Stacked light-emitting device, display substrate and display apparatus

Abstract

A stacked light-emitting device, a display substrate and a display apparatus, which belong to the technical field of display. The stacked light-emitting device comprises: a first electrode; a second electrode; at least two light-emitting units, which are stacked between the first electrode and the second electrode, wherein each light-emitting unit comprises an electron transport layer, a light-emitting layer and a hole transport layer which are stacked; and at least one stack connecting layer, which is disposed between the electron transport layer comprised in one of two adjacent light-emitting units and the hole transport layer comprised in the other light-emitting unit, wherein the stack connecting layer comprises an N-type charge generation layer and a P-type charge generation layer which are stacked, the electron transport layer stacked with the N-type charge generation layer is a polarized electron transport layer, the hole transport layer stacked with the P-type charge generation layer is a polarized hole transport layer, and a polarized electric field is formed between the polarized electron transport layer and the polarized hole transport layer.

Description

Multilayer light-emitting devices, display substrates and display devices

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410705682X, filed on May 31, 2024, entitled "Stacked Light Emitting Device, Display Substrate and Display Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of display technology, specifically relating to a multilayer light-emitting device, a display substrate, and a display apparatus. Background Technology

[0004] With the development of display technology, display products such as mobile phones and computers are being used more and more widely. Typically, display devices have a display substrate, through which displays are generated. The display substrate contains stacked light-emitting devices.

[0005] Overview

[0006] The purpose of this application is to provide a multilayer light-emitting device, a display substrate, and a display device that can alleviate the problem of lateral charge crosstalk easily generated by multilayer light-emitting devices in a display substrate.

[0007] In a first aspect, embodiments of this application provide a stacked light-emitting device, comprising:

[0008] First electrode;

[0009] Second electrode;

[0010] At least two light-emitting units are stacked between the first electrode and the second electrode, and each of the at least two light-emitting units includes a stacked electron transport layer, a light-emitting layer, and a hole transport layer; and

[0011] At least one stacked connecting layer is disposed between the electron transport layer of one of two adjacent light-emitting units and the hole transport layer of the other light-emitting unit;

[0012] Each of the at least one stacked interconnecting layers includes an N-type charge generation layer and a P-type charge generation layer stacked together. The N-type charge generation layer is stacked on the electron transport layer of one of the two adjacent light-emitting units, and the hole transport layer of the other of the two adjacent light-emitting units is stacked on the P-type charge generation layer.

[0013] The electron transport layer stacked with the N-type charge generation layer is a polarized electron transport layer, and the hole transport layer stacked with the P-type charge generation layer is a polarized hole transport layer. A polarized electric field is formed between the polarized electron transport layer and the polarized hole transport layer.

[0014] Optionally, under the polarization effect of the polarized electron transport and the polarized hole transport layer, a polarized layer is generated between the N-type charge generation layer and the P-type charge generation layer, wherein the size of the polarized layer in the first direction is greater than or equal to the first size;

[0015] Wherein, the first dimension is the maximum dimension in which the charge in the N-type charge generation layer and the P-type charge generation layer can move along the second direction, the first direction is the direction perpendicular to the plane where the light-emitting layer is located, and the first direction and the second direction intersect.

[0016] Optionally, the molecular dipole moment of the polarized electron transport layer is greater than 2 Debye, and the molecular dipole moment of the polarized hole transport layer is greater than 2 Debye.

[0017] Optionally, the size of the polarized electron transport layer in the first direction is between 5 nanometers and 30 nanometers, wherein the first direction is perpendicular to the plane of the light-emitting layer; and / or

[0018] The size of the polarized hole transport layer is between 10 nanometers and 50 nanometers in a first direction, wherein the first direction is perpendicular to the plane of the light-emitting layer.

[0019] Optionally, the N-type charge generation layer is a host-guest doped structure, comprising a first host material and a first guest material, wherein the proportion of the first guest material in the N-type charge generation layer is between 0.2% and 3%.

[0020] Optionally, the size of the N-type charge generating layer in the first direction is between 10 nanometers and 30 nanometers, wherein the first direction is perpendicular to the plane where the light-emitting layer is located.

[0021] Optionally, the P-type charge generation layer is a host-guest doped structure, comprising a second host material and a second guest material, wherein the proportion of the second guest material in the P-type charge generation layer is between 1% and 10%.

[0022] Optionally, the size of the P-type charge generating layer in a first direction is between 5 nanometers and 20 nanometers, wherein the first direction is perpendicular to the plane where the light-emitting layer is located.

[0023] Secondly, embodiments of this application provide a display substrate, comprising:

[0024] Substrate;

[0025] The stacked light-emitting device as described in any one of the first aspects above;

[0026] Multiple pixel driving circuits are used to drive at least one of the stacked light-emitting devices to emit light; and

[0027] An encapsulation layer is used to encapsulate the plurality of stacked light-emitting devices and the plurality of pixel driving circuits.

[0028] Optionally, the display substrate includes alternately arranged pixel areas and non-pixel areas;

[0029] The overlapping portion of the orthographic projection of the pixel region and the orthographic projection of the polarization layer between the N-type charge generation layer and the P-type charge generation layer is the first polarization layer.

[0030] The overlapping portion of the orthographic projection of the non-pixel region and the orthographic projection of the polarization layer between the N-type charge generation layer and the P-type charge generation layer constitutes the second polarization layer; and

[0031] The size of the first polarization layer in the first direction is smaller than the size of the second polarization layer in the first direction, wherein the first direction is a direction perpendicular to the plane of the substrate layer.

[0032] Thirdly, an embodiment of this application provides a display device comprising the display substrate described in any one of the second aspects above.

[0033] Brief description of the attached diagram

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 is a schematic cross-sectional view of the stacked light-emitting device in the related technology;

[0036] Figure 2 is a schematic diagram of the stacked light-emitting device provided in an embodiment of this application;

[0037] Figure 3 is a schematic cross-sectional view of the stacked light-emitting device provided in an embodiment of this application;

[0038] Figure 4 is a schematic diagram of the display substrate provided in an embodiment of this application;

[0039] Figure 5 is a schematic diagram of a display device provided in an embodiment of this application; and

[0040] Figure 6 is a schematic diagram of a display device provided in another embodiment of this application.

[0041] Detailed description

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0043] The technical solutions in some embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application are within the scope of protection of this application.

[0044] Unless the context otherwise requires, throughout the specification and claims, the term "comprise" and its other forms, such as the third-person singular "comprises" and the present participle "comprising," are interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific example," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this application. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0045] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0046] In describing some embodiments, the term "electrical connection" and its derivative expressions may be used. For example, the term "electrical connection" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact with each other.

[0047] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0048] The use of “configured as” in this article implies an open and inclusive language that does not exclude the applicability to or configuration of devices to perform additional tasks or steps.

[0049] As used herein, “approximately” includes the values ​​stated and the average value within an acceptable range of deviation from the given values, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).

[0050] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and regions is enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched regions shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0051] Before explaining the stacked light-emitting device provided in the embodiments of this application, the application scenarios of the stacked light-emitting device provided in the embodiments of this application will be specifically described: As shown in Figure 1, in related technologies, a stacked light-emitting device includes at least two light-emitting units, and two adjacent light-emitting units are connected by a stacked connection layer, which includes an N-type charge generation layer 41 and a P-type charge generation layer 42. However, a depletion region is generated between the N-type charge generation layer 41 and the P-type charge generation layer 42. The width of the depletion region is small, which makes the stacked light-emitting device prone to lateral charge movement, forming charge crosstalk.

[0052] As shown in Figure 2, in this embodiment of the application, the stacked light-emitting device D includes: a first electrode 10; a second electrode 20; at least two light-emitting units 30, which are stacked between the first electrode 10 and the second electrode 20, and each of the at least two light-emitting units 30 includes a stacked electron transport layer 31, a light-emitting layer 32, and a hole transport layer 33; at least one stacked connecting layer 40, which is disposed between the electron transport layer 31 of one of the two adjacent light-emitting units 30 and the hole transport layer 33 of the other light-emitting unit 30. Each stacked connecting layer 40 in 0 includes an N-type charge generation layer 41 and a P-type charge generation layer 42 stacked together. The N-type charge generation layer 41 is stacked on the electron transport layer 31 of one of the two adjacent light-emitting units 30, and the hole transport layer 33 of the other light-emitting unit 30 is stacked on the P-type charge generation layer 42. The electron transport layer 31 stacked with the N-type charge generation layer 41 is a polarized electron transport layer, and the hole transport layer 33 stacked with the P-type charge generation layer 42 is a polarized hole transport layer. A polarized electric field is formed between the polarized electron transport layer and the polarized hole transport layer.

[0053] In this embodiment, since at least two light-emitting units 30 are stacked between the first electrode 10 and the second electrode 20, and a stacked connection layer 40 is disposed between the electron transport layer 31 of one of the two adjacent light-emitting units 30 and the hole transport layer 33 of the other light-emitting unit 30, each pair of adjacent light-emitting units 30 between the first electrode 10 and the second electrode 20 is connected by a stacked connection layer 40, so that at least two light-emitting units 30 can emit light simultaneously, thereby improving the luminous efficiency of the stacked light-emitting device D. Since each light-emitting unit 30 includes a stacked electron transport layer 31, a light-emitting layer 32, and a hole transport layer 33, and each stacked connecting layer 40 includes a stacked N-type charge generation layer 41 and a P-type charge generation layer 42, with the N-type charge generation layer 41 stacked on top of the electron transport layer 31 of one of two adjacent light-emitting units 30, and the hole transport layer 33 of the other light-emitting unit 30 stacked on top of the P-type charge generation layer 42, the free electrons in the N-type charge generation layer 41 are majority carriers. A region with almost zero holes is called a minority carrier region. In the P-type charge generation layer 42, holes are majority carriers, and free electrons are minority carriers. At their boundary, a concentration gradient of electrons and holes appears. Some electrons diffuse from the N-type charge generation layer 41 to the P-type charge generation layer 42, while some holes diffuse from the P-type charge generation layer 42 to the N-type charge generation layer 41. This diffusion results in one side of the P-type charge generation layer 42 losing holes and leaving behind negatively charged impurity ions, while the other side of the N-type charge generation layer 41 loses electrons and leaves behind positively charged impurity ions, forming a space charge region. This creates a depletion region, while the space charge region experiences a significant decrease in conductivity due to the reduced concentration of mobile electrons, hindering lateral charge transport. This positively impacts the reduction of lateral crosstalk between the N-type charge generation layer 41 and the P-type charge generation layer 42 in the stacked light-emitting device D and other stacked light-emitting devices D. Furthermore, the electron transport layer 31, stacked with the N-type charge generation layer 41, is a polarized electron transport layer, and the hole transport layer 33, stacked with the P-type charge generation layer 42, is a polarized hole transport layer. A polarized electric field is formed between the polarized electron transport layer and the polarized hole transport layer. Thus, a polarization electric field is generated between the electron transport layer 31 of one light-emitting unit 30 and the hole transport layer 33 of the other light-emitting unit 30 in every two adjacent light-emitting units 30. The built-in electric field is also generated in the N-type charge generation layer 41 and the P-type charge generation layer 42 due to the movement of electrons and holes. The direction of the polarization electric field is consistent with the direction of the built-in electric field, thereby increasing the width of the depletion region and reducing the concentration of mobile free charge. Thus, after the stacked light-emitting device D is applied to the display substrate 111, the lateral crosstalk in the display substrate 111 can be improved.That is, in the embodiments of this application, by setting the polarized electron transport layer and the polarized hole transport layer, the polarized electron transport layer and the polarized hole transport layer between every two adjacent light-emitting units 30 can generate a polarized electric field, and the direction of the polarized electric field is consistent with the direction of the built-in electric field, thereby effectively reducing the concentration of mobile free charges, thereby effectively reducing the lateral crosstalk between the stacked light-emitting devices D.

[0054] It should be noted that the first electrode 10 can be either an anode or a cathode; correspondingly, the second electrode 20 can be either a cathode or an anode.

[0055] In some examples, the material of the first electrode 10 is a metal. Exemplarily, the material of the first electrode 10 may be selected from at least one of silver (Ag), magnesium (Mg), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), Ca-LiF alloy, Al-LiF alloy, molybdenum (Mo), titanium (Ti), indium (In), tin (Sn), and zinc (Zn).

[0056] In some examples, the material of the second electrode 20 is a metallic material or a metallic compound. For example, when the material of the second electrode 20 is a metallic material, the material of the second electrode 20 can be silver (Ag), magnesium (Mg), ytterbium (Yb), lithium (Li), or calcium (Ca); when the material of the second electrode 20 is an inorganic material of metallic compound type, the material of the second electrode 20 can be lithium oxide (Li2O), calcium oxide (CaO), lithium fluoride (LiF), or magnesium fluoride (MgF2), etc.

[0057] It should also be noted that in the embodiments of this application, the polarized electron transport layer and the polarized hole transport layer are polarized film layers, which are film layers with added polarizing materials. Since the atomic orientation in the film layer with added polarizing materials is spontaneous and disordered, when a voltage is applied to the polarized film layer, the atoms of the polarized film layer are aligned according to the electric field direction of the applied voltage, that is, the polarization direction of the polarized film layer is the electric field direction.

[0058] In addition, in some embodiments, a polarization layer is generated between the N-type charge generation layer 41 and the P-type charge generation layer 42 under the polarization effect of the polarized electron transport layer and the polarized hole transport layer. The size of the polarization layer in the first direction X is greater than or equal to the first size. The first size is the maximum size at which the charge in the N-type charge generation layer 41 and the P-type charge generation layer 42 can move along the second direction Y. The first direction X is a direction perpendicular to the plane where the light-emitting layer 32 is located. The first direction X and the second direction Y intersect.

[0059] Since the size of the polarization layer in the first direction X is greater than or equal to the first size, it can be ensured that the charges in the N-type charge generation layer 41 and the P-type charge generation layer 42 move as far as possible in the depletion region when they move, and the problem of possible lateral crosstalk between the charges in the N-type charge generation layer 41 and the P-type charge generation layer 42 can be avoided.

[0060] It should be noted that the first direction X and the second direction Y can be perpendicular, that is, the angle between the first direction X and the second direction Y is 90°. Of course, the angle between the first direction X and the second direction Y can also be 89°, or even 92°, as long as the first direction X and the second direction Y intersect. The specific value of the angle between the first direction X and the second direction Y is not limited in the embodiments of this application.

[0061] In addition, in some embodiments, the molecular dipole moment of the polarized electron transport layer is greater than 2 Debye, and the molecular dipole moment of the polarized hole transport layer is greater than 2 Debye.

[0062] This configuration ensures that after a polarized electric field is generated between the polarized electron transport layer of one light-emitting unit 30 and the polarized hole transport layer of the other, the width of the depletion region is sufficiently large, effectively increasing the width of the depletion region. This effectively avoids the problem of lateral crosstalk that may occur between the stacked light-emitting units 30. Specifically, by setting the molecular dipole moment of the polarized electron transport layer to be greater than 2 Debye times and the molecular dipole moment of the polarized hole transport layer to be greater than 2 Debye times, the probability of lateral crosstalk between the stacked light-emitting units 30 can be effectively reduced.

[0063] It should be noted that the molecular dipole moment of the polarized electron transport layer can be any value greater than 2 Debyes. For example, the molecular dipole moment of the polarized electron transport layer is 3 Debyes, another example is 2.5 Debyes, and yet another example is 2.8 Debyes. Similarly, the molecular dipole moment of the polarized hole transport layer can be any value greater than 2 Debyes. For example, the molecular dipole moment of the polarized hole transport layer is 3 Debyes, another example is 2.5 Debyes, and yet another example is 3.5 Debyes.

[0064] In addition, in some embodiments, the size of the polarized electron transport layer in the first direction X is between 5 nanometers and 30 nanometers, wherein the first direction X is a direction perpendicular to the plane where the light-emitting layer 32 is located.

[0065] Since the intensity of the polarization electric field is proportional to the thickness of the film, by setting the size of the polarization electron transport layer in the first direction X to be between 5 nanometers and 30 nanometers, the thickness of the polarization electron transport layer can be made larger. This is beneficial because after the formation of the polarization electron transport layer 31, the polarization electric field intensity generated by the polarization electron transport layer is larger, which in turn helps to improve the lateral crosstalk between the stacked light-emitting devices D.

[0066] It should be noted that the size of the polarized electron transport layer in the first direction X can be any value between 5 nanometers and 30 nanometers. For example, the size of the polarized electron transport layer in the first direction X can be 5 nanometers, or 10 nanometers, or 20 nanometers, or 25 nanometers, or 30 nanometers.

[0067] In addition, in some embodiments, the size of the polarized hole transport layer in the first direction X is between 10 nanometers and 50 nanometers, wherein the first direction X is a direction perpendicular to the plane where the light-emitting layer 32 is located.

[0068] Since the intensity of the polarization electric field is proportional to the thickness of the film, by setting the size of the polarization hole transport layer in the first direction X to be between 10 nanometers and 50 nanometers, the thickness of the polarization hole transport layer can be made larger. This is beneficial because after the hole transport layer 33 is formed, the polarization electric field intensity generated by the polarization hole transport layer is larger, which in turn helps to improve the lateral crosstalk between the stacked light-emitting devices D.

[0069] It should be noted that the size of the polarized hole transport layer in the first direction X can be any value between 10 nanometers and 50 nanometers. For example, the size of the polarized hole transport layer in the first direction X can be 10 nanometers, 15 nanometers, 20 nanometers, 25 nanometers, 30 nanometers, 40 nanometers, or 50 nanometers.

[0070] In addition, in some embodiments, the N-type charge generation layer 41 is a host-guest doped structure, including a first host material and a first guest material, wherein the proportion of the first guest material in the N-type charge generation layer 41 is between 0.2% and 3%.

[0071] This configuration ensures that the N-type charge generation layer 41 effectively forms the stacked connection layer 40, which is beneficial for the subsequent connection of the stacked connection layer 40 to two adjacent light-emitting units 30.

[0072] The first host material can be an organic material with electron transport properties, and the first guest material can be an active metal such as magnesium or ytterbium.

[0073] It should be noted that the proportion of the first guest material in the N-type charge generation layer 41 can be any value between 0.2% and 3%. For example, the proportion of the first guest material in the N-type charge generation layer 41 can be 0.2%, 1%, 2%, 2.5%, or 3%.

[0074] In addition, in some embodiments, the size of the N-type charge generation layer 41 in the first direction X is between 10 nanometers and 30 nanometers, wherein the first direction X is a direction perpendicular to the plane where the light-emitting layer 32 is located.

[0075] This configuration allows for a moderate thickness of the N-type charge generation layer 41, facilitating the formation of the stacked connection layer 40 and ensuring that every two adjacent light-emitting units 30 in the stacked light-emitting unit 30 can be effectively connected.

[0076] It should be noted that the size of the N-type charge generation layer 41 in the first direction X can be any value between 10 nanometers and 30 nanometers. For example, the size of the N-type charge generation layer 41 in the first direction X is 10 nanometers, or 15 nanometers, or 20 nanometers, or 25 nanometers, or 30 nanometers.

[0077] In addition, in some embodiments, the P-type charge generation layer 42 is a host-guest doped structure, including a second host material and a second guest material, wherein the proportion of the second guest material in the P-type charge generation layer 42 is between 1% and 10%.

[0078] This configuration ensures that the P-type charge generation layer 42 effectively forms the stacked connection layer 40, which facilitates the subsequent connection of the stacked connection layer 40 to two adjacent light-emitting units 30.

[0079] The second host material can be an organic material with hole transport properties, and the second guest material can be a metal oxide such as molybdenum trioxide, tungsten trioxide, or F4-TCNQ.

[0080] It should be noted that the proportion of the second guest material in the P-type charge generation layer 42 can be any value between 1% and 10%. For example, the proportion of the second guest material in the P-type charge generation layer 42 can be 1%, 3%, 5%, 8%, or 10%.

[0081] In addition, in some embodiments, the size of the P-type charge generating layer 42 in the first direction X is between 5 nanometers and 20 nanometers, wherein the first direction X is a direction perpendicular to the plane where the light-emitting layer 32 is located.

[0082] This configuration allows for a suitable thickness of the P-type charge generation layer 42, facilitating the formation of the stacked connection layer 40 and ensuring that every two adjacent light-emitting units 30 in the stacked light-emitting unit 30 can be effectively connected.

[0083] It should be noted that the size of the P-type charge generation layer 42 in the first direction X can be any value between 5 nanometers and 20 nanometers. For example, the size of the P-type charge generation layer 42 in the first direction X is 5 nanometers, or 10 nanometers, 15 nanometers, or 20 nanometers.

[0084] In this embodiment, since at least two light-emitting units 30 are stacked between the first electrode 10 and the second electrode 20, and a stacked connection layer 40 is disposed between the electron transport layer 31 of one of the two adjacent light-emitting units 30 and the hole transport layer 33 of the other light-emitting unit 30, each pair of adjacent light-emitting units 30 between the first electrode 10 and the second electrode 20 is connected by a stacked connection layer 40, so that at least two light-emitting units 30 can emit light simultaneously, thereby improving the luminous efficiency of the stacked light-emitting device D. Since each light-emitting unit 30 includes a stacked electron transport layer 31, a light-emitting layer 32, and a hole transport layer 33, and each stacked connecting layer 40 includes a stacked N-type charge generation layer 41 and a P-type charge generation layer 42, with the N-type charge generation layer 41 stacked on top of the electron transport layer 31 of one of two adjacent light-emitting units 30, and the hole transport layer 33 of the other light-emitting unit 30 stacked on top of the P-type charge generation layer 42, the free electrons in the N-type charge generation layer 41 are majority carriers. A region with almost zero holes is called a minority carrier region. In the P-type charge generation layer 42, holes are majority carriers, and free electrons are minority carriers. At their boundary, a concentration gradient of electrons and holes appears. Some electrons diffuse from the N-type charge generation layer 41 to the P-type charge generation layer 42, while some holes diffuse from the P-type charge generation layer 42 to the N-type charge generation layer 41. This diffusion results in one side of the P-type charge generation layer 42 losing holes and leaving behind negatively charged impurity ions, while the other side of the N-type charge generation layer 41 loses electrons and leaves behind positively charged impurity ions, forming a space charge region. This creates a depletion region, while the space charge region experiences a significant decrease in conductivity due to the reduced concentration of mobile electrons, hindering lateral charge transport. This positively impacts the reduction of lateral crosstalk between the N-type charge generation layer 41 and the P-type charge generation layer 42 in the stacked light-emitting device D and other stacked light-emitting devices D. Furthermore, the electron transport layer 31, stacked with the N-type charge generation layer 41, is a polarized electron transport layer, and the hole transport layer 33, stacked with the P-type charge generation layer 42, is a polarized hole transport layer. A polarized electric field is formed between the polarized electron transport layer and the polarized hole transport layer. Thus, a polarization electric field is generated between the electron transport layer 31 of one light-emitting unit 30 and the hole transport layer 33 of the other light-emitting unit 30 in every two adjacent light-emitting units 30. The built-in electric field is also generated in the N-type charge generation layer 41 and the P-type charge generation layer 42 due to the movement of electrons and holes. The direction of the polarization electric field is consistent with the direction of the built-in electric field, thereby increasing the width of the depletion region and reducing the concentration of mobile free charge. Thus, after the stacked light-emitting device D is applied to the display substrate 111, the lateral crosstalk in the display substrate 111 can be improved.That is, in the embodiments of this application, by setting the polarized electron transport layer and the polarized hole transport layer, the polarized electron transport layer and the polarized hole transport layer between every two adjacent light-emitting units 30 can generate a polarized electric field, and the direction of the polarized electric field is consistent with the direction of the built-in electric field, thereby effectively reducing the concentration of mobile free charges, thereby effectively reducing the lateral crosstalk between the stacked light-emitting devices D.

[0085] As shown in Figure 6, some embodiments of this application provide a display device 100, which can be any device that displays images, whether moving (e.g., video) or fixed (e.g., still images), and whether text or images. More specifically, some embodiments of this application can be implemented in or associated with a variety of electronic devices. These various electronic devices may include, for example (but are not limited to), mobile phones, wireless devices, personal digital assistants (PDAs), handheld or portable computers, Global Positioning System (GPS) receivers / navigators, cameras, MP4 video players, camcorders, game consoles, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controllers and / or displays, displays of camera views (e.g., displays of rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging and aesthetic structures (e.g., displays of images of a piece of jewelry), etc.

[0086] In some embodiments, referring to FIG6, the display device 100 includes a display module 110 and a housing 120.

[0087] In some examples, as shown in Figure 5, the display module 110 includes a display substrate 111, a flexible circuit board 112, and other electronic components.

[0088] It should be noted that the above-mentioned display substrate 111 includes various types, and can be selected and set according to actual needs.

[0089] For example, the display substrate 111 described above can be an electroluminescent display substrate, such as an organic light-emitting diode (OLED) display substrate, a quantum dot light-emitting diode (QLED) display substrate, etc. This application embodiment does not specifically limit this.

[0090] Below, taking the above-mentioned display substrate 111 as an OLED display substrate as an example, some embodiments of this application will be described by way of example.

[0091] In some embodiments, as shown in FIG5, the display substrate 111 may have a display area A within the dashed frame and a peripheral area B outside the dashed frame. The display area A is the area on the display substrate 111 where an image is displayed; the peripheral area B is the area where no image is displayed, and the peripheral area B is configured to house display driving circuitry, such as a gate driving circuit and a source driving circuit.

[0092] It should be noted that this application does not restrict the location of the peripheral area B. For example, the peripheral area B can be located on one side, both sides, or three sides of the display area A. Alternatively, the peripheral area B can surround the display area A. Figure 2 illustrates this example with the peripheral area B surrounding the display area A.

[0093] In some examples, as shown in FIG5, the display substrate 111 includes a plurality of sub-pixels P disposed on one side of the substrate 1 and located in the display area A. Exemplarily, the plurality of sub-pixels P includes at least a first color sub-pixel, a second color sub-pixel, and a third color sub-pixel. The first color, the second color, and the third color can be three primary colors (e.g., red, green, and blue).

[0094] The aforementioned sub-pixels P are arranged in multiple rows and columns. Each row includes multiple sub-pixels P arranged along a third direction, and each column includes multiple sub-pixels P arranged along a fourth direction. Multiple sub-pixels P arranged in a row along the third direction can be referred to as sub-pixels P in the same row, and multiple sub-pixels P arranged in a column along the fourth direction can be referred to as sub-pixels P in the same column.

[0095] Here, the third and fourth directions intersect each other. The angle between the third and fourth directions can be selected and set according to actual needs. For example, the angle between the third and fourth directions can be 85°, 89°, or 90°, etc.

[0096] In some embodiments, as shown in FIG5, the display substrate 111 includes a substrate 1, a circuit structure layer, a light-emitting structure layer, and an encapsulation layer 4. The circuit structure layer is disposed on the substrate 1 and includes multiple pixel driving circuits, each including multiple transistors. The light-emitting structure layer is disposed on the side of the circuit structure layer away from the substrate 1 and includes multiple stacked light-emitting devices D, each stacked light-emitting device D being correspondingly connected to one pixel driving circuit. The encapsulation layer 4 is disposed on the side of the light-emitting structure layer away from the substrate 1 and is configured to encapsulate the circuit structure layer and the light-emitting structure layer on the substrate 1.

[0097] It should be noted that the types of transistors included in the pixel driving circuit described above are various. For example, each transistor in the pixel driving circuit can be a bottom-gate thin-film transistor or a top-gate thin-film transistor.

[0098] In some examples, the pixel driving circuit includes a driving transistor among the multiple transistors that is electrically connected to the stacked light-emitting device D.

[0099] It should be noted that the driving transistor and the stacked light-emitting device D can be directly or indirectly electrically connected.

[0100] It should be noted that the first electrodes of the multiple stacked light-emitting devices D together constitute the first electrode layer, the second electrodes of the multiple stacked light-emitting devices D together constitute the second electrode layer, and the light-emitting layers of the multiple stacked light-emitting devices D together constitute the organic light-emitting layer.

[0101] It should be noted that the first electrode layer can be a block structure, for example; the second electrode layer can be a full-surface structure and cover the entire display area A; in addition, the organic light-emitting layer can be a full-surface structure or a block structure.

[0102] The first electrode mentioned above can be either an anode or a cathode; correspondingly, the second electrode mentioned above can be either a cathode or an anode.

[0103] In some examples, the first electrode 10 is the anode, and the first electrode layer is the anode layer; correspondingly, the second electrode 20 is the cathode, and the second electrode layer is the cathode layer. In this case, the stacked light-emitting device D is a top-emitting light-emitting device. At this time, since the first electrode 10 is opaque and the second electrode 20 is transparent or semi-transparent, the light emitted by the light-emitting layer 32 is emitted from the side of the stacked light-emitting device D away from the substrate 1.

[0104] It should be understood that the following embodiments are all illustrated by taking the first electrode 10 as the anode and the second electrode 20 as the cathode.

[0105] In some examples, the encapsulation layer 4 described above can be an encapsulation film or an encapsulation cover.

[0106] In some examples, as shown in Figure 4, the display substrate 111 further includes a pixel defining layer 1110, which includes multiple opening areas, and a stacked light-emitting device D is disposed in one of the opening areas. This arrangement ensures that the stacked light-emitting device D emits light normally, avoiding the problem of the stacked light-emitting device D being blocked.

[0107] It should be noted that the N-type charge generation layer 41 has electron injection capability and the P-type charge generation layer 42 has hole injection capability. Therefore, the N-type charge generation layer 41 can be reused as the electron injection layer in the light-emitting unit 30, and the P-type charge generation layer 42 can be reused as the hole injection layer in the light-emitting unit 30. That is, the light-emitting unit 30 of the above-mentioned stacked light-emitting device D does not need to be provided with an additional electron injection layer, and the light-emitting unit 30 does not need to be provided with an additional hole injection layer.

[0108] In some embodiments, the display substrate 111 may further include alternately arranged pixel areas and non-pixel areas; wherein the overlapping portion of the orthographic projection of the pixel area and the orthographic projection of the polarization layer between the N-type charge generation layer 41 and the P-type charge generation layer 42 constitutes a first polarization layer. The overlapping portion of the orthographic projection of the non-pixel area and the orthographic projection of the polarization layer between the N-type charge generation layer 41 and the P-type charge generation layer 42 constitutes a second polarization layer; the dimension of the first polarization layer in the first direction X is smaller than the dimension of the second polarization layer in the first direction X, wherein the first direction X is a direction perpendicular to the plane of the substrate 1 layer.

[0109] Since an external electric field is usually applied to the pixel area to make it emit light, and the polarization electric field is relatively weak and can be ignored compared to the external electric field, the polarization electric field has little effect on the charge transport of the stacked light-emitting device D. However, the non-pixel area has no anode, that is, no external electric field, and the polarization electric field has a greater effect on the charge transport of the stacked light-emitting device D. Therefore, the second polarization layer formed by the overlap of the orthographic projection of the non-pixel area and the orthographic projection of the polarization layer between the N-type charge generation layer 41 and the P-type charge generation layer 42 can effectively increase the width of the depletion region, thereby effectively reducing the lateral crosstalk of the charge in the stacked light-emitting device D.

[0110] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0111] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A multilayer light-emitting device, comprising: First electrode; Second electrode; At least two light-emitting units are stacked between the first electrode and the second electrode, and each of the at least two light-emitting units includes a stacked electron transport layer, a light-emitting layer and a hole transport layer. as well as At least one stacked connecting layer is disposed between the electron transport layer of one of two adjacent light-emitting units and the hole transport layer of the other light-emitting unit; Each of the at least one stacked interconnecting layers includes an N-type charge generation layer and a P-type charge generation layer stacked together. The N-type charge generation layer is stacked on the electron transport layer of one of the two adjacent light-emitting units, and the hole transport layer of the other of the two adjacent light-emitting units is stacked on the P-type charge generation layer. The electron transport layer stacked with the N-type charge generation layer is a polarized electron transport layer, and the hole transport layer stacked with the P-type charge generation layer is a polarized hole transport layer. A polarized electric field is formed between the polarized electron transport layer and the polarized hole transport layer.

2. The stacked light-emitting device according to claim 1, wherein, Under the polarization effect of the polarized electron transport and the polarized hole transport layer, a polarized layer is generated between the N-type charge generation layer and the P-type charge generation layer, wherein the size of the polarized layer in the first direction is greater than or equal to the first size; Wherein, the first dimension is the maximum dimension in which the charge in the N-type charge generation layer and the P-type charge generation layer can move along the second direction, the first direction is the direction perpendicular to the plane where the light-emitting layer is located, and the first direction and the second direction intersect.

3. The stacked light-emitting device according to claim 1, wherein, The molecular dipole moment of the polarized electron transport layer is greater than 2 Debye, and the molecular dipole moment of the polarized hole transport layer is greater than 2 Debye.

4. The stacked light-emitting device according to claim 1, wherein, The polarized electron transport layer has a dimension between 5 nanometers and 30 nanometers in a first direction, wherein the first direction is perpendicular to the plane of the light-emitting layer; and / or The size of the polarized hole transport layer is between 10 nanometers and 50 nanometers in a first direction, wherein the first direction is perpendicular to the plane of the light-emitting layer.

5. The stacked light-emitting device according to claim 1, wherein, The N-type charge generation layer is a host-guest doped structure, comprising a first host material and a first guest material, wherein the proportion of the first guest material in the N-type charge generation layer is between 0.2% and 3%.

6. The stacked light-emitting device according to claim 5, wherein, The size of the N-type charge generating layer is between 10 nanometers and 30 nanometers in a first direction, wherein the first direction is perpendicular to the plane in which the light-emitting layer is located.

7. The stacked light-emitting device according to claim 5, wherein, The first host material is an organic material with electron transport properties, and the first guest material is an active metal.

8. The stacked light-emitting device according to claim 1, wherein, The P-type charge generation layer is a host-guest doped structure, comprising a second host material and a second guest material, wherein the proportion of the second guest material in the P-type charge generation layer is between 1% and 10%.

9. The stacked light-emitting device according to claim 8, wherein, The size of the P-type charge generating layer is between 5 nanometers and 20 nanometers in a first direction, wherein the first direction is perpendicular to the plane in which the light-emitting layer is located.

10. The stacked light-emitting device according to claim 8, wherein, The second host material is an organic material with hole transport properties, and the second guest material is a metal oxide.

11. The stacked light-emitting device according to any one of claims 1 to 10, wherein, The first electrode is the anode and the second electrode is the cathode; or, the first electrode is the cathode and the second electrode is the anode.

12. The stacked light-emitting device according to any one of claims 1 to 10, wherein, The first electrode is made of metal, and the second electrode is made of metal or a metal compound.

13. The stacked light-emitting device according to any one of claims 1 to 10, wherein, The polarized electron transport layer and the polarized hole transport layer are polarized film layers, and the polarized film layer is a film layer with added polarizing material.

14. The stacked light-emitting device according to claim 13, wherein, The intensity of the polarization electric field is proportional to the thickness of the film.

15. A display substrate, comprising: Substrate; The stacked light-emitting device as described in any one of claims 1 to 14; Multiple pixel driving circuits are used to drive at least one of the stacked light-emitting devices to emit light; as well as An encapsulation layer is used to encapsulate the plurality of stacked light-emitting devices and the plurality of pixel driving circuits.

16. The display substrate according to claim 15, wherein, The display substrate includes alternately arranged pixel areas and non-pixel areas; The overlapping portion of the orthographic projection of the pixel region and the orthographic projection of the polarization layer between the N-type charge generation layer and the P-type charge generation layer is the first polarization layer. The overlapping portion of the orthographic projection of the non-pixel region and the orthographic projection of the polarization layer between the N-type charge generation layer and the P-type charge generation layer constitutes the second polarization layer; and The size of the first polarization layer in the first direction is smaller than the size of the second polarization layer in the first direction, wherein the first direction is a direction perpendicular to the plane of the substrate layer.

17. The display substrate according to claim 15, wherein, The display substrate further includes a pixel defining layer, wherein the pixel defining layer includes a plurality of opening regions, and one of the stacked light-emitting devices is disposed in one of the plurality of opening regions.

18. The display substrate according to claim 15, wherein, The encapsulation layer is an encapsulation film or an encapsulation cover.

19. A display device comprising a display substrate as claimed in any one of claims 15 to 18.

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