Display substrate and display device

Abstract

The embodiment of the invention provides a display substrate and a display device. The display substrate comprises a laminated organic light-emitting device, the laminated organic light-emitting device comprises a first light-emitting unit, a charge generation layer and a second light-emitting unit, and the first light-emitting unit comprises a first hole transport layer, a first auxiliary light-emitting layer, a first light-emitting layer, a first hole blocking layer and a first electron transport layer which are stacked. The second light-emitting unit comprises a second hole transport layer, a second auxiliary light-emitting layer, a second light-emitting layer, a second hole blocking layer and a second electron transport layer which are stacked; the charge generation layer comprises an N-type charge generation layer and a P-type charge generation layer which are stacked; thickness of first hole transport layer greater than # imgabs0 # first electron transport layer greater than # imgabs1 # second electron transport layer greater than # imgabs2 # N-type charge generation layer greater than # imgabs3 # and thickness of P-type charge generation layer less than or equal to # imgabs4 #

Description

Technical Field

[0001] Embodiments of the present disclosure relate to, but are not limited to, the field of display technologies, and particularly relate to a display substrate and a display device. Background Art

[0002] An organic light emitting device (OLED) is an active light emitting device, which has the advantages of light emission, ultrathin, wide viewing angle, high brightness, high contrast ratio, low power consumption, extremely high response speed, etc., and has gradually become a next-generation display technology with great development prospects. Summary of the Invention

[0003] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of protection of the claims.

[0004] In a first aspect, embodiments of the present disclosure provide a display substrate, including: a stacked organic light emitting device, the stacked organic light emitting device including: an anode, a cathode, and a first light emitting unit, a charge generation layer, and a second light emitting unit that are sequentially stacked between the anode and the cathode. Along the direction away from the anode, the first light emitting unit includes: a first hole transport layer, a first auxiliary light emitting layer, a first light emitting layer, a first hole blocking layer, and a first electron transport layer that are sequentially stacked. The second light emitting unit includes: a second hole transport layer, a second auxiliary light emitting layer, a second light emitting layer, a second hole blocking layer, and a second electron transport layer that are sequentially stacked. The charge generation layer includes: an N-type charge generation layer and a P-type charge generation layer that are sequentially stacked; wherein, the thickness of the first hole transport layer is greater than (angstroms), the thickness of the first electron transport layer is greater than the thickness of the second electron transport layer is greater than the thickness of the N-type charge generation layer is greater than and the thickness of the P-type charge generation layer is less than or equal to

[0005] In some exemplary embodiments, it further includes: a plurality of pixel units arranged in an array, at least one of the plurality of pixel units including: a first sub-pixel that emits first color light, a second sub-pixel that emits second color light, and a third sub-pixel that emits third color light. The wavelength of the first color light is greater than the wavelength of the second color light, and the wavelength of the second color light is greater than the wavelength of the third color light. Each sub-pixel includes: the stacked organic light emitting device.

[0006] In some exemplary embodiments, the equivalent cavity length of the microcavity of the stacked organic light emitting device in the first sub-pixel is to The equivalent cavity length of the microcavity of the stacked organic electroluminescent device in the second sub-pixel is to And, the equivalent cavity length of the microcavity of the stacked organic electroluminescent device in the third sub-pixel is to

[0007] In some exemplary embodiments, the total thickness from the anode to the first light-emitting layer in the first sub-pixel is to The total thickness from the anode to the first light-emitting layer in the second sub-pixel is to The total thickness from the anode to the first light-emitting layer in the third sub-pixel is to The total thickness from the cathode to the second light-emitting layer in different color sub-pixels is to

[0008] In some exemplary embodiments, the sum of the thickness of the first hole transport layer and the thickness of the first auxiliary light-emitting layer in the first sub-pixel is to The sum of the thickness of the first hole transport layer and the thickness of the first auxiliary light-emitting layer in the second sub-pixel is to The sum of the thickness of the first hole transport layer and the thickness of the first auxiliary light-emitting layer in the third sub-pixel is to And the sum of the thicknesses of the first electron transport layer, the second electron transport layer, and the second hole transport layer in different color sub-pixels is to

[0009] In some exemplary embodiments, the second auxiliary light-emitting layer in the first sub-pixel is a host-guest doping structure, including an auxiliary host material and an auxiliary guest material, and the doping ratio of the auxiliary guest material is 0.1% to 0.5%.

[0010] In some exemplary embodiments, the sum of the thickness of the N-type charge generation layer and the thickness of the P-type charge generation layer is greater than

[0011] In some exemplary embodiments, the thickness of the second hole transport layer is less than the thickness of the first hole transport layer, and the thickness of the second hole transport layer is less than

[0012] In some exemplary embodiments, the thickness of the first auxiliary light-emitting layer in the first sub-pixel is greater than The thickness of the first light-emitting layer in the first sub-pixel is less than The thickness of the first auxiliary light-emitting layer in the second sub-pixel is less than The thicknesses of the first light-emitting layer and the second light-emitting layer in the third sub-pixel are both less than And the second auxiliary light-emitting layer in the third sub-pixel is greater than

[0013] In some exemplary embodiments, the optical path difference between the reflected light and the transmitted light of the stacked organic electroluminescent device in the first sub-pixel from the light-emitting position to the electrode in the light-emitting direction satisfies 1 to 2 times the wavelength of the first color light; the optical path difference between the reflected light and the transmitted light of the stacked organic electroluminescent device in the second sub-pixel from the light-emitting position to the electrode in the light-emitting direction satisfies 1 to 2 times the wavelength of the second color light; and the optical path difference between the reflected light and the transmitted light of the stacked organic electroluminescent device in the third sub-pixel from the light-emitting position to the electrode in the light-emitting direction satisfies 1 to 2 times the wavelength of the third color light.

[0014] In a second aspect, an embodiment of the present disclosure provides a display device, including the display substrate described in any one of the above exemplary embodiments.

[0015] For the display substrate and the display device provided by the embodiments of the present disclosure, by increasing the thicknesses of the hole transport layer adjacent to the anode, the electron transport layer adjacent to the cathode, and the N-type charge generation layer, the surface plasmon polaritons (SPPs) generated by the metal in the electrode and the N-type charge generation layer can be significantly reduced, thereby improving the light-emitting efficiency of the device and improving the device performance.

[0016] Other features and advantages of the present disclosure will be described in the following description, and, in part, will be obvious from the description, or will be understood by implementing the present disclosure. Other advantages of the present disclosure can be realized and obtained by the solutions described in the description and the drawings.

[0017] After reading and understanding the drawings and the detailed description, other aspects can be understood. Description of the Drawings

[0018] The drawings are used to provide an understanding of the technical solutions of the present disclosure, and constitute a part of the description. They are used together with the embodiments of the present disclosure to explain the technical solutions of the present disclosure, and do not constitute a limitation to the technical solutions of the present disclosure. The shapes and sizes of the components in the drawings do not reflect the actual proportions, and the purpose is only to schematically illustrate the content of the present disclosure.

[0019] Figure 1It is a schematic structural diagram of an OLED display device;

[0020] Figure 2 It is a schematic plan view of a display area of a display substrate;

[0021] Figure 3 It is a schematic cross-sectional view of a display substrate;

[0022] Figure 4 It is a schematic structural diagram of a stacked organic light-emitting device in a display substrate in an exemplary embodiment of the present disclosure.

[0023] Description of reference numerals:

[0024] 101 - Substrate; 102 - Driving circuit layer; 103 - Light-emitting structure layer;

[0025] 104 - Encapsulation structure layer; 210 - Transistor; 211 - Storage capacitor;

[0026] 310 - Pixel definition layer; 401 - First encapsulation layer; 402 - Second encapsulation layer;

[0027] 403 - Third encapsulation layer; 10 - Anode; 20 - First light-emitting unit;

[0028] 21 - Hole injection layer; 22 - First hole transport layer; 23 - First auxiliary light-emitting layer;

[0029] 24 - First light-emitting layer; 25 - First hole blocking layer; 26 - First electron transport layer;

[0030] 30 - Charge generation layer; 31 - First charge generation layer; 32 - Second charge generation layer;

[0031] 40 - Second light-emitting unit; 41 - Electron injection layer; 42 - Second electron transport layer;

[0032] 43 - Second hole blocking layer; 44 - Second light-emitting layer; 45 - Second auxiliary light-emitting layer;

[0033] 46 - Second hole transport layer; 50 - Cathode; 60 - Light-emitting functional layer;

[0034] 70 - Light-emitting device. Detailed implementation manners

[0035] The present disclosure describes multiple embodiments, but the description is exemplary rather than restrictive, and it will be apparent to those of ordinary skill in the art that there can be more embodiments and implementation solutions within the scope encompassed by the embodiments described in the present disclosure. Although many possible combinations of features are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are also possible. Unless specifically restricted, any feature or element of any embodiment can be combined with any other feature or element in any other embodiment, or can replace any other feature or element in any other embodiment.

[0036] The present disclosure includes and contemplates combinations with features and elements known to those of ordinary skill in the art. The embodiments, features, and elements already disclosed in the present disclosure can also be combined with any conventional features or elements to form unique inventive solutions. Any feature or element of any embodiment can also be combined with features or elements from other inventive solutions to form another unique inventive solution. Therefore, it should be understood that any feature shown and / or discussed in the present disclosure can be implemented alone or in any suitable combination. Therefore, the embodiments are not limited except by the limitations set forth in the appended claims and their equivalents. In addition, various modifications and changes can be made within the scope of the appended claims.

[0037] Furthermore, when describing representative embodiments, the specification may have presented the method and / or process as a particular sequence of steps. However, to the extent that the method or process does not depend on the particular sequence of steps described herein, the method or process should not be limited to the particular sequence of steps described. As will be understood by those of ordinary skill in the art, other sequences of steps are possible. Therefore, the particular sequence of steps set forth in the specification should not be construed as a limitation on the claims. In addition, the claims directed to the method and / or process should not be limited to performing their steps in the order written, and those skilled in the art can readily understand that these orders can vary and still remain within the spirit and scope of the embodiments of the present disclosure.

[0038] The scale of the drawings in the present disclosure can be used as a reference in actual processes, but is not limited thereto. For example: the width-to-length ratio of the channel, the thickness and spacing of each film layer, the width and spacing of each signal line, can be adjusted according to actual needs. The number of pixels in the display substrate and the number of sub-pixels in each pixel are not limited to the numbers shown in the figures. The drawings described in the present disclosure are only schematic diagrams, and one aspect of the present disclosure is not limited to the shapes or values shown in the drawings.

[0039] In the exemplary embodiments of the present disclosure, ordinal numbers such as "first", "second", or "third", and similar terms are provided to avoid confusion of components, rather than to limit in terms of quantity, order, importance, etc. It should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include at least one such feature.

[0040] In the exemplary embodiments of the present disclosure, for convenience, terms indicating orientation or positional relationship such as "middle", "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", or "circumferential" are used to describe the positional relationship of components with reference to the drawings, merely for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the indicated device or element has a specific orientation, is constructed and operates in a specific orientation, and thus should not be construed as a limitation to the present disclosure. The positional relationship of components changes appropriately according to the direction of each component described. Therefore, it is not limited to the terms described in the specification and can be appropriately replaced according to the situation.

[0041] In the exemplary embodiments of the present disclosure, unless otherwise clearly defined and limited, terms such as "mounted", "connected", "coupled", or "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or can be indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the meanings of the above terms in the present disclosure can be understood according to the actual situation.

[0042] In the embodiments of the present disclosure, a transistor refers to an element including at least three terminals: a gate electrode (also referred to as a gate or control electrode), a drain electrode (also referred to as a drain electrode terminal, drain region, or drain), and a source electrode (also referred to as a source electrode terminal, source region, or source). The transistor has a channel region between the drain electrode and the source electrode, and current can flow through the drain electrode, the channel region, and the source electrode. Note that in this specification, the channel region refers to the region where current mainly flows.

[0043] In the embodiments of the present disclosure, in order to distinguish between the two poles of a transistor other than the control pole, one of the poles is directly described as the first pole and the other as the second pole. Herein, the first pole may be a drain electrode and the second pole may be a source electrode, or the first pole may be a source electrode and the second pole may be a drain electrode. In cases where transistors with opposite polarities are used or the direction of current changes during the operation of a circuit, etc., the functions of the "source electrode" and the "drain electrode" sometimes swap with each other. Therefore, in this specification, the "source electrode" and the "drain electrode" may be swapped with each other.

[0044] The transistors in the embodiments of the present disclosure may all be thin film transistors (TFTs), field effect transistors (FETs), or other devices with the same characteristics. For example, the thin film transistors used in the embodiments of the present disclosure may include, but are not limited to, oxide transistors (Oxide TFTs) or low temperature poly-silicon thin film transistors (LTPS TFTs), etc. For example, the thin film transistors may be bottom-gate structure thin film transistors or top-gate structure thin film transistors, as long as they can achieve the switching function. Here, the embodiments of the present disclosure do not make any limitations in this regard.

[0045] In the embodiments of the present disclosure, the term "about" is used to mean that the boundary is not strictly defined, and values within the process and measurement error ranges are allowed.

[0046] In the embodiments of the present disclosure, the term "stacked in sequence" may mean that multiple film layers are stacked in one direction, but it does not mean that these film layers must be in direct contact with each other pairwise.

[0047] In the embodiments of the present disclosure, expressions such as "on", "formed on", "disposed on", or similar expressions may mean that one layer is directly formed or disposed on another layer, or may mean that one layer is indirectly formed or disposed on another layer, that is, there are other layers between the two layers. Moreover, the first feature being "above", "over", and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely means that the first feature has a higher horizontal height than the second feature. The first feature being "below", "beneath", and "underneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or merely means that the first feature has a lower horizontal height than the second feature. In this document, unless otherwise specified, the term "being on the same layer" means that two layers, components, members, elements, or parts can be formed by the same patterning process, and generally, these two layers, components, members, elements, or parts are formed of the same material. In this document, unless otherwise specified, the expression "patterning process" generally includes steps such as coating of photoresist, exposure, development, etching, stripping of photoresist, etc. The expression "one patterning process" means a process of forming a patterned layer, component, member, etc. using one mask.

[0048] In the embodiments of the present disclosure, "thickness" refers to the height of the surface farther from the substrate minus the height of the surface closer to the substrate in a plane direction perpendicular to the substrate.

[0049] The embodiments will be described below with reference to the accompanying drawings. Among them, the embodiments can be implemented in multiple different forms. It is easy for those of ordinary skill in the art to understand the fact that the manner and content can be transformed into different forms without departing from the gist and scope of the present disclosure. Therefore, the present disclosure should not be construed as being limited only to the content described in the following embodiments.

[0050] To keep the following description of the embodiments of the present disclosure clear and concise, detailed descriptions of some known functions and known components are omitted in the present disclosure. The drawings of the embodiments of the present disclosure only relate to the structures involved in the embodiments of the present disclosure, and other structures can refer to the general design.

[0051] Figure 1 It is a schematic structural diagram of a display device. As Figure 1As shown, the display device may include a timing controller, a data driver, a scan driver, a light-emitting driver, and a pixel array. The timing controller is respectively connected to the data driver, the scan driver, and the light-emitting driver. The data driver is respectively connected to a plurality of data signal lines (D1 to Dn), the scan driver is respectively connected to a plurality of scan signal lines (S1 to Sm), and the light-emitting driver is respectively connected to a plurality of light-emitting signal lines (E1 to Eo). The pixel array may include a plurality of sub-pixels Pxij, where i and j may be natural numbers. At least one sub-pixel Pxij may include a circuit unit and a light-emitting device connected to the circuit unit. The circuit unit may include a pixel driving circuit, and the pixel driving circuit may be respectively connected to the scan signal line, the light-emitting signal line, and the data signal line. In some exemplary embodiments, the timing controller may provide a gray value and a control signal suitable for the specification of the data driver to the data driver, may provide a clock signal, a scan start signal, etc. suitable for the specification of the scan driver to the scan driver, and may provide a clock signal, an emission stop signal, etc. suitable for the specification of the light-emitting driver to the light-emitting driver. The data driver may use the gray value and the control signal received from the timing controller to generate data voltages to be provided to the data signal lines D1, D2, D3,..., and Dn, where n may be a natural number. For example, the data driver may sample the gray value using a clock signal and apply the data voltage corresponding to the gray value to the data signal lines D1 to Dn in units of pixel rows. The scan driver may generate scan signals to be provided to the scan signal lines S1, S2, S3,..., and Sm by receiving a clock signal, a scan start signal, etc. from the timing controller, where m may be a natural number. For example, the scan driver may sequentially provide scan signals having conductive level pulses to the scan signal lines S1 to Sm. For example, the scan driver may be configured in the form of a shift register and may generate scan signals in such a way that the scan start signal provided in the form of a conductive level pulse is sequentially transmitted to the next-stage circuit under the control of the clock signal. The light-emitting driver may generate emission signals to be provided to the light-emitting signal lines E1, E2, E3,..., and Eo by receiving a clock signal, an emission stop signal, etc. from the timing controller, where o may be a natural number. For example, the light-emitting driver may sequentially provide emission signals having cut-off level pulses to the light-emitting signal lines E1 to Eo. For example, the light-emitting driver may be configured in the form of a shift register and may generate emission signals in such a way that the emission stop signal provided in the form of a cut-off level pulse is sequentially transmitted to the next-stage circuit under the control of the clock signal.

[0052] Figure 2 It is a schematic plan view of a display substrate. As Figure 2As shown, the display substrate may include a plurality of pixel units P arranged regularly (e.g., in a matrix), and at least one pixel unit P among the plurality of pixel units P may include a first sub-pixel P1 that emits light of a first color, a second sub-pixel P2 that emits light of a second color, and a third sub-pixel P3 that emits light of a third color. Each sub-pixel may include a circuit unit and a light-emitting device connected to the circuit unit. The circuit unit may include a pixel driving circuit and scanning signal lines, data signal lines, light-emitting signal lines, etc. connected to the pixel driving circuit. The pixel driving circuit is configured to receive a data voltage transmitted by the data signal line under the control of the scanning signal line and the light-emitting signal line, and output a corresponding current to the light-emitting device. The light-emitting devices in the first sub-pixel P1, the second sub-pixel P2, and the third sub-pixel P3 are respectively connected to the pixel driving circuits of their respective sub-pixels, and the light-emitting devices are configured to emit light of corresponding brightness in response to the current output by the pixel driving circuits of their respective sub-pixels.

[0053] In some exemplary embodiments, the pixel unit P may include a red (R) sub-pixel, a green (G) sub-pixel, and a blue (B) sub-pixel, or may include a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel, which are not limited herein in the present disclosure. In some exemplary embodiments, the shape of the sub-pixels in the pixel unit may be rectangular, rhombic, pentagonal, hexagonal, etc. In some exemplary embodiments, when the pixel unit includes three sub-pixels, the three sub-pixels may be arranged in a horizontal side-by-side, vertical side-by-side, or triangular pyramid manner. In some other exemplary embodiments, when the pixel unit includes four sub-pixels, the four sub-pixels may be arranged in a horizontal side-by-side, vertical side-by-side, or square manner, which are not limited herein in the present disclosure.

[0054] Figure 3 It is a schematic cross-sectional structure diagram of a display substrate, showing the structure of a sub-pixel of an OLED display substrate. As Figure 3 shown, in a plane perpendicular to the display substrate, the display substrate may include a driving circuit layer 102 provided on a substrate 101, a light-emitting structure layer 103 provided on a side of the driving circuit layer 102 away from the substrate 101, and a packaging structure layer 104 provided on a side of the light-emitting structure layer 103 away from the substrate 101. In some possible implementation manners, the display substrate may include other film layers, such as a touch control structure layer, etc., which are not limited herein in the present disclosure.

[0055] In some exemplary embodiments, the substrate 101 may be a flexible substrate or a rigid substrate.

[0056] In some exemplary embodiments, the packaging structure layer 104 may be a packaging film or a packaging cover plate.

[0057] In some exemplary embodiments, as Figure 3As shown, the encapsulation structure layer 104 may include a stacked first encapsulation layer 401, a second encapsulation layer 402, and a third encapsulation layer 403. For example, the first encapsulation layer 401 and the third encapsulation layer 403 may be made of inorganic materials, and the second encapsulation layer 402 may be made of organic materials. The second encapsulation layer 402 is disposed between the first encapsulation layer 401 and the third encapsulation layer 403, which can prevent external moisture from entering the light-emitting structure layer 103.

[0058] In some exemplary embodiments, as Figure 3 shown, the driving circuit layer 102 of each sub-pixel may include a plurality of transistors and storage capacitors that constitute the pixel driving circuit, Figure 3 and only one transistor 210 and one storage capacitor 211 are taken as examples in

[0059] In some exemplary embodiments, the pixel driving circuit may adopt a pixel circuit with a structure of 2T1C (i.e., two transistors and one capacitor), 3T1C, 4T1C, 5T1C, 5T2C, 6T1C, 7T1C, or 8T1C, etc., nTmC (n and m are positive integers). In different exemplary embodiments, the pixel circuit may further include a compensation sub-circuit, and the compensation sub-circuit may include an internal compensation sub-circuit or an external compensation sub-circuit. The compensation sub-circuit may include transistors, capacitors, etc. For example, according to needs, the pixel circuit may further include: a reset sub-circuit, a light-emitting control sub-circuit, etc. The embodiments of the present disclosure are not limited thereto.

[0060] In some exemplary embodiments, as Figure 3 shown, the light-emitting structure layer 103 may include: a plurality of light-emitting devices 70 and a pixel definition layer 310. The pixel definition layer 310 is provided with a plurality of pixel openings, and the light-emitting device 70 of one sub-pixel may be disposed in one pixel opening. For example, the plurality of light-emitting devices 70 may include: the light-emitting device 70 of the first sub-pixel P1, the light-emitting device 70 of the second sub-pixel P2, and the light-emitting device 70 of the third sub-pixel P3. Here, Figure 3 the light-emitting device of one sub-pixel is taken as an example for illustration.

[0061] In some exemplary embodiments, as Figure 3 shown, along the direction away from the substrate 101, the light-emitting device 70 may include: an anode 10, a light-emitting functional layer 60, and a cathode 50 that are sequentially arranged. Among them, the anode 10 is connected to the drain electrode of at least one of the plurality of transistors 210 through a via hole. The pixel opening in the pixel definition layer 310 exposes the anode 10. The light-emitting functional layer 60 is connected to the anode 10, and the cathode 50 is connected to the light-emitting functional layer 60. The light-emitting functional layer 60 emits corresponding color light under the drive of the anode 10 and the cathode 50.

[0062] In some exemplary embodiments, the light-emitting functional layer 60 may include: at least two stacked light-emitting units and at least one charge generation layer, and the charge generation layer is disposed between every two adjacent light-emitting units. At this time, the light-emitting device may be referred to as a stacked organic electroluminescent device or a tandem organic light-emitting diode (Tandem OLED, TOLED). Thus, every two light-emitting units in the stacked organic electroluminescent device are connected in series through the charge generation layer, thereby improving the luminous efficiency of the stacked organic electroluminescent device and prolonging the service life of the stacked organic electroluminescent device. Moreover, as the number of light-emitting units included in the stacked organic electroluminescent device increases, the luminous efficiency and service life of the stacked organic electroluminescent device increase linearly in a doubling manner.

[0063] In some exemplary embodiments, as Figure 4 shown, the light-emitting functional layer 60 may include: two stacked light-emitting units (the first light-emitting unit 20 and the second light-emitting unit 40 respectively) and the charge generation layer 30. Thus, in a direction away from the anode 10, the light-emitting device (i.e., the stacked organic electroluminescent device) may include: the anode 10, the first light-emitting unit 20 disposed on one side of the anode 10, the charge generation layer (CGL) 30 disposed on a side of the first light-emitting unit 20 away from the anode 10, the second light-emitting unit 40 disposed on a side of the charge generation layer 30 away from the anode 10, and the cathode 50 disposed on a side of the second light-emitting unit 40 away from the anode 10.

[0064] In some exemplary embodiments, the light-emitting unit may include: an emitting layer (EML), and any one or more of the following film layers: a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL).

[0065] In some exemplary embodiments, the light-emitting layers of the light-emitting devices (i.e., stacked organic electroluminescent devices) in different color sub-pixels are different. For example, the light-emitting device in the red sub-pixel includes a red light-emitting layer, the light-emitting device in the green sub-pixel includes a green light-emitting layer, and the light-emitting device in the blue sub-pixel includes a blue light-emitting layer. In some exemplary embodiments, the organic light-emitting layer can be formed by evaporation using a fine metal mask (FMM) or an open mask, or by an inkjet process.

[0066] A stacked organic electroluminescent device (TOLED) improves display performance and extends screen life by stacking two or more OLED light-emitting layers. Compared with single-emission OLED devices, TOLEDs have attracted extensive attention due to their potential high brightness, long service life, and an internal quantum efficiency (IQE) of approximately 100%.

[0067] The inventors of the present disclosure have found that some TOLED structures use a 1&2 cycle device structure. Since the light-emitting layer (EML1) in the 1&2 cycle device is closer to the anode composed of ITO / Ag, the electromagnetic oscillation during the propagation of light waves will strongly couple and be highly localized with the electron oscillation of the metal material in the electrode, thus forming a hybrid electromagnetic mode at the interface between the two media (i.e., the interface between the electrode and the light-emitting layer). Its electromagnetic field is concentrated near the interface and exponentially decays along the normal directions on both sides of the interface, resulting in a significant increase in the SPP effect and a decrease in the light-emitting efficiency of the device. In some other TOLED structures, by increasing the thickness of the hole transport layer near the anode, the 1&2 cycle device structure is changed to a 2&3 cycle device structure to reduce the SPP effect. However, this measure will cause hindrance to hole transport on the anode side, resulting in a significant increase in the driving voltage of the device and breaking the carrier balance in the device, thus significantly reducing the device life. Therefore, how to reasonably suppress the SPP effect is crucial for improving device performance.

[0068] Among them, the use of a 1&2 cycle device structure means that the optical path difference between the reflected light and the transmitted light of the light-emitting device of the sub-pixel emitting a certain color of light from the light-emitting position to the electrode in the emission direction satisfies 1 to 2 times half of the wavelength of this color of light, and the use of a 2&3 cycle device structure means that the optical path difference between the reflected light and the transmitted light of the light-emitting device of the sub-pixel emitting a certain color of light from the light-emitting position to the electrode in the emission direction satisfies 2 to 3 times half of the wavelength of this color of light.

[0069] An exemplary embodiment of the present disclosure provides a display substrate, which includes a stacked organic light-emitting device. By increasing the thicknesses of the hole transport layer adjacent to the anode, the electron transport layer adjacent to the cathode, and the N-type charge generation layer, the surface plasmon polariton (SPP) effect generated by the metal in the electrode and the N-type charge generation layer can be significantly reduced, thereby improving the light-emitting efficiency of the device and enhancing the device performance. In addition, by correspondingly adjusting the structures of sub-pixels of different colors, the carrier balance in pixels of different colors can be prevented from being broken, thereby improving the light-emitting efficiency of the device and ensuring that the device voltage and lifespan do not decrease significantly, enhancing the device performance.

[0070] An exemplary embodiment of the present disclosure provides a display substrate, which includes: a stacked organic light-emitting device, which includes: an anode, a cathode, and a first light-emitting unit, a charge generation layer, and a second light-emitting unit sequentially stacked between the anode and the cathode. Along the direction away from the anode, the first light-emitting unit includes: a first hole transport layer, a first auxiliary light-emitting layer, a first light-emitting layer, a first hole blocking layer, and a first electron transport layer stacked in sequence; the second light-emitting unit includes: a second hole transport layer, a second auxiliary light-emitting layer, a second light-emitting layer, a second hole blocking layer, and a second electron transport layer stacked in sequence; the charge generation layer includes: an N-type charge generation layer and a P-type charge generation layer stacked in sequence; wherein, the thickness of the first hole transport layer is greater than the thickness of the first electron transport layer is greater than the thickness of the second electron transport layer is greater than the thickness of the N-type charge generation layer is greater than and the thickness of the P-type charge generation layer is less than or equal to In this way, the SPP effect generated by the metal in the electrode and the N-type charge generation layer can be significantly reduced, thereby improving the light-emitting efficiency of the device and enhancing the device performance.

[0071] In some exemplary embodiments, the display substrate further includes: a plurality of pixel units arranged in an array, at least one of the plurality of pixel units includes: a first sub-pixel emitting first-color light, a second sub-pixel emitting second-color light, and a third sub-pixel emitting third-color light. The wavelength of the first-color light is greater than the wavelength of the second-color light, and the wavelength of the second-color light is greater than the wavelength of the third-color light. Each sub-pixel includes: a stacked organic light-emitting device.

[0072] In some exemplary embodiments, the equivalent cavity length of the microcavity of the stacked organic light-emitting device in the first sub-pixel is to the equivalent cavity length of the microcavity of the stacked organic light-emitting device in the second sub-pixel is to And, the equivalent cavity length of the microcavity of the stacked organic electroluminescent device in the third sub-pixel is to In this way, the device efficiency can be made better.

[0073] In some exemplary embodiments, the total thickness from the anode to the first light-emitting layer in the first sub-pixel can be approximately to The total thickness from the anode to the first light-emitting layer in the second sub-pixel is to The total thickness from the anode to the first light-emitting layer in the third sub-pixel is to The total thickness from the cathode to the second light-emitting layer in different color sub-pixels is all to In this way, the exciton recombination region of the first light-emitting unit and the second light-emitting unit in the stacked organic electroluminescent device does not shift significantly, and the device performance is more stable.

[0074] In some exemplary embodiments, the sum of the thickness of the first hole transport layer and the thickness of the first auxiliary light-emitting layer in the first sub-pixel is to The sum of the thickness of the first hole transport layer and the thickness of the first auxiliary light-emitting layer in the second sub-pixel is to The sum of the thickness of the first hole transport layer and the thickness of the first auxiliary light-emitting layer in the third sub-pixel is to And the sum of the thicknesses of the first electron transport layer, the second electron transport layer, and the second hole transport layer in different color sub-pixels is to In this way, it is ensured that the position of the exciton recombination region does not change significantly, and the device performance is more stable.

[0075] In some exemplary embodiments, the second auxiliary light-emitting layer in the first sub-pixel is a host-guest doping structure, including an auxiliary host material and an auxiliary guest material, and the doping ratio of the auxiliary guest material is 0.1% to 0.5%.

[0076] In some exemplary embodiments, the material of at least one of the first auxiliary light-emitting layer in the first sub-pixel, the first auxiliary light-emitting layer in the second sub-pixel, the second auxiliary light-emitting layer in the second sub-pixel, the first auxiliary light-emitting layer in the third sub-pixel, and the second auxiliary light-emitting layer in the third sub-pixel is the same as the material of the auxiliary host material.

[0077] In some exemplary embodiments, the sum of the thickness of the N-type charge generation layer and the thickness of the P-type charge generation layer is greater than

[0078] In some exemplary embodiments, the thickness of the second hole transport layer is less than that of the first hole transport layer, and the thickness of the second hole transport layer is less than

[0079] In some exemplary embodiments, the thickness of the first auxiliary light-emitting layer in the first sub-pixel is greater than The thickness of the first light-emitting layer in the first sub-pixel is less than The thickness of the first auxiliary light-emitting layer in the second sub-pixel is less than The thicknesses of both the first light-emitting layer and the second light-emitting layer in the third sub-pixel are less than And the second auxiliary light-emitting layer in the third sub-pixel is greater than

[0080] In some exemplary embodiments, for the stacked organic light-emitting device in the first sub-pixel, the optical path difference between the reflected light and the transmitted light from the light-emitting position to the electrode in the light-emitting direction approximately satisfies 1 to 2 times the wavelength of the first color light divided by two; for the stacked organic light-emitting device in the second sub-pixel, the optical path difference between the reflected light and the transmitted light from the light-emitting position to the electrode in the light-emitting direction approximately satisfies 1 to 2 times the wavelength of the second color light divided by two; and for the stacked organic light-emitting device in the third sub-pixel, the optical path difference between the reflected light and the transmitted light from the light-emitting position to the electrode in the light-emitting direction approximately satisfies 1 to 2 times the wavelength of the third color light divided by two. Here, since the light-emitting functional layer has a certain thickness, the optical path difference between the reflected light and the transmitted light in the embodiments of the present disclosure satisfying an integer multiple of the wavelength of the light divided by two may refer to not strictly limiting the boundary, allowing values within the process and measurement error range.

[0081] In some exemplary embodiments, the first sub-pixel is a red sub-pixel, the second sub-pixel is a green sub-pixel, and the third sub-pixel is a blue sub-pixel.

[0082] Figure 4 This is a schematic structural diagram of the stacked organic light-emitting device in the display substrate according to the exemplary embodiments of the present disclosure. As Figure 4 shown, the stacked organic light-emitting device may include: an anode 10, a first light-emitting unit 20 disposed on one side of the anode 10, a charge generation layer (CGL) 30 disposed on the side of the first light-emitting unit 20 away from the anode 10, a second light-emitting unit 40 disposed on the side of the charge generation layer 30 away from the anode 10, and a cathode 50 disposed on the side of the second light-emitting unit 40 away from the anode 10. Among them, the charge generation layer 30 is disposed to connect two adjacent light-emitting units (such as the first light-emitting unit 20 and the second light-emitting unit 40) to ensure that sufficient electrons and holes can be formed between the superposed light-emitting layers.

[0083] In some exemplary embodiments, as Figure 4As shown, in a direction away from the anode 10, the first light-emitting unit 20 may include: a hole injection layer (HIL) 21 disposed on a side of the anode 10 close to the cathode 50, a first hole transport layer (HTL1) 22 disposed on a side of the hole injection layer (HIL) 21 close to the charge generation layer (CGL) 30, a first auxiliary light-emitting layer (Prime1) 23 disposed on a side of the first hole transport layer (HTL1) 22 close to the charge generation layer (CGL) 30, a first light-emitting layer (EML1) 24 disposed on a side of the first auxiliary light-emitting layer (Prime1) 23 close to the charge generation layer (CGL) 30, a first hole blocking layer (HBL1) 25 disposed on a side of the first light-emitting layer (EML1) 24 close to the charge generation layer (CGL) 30, and a first electron transport layer (ETL1) 26 disposed on a side of the first hole blocking layer (HBL1) 25 close to the charge generation layer (CGL) 30. Among them, the hole injection layer (HIL) 21 is configured to reduce the barrier for injecting holes from the anode 10, so that holes can be effectively injected from the anode 10 into the first light-emitting layer (EML1). The first hole transport layer (HTL1) 22 is configured to achieve a controllable migration of the injected holes in a directed and orderly manner. The first light-emitting layer (EML1) 24 is configured to cause electrons and holes to recombine to emit light. The first hole blocking layer (HBL1) 25 is configured to form a migration barrier for holes to prevent holes from migrating out of the first light-emitting layer (EML1). The first electron transport layer (ETL1) 26 is configured to achieve a controllable migration of the injected electrons in a directed and orderly manner. The electron injection layer 80 is configured to reduce the barrier for injecting electrons from the cathode, so that electrons can be effectively injected from the cathode into the light-emitting layer 50.

[0084] In some exemplary embodiments, such as Figure 4As shown, along the direction close to the anode 10, the second light-emitting unit 40 may include: an electron injection layer (EIL) 41 disposed on the side of the cathode 50 close to the anode 10, a second electron transport layer (ETL2) 42 disposed on the side of the electron injection layer (EIL) 41 close to the charge generation layer (CGL) 30, a second hole blocking layer (HBL2) 43 disposed on the side of the second electron transport layer (ETL2) 42 close to the charge generation layer (CGL) 30, a second light-emitting layer (EML2) 44 disposed on the side of the second hole blocking layer (HBL2) 43 close to the charge generation layer (CGL) 30, a second auxiliary light-emitting layer (Prime2) 45 disposed on the side of the second light-emitting layer (EML2) 44 close to the charge generation layer (CGL) 30, and a second hole transport layer (HTL2) 46 disposed on the side of the second auxiliary light-emitting layer (Prime2) 45 close to the charge generation layer (CGL) 30. Among them, the electron injection layer (EIL) 41 is configured to reduce the barrier for injecting electrons from the cathode 50, so that electrons can be effectively injected from the cathode 50 into the second light-emitting layer (EML2) 44. The second electron transport layer (ETL2) 42 is configured to achieve a controllable migration of the injected electrons in an orderly direction. The second hole blocking layer (HBL2) 43 is configured to form a migration barrier for holes to prevent holes from migrating out of the second light-emitting layer (EML2) 44. The second light-emitting layer (EML2) 44 is configured to cause electrons and holes to recombine to emit light. The second hole transport layer (HTL2) 46 is configured to achieve a controllable migration of the injected holes in an orderly direction.

[0085] In some exemplary embodiments, the first auxiliary light-emitting layer 23 is configured to reduce the barrier and improve the matching degree with the host material, such as reducing the barrier between the hole transport layer and the host material and efficiently transporting holes to the host material; or, the first auxiliary light-emitting layer 23 is configured to act as an electron blocking layer to block electrons transmitted from the first charge generation layer 31 - the first electron transport layer 26 - the host material direction, so as to prevent electrons from entering the first hole transport layer 22 to cause non-radiative decay transitions or entering the anode to cause leakage current, so that electrons and holes are preferably recombined in the light-emitting layer to form excitons, thereby improving the recombination efficiency of electrons and holes. Or, the auxiliary light-emitting layer is configured to improve the light-emitting efficiency of the first light-emitting layer and prevent excitons in the first light-emitting layer from transferring energy to the first hole transport layer 22 by means of carriers, resulting in non-radiative decay transitions of excitons in the first hole transport layer 22, thereby improving the light-emitting efficiency of the first light-emitting layer. Thus, in some exemplary embodiments, the first auxiliary light-emitting layer 23 can be reused as an electron blocking layer, or, in some other exemplary embodiments, an electron blocking layer can be additionally provided between the first hole transport layer and the first light-emitting layer. The second auxiliary light-emitting layer can refer to the description of the first auxiliary light-emitting layer and will not be elaborated here.

[0086] In some exemplary embodiments, the charge generation layer (CGL) 30 includes a first charge generation layer 31 and a second charge generation layer 32 which are stacked. Among them, the first charge generation layer 31 is located on the side of the charge generation layer (CGL) 30 close to the anode 10, and is configured to inject electrons generated in the contact region between the first charge generation layer 31 and the second charge generation layer 32 into the first electron transport layer 26; the second charge generation layer 32 is located on the side of the charge generation layer (CGL) 30 close to the cathode 50, and is configured to inject holes generated in the contact region between the first charge generation layer 31 and the second charge generation layer 32 into the second hole transport layer 46.

[0087] In some exemplary embodiments, the first charge generation layer 31 may be an N-type charge generation layer (N-CGL), and the second charge generation layer 32 may be a P-type charge generation layer (P-CGL). Among them, the material of the N-type charge generation layer may be an N-type material (also referred to as an electron-type material), that is, the N-type charge generation layer has the ability to inject electrons, and the material of the P-type charge generation layer may be a P-type material (also referred to as a hole-type material), that is, the P-type charge generation layer has the ability to inject holes.

[0088] In some exemplary embodiments, the material of the N-type charge generation layer may be a first doping structure, and the first doping structure includes: a first host material and a first guest material. The first guest material may be an organic compound containing a strong electron-donating group, a metal (such as an alkali metal), or a metal-containing compound. Exemplarily, the first host material may be 4,7-diphenyl-1,10-phenanthroline (abbreviated as Bphen), 1,3,5-Tris(3-pyridyl-3-phenyl)benzene (abbreviated as TmPyPB), 4,6-Bis(3,5-di-3-pyridylphenyl)-2-methylpyrimidine (abbreviated as B3PYMPM), 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (abbreviated as TPBi), or 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (Bathocuproine, abbreviated as BCP), etc. Exemplarily, the first guest material may be selected from invisible crystal violet (LCV), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), magnesium (Mg), calcium (Ca), ytterbium (Yb), or lithium fluoride (LiF), etc. Exemplarily, the doping ratio of the first guest material may be about 1% to 3%. For example, the doping ratio of the first guest material may be about 1%, 2%, or 3%, etc.

[0089] In some exemplary embodiments, the material of the N-type charge generation layer may be Bphen doped with 1% Yb, TmPyPB doped with 1% Yb, B3PYMPM doped with 1% Yb, TPBi doped with 1% Yb, or BCP doped with 1% Yb, etc.

[0090] In some exemplary embodiments, the material of the P-type charge generation layer may be a second doping structure, and the second doping structure includes: a second host material and a second guest material. The second host material may be an arylamine material, dimethylfluorene, or carbazole material having hole transport characteristics. For example, the second host material may be selected from 4,4'-bis[N-(1-naphthalenyl)-N-phenylamino]biphenyl (N,N'-Bis-(1-naphthalenyl)-N,N'-bis-phenyl-(1,1'-biphenyl)-4,4'-diamine, abbreviated as NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (N,N'-Bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine, abbreviated as TPD), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (BAFLP), 4,4'-bis[N-(9,9-dimethylfluoren-2-yl)-N-phenylamino]biphenyl (DFLDPBi), 4,4'-bis(9-carbazolyl)biphenyl (4,4'-Bis(N-carbazolyl)-1,1'-biphenyl, abbreviated as CBP), 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (PCzPA), or 4,4',4”-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), etc. The second guest material may be an organic material containing a strong electron-withdrawing group. For example, the second guest material may be selected from 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (Dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile, abbreviated as HATCN), hexacyanohexaazatriphenylene, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-benzoquinodimethane (2,3,5,6-Tetrafluoro-7,7',8,8'-Tetracyanoquino-dimethane, abbreviated as F4TCNQ, TCNQF4), 1,2,3-tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane, etc. Exemplarily, the doping ratio of the second guest material may be about 3% to 10%. For example, the doping ratio of the second guest material may be about 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0091] In some exemplary embodiments, the material of the P-type charge generation layer may be NPB doped with 5% HATCN.

[0092] Thus, since the first charge generation layer 31 has electron injection ability and the second charge generation layer 32 has hole injection ability, in some exemplary embodiments, the first charge generation layer 31 can be reused as the electron injection layer in the first light-emitting unit 20, and the second charge generation layer 32 can be reused as the hole injection layer in the second light-emitting unit 40. At this time, an additional electron injection layer may not be provided in the first light-emitting unit 20 of the stacked organic electroluminescent device, and an additional hole injection layer may not be provided in the second light-emitting unit 40. Alternatively, in some other exemplary embodiments, an additional electron injection layer may be provided between the first charge generation layer 31 and the first electron transport layer 26 in the first light-emitting unit 20. Similarly, an additional hole injection layer may be provided between the second charge generation layer 32 and the second hole transport layer 46 in the second light-emitting unit 40.

[0093] In some exemplary embodiments, the thickness of the first charge generation layer 31 is greater than Exemplarily, the thickness of the first charge generation layer 31 can be about to For example, the thickness of the first charge generation layer 31 can be about or etc.

[0094] In some exemplary embodiments, the thickness of the second charge generation layer 32 is not higher than Thus, the lateral leakage characteristics of the stacked organic electroluminescent device can be controlled. Exemplarily, the thickness of the second charge generation layer 32 can be about to For example, the thickness of the first charge generation layer 31 can be about or etc.

[0095] Luminescence process of the stacked organic light-emitting device: When the pixel driving circuit is working, the driving voltage can be transmitted to the stacked organic light-emitting device through the transistor 210 electrically connected to the anode 10. At this time, under the drive of a direct current low voltage and high electric field, the anode 10 can generate holes, the cathode 50 can generate electrons, and holes and electrons can be generated in the contact area between the first charge generation layer 31 and the second charge generation layer 32. Then, the holes generated by the anode 10 can migrate to the first light-emitting layer 24 successively through the hole injection layer 21, the first hole transport layer 22, and the first auxiliary light-emitting layer 23. Correspondingly, the electrons generated in the contact area between the first charge generation layer 31 and the second charge generation layer 32 can migrate to the first light-emitting layer 24 successively through the first charge generation layer 31, the first electron transport layer 26, and the first hole blocking layer 25. Similarly, the electrons generated by the cathode 50 can migrate to the second light-emitting layer 44 successively through the electron injection layer 41, the second electron transport layer 42, and the second hole blocking layer 43. Correspondingly, the holes generated in the contact area between the first charge generation layer 31 and the second charge generation layer 32 can migrate to the second light-emitting layer 44 successively through the second charge generation layer 32, the second hole transport layer 46, and the second auxiliary light-emitting layer 45. A part of the holes and electrons meet and recombine in the first light-emitting layer 24 to form excitons, and another part of the holes and electrons meet and recombine in the second light-emitting layer 44 to form excitons. Under the action of the electric field, the excitons transfer energy to the organic light-emitting molecules, and excite the electrons in the organic light-emitting molecules to transition from the ground state to the excited state. The excited state energy is released in the form of photons through the transition, generating light energy, so that the stacked organic light-emitting device emits light.

[0096] In some exemplary embodiments, the total cavity length of the stacked organic light-emitting device (i.e., the equivalent cavity length of the microcavity corresponding to the stacked organic light-emitting device) satisfies the following range: The total cavity length of the red stacked organic light-emitting device in the red sub-pixel can be about to such as or etc. The total cavity length of the green stacked organic light-emitting device in the green sub-pixel can be about to such as or etc. The total cavity length of the blue stacked organic light-emitting device in the blue sub-pixel can be about to such as or etc. In this way, the device efficiency can be effectively improved. Beyond this range, the device efficiency will decrease by more than 10%. For example, the total cavity length of the red stacked organic light-emitting device in the red sub-pixel can be about The total cavity length of the green stacked organic light-emitting device in the green sub-pixel can be about The total cavity length of the blue stacked organic electroluminescent device in the blue sub-pixel can be approximately In this way, the device efficiency can be optimized.

[0097] In this way, the optical path difference between the reflected light and the transmitted light from the light-emitting position to the electrode in the out-of-emission direction of the red stacked organic electroluminescent device in the red sub-pixel can satisfy 1 to 2 times the wavelength of the red light, the optical path difference between the reflected light and the transmitted light from the light-emitting position to the electrode in the out-of-emission direction of the green stacked organic electroluminescent device in the green sub-pixel can satisfy 1 to 2 times the wavelength of the green light, and the optical path difference between the reflected light and the transmitted light from the light-emitting position to the electrode in the out-of-emission direction of the blue stacked organic electroluminescent device in the blue sub-pixel can satisfy 1 to 2 times the wavelength of the blue light. It can meet the optical path requirements of the optical microcavity (also known as the microresonator or microcavity), and can strengthen the microcavity effect corresponding to different color sub-pixels. Thus, the light-emitting device in the display panel can adopt a device structure of 1&2 cycles, which can avoid the problem of blocked hole transport on the anode side generated by the 2&3 cycle device, avoid a significant increase in the driving voltage of the device, and improve the light-emitting efficiency of the display panel.

[0098] Among them, the total cavity length of the stacked organic electroluminescent device satisfies the following relationship:

[0099] D = d0*n0 + (d 11 *n 11 +…+ d 1k *n 1k ) + (d 21 *n 21 +…+ d 2j *n 2j ) Formula (1);

[0100] Among them, D represents the total cavity length of the stacked organic electroluminescent device, d0 represents the thickness of the electrode with higher transmittance among the first electrode and the second electrode of the stacked organic electroluminescent device, n0 represents the refractive index of the electrode with higher transmittance among the first electrode and the second electrode of the stacked organic electroluminescent device, d 11 represents the thickness of the first functional layer of the first light-emitting unit in the stacked organic electroluminescent device, n 11 represents the refractive index of the first functional layer of the first light-emitting unit in the stacked organic electroluminescent device, d 1k represents the thickness of the kth functional layer of the first light-emitting unit in the sub-pixel, n 1k represents the refractive index of the kth functional layer of the first light-emitting unit in the sub-pixel, d 21 represents the thickness of the first functional layer of the second light-emitting unit in the stacked organic electroluminescent device, n 21Refractive index of the first functional layer of the second light-emitting unit in the stacked organic electroluminescent device, d 2j Thickness of the j-th functional layer of the second light-emitting unit in the stacked organic electroluminescent device, n 2j Refractive index of the k-th functional layer of the second light-emitting unit in the stacked organic electroluminescent device, where k and j are positive integers greater than 1.

[0101] For example, the functional layers of the first light-emitting unit may include: a hole injection layer (HIL) 21, a first hole transport layer (HTL1) 22, a first auxiliary light-emitting layer (Prime1) 23, a first light-emitting layer (EML1) 24, a first hole blocking layer (HBL1) 25, and a first electron transport layer (ETL1) 26. The functional layers of the second light-emitting unit may include: a second hole transport layer (HTL2) 46, a second auxiliary light-emitting layer (Prime2) 45, a second light-emitting layer (EML2) 44, a second hole blocking layer (HBL2) 43, a second electron transport layer (ETL2) 42, and an electron injection layer (EIL) 41. At this time, k and j are 6.

[0102] In some exemplary embodiments, both the first light-emitting layer and the second light-emitting layer may include a light-emitting host material and a light-emitting guest material. Exemplarily, the light-emitting host material may be a bipolar single host, or may be a dual host formed by blending a hole-type host and an electron-type host, such as CBP. Exemplarily, the light-emitting guest material may include, but is not limited to, one or more of a phosphorescent material, a fluorescent material, and a delayed fluorescent material, such as Bis[2-(2'-benzothienyl)pyridinato-N,C3'](acetylacetonato)iridium (abbreviated as Btp2Ir(acac)), Tris(2-phenylpyridine)iridium(III) (abbreviated as Ir(ppy)3), Bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (abbreviated as FIrpic), etc.

[0103] Exemplarily, the doping ratio of the light-emitting guest material in the light-emitting layer is about 5% to 15%. For example, the doping ratio of the light-emitting guest material in the light-emitting layer can be about 4%, 5%, 6%, 7%, 7.5%, 8%, 9%, 9.5% or 10%, etc. Here, the doping ratio can refer to the weight ratio of the light-emitting guest material to the weight of the light-emitting layer where it is located. Alternatively, the doping ratio can refer to the rate ratio during evaporation, corresponding to the ratio of the evaporation thickness of the light-emitting guest material to the total thickness of the light-emitting layer where it is located. For example, taking the thickness of the first light-emitting layer to be about as an example, for a light-emitting layer with a thickness of , a doping ratio of 10% means that the evaporation thickness of the light-emitting guest material is about Thus, by limiting the doping ratio of the light-emitting guest material D within the above range, high efficiency can be ensured while ensuring a long lifespan. Here, the embodiments of the present disclosure do not limit the materials of the first light-emitting layer and the second light-emitting layer.

[0104] In some exemplary embodiments, the first light-emitting layer in the red sub-pixel and the second light-emitting layer in the red sub-pixel can adopt CBP doped with 2% Btp2Ir(acac). The first light-emitting layer in the green sub-pixel can adopt CBP doped with 8% Ir(ppy)3, and the second light-emitting layer in the green sub-pixel can adopt CBP doped with 6% Ir(ppy)3. The first light-emitting layer in the blue sub-pixel and the second light-emitting layer in the blue sub-pixel can adopt CBP doped with 2% FIrpic.

[0105] In some exemplary embodiments, the thickness of the first light-emitting layer in the red sub-pixel is less than the thickness of the second light-emitting layer in the red sub-pixel, and the thickness of the first light-emitting layer in the red sub-pixel is less than Exemplarily, the thickness of the first light-emitting layer in the red sub-pixel can be about to For example, the thickness of the first light-emitting layer in the red sub-pixel can be about Or etc. Exemplarily, the thickness of the second light-emitting layer in the red sub-pixel can be about to For example, the thickness of the second light-emitting layer in the red sub-pixel can be about Or etc.

[0106] In some exemplary embodiments, the thickness of the first light-emitting layer in the red sub-pixel and the thickness of the first light-emitting layer in the green sub-pixel. In some other exemplary embodiments, the thickness of the first light-emitting layer in the red sub-pixel, the thickness of the first light-emitting layer in the green sub-pixel, and the thickness of the second light-emitting layer in the green sub-pixel are the same. For example, the thickness of the first light-emitting layer in the red sub-pixel, the thickness of the first light-emitting layer in the green sub-pixel, and the thickness of the second light-emitting layer in the green sub-pixel can all be approximately

[0107] In some exemplary embodiments, the thickness of the first light-emitting layer in the green sub-pixel and the thickness of the second light-emitting layer in the green sub-pixel are the same. Exemplarily, the thickness of the first light-emitting layer in the green sub-pixel and the thickness of the second light-emitting layer in the green sub-pixel can both be approximately to For example, the thickness of the first light-emitting layer and the second light-emitting layer in the green sub-pixel can be approximately or etc.

[0108] In some exemplary embodiments, the thickness of the first light-emitting layer in the blue sub-pixel and the thickness of the second light-emitting layer in the blue sub-pixel are the same. Exemplarily, the thickness of the first light-emitting layer and the second light-emitting layer in the blue sub-pixel can be approximately to For example, the thickness of the first light-emitting layer and the second light-emitting layer in the blue sub-pixel can be approximately or etc. In some other exemplary embodiments, the thickness of the first light-emitting layer in the blue sub-pixel and the thickness of the second light-emitting layer in the blue sub-pixel are the same, and the thickness of the first light-emitting layer in the blue sub-pixel and the thickness of the second light-emitting layer in the blue sub-pixel are less than For example, the thickness of the first light-emitting layer in the blue sub-pixel and the thickness of the second light-emitting layer in the blue sub-pixel can be approximately

[0109] In some exemplary embodiments, the thickness of the first light-emitting layer in the green sub-pixel can be the same as the thickness of the first light-emitting layer in the red sub-pixel, and the thickness of the first light-emitting layer in the green sub-pixel is greater than the thickness of the first light-emitting layer in the blue sub-pixel. For example, the thickness of the first light-emitting layer in the green sub-pixel can be approximately The thickness of the first light-emitting layer in the red sub-pixel can be approximately The thickness of the first light-emitting layer in the blue sub-pixel can be approximately

[0110] In some exemplary embodiments, the thickness of the second light-emitting layer in the green sub-pixel is less than the thickness of the second light-emitting layer in the red sub-pixel, and the thickness of the second light-emitting layer in the green sub-pixel is greater than the thickness of the second light-emitting layer in the blue sub-pixel. For example, the thickness of the second light-emitting layer in the green sub-pixel can be about The thickness of the second light-emitting layer in the red sub-pixel can be about The thickness of the first light-emitting layer in the blue sub-pixel can be about

[0111] In some exemplary embodiments, the thickness of the first auxiliary light-emitting layer in the red sub-pixel is greater than Exemplarily, the thickness of the first auxiliary light-emitting layer in the red sub-pixel can be about to For example, the thickness of the first auxiliary light-emitting layer in the red sub-pixel can be about or etc.

[0112] In some exemplary embodiments, the thickness of the first auxiliary light-emitting layer in the red sub-pixel is the same as the thickness of the first light-emitting layer in the red sub-pixel, and the thickness of the second auxiliary light-emitting layer in the red sub-pixel is the same as the thickness of the second light-emitting layer in the red sub-pixel. For example, the thickness of the first auxiliary light-emitting layer in the red sub-pixel and the thickness of the first light-emitting layer in the red sub-pixel are about and the thickness of the second auxiliary light-emitting layer in the red sub-pixel and the thickness of the second light-emitting layer in the red sub-pixel are about

[0113] In some exemplary embodiments, the thickness of the first auxiliary light-emitting layer in the green sub-pixel is less than Exemplarily, the thickness of the first auxiliary light-emitting layer in the green sub-pixel can be about to For example, the thickness of the first auxiliary light-emitting layer in the green sub-pixel can be about or etc.

[0114] In some exemplary embodiments, the thickness of the first auxiliary light-emitting layer in the blue sub-pixel is the same as the thickness of the first auxiliary light-emitting layer in the green sub-pixel, and less than the thickness of the first auxiliary light-emitting layer in the red sub-pixel. For example, the thickness of the first auxiliary light-emitting layer in the blue sub-pixel and the thickness of the first auxiliary light-emitting layer in the green sub-pixel are about The thickness of the first auxiliary light-emitting layer in the red sub-pixel is about Or, the thickness of the first auxiliary light-emitting layer in the blue sub-pixel and the thickness of the first auxiliary light-emitting layer in the green sub-pixel are both about The thickness of the first auxiliary light-emitting layer in the red sub-pixel is about

[0115] In some exemplary embodiments, the thickness of the first auxiliary light-emitting layer in the blue sub-pixel is less than Exemplarily, the thickness of the first auxiliary light-emitting layer in the blue sub-pixel can be approximately to For example, the thickness of the first auxiliary light-emitting layer in the blue sub-pixel can be approximately or and so on.

[0116] In some exemplary embodiments, the thickness of the second auxiliary light-emitting layer in the red sub-pixel can be approximately to For example, the thickness of the second auxiliary light-emitting layer in the red sub-pixel can be approximately or and so on.

[0117] In some exemplary embodiments, the thickness of the second auxiliary light-emitting layer in the green sub-pixel can be approximately to For example, the thickness of the second auxiliary light-emitting layer in the green sub-pixel can be approximately or and so on.

[0118] In some exemplary embodiments, the thickness of the second auxiliary light-emitting layer in the blue sub-pixel is greater than Exemplarily, the thickness of the second auxiliary light-emitting layer in the blue sub-pixel can be approximately to For example, the thickness of the second auxiliary light-emitting layer in the blue sub-pixel can be approximately or and so on.

[0119] In some exemplary embodiments, the first auxiliary light-emitting layer in the red sub-pixel has a binary doping structure including an auxiliary host material R' and an auxiliary guest material RD. The auxiliary host material R' can be N,N'-Bis-(1-naphthalenyl)-N,N'-bis-phenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviated as NPB), N,N'-Diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), 4,4'-Cyclohexylidenebis[N,N-bis(4-methylphenyl)aniline (abbreviated as TAPC), etc. The auxiliary guest material RD is a phosphorescent material, such as PtOEP, Btp2Ir(acac), Ir(piq)3, etc. The doping ratio of the auxiliary guest material in the first auxiliary light-emitting layer can be about 0.1% to 0.5%, such as 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc. Here, the doping ratio can refer to the weight ratio of the auxiliary guest material to the weight of the first auxiliary light-emitting layer where it is located, or the doping ratio can refer to the rate ratio during evaporation, corresponding to the ratio of the evaporation thickness of the auxiliary guest material to the total thickness of the auxiliary guest material where it is located. For example, taking the thickness of the first auxiliary light-emitting layer in the red sub-pixel to be about as an example, for the first auxiliary light-emitting layer with a thickness of , a doping ratio of 0.3% means that the evaporation thickness of the auxiliary guest material is about Thus, by limiting the doping ratio of the auxiliary guest material within the above range, the electron transport distance can be increased, and the light-emitting efficiency can be improved. For example, taking the auxiliary host material R' as TPD and the auxiliary guest material RD as Btp2Ir(acac), and the doping ratio being about 0.3% as an example, the first auxiliary light-emitting layer in the red sub-pixel can be formed by co-evaporating TPD and Btp2Ir(acac) in a volume ratio of 99.7:0.3 to form the first red auxiliary light-emitting layer.

[0120] In some exemplary embodiments, the second auxiliary light-emitting layer in the red sub-pixel has the same material as the auxiliary host material R' in the first auxiliary light-emitting layer in the red sub-pixel. For example, both the second auxiliary light-emitting layer in the red sub-pixel and the auxiliary host material R' in the first auxiliary light-emitting layer in the red sub-pixel can use TPD material.

[0121] In some exemplary embodiments, the materials of the second auxiliary light-emitting layer in the red sub-pixel, the first auxiliary light-emitting layer in the green sub-pixel, the second auxiliary light-emitting layer in the green sub-pixel, the first auxiliary light-emitting layer in the blue sub-pixel, and the second auxiliary light-emitting layer in the blue sub-pixel can be any one of materials such as N,N'-Bis-(1-naphthalenyl)-N,N'-bis-phenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviated as NPB), N,N'-Bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine (abbreviated as TPD), 4,4'-Cyclohexylidenebis[N,N-bis(4-methylphenyl)aniline (abbreviated as TAPC), etc. For example, the materials of the second auxiliary light-emitting layer in the red sub-pixel, the first auxiliary light-emitting layer in the green sub-pixel, the second auxiliary light-emitting layer in the green sub-pixel, the first auxiliary light-emitting layer in the blue sub-pixel, and the second auxiliary light-emitting layer in the blue sub-pixel can all adopt TPD materials.

[0122] In some exemplary embodiments, the hole injection layer can adopt materials such as HATCN.

[0123] In some exemplary embodiments, the thicknesses of the hole injection layers in different color sub-pixels can be the same. For example, the thicknesses of the hole injection layers in different color sub-pixels can all be about

[0124] In some exemplary embodiments, the materials of the first hole transport layer and the second hole transport layer are the same. Exemplarily, the materials of the first hole transport layer and the second hole transport layer can be NPB, N,N'-Bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), 4-Phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (BAFLP), 4,4'-Bis[N-(9,9-dimethylfluoren-2-yl)-N-phenylamino]biphenyl (DFLDPBi), 4,4'-Di(9-carbazolyl)biphenyl (CBP), 9-Phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (PCzPA), or 4,4',4”-Tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), etc. For example, the first hole transport layer and the second hole transport layer can both adopt NPB materials.

[0125] In some exemplary embodiments, the thickness of the first hole transport layer is greater than the thickness of the second hole transport layer. For example, the thickness of the first hole transport layer can be about and the thickness of the second hole transport layer can be about

[0126] In some exemplary embodiments, the thickness of the first hole transport layer is greater than and the thickness of the second hole transport layer is less than Exemplarily, the thickness of the first hole transport layer can be about to The thickness of the second hole transport layer can be about to For example, the thickness of the first hole transport layer can be about or etc. For example, the thickness of the second hole transport layer can be about or etc.

[0127] In some exemplary embodiments, the thicknesses of the first hole blocking layer and the second hole blocking layer can be the same. Exemplarily, the thicknesses of the first hole blocking layer and the second hole blocking layer can be about to For example, the thicknesses of the first hole blocking layer and the second hole blocking layer can be about

[0128] In some exemplary embodiments, the materials of the first hole blocking layer and the second hole blocking layer can be the same. For example, an aromatic heterocyclic compound can be used, such as imidazole derivatives such as benzimidazole derivatives, imidazopyridine derivatives, benzimidazole phenanthridine derivatives, etc.; pyrimidine derivatives, triazine derivatives and other pyrazine derivatives; quinoline derivatives, isoquinoline derivatives, phenanthroline derivatives and other compounds containing a nitrogen-containing six-membered ring structure (also including compounds having a phosphine oxide-based substituent on the heterocycle), etc. For example, the materials of both the first hole blocking layer and the second hole blocking layer can use the BCP material.

[0129] In some exemplary embodiments, the thickness of the first electron transport layer is less than the thickness of the second electron transport layer. For example, the thickness of the first electron transport layer is greater than and the thickness of the second electron transport layer is greater than For example, the thickness of the first electron transport layer can be about and the thickness of the second electron transport layer can be about

[0130] In some exemplary embodiments, the thickness of the first electron transport layer is the same as or different from the thickness of the N-type charge generation layer. For example, the thicknesses of both the first electron transport layer and the N-type charge generation layer can be approximately Alternatively, the thickness of the first electron transport layer can be approximately The thickness of the N-type charge generation layer can be approximately

[0131] In some exemplary embodiments, the thicknesses of the first electron transport layer, the N-type charge generation layer, and the first hole transport layer are the same as or different from each other. For example, the thicknesses of the first electron transport layer, the N-type charge generation layer, and the first hole transport layer can all be approximately Alternatively, the thickness of the first electron transport layer can be approximately The thickness of the N-type charge generation layer can be approximately And the thickness of the first hole transport layer can all be approximately

[0132] In some exemplary embodiments, the first electron transport layer and the second electron transport layer can be prepared by blending with lithium quinolate, such as thiophene-based, imidazole-based, or azine-based derivatives, and the doping ratio of lithium quinolate in the electron transport layer is about 30% to 70%. For example, both the first electron transport layer and the second electron transport layer can use 8-(4-(4,6-di(naphthalene-2-yl)-1,3,5-triazin-2-yl)phenyl)quinoline (abbreviated as DNPQTrz) material.

[0133] In some exemplary embodiments, the thickness of the electron injection layer can be about 21 nm to 27 nm. For example, the thickness of the electron injection layer can be about 23 nm.

[0134] In some exemplary embodiments, the material of the electron injection layer can be an alkali metal or a metal, such as lithium fluoride (LiF), lithium 8-hydroxyquinolate (LiQ), ytterbium (Yb), or calcium (Ca), etc., or compounds of these alkali metals or metals. For example, the electron injection layer is formed by a vapor deposition process.

[0135] In some exemplary embodiments, the anode can be made of a material with a high work function. For bottom-emission type, the anode can be made of a transparent oxide material, such as Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO), etc. The thickness of the anode can be about 80 nm to 200 nm. For top-emission type, the anode can adopt a composite structure of metal and transparent oxide, such as Ag / ITO, Ag / IZO or ITO / Ag / ITO, etc. The thickness of the metal layer in the anode can be about 80 nm to 100 nm, and the thickness of the transparent oxide in the anode can be about 5 nm to 20 nm, so that the average reflectivity of the anode in the visible light region is about 85% to 95%.

[0136] In some exemplary embodiments, for top-emission type OLEDs, the cathode can be made of a metal material and formed by evaporation coating process. The metal material can be magnesium (Mg), silver (Ag) or aluminum (Al), or an alloy material, such as an alloy of Mg:Ag with a ratio of about 3:7 to 1:9. The thickness of the cathode can be about 10 nm to 20 nm, so that the average transmittance of the cathode at a wavelength of 530 nm is about 50% to 60%. For bottom-emission type OLEDs, the cathode can be magnesium (Mg), silver (Ag), aluminum (Al) or an alloy of Mg:Ag, and the thickness of the cathode can be greater than about 80 nm, so that the cathode has good reflectivity.

[0137] Of course, the settings of the thickness and other values of the film layers (the first light-emitting unit, charge generation layer and second light-emitting unit) located between the anode and the cathode in the stacked organic light-emitting device in the above exemplary embodiments are only examples in some exemplary embodiments of the present disclosure. In actual applications, they are not limited to the above numerical settings. When changing the thickness of the film layers (the first light-emitting unit, charge generation layer and second light-emitting unit) located between the anode and the cathode in the stacked organic light-emitting device, the design can be carried out according to the following preset conditions 1 to preset conditions 4:

[0138] Preset condition 1 can be: the total cavity length of the stacked organic light-emitting device remains unchanged, which can make the device efficiency better.

[0139] In some exemplary embodiments, the total cavity length of the red stacked organic light-emitting device in the red sub-pixel can be about to such as or etc. The total cavity length of the green stacked organic light-emitting device in the green sub-pixel can be about to such as or etc. The total cavity length of the blue stacked organic light-emitting device in the blue sub-pixel can be approximately to such as or etc. In this way, the device efficiency can be effectively improved. Beyond this range, the device efficiency will decrease by more than 10%.

[0140] In some exemplary embodiments, the total cavity length of the red stacked organic light-emitting device in the red sub-pixel can be approximately The total cavity length of the green stacked organic light-emitting device in the green sub-pixel can be approximately The total cavity length of the blue stacked organic light-emitting device in the blue sub-pixel can be approximately In this way, the device efficiency can be made better.

[0141] Preset condition 2 can include: the total thickness from the anode to the first light-emitting layer and the total thickness from the cathode to the second light-emitting layer remain unchanged, which can prevent a significant shift in the exciton recombination region between the first light-emitting unit and the second light-emitting unit in the stacked organic light-emitting device.

[0142] In some exemplary embodiments, the total thickness from the anode to the first light-emitting layer in the red sub-pixel can be approximately to such as or The total thickness from the anode to the first light-emitting layer in the green sub-pixel can be approximately to such as or The total thickness from the anode to the first light-emitting layer in the blue sub-pixel can be approximately to such as or The total thickness from the cathode to the second light-emitting layer in different color sub-pixels can be approximately to such as or In this way, the device efficiency can be effectively improved. Here, the total thickness from the anode to the first light-emitting layer refers to the sum of the thicknesses of the film layers between the anode and the first light-emitting layer, such as the hole injection layer (HIL), the first hole transport layer (HTL1), and the first auxiliary light-emitting layer (Prime1). The total thickness from the cathode to the second light-emitting layer refers to the sum of the thicknesses of the film layers between the cathode and the second light-emitting layer, such as the second electron transport layer (ETL2) and the second hole blocking layer (HBL2).

[0143] In some exemplary embodiments, the total thickness from the anode to the first light-emitting layer in the red sub-pixel can be approximately The total thickness from the anode to the first light-emitting layer in the green sub-pixel can be approximately The total thickness from the anode to the first light-emitting layer in the blue sub-pixel can be approximately The total thickness from the cathode to the second light-emitting layer in different-color sub-pixels can be approximately In some other exemplary embodiments, the total thickness from the anode to the first light-emitting layer in the red sub-pixel can be approximately The total thickness from the anode to the first light-emitting layer in the green sub-pixel can be approximately The total thickness from the anode to the first light-emitting layer in the blue sub-pixel can be approximately The total thickness from the cathode to the second light-emitting layer in different-color sub-pixels can be approximately In this way, the device efficiency can be made better.

[0144] The preset condition 3 can include: the thickness variation compensation of the first hole transport layer (HTL1) in the first light-emitting unit on the thickness of the first auxiliary light-emitting layer (Prime1) in the first light-emitting unit, and the thickness variation compensation of the first electron transport layer (ETL1) in the first light-emitting unit and the second electron transport layer (ETL2) in the second light-emitting unit on the second hole transport layer (HTL2) in the second light-emitting unit, which can make the exciton recombination regions of the first light-emitting unit and the second light-emitting unit in the stacked organic electroluminescent device not change significantly, and the device performance is more stable.

[0145] In some exemplary embodiments, the sum of the thickness of the first hole transport layer (HTL1) and the thickness of the first auxiliary light-emitting layer (Prime1) in the red sub-pixel is approximately to The sum of the thickness of the first hole transport layer (HTL1) and the thickness of the first auxiliary light-emitting layer (Prime1) in the blue sub-pixel is approximately to The sum of the thickness of the first hole transport layer (HTL1) and the thickness of the first auxiliary light-emitting layer (Prime1) in the green sub-pixel is approximately to And the sum of the thicknesses of the first electron transport layer (ETL1), the second electron transport layer (ETL2), and the second hole transport layer (HTL2) in different-color sub-pixels is approximately to In this way, the exciton recombination regions of the first light-emitting unit and the second light-emitting unit in the stacked organic electroluminescent device can be made not to change significantly, and the device performance is more stable.

[0146] In some exemplary embodiments, the sum of the thickness of the first hole transport layer (HTL1) and the thickness of the first auxiliary light-emitting layer (Prime1) in the red sub-pixel is approximately The sum of the thickness of the first hole transport layer (HTL1) and the first auxiliary light-emitting layer (Prime1) in the blue sub-pixel is approximately The sum of the thickness of the first hole transport layer (HTL1) and the first auxiliary light-emitting layer (Prime1) in the green sub-pixel is approximately And the sum of the thickness of the first electron transport layer (ETL1), the second electron transport layer (ETL2), and the second hole transport layer (HTL2) in sub-pixels of different colors is approximately In some other exemplary embodiments, the sum of the thickness of the first hole transport layer (HTL1) and the first auxiliary light-emitting layer (Prime1) in the red sub-pixel is approximately The sum of the thickness of the first hole transport layer (HTL1) and the first auxiliary light-emitting layer (Prime1) in the blue sub-pixel is approximately The sum of the thickness of the first hole transport layer (HTL1) and the first auxiliary light-emitting layer (Prime1) in the green sub-pixel is approximately And the sum of the thickness of the first electron transport layer (ETL1), the second electron transport layer (ETL2), and the second hole transport layer (HTL2) in sub-pixels of different colors is approximately

[0147] The preset condition 4 may include: the thickness of the P-type charge generation layer (P-CGL) in the charge generation layer is not less than

[0148] In this way, by correspondingly adjusting the film thicknesses of sub-pixels of different colors, it can be ensured that the device structure of the stacked organic electroluminescent device meets the optical path requirements of the optical microcavity, the optimal light output intensity and color can be obtained, the SPP effect can be greatly reduced, and the carrier balance in each of the R / G / B sub-pixels is not broken, so that the luminous efficiency of the device can be improved, and it is ensured that the device voltage and lifetime do not decrease significantly, thus improving the device performance.

[0149] The devices in the embodiments of the present disclosure and the comparative devices both adopt the structure as Figure 4 shown. The device structure is: ITO / HIL / HTL1 / Prime1 / EML1 / HBL1 / ETL1 / NCGL / PCGL / HTL2 / Prime2 / EML2 / HBL2 / ETL2 / EIL / Cathode. The anode uses ITO, and the cathode uses an alloy of Mg:Ag.

[0150] Table 1. Thickness comparison between the devices in the embodiments of the present disclosure and the comparative devices (unit: )

[0151]

[0152] As shown in Table 1, the thicknesses of the respective film layers of the comparative device are as follows: the thickness of the hole injection layer (HIL) is the thickness of the first hole transport layer (HTL1) is the thickness of the first auxiliary light-emitting layer (Prime1) in the red sub-pixel (R) is the thickness of the first auxiliary light-emitting layer (Prime1) in the green sub-pixel (G) is the thickness of the first auxiliary light-emitting layer (Prime1) in the blue sub-pixel (B) is the thickness of the first light-emitting layer (EML1) in the red sub-pixel (R) is the thickness of the first light-emitting layer (EML1) in the green sub-pixel (G) is the thickness of the first light-emitting layer (EML1) in the blue sub-pixel (B) is the thickness of the first hole blocking layer (HBL1) is the thickness of the first electron transport layer (ETL1) is the thickness of the first charge generation layer (NCGL) is the thickness of the second charge generation layer (PCGL) is the thickness of the second hole transport layer (HTL2) is the thickness of the second auxiliary light-emitting layer (Prime2) in the red sub-pixel (R) is the thickness of the second auxiliary light-emitting layer (Prime2) in the green sub-pixel (G) is the thickness of the second auxiliary light-emitting layer (Prime2) in the blue sub-pixel (B) is the thickness of the second light-emitting layer (EML2) in the red sub-pixel (R) is the thickness of the second light-emitting layer (EML2) in the green sub-pixel (G) is the thickness of the second light-emitting layer (EML2) in the blue sub-pixel (B) is the thickness of the second hole blocking layer (HBL2) is the thickness of the second electron transport layer (ETL2) is

[0153] As shown in Table 1, the thicknesses of the respective film layers of the device of Example 1 are as follows: the thickness of the hole injection layer (HIL) is the thickness of the first hole transport layer (HTL1) is the thickness of the first auxiliary light-emitting layer (Prime1) in the red sub-pixel (R) is the thickness of the first auxiliary light-emitting layer (Prime1) in the green sub-pixel (G) is the thickness of the first auxiliary light-emitting layer (Prime1) in the blue sub-pixel (B) is the thickness of the first light-emitting layer (EML1) in the red sub-pixel (R) is The thickness of the first emission layer (EML1) in the green sub-pixel (G) is The thickness of the first emission layer (EML1) in the blue sub-pixel (B) is The thickness of the first hole blocking layer (HBL1) is The thickness of the first electron transport layer (ETL1) is The thickness of the first charge generation layer (NCGL) is The thickness of the second charge generation layer (PCGL) is The thickness of the second hole transport layer (HTL2) is The thickness of the second auxiliary emission layer (Prime2) in the red sub-pixel (R) is The thickness of the second auxiliary emission layer (Prime2) in the green sub-pixel (G) is The thickness of the second auxiliary emission layer (Prime2) in the blue sub-pixel (B) is The thickness of the second emission layer (EML2) in the red sub-pixel (R) is The thickness of the second emission layer (EML2) in the green sub-pixel (G) is The thickness of the second emission layer (EML2) in the blue sub-pixel (B) is The thickness of the second hole blocking layer (HBL2) is The thickness of the second electron transport layer (ETL2) is

[0154] As shown in Table 1, the thicknesses of the respective film layers of the device of Example 2 are: the thickness of the hole injection layer (HIL) is The thickness of the first hole transport layer (HTL1) is The thickness of the first auxiliary emission layer (Prime1) in the red sub-pixel (R) is The thickness of the first auxiliary emission layer (Prime1) in the green sub-pixel (G) is The thickness of the first auxiliary emission layer (Prime1) in the blue sub-pixel (B) is The thickness of the first emission layer (EML1) in the red sub-pixel (R) is The thickness of the first emission layer (EML1) in the green sub-pixel (G) is The thickness of the first emission layer (EML1) in the blue sub-pixel (B) is The thickness of the first hole blocking layer (HBL1) is The thickness of the first electron transport layer (ETL1) is The thickness of the first charge generation layer (NCGL) is The thickness of the second charge generation layer (PCGL) is The thickness of the second hole transport layer (HTL2) is The thickness of the second auxiliary light-emitting layer (Prime2) in the red sub-pixel (R) is The thickness of the second auxiliary light-emitting layer (Prime2) in the green sub-pixel (G) is The thickness of the second auxiliary light-emitting layer (Prime2) in the blue sub-pixel (B) is The thickness of the second light-emitting layer (EML2) in the red sub-pixel (R) is The thickness of the second light-emitting layer (EML2) in the green sub-pixel (G) is The thickness of the second light-emitting layer (EML2) in the blue sub-pixel (B) is The thickness of the second hole blocking layer (HBL2) is The thickness of the second electron transport layer (ETL2) is

[0155] As can be seen from the data in Table 1, compared with the devices of the comparative examples, the thicknesses of the first hole transport layer (HTL1) in the devices 1 and 2 of the present disclosure embodiment are increased by The thicknesses of the first electron transport layer (ETL1) in the devices 1 and 2 of the present disclosure embodiment are increased by The thickness of the N-type charge generation layer (N-CGL) in the devices 1 and 2 of the present disclosure embodiment is increased by The thickness of the second electron transport layer (ETL2) in the devices 1 and 2 of the present disclosure embodiment is increased by The thickness of the P-type charge generation layer (P-CGL) in the devices 1 and 2 of the present disclosure embodiment is decreased by In the red sub-pixels of the devices 1 and 2 of the present disclosure embodiment, the first auxiliary light-emitting layer (Prime1) is increased by The first light-emitting layer (EML1) is thinned The second auxiliary light-emitting layer (Prime2) is doped with 0.3% of the auxiliary guest material RD using the auxiliary host material R', the thickness of the second auxiliary light-emitting layer (Prime2) remains unchanged, and the thickness of the second light-emitting layer (EML2) remains unchanged. In the green sub-pixels of the devices 1 and 2 of the present disclosure embodiment, the first auxiliary light-emitting layer (Prime1) is thinned by The thickness of the first light-emitting layer (EML1) remains unchanged, the thickness of the second auxiliary light-emitting layer (Prime2) remains unchanged, and the thickness of the green second light-emitting layer (EML2) remains unchanged. In the blue sub-pixels of the devices 1 and 2 of the present disclosure embodiment, both the first light-emitting layer (EML1) and the second light-emitting layer (EML2) are thinned The second auxiliary light-emitting layer (Prime2) is increased The first auxiliary light-emitting layer (Prime1) is thinned by

[0156] Thus, by increasing the thicknesses of the first hole transport layer (HTL1) adjacent to the anode, the first electron transport layer (ETL1) adjacent to the cathode, and the N-type charge generation layer (N-CGL), the SPP effect generated by the metal in the electrodes and the N-type charge generation layer can be significantly reduced, thereby improving the light-emitting efficiency of the device and enhancing the device performance. In addition, by correspondingly adjusting the structures of the sub-pixels of different colors, the carrier balance in the pixels of different colors can be prevented from being broken, thereby improving the light-emitting efficiency of the device and ensuring that the device voltage and lifespan do not decrease significantly, enhancing the device performance.

[0157] As shown in Table 2, the film layer materials and refractive indices of each film layer of the device of the embodiment and the device of the comparative example are as follows: the hole injection layer (HIL) uses HATCN material (refractive index is 1.3); the first hole transport layer (HTL1) and the second hole transport layer (HTL2) use NPB material (refractive index is 1.65); the first hole blocking layer (HBL1) and the second hole blocking layer (HBL2) use BCP material (refractive index is 1.74); the first electron transport layer (ETL1) and the second electron transport layer (ETL2) use DNPQTrz material (refractive index is 1.8); the first charge generation layer (NCGL) uses Bphen doped with 1% Yb (refractive index is 1.88); the second charge generation layer (PCGL) uses NPB doped with 5% HATCN (refractive index is 1.3); the first auxiliary light-emitting layer in the red sub-pixel uses TPD doped with 3% Btp2Ir(acac) (refractive index is 1.82), the second auxiliary light-emitting layer (Prime2) in the red sub-pixel uses TPD (refractive index is 1.82), the first auxiliary light-emitting layer (Prime1) and the second auxiliary light-emitting layer (Prime2) in the green sub-pixel use TPD material (refractive index is 1.73), the first auxiliary light-emitting layer (Prime1) and the second auxiliary light-emitting layer (Prime2) in the blue sub-pixel use TPD material (refractive index is 1.81); the first light-emitting layer (EML1) and the second light-emitting layer (EML2) materials in the red sub-pixel use CBP doped with 2% Btp2Ir(acac) (refractive index is 1.66), the first light-emitting layer (EML1) in the green sub-pixel uses CBP doped with 8% Ir(ppy)3 (refractive index is 1.70), the second light-emitting layer (EML2) in the green sub-pixel uses CBP doped with 6% Ir(ppy)3 (refractive index is 1.70), the first light-emitting layer (EML1) and the second light-emitting layer (EML2) in the blue sub-pixel use CBP doped with 1% FIrpic (refractive index is 1.78).

[0158] Table 2. Film layer materials and their refractive indices of the device of the present disclosure embodiment

[0159]

[0160] Taking the wavelength of red light as 630 nm, the wavelength of green light as 530 nm, and the wavelength of blue light as 420 nm as an example, according to the data in Table 1 and Table 2, through formula (1), it can be determined that the equivalent cavity length of the microcavity corresponding to the red stacked organic light-emitting device is to The equivalent cavity length of the microcavity corresponding to the green stacked organic light-emitting device is to And the equivalent cavity length of the microcavity corresponding to the blue stacked organic light-emitting device is to It can be seen that the device in the exemplary embodiment of the present disclosure can meet the equivalent cavity length condition of the 1&2 cycle device structure, ensuring that the 1&2 cycles remain unchanged.

[0161] Table 3. Performance comparison between the device of the embodiment of the present disclosure and the device of the comparative example

[0162]

[0163] It can be seen from the data in Table 3 that compared with the device of the comparative example using some technologies, in the device of the embodiment using the technology in the present disclosure, the efficiency of the stacked organic light-emitting device (R) in the red sub-pixel is increased by 9%, the efficiency of the stacked organic light-emitting device (G) in the green sub-pixel is increased by 18%, and the efficiency of the stacked organic light-emitting device (B) in the blue sub-pixel is increased by 23%. It can be seen that there is an obvious improvement in the device efficiency. In addition, the change ranges of the voltage and life of the device are both within ±5%, which is basically consistent with the device of the comparative example.

[0164] Here, the efficiency improvement of the stacked organic light-emitting device in the blue sub-pixel is more obvious than that in the green sub-pixel and the red sub-pixel because the SPP effect is more obvious in the blue light band (420 nm to 460 nm). By increasing the thicknesses of the first hole transport layer (HTL1), the first electron transport layer (ETL1), the N-type charge generation layer (N-CGL), and the second electron transport layer (ETL2), the SPP effect is most weakened for blue light, followed by green light and red light. After doping RD in the second auxiliary light-emitting layer (Prime2) in the red stacked organic light-emitting device, the exciton recombination region moves towards the interface of the second auxiliary light-emitting layer (Prime2) / the second light-emitting layer (EML2), resulting in an increase in the electron transport distance, a 3% increase in voltage, and a 4% decrease in life.

[0165] As can be seen from the above experimental results, for the display substrate in the exemplary embodiments of the present disclosure, by increasing the thickness of the first hole transport layer (HTL1) adjacent to the anode, the thickness of the second electron transport layer (ETL2) adjacent to the cathode, the thickness of the N-type charge generation layer (N-CGL), and the thickness of the first electron transport layer (ETL1) adjacent to the N-type charge generation layer (N-CGL), the SPP effect generated by the metal in the electrode and the N-type charge generation layer (N-CGL) can be significantly reduced, thereby improving the light-emitting efficiency of the device. Moreover, by correspondingly adjusting the film thicknesses of different color sub-pixels, the carrier balance in each pixel can be prevented from being disrupted, so that the light-emitting efficiency of the devices in the display substrate can be improved without changing other performance of the device (such as voltage and lifespan).

[0166] An embodiment of the present disclosure further provides a display device, which may include: the display substrate described in one or more of the above embodiments.

[0167] Here, the display device may be a product with an image display function (including static images or dynamic images, where the dynamic image may be a video). In some exemplary embodiments, the display device may include, but is not limited to: a mobile phone, a tablet computer, a television, a monitor, a laptop computer, an in-vehicle display, or a navigator, etc., any product or component with a display function. Here, the type of the display device is not limited in the embodiments of the present disclosure. Other essential components of the display device are understood to be possessed by those of ordinary skill in the art, and will not be elaborated herein, nor should they be regarded as a limitation to the present disclosure.

[0168] In addition, the display device in the embodiments of the present disclosure may further include other necessary components and structures in addition to the structures exemplified in the above embodiments. For example, a circuit for providing an electrical signal to the display substrate to drive the display substrate to emit light, which may be referred to as a control circuit, and may include at least one of a circuit board and an integrated circuit (IC) electrically connected to the display substrate; another example is a power supply system for supplying power to the display substrate. Those skilled in the art can make corresponding designs and supplements according to the type and usage requirements of the display substrate, and will not be elaborated herein.

[0169] The description of the above display device embodiments is similar to the description of the above display substrate embodiments, and has similar beneficial effects to those of the display substrate embodiments. For the technical details not disclosed in the display device embodiments of the present disclosure, those skilled in the art may refer to the description in the display substrate embodiments of the present disclosure for understanding, and will not be elaborated herein.

[0170] Although the embodiments disclosed in the present disclosure are as above, the above content is only an embodiment adopted for the convenience of understanding the present disclosure and is not intended to limit the present disclosure. Any person skilled in the art within the scope of the present disclosure may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present disclosure. However, the scope of patent protection of the present disclosure shall still be subject to the scope defined by the appended claims.

Claims

1. A display substrate, characterized in that: include: A stacked organic electroluminescent device, the stacked organic electroluminescent device comprising: an anode, a cathode, and a first light-emitting unit, a charge generation layer, and a second light-emitting unit stacked sequentially between the anode and the cathode, in a direction away from the anode, the first light-emitting unit comprising: a first hole transport layer, a first auxiliary light-emitting layer, a first light-emitting layer, a first hole blocking layer, and a first electron transport layer stacked sequentially, the second light-emitting unit comprising: a second hole transport layer, a second auxiliary light-emitting layer, a second light-emitting layer, a second hole blocking layer, and a second electron transport layer stacked sequentially, the charge generation layer comprising: an N-type charge generation layer and a P-type charge generation layer stacked sequentially; wherein the thickness of the first hole transport layer is greater than The thickness of the first electron transport layer is greater than The thickness of the second electron transport layer is greater than The thickness of the N-type charge generation layer is greater than The thickness of the P-type charge generation layer is less than or equal to 2. The display substrate according to claim 1, characterized in that: Also includes: A plurality of pixel units are arranged in an array, at least one of the plurality of pixel units comprises: a first sub-pixel emitting a first color light, a second sub-pixel emitting a second color light, and a third sub-pixel emitting a third color light, the wavelength of the first color light is greater than the wavelength of the second color light, and the wavelength of the second color light is greater than the wavelength of the third color light, and each sub-pixel comprises: the stacked organic electroluminescent device.

3. The display substrate according to claim 2, characterized in that: The equivalent cavity length of the microcavity of the stacked organic electroluminescent device in the first sub-pixel is to The equivalent cavity length of the microcavity of the stacked organic electroluminescent device in the second sub-pixel is to And, the equivalent cavity length of the microcavity of the stacked organic electroluminescent device in the third sub-pixel is to 4. The display substrate according to claim 2, characterized in that: The total thickness from the anode to the first light-emitting layer in the first sub-pixel is to The total thickness from the anode to the first light-emitting layer in the second sub-pixel is to The total thickness from the anode to the first light-emitting layer in the third sub-pixel is to The total thickness from the cathode to the second light-emitting layer in sub-pixels of different colors is to 5. The display substrate according to claim 2, characterized in that: The sum of the thickness of the first hole transport layer and the thickness of the first auxiliary light-emitting layer in the first sub-pixel is to The sum of the thickness of the first hole transport layer and the thickness of the first auxiliary light-emitting layer in the second sub-pixel is to The sum of the thickness of the first hole transport layer and the thickness of the first auxiliary light-emitting layer in the third sub-pixel is to The sum of the thicknesses of the first electron transport layer, the second electron transport layer and the second hole transport layer in different color sub-pixels is to 6. The display substrate according to any one of claims 2 to 5, characterized in that: The second auxiliary light-emitting layer in the first sub-pixel is a host-guest doping type structure, including an auxiliary host material and an auxiliary guest material, and the doping ratio of the auxiliary guest material is 0.1% to 0.5%.

7. The display substrate according to any one of claims 2 to 5, characterized in that: The sum of the thickness of the N-type charge generation layer and the thickness of the P-type charge generation layer is greater than 8. The display substrate according to any one of claims 2 to 5, characterized in that: The thickness of the second hole transport layer is less than the thickness of the first hole transport layer, and the thickness of the second hole transport layer is less than 9. The display substrate according to any one of claims 2 to 5, characterized in that: The thickness of the first auxiliary light-emitting layer in the first sub-pixel is greater than The thickness of the first light-emitting layer in the first sub-pixel is less than The thickness of the first auxiliary light-emitting layer in the second sub-pixel is less than The thickness of the first light-emitting layer and the thickness of the second light-emitting layer in the third sub-pixel are both less than and the second auxiliary light emitting layer in the third sub-pixel is larger than 10. The display substrate according to any one of claims 2 to 5, characterized in that: The optical path difference between the reflected light and the transmitted light of the stacked organic electroluminescent device from the light emitting position to the electrode in the emitting direction in the first sub-pixel satisfies 1 to 2 times the wavelength of half the first color light; the optical path difference between the reflected light and the transmitted light of the stacked organic electroluminescent device from the light emitting position to the electrode in the emitting direction in the second sub-pixel satisfies 1 to 2 times the wavelength of half the second color light; and the optical path difference between the reflected light and the transmitted light of the stacked organic electroluminescent device from the light emitting position to the electrode in the emitting direction in the third sub-pixel satisfies 1 to 2 times the wavelength of half the third color light.

11. A display device, characterized in that: The invention comprises the display substrate according to any one of claims 1 to 10.

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