equal to 10 nm. For example, the second hole blocking layer 261 has a thickness of 1 nm, 3 nm, 5 nm, 8 nm, or 10 nm, etc.

[0337] ​Exemplarily, the material of the second electron transport layer 262 includes at least one of a thiophene material, an imidazole material, an azine derivative material, and lithium quinolate. The second electron transport layer 262 can be prepared by blending the thiophene material, the imidazole material, or the azine derivative material with the lithium quinolate, where the mass ratio of the lithium quinolate ranges from 30% to 70%.

[0338] For example, the mass ratio of the lithium quinolate can be 30%, 40%, 50%, 60%, or 70%, etc.

[0339] Exemplarily, the thickness of the second electron transport layer 262 ranges from 15 nm to 50 nm. For example, the thickness of the second electron transport layer 262 can be 15 nm, 23 nm, 35 nm, 40 nm, or 50 nm, etc.

[0340] Exemplarily, the electron injection layer 263 is configured to reduce the injection barrier of electrons, so as to facilitate the injection and transport of electrons from the cathode layer 27 to the second light-emitting layer 25, thereby increasing the accumulation of electrons in the second light-emitting layer 25 and improving the light-emitting efficiency and the light-emitting lifetime of the second light-emitting layer 25.

[0341] Exemplarily, the material of the electron injection layer 263 includes lithium fluoride (LiF), ytterbium (Yb), or calcium (Ca), etc. The electron injection layer 263 can be formed by an evaporation process.

[0342] Exemplarily, the thickness of the electron injection layer 263 ranges from 0.5 nm to 2 nm. For example, the thickness of the electron injection layer 263 can be 0.5 nm, 0.8 nm, 1.2 nm, 1.7 nm, or 2 nm, etc.

[0343] In some examples, as shown in FIG. 1, the display substrate 100 further includes an optical cover layer 3 and / or an encapsulation layer 4 which are sequentially stacked on the cathode layer 27. Figure 9

[0344] Exemplarily, the material of the optical cover layer 3 includes a high-refractive organic material. For example, the refractive index of the optical cover layer 3 for light with a wavelength of 530 nm is greater than 1.9.

[0345] Exemplarily, the thickness of the optical cover layer 3 is less than or equal to 100 nm. For example, the thickness of the optical cover layer 3 can be 10 nm, 30 nm, 50 nm, 80 nm, or 100 nm, etc.

[0346] Exemplarily, the encapsulation layer 4 can prevent the film layers (e.g., the first light-emitting layer 23 and the second light-emitting layer 25, etc.) in the display substrate 100 from contacting water oxygen in the air, so as to reduce the aging rate of the above-mentioned film layers and prolong the service life of the display substrate 100.

[0347] ​Exemplarily, the encapsulation type of the encapsulation layer 4 includes: frame glue encapsulation, film encapsulation, etc.

[0348] In some examples, as shown in FIG. 1, the number of the second auxiliary layers 24 is multiple, and at least two first light-emitting layers 23 of different colors or at least two second light-emitting layers 25 of different colors are arranged between any two adjacent second auxiliary layers 24. Figure 10

[0349] Exemplarily, the number of the second auxiliary layers 24, the first light-emitting layers 23 or the second light-emitting layers 25 is: 2, 3, 4, 5 or 6, etc.

[0350] By arranging multiple first light-emitting layers 23, the total intensity of the light emitted by the first light-emitting layers 23 can be increased, and thus the intensity of the excitation light of the second light-emitting layer 25 can be increased, thereby increasing the light-emitting brightness of the display substrate 100.

[0351] By arranging multiple second light-emitting layers 25, the total intensity of the light emitted by the second light-emitting layers 25 can be increased, and thus the absorption of the light emitted by the first light-emitting layer 23 by the second light-emitting layer 25 can be increased, and thus the intensity of the excitation light of the second light-emitting layer 25 can be increased, thereby increasing the light-emitting brightness of the display substrate 100.

[0352] By arranging multiple second auxiliary layers 24, it can be ensured that holes and electrons can be transmitted into the multiple first light-emitting layers 23 and the second light-emitting layers 25 to generate excitons and thus make the first light-emitting layers 23 and the second light-emitting layers 25 emit light.

[0353] The inventors of the present disclosure have verified the color purity and light-emitting efficiency of the display substrate 100 of the present disclosure.

[0354] Verification Example 1: Comparative Example 1 and Example 1.

[0355] The first display substrate of Comparative Example 1 has a red light-emitting device, a green light-emitting device and a blue light-emitting device, and the display substrate comprises an anode layer, a light-transmitting conductive layer, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer (for example, 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 which are sequentially stacked.

[0356] The red light-emitting layer in the red light-emitting device in the first display substrate comprises a red host material and a red fluorescent material containing boron element, and the mass ratio of the red fluorescent material is 5%; the green light-emitting layer in the green light-emitting device comprises a green host material and a green fluorescent material with multiple resonance characteristics, and the mass ratio of the green fluorescent material is 5%; the blue light-emitting layer in the blue light-emitting device comprises a blue host material and a deep blue fluorescent material, and the mass ratio of the deep blue fluorescent material is 1%. ​

[0357] The thicknesses of the film layers corresponding to the light-emitting devices in the first display substrate of Comparative Example 1 are shown in Table 2 below.

[0358] Table 2

[0359] First display substrate item Red light emitting device Green light emitting device Blue light emitting device Anode layer thickness (nm) 100 100 100 Light-transmitting conductive layer thickness (nm) 8 8 8 Hole injection layer thickness (nm) 10 10 10 Hole transport layer thickness (nm) 15 15 15 Electron blocking layer thickness (nm) 5 5 5 Light emitting layer thickness (nm) 20 30 20 Hole blocking layer thickness (nm) 10 10 5 Electron transport layer thickness (nm) 35 35 35 Electron injection layer thickness (nm) 1 1 1 Cathode layer thickness (nm) 15 15 15

[0360] The second display substrate of Comparative Example 1 has the same structure as the first display substrate.

[0361] The red light-emitting layer in the red light-emitting device in the second display substrate of Comparative Example 1 includes a common P-type red host material and a red light-emitting material having a thermally activated delayed fluorescence characteristic, and the mass ratio of the red light-emitting material is 30%; the green light-emitting layer in the green light-emitting device includes a common P-type green host material and a green light-emitting material having a thermally activated delayed fluorescence characteristic, and the mass ratio of the green light-emitting material is 30%; and the blue light-emitting layer in the blue light-emitting device includes a blue host material and a blue fluorescent material containing boron, and the mass ratio of the blue fluorescent material is 1%.

[0362] The thicknesses of the film layers corresponding to the light-emitting devices in the second display substrate of Comparative Example 1 are shown in Table 3 below.

[0363] Table 3

[0364] Second display substrate item Red light emitting device Green light emitting device Blue light emitting device Light-transmitting conductive layer thickness (nm) 70 70 70 Hole injection layer thickness (nm) 10 10 10 Hole transport layer thickness (nm) 100 100 100 Electron blocking layer thickness (nm) 5 5 5 Light emitting layer thickness (nm) 20 30 20 Hole blocking layer thickness (nm) 5 5 5 Electron transport layer thickness (nm) 35 35 35 Electron injection layer thickness (nm) 1 1 1 Cathode layer thickness (nm) 100 100 100

[0365] The display substrate 100 of Example 1 has a red light-emitting device, a green light-emitting device, and a blue light-emitting device. The display substrate 100 includes an anode layer, a light-transmitting 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-specific microcavity adjustment layer, a color-specific second light-emitting layer, a second hole blocking layer, a second electron transport layer, an electron injection layer, and a cathode layer.

[0366] In Example 1, the material of the first light-emitting layer 23 is the same as the material of the light-emitting layer of the second display substrate in Comparative Example 1. The material of the second light-emitting layer 25 is the same as the material of the light-emitting layer of the first display substrate in Comparative Example 1.

[0367] The thicknesses of the film layers corresponding to the light-emitting devices in the display substrate 100 of Example 1 are shown in Table 4 below.

[0368] Table 4

[0369] Item Red light emitting device Green light emitting device Blue light emitting device Anode layer thickness (nm) 100 100 100 Light-transmitting conductive layer thickness (nm) 8 8 8 Hole injection layer thickness (nm) 10 10 10 First hole transport layer thickness (nm) 20 20 20 Electron blocking layer thickness (nm) 5 5 5 First light emitting layer thickness (nm) 20 30 20 First hole blocking layer thickness (nm) 8 8 8 First electron transport layer thickness (nm) 12 12 12 First charge generation layer thickness (nm) 10 10 10 Second charge generation layer thickness (nm) 10 10 10 Second hole transport layer thickness (nm) 35 35 35 Color sub-cavity adjustment layer thickness (nm) 15 15 15 Second light emitting layer thickness (nm) 20 30 20 Second hole blocking layer thickness (nm) 5 5 5 Second electron transport layer thickness (nm) 35 35 35 Electron injection layer thickness (nm) 1 1 1 Cathode layer thickness (nm) 15 15 15

[0370] In the above-mentioned examples, the P-doped ratio of the hole injection layer is 3%. The material of the cathode layer is 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 quinolate.

[0371] As shown in FIG. 1, the horizontal axis of the curve is wavelength, and the vertical axis is the relative intensity of the spectrum. Figure 11 and Figure 12 As shown in FIG. 2, the horizontal axis of the curve is wavelength, and the vertical axis is the relative intensity of the spectrum. Figure 11 As shown in FIG. 2, the emission spectrum p1 of the light-emitting material of the red light-emitting layer of the second display substrate in Comparative Example 1 overlaps with the absorption spectrum p2 of the light-emitting material of the red light-emitting layer of the first display substrate. Figure 12 As shown in FIG. 3, the emission spectrum p3 of the light-emitting material of the green light-emitting layer of the second display substrate in Comparative Example 1 overlaps with the absorption spectrum p4 of the light-emitting material of the green light-emitting layer of the first display substrate.

[0372] The comparative relationship of each relevant quantity of the first display substrate of Comparative Example 1 and the display substrate in Example 1 is shown in Table 5.

[0373] In the second display substrate of Comparative Example 1, the driving voltage of the red light-emitting device is 4.0 V, the luminous brightness is 3000 nits, the color coordinates are (0.552, 0.446), and the luminous efficiency is 40 cd / A. The driving voltage of the green light-emitting device is 3.7 V, the luminous brightness is 10000 nits, the color coordinates are (0.340, 0.599), and the luminous efficiency is 55 cd / A.

[0374] Table 5

[0375]

[0376] From the above results, it can be seen that when the second light-emitting layer 25 in the light-emitting device of Example 1 is combined with the first light-emitting layer 23 in series, the red and green light-emitting devices of Example 1 both exhibit several times higher efficiency and several times longer lifetime at the same brightness compared with the corresponding color light-emitting devices in the first display substrate of Comparative Example 1. The components of the second light-emitting layer 25 and the first light-emitting layer 23 in Example 1 are consistent, forming a series structure, so the efficiency and the lifetime at the same brightness are also significantly improved compared with the blue light-emitting device in the second display substrate.

[0377] Verification Example 2 includes Example 2-1, Example 2-2, and Example 2-3.

[0378] The film layer structure and film layer material of the display substrate 100 of Embodiment 2-1, Embodiment 2-2, Embodiment 2-3 and the display substrate 100 of Embodiment 1 are the same except that the red electron blocking layer is further included in the red microcavity adjusting layer and the second red light emitting layer, and the green electron blocking layer is further included in the green microcavity adjusting layer and the second green light emitting layer.

[0379] The thickness of each film layer corresponding to the light emitting device in the display substrate of Embodiment 2-1 is shown in Table 6 below.

[0380] Table 6

[0381] Item Red light emitting device Green light emitting device Blue light emitting device Anode layer thickness (nm) 100 100 100 Light-transmitting conductive layer thickness (mm) 8 8 8 Hole injection layer thickness (nm) 10 10 10 First hole transport layer thickness (nm) 20 20 20 Second sub-cavity adjustment layer thickness (nm) 5 5 5 First light emitting layer thickness (nm) 20 20 20 First hole blocking layer thickness (nm) 8 8 8 First electron transport layer thickness (nm) 10 10 10 First charge generation layer thickness (nm) 8 8 8 Second charge generation layer thickness (nm) 10 10 10 Second hole transport layer thickness (nm) 39 39 39 Color sub-cavity adjustment layer thickness (nm) 10 10 15 Color electron blocking layer thickness (nm) 5 5 None Second light emitting layer thickness (nm) 20 20 20 Second hole blocking layer thickness (nm) 5 5 5 Second electron transport layer thickness (nm) 35 35 35 Electron injection layer thickness (nm) 1 1 1 Cathode layer thickness (nm) 15 15 15

[0382] The thickness of each film layer corresponding to the light emitting device in the display substrate of Embodiment 2-2 is shown in Table 7 below.

[0383] Table 7

[0384] Item Red light emitting device Green light emitting device Blue light emitting device Anode layer thickness (nm) 100 100 100 Light-transmitting conductive layer thickness (nm) 8 8 8 Hole injection layer thickness (nm) 10 10 10 First hole transport layer thickness (nm) 30 30 30 Second microcavity adjustment layer thickness (nm) 5 5 5 First light emitting layer thickness (nm) 20 20 20 First hole blocking layer thickness (nm) 8 8 8 First electron transport layer thickness (nm) 10 10 10 First charge generation layer thickness (nm) 8 8 8 Second charge generation layer thickness (nm) 10 10 10 Second hole transport layer thickness (nm) 29 29 29 Color-specific microcavity adjustment layer thickness (nm) 10 10 15 Color-specific electron blocking layer thickness (nm) 5 5 None Second light emitting layer thickness (nm) 20 20 20 Second hole blocking layer thickness (nm) 5 5 5 Second electron transport layer thickness (nm) 35 35 35 Electron injection layer thickness (nm) 1 1 1 Cathode layer thickness (nm) 15 15 15

[0385] The thickness of each film layer corresponding to the light emitting device in the display substrate of Embodiment 2-3 is shown in Table 8 below.

[0386] Table 8

[0387] Item Red light emitting device Green light emitting device Blue light emitting device Anode layer thickness (nm) 100 100 100 Light transparent conductive layer thickness (nm) 8 8 8 Hole injection layer thickness (nm) 10 10 10 First hole transport layer thickness (nm) 40 40 40 Second microcavity adjustment layer thickness (nm) 5 5 5 First light emitting layer thickness (nm) 20 20 20 First hole blocking layer thickness (nm) 8 8 8 First electron transport layer thickness (nm) 10 10 10 First charge generation layer thickness (nm) 8 8 8 Second charge generation layer thickness (nm) 10 10 10 Second hole transport layer thickness (nm) 19 19 19 Color-specific microcavity adjustment layer thickness (nm) 10 10 15 Color-specific electron blocking layer thickness (nm) 5 5 None Second light emitting layer thickness (nm) 20 20 20 Second hole blocking layer thickness (nm) 5 5 5 Second electron transport layer thickness (nm) 35 35 35 electron injection layer thickness n m) 1 1 1 Cathode layer thickness (nm) 15 15 15

[0388] In the above three embodiments, the size of L1 is adjusted by changing the thickness of the first hole transport layer which is closer to the anode layer, and the length of the sub-microcavity of each light emitting device is kept consistent by adjusting the thickness of the second hole transport layer which is farther from the anode layer.

[0389] The light emitting parameters of each light emitting device in Embodiment 2-1, Embodiment 2-2 and Embodiment 2-3 are shown in Table 9 below.

[0390] Table 9

[0391]

[0392] From the above results, it can be known from the comparison that when the thickness of the first hole transport layer which is closer to the anode layer is continuously increased, the overall characteristics of the red light emitting device and the green light emitting device change less obviously, but the efficiency of the blue light emitting device decreases obviously, and the color purity also decreases obviously.

[0393] As Figure 13The spectra of the blue light emitting devices of Example 2-1, Example 2-2, and Example 2-3 are p3, p4, and p5, respectively. Further observation by performing the corresponding bottom emission experiment shows that when the thickness of the first hole transport layer is continuously increased, the emission spectrum of the blue light emitting device is continuously widened and a relatively obvious double-peak structure appears. This change in the spectrum has a clear correlation with the decrease in the light emitting efficiency and color purity of the top emission device.

[0394] The light emitting efficiency of the blue light emitting device in Example 2-3 is shown to be too low (less than 90%), and the corresponding

[0395] |L1-L2| = 51.8 nm, which does not meet the formula: |L1-L2| ≤ 37 nm (corresponding to the target wavelength of blue light, corresponding to ), and is determined to be unqualified.

[0396] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and any person skilled in the art can think of changes or replacements within the technical scope disclosed by the present disclosure, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A display substrate, comprising: a backplane comprising a substrate and a plurality of pixel driving circuits disposed on the substrate; the pixel driving circuit comprising a plurality of transistors and at least one storage capacitor; an anode layer, a first auxiliary layer, a second auxiliary layer, a third auxiliary layer and a cathode layer disposed in sequence on the backplane, a microcavity being formed between the anode layer and the cathode layer; a plurality of first light-emitting layers of at least two different colors disposed between the first auxiliary layer and the second auxiliary layer, the plurality of first light-emitting layers comprising at least a plurality of first blue light-emitting layers; and, a plurality of second light-emitting layers of at least two different colors disposed between the second auxiliary layer and the third auxiliary layer, the plurality of second light-emitting layers comprising at least a plurality of second blue light-emitting layers; wherein the first auxiliary layer comprises a film layer stacked in sequence, an optical thickness of a portion of the a film layers opposite to the first blue light-emitting layer is L1, L1 satisfies: a is a positive integer, n h is the refractive index of the hth film layer of the a film layers, r h is the thickness of the hth film layer; the third auxiliary layer comprises a film layer stacked in sequence, an optical thickness of a portion of the b film layers opposite to the first blue light-emitting layer is L2, L2 satisfies: b is a positive integer, n i ni is the refractive index of the i-th film layer of the b film layers, r i di is the thickness of the i-th film layer; L1 and L2 satisfy the formula: an average refractive index of a film layer located between the first auxiliary layer and the third auxiliary layer and opposite to the first blue light emitting layer to the central wavelength of blue light, is a target spectral peak wavelength of blue light, and k is a positive integer.

2. The display substrate according to claim 1, wherein: The is in the range of 1.7 to 2.

0. 3.The display substrate of claim 1, wherein, the plurality of first light-emitting layers further comprise a plurality of first red light-emitting layers and a plurality of first green light-emitting layers; wherein the thickness of the first red light-emitting layer and the first blue light-emitting layer is different, and / or the thickness of the first green light-emitting layer and the first blue light-emitting layer is different. 4.The display substrate of claim 3, wherein, the plurality of second light-emitting layers further comprise a plurality of second red light-emitting layers and a plurality of second green light-emitting layers; the thickness of the second red light-emitting layer and the second blue light-emitting layer is different, and / or the thickness of the second green light-emitting layer and the second blue light-emitting layer is different. 5.The display substrate of claim 4, wherein, the second auxiliary layer comprises a first microcavity adjustment layer; the thickness of a portion of the first microcavity adjustment layer opposite to the second red light-emitting layer and the thickness of a portion of the first microcavity adjustment layer opposite to the second blue light-emitting layer are different, and / or the thickness of a portion of the first microcavity adjustment layer opposite to the second green light-emitting layer and the thickness of a portion of the first microcavity adjustment layer opposite to the second blue light-emitting layer are different. 6.The display substrate of claim 5, wherein, the first microcavity adjustment layer comprises: a second hole transport layer; a first red sub-microcavity adjustment layer disposed between the second hole transport layer and the second red light-emitting layer; a first green sub-microcavity adjustment layer disposed between the second hole transport layer and the second green light-emitting layer; and a first blue sub-microcavity adjustment layer disposed between the second hole transport layer and the second blue light-emitting layer; the thickness between the first red sub-microcavity adjustment layer and the first blue sub-microcavity adjustment layer is different, and / or the thickness between the first green sub-microcavity adjustment layer and the first blue sub-microcavity adjustment layer is different. 7.The display substrate of claim 6, wherein, the first red sub-microcavity adjustment layer comprises a red hole transport layer and a red electron blocking layer stacked in sequence away from the backplane, the first green sub-microcavity adjustment layer comprises a green hole transport layer and a green electron blocking layer stacked in sequence away from the backplane; The red hole transport layer and the green hole transport layer are respectively used for adjusting the microcavity length. 8.The display substrate according to any one of claims 4-7, wherein, The wavelength of the light emitted by the first light-emitting layer of at least one color is less than the wavelength of the light emitted by the second light-emitting layer of the corresponding color. 9.The display substrate of claim 4, wherein, The first light-emitting layer comprises a first guest material, and the second light-emitting layer comprises a second guest material. The emission spectrum of the first guest material of the first light-emitting layer of at least one color at least partially overlaps with the absorption spectrum of the second guest material of the second light-emitting layer of the corresponding color. 10.The display substrate of claim 9, wherein, The overlapping range of the emission spectrum of the first guest material and the absorption spectrum of the second guest material is greater than or equal to 60% of the wavelength range of the emission spectrum of the first guest material. 11.The display substrate of claim 9, wherein, The overlapping range of the emission spectrum of the first guest material and the absorption spectrum of the second guest material is greater than or equal to 60% of the wavelength range of the absorption spectrum of the second guest material. 12.The display substrate of claim 9, wherein, The peak value of the emission spectrum of the first guest material of the first red light-emitting layer ranges from 560 nm to 570 nm, and the peak value of the absorption spectrum of the second guest material of the second red light-emitting layer ranges from 595 nm to 605 nm. 13.The display substrate of claim 9, wherein, The peak value of the emission spectrum of the first guest material of the first green light-emitting layer ranges from 500 nm to 510 nm, and the peak value of the absorption spectrum of the second guest material of the second green light-emitting layer ranges from 515 nm to 525 nm. 14.The display substrate of claim 9, wherein, The first guest material of the first light-emitting layer of at least one color comprises at least one light-emitting material. In the case where the first guest material comprises two light-emitting materials, the interval between the peak values of the emission spectra of the two light-emitting materials is less than or equal to 30 nm. 15.The display substrate of claim 14, wherein, The first guest material comprises two light-emitting materials. In the two light-emitting materials, at least one light-emitting material is doped with boron elements, and the doping proportion of the boron elements ranges from 0.5% to 5%. 16.The display substrate of claim 9, wherein, The second guest material of the second light-emitting layer of at least one color comprises at least one light-emitting material. In the case where the second guest material comprises two light-emitting materials, the interval between the peak values of the emission spectra of the two light-emitting materials is less than or equal to 30 nm. 17.The display substrate of claim 16, wherein, The second guest material comprises two light-emitting materials. In the two light-emitting materials, at least one light-emitting material is doped with boron elements, and the doping proportion of the boron elements ranges from 0.5% to 5%. 18.The display substrate of claim 9, wherein, The first guest material comprises at least one of a fluorescent material, a phosphorescent material and a thermally activated delayed fluorescence material; and / or, The second guest material comprises at least one of a fluorescent material, a phosphorescent material and a thermally activated delayed fluorescence material with multiple resonance characteristics.

19. The display substrate of claim 9, wherein, The first light-emitting layer further comprises a first host material, and the first host material is a single host material or a PN hybrid host material. The second light-emitting layer further comprises a second host material, and the second host material comprises a bipolar host material.

20. The display substrate of claim 19, wherein, The second host material is a single host material or a PN hybrid host material. In the case where the second host material is a PN hybrid host material, the host material of the N-type component has a thermally activated delayed fluorescence characteristic.

21. The display substrate of claim 4, wherein, The first red light-emitting layer and the second red light-emitting layer are oppositely arranged, the first green light-emitting layer and the second green light-emitting layer are oppositely arranged, and the first blue light-emitting layer and the second blue light-emitting layer are oppositely arranged.

22. The display substrate of claim 3, wherein, The first auxiliary layer comprises: The light-transmitting conductive layer, the hole injection layer and the second microcavity adjusting layer are sequentially stacked in the direction away from the back plate; The second microcavity adjusting layer comprises: The second red sub-microcavity adjusting layer arranged between the first hole transport layer and the first red light-emitting layer; The second green sub-microcavity adjusting layer arranged between the first hole transport layer and the first green light-emitting layer; and The second blue sub-microcavity adjusting layer arranged between the first hole transport layer and the first blue light-emitting layer.

23. The display substrate of claim 3, wherein, The first auxiliary layer comprises: The light-transmitting conductive layer, the hole injection layer and the second microcavity adjusting layer are sequentially stacked in the direction away from the back plate; 24. The display substrate of claim 3, wherein, The second microcavity adjusting layer comprises: The first auxiliary layer comprises: The light-transmitting conductive layer, the hole injection layer and the second microcavity adjusting layer are sequentially stacked in the direction away from the back plate; The second microcavity adjusting layer comprises: The second blue sub-microcavity adjusting layer arranged on the side of the first hole transport layer away from the back plate; The second red sub-microcavity adjusting layer arranged between the second blue sub-microcavity adjusting layer and the first red light-emitting layer; and The second green sub-microcavity adjusting layer arranged between the second blue sub-microcavity adjusting layer and the first green light-emitting layer.

25. The display substrate of claim 22, wherein The material of the light-transmitting conductive layer comprises indium tin oxide or indium zinc oxide, and / or the thickness of the light-transmitting conductive layer is less than or equal to 10 nm.

26. The display substrate of claim 23, wherein The material of the first hole transport layer comprises a carbazole material; and / or The highest occupied molecular orbital energy level of the material of the first hole transport layer ranges from -5.2 eV to -5.6 eV; and / or 27. The display substrate of claim 3, wherein, The highest occupied molecular orbital energy level of the material of the electron blocking layer ranges from -5.5 eV to -5.9 eV. The microcavity comprises a plurality of sub-microcavities, the plurality of sub-microcavities comprising a red sub-microcavity corresponding to the first red light-emitting layer, a green sub-microcavity corresponding to the first green light-emitting layer, and a blue sub-microcavity corresponding to the first blue light-emitting layer; c is a positive integer, n j n is the refractive index of the jth film layer of the c film layers, r j r is the thickness of the jth film layer; Wherein, the number of film layers corresponding to any color sub-microcavity and located between the anode layer and the cathode layer is c, and the optical thickness of the c film layers is L3, L3 satisfies: m is a natural number, is the interference wavelength, is the phase shift caused by the anode layer. 28.The display substrate of claim 27, wherein, Any color sub-microcavity satisfies: The length of the blue sub-microcavity is less than the length of the red sub-microcavity; 29.The display substrate of claim 5, wherein, The length of the blue sub-microcavity is less than the length of the green sub-microcavity. The second auxiliary layer further comprises: a first hole blocking layer, a first electron transport layer, a first charge generation layer and a second charge generation layer sequentially stacked in the direction away from the back plate on the side of the first microcavity adjusting layer close to the back plate; And / or, The third auxiliary layer comprises, in sequence from the direction away from the back plate, a second hole blocking layer, a second electron transport layer, and an electron injection layer. 30.The display substrate of claim 29, wherein, The thickness of the first hole blocking layer is less than or equal to 10 nm; and / or, The thickness of the first electron transport layer ranges from 15 nm to 50 nm; and / or, The thickness of the first charge generation layer is less than or equal to 10 nm; and / or, The thickness of the second charge generation layer is less than or equal to 10 nm; and / or, The thickness of the second hole blocking layer is less than or equal to 10 nm; and / or, The thickness of the second electron transport layer ranges from 15 nm to 50 nm.

31. The display substrate of claim 30, wherein, The material of the first electron transport layer comprises at least one of a thiophene material, an imidazole material, an azine derivative material, and lithium quinolate; and / or, The material of the second hole blocking layer comprises a triazine material; and / or, The material of the second electron transport layer comprises at least one of a thiophene material, an imidazole material, an azine derivative material, and lithium quinolate. 32.The display substrate of claim 1, wherein The thickness of the first blue light-emitting layer ranges from 15 nm to 60 nm; and / or, The thickness of the second blue light-emitting layer ranges from 10 nm to 50 nm. 33.The display substrate of claim 1, wherein, The number of the second auxiliary layers is multiple, and at least two first light-emitting layers of different colors or at least two second light-emitting layers of different colors are arranged between any two adjacent second auxiliary layers.

34. The display substrate of claim 1, wherein, The anode layer comprises a reflective layer; or, The anode layer comprises a reflective layer and a light-transmitting layer located on the side of the reflective layer close to the back plate.

35. A display device comprising: The display substrate of any one of claims 1-34.

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