Stacked light emitting device, display substrate, and display apparatus

Abstract

The application discloses a laminated light-emitting device, a display substrate and a display device, and belongs to the technical field of display. The laminated light-emitting device comprises a first electrode, a second electrode, at least two light-emitting units, at least two light-emitting units are arranged in layers between the first electrode and the second electrode, the light-emitting unit comprises an electron transport layer, a light-emitting layer and a hole transport layer arranged in layers, at least one laminated connecting layer, the laminated connecting layer is arranged between the electron transport layer included in one of the two adjacent light-emitting units and the hole transport layer included in the other light-emitting unit, the laminated connecting layer comprises an N-type charge generation layer and a P-type charge generation layer arranged in layers, wherein the electron transport layer arranged in layers with the N-type charge generation layer is a polarized electron transport layer, the hole transport layer arranged in layers with the P-type charge generation layer is a polarized hole transport layer, and a polarization electric field is formed between the polarized electron transport layer and the polarized hole transport layer.

Description

Technical Field

[0001] The present application belongs to the field of display technology, and specifically relates to a stacked light-emitting device, a display substrate, and a display apparatus. Background Art

[0002] With the development of display technology, the application of display products such as mobile phones and computers is becoming increasingly widespread. Typically, a display device is provided with a display substrate, which is used for display. The display substrate is provided with a stacked light-emitting device. However, in related art, the stacked light-emitting devices in the display substrate are prone to the problem of lateral charge crosstalk. Summary of the Invention

[0003] The purpose of the embodiments of the present application is to provide a stacked light-emitting device, a display substrate, and a display apparatus, which can alleviate the problem that the stacked light-emitting device in the display substrate is prone to charge lateral crosstalk.

[0004] In a first aspect, an embodiment of the present application provides a stacked light-emitting device, comprising:

[0005] a first electrode;

[0006] a second electrode;

[0007] At least two light-emitting units, wherein the at least two light-emitting units are stacked between the first electrode and the second electrode, and the light-emitting units include an electron transport layer, a light-emitting layer, and a hole transport layer stacked;

[0008] at least one stacked connecting layer, the stacked connecting layer being disposed between the electron transport layer included in one of the two adjacent light-emitting units and the hole transport layer included in the other light-emitting unit;

[0009] The stacked connection layer includes an N-type charge generation layer and a P-type charge generation layer stacked, the N-type charge generation layer is stacked on the electron transport layer included in one of the two adjacent light-emitting units, and the hole transport layer included in the other of the two adjacent light-emitting units is stacked on the P-type charge generation layer;

[0010] Among them, 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, and a polarized electric field is formed between the polarized electron transport layer and the polarized hole transport layer.

[0011] Optionally, under the polarization action of the polarized electron transport layer and the polarized hole transport layer, a polarization layer is generated between the N-type charge generation layer and the P-type charge generation layer, wherein a size of the polarization layer in the first direction is greater than or equal to the first size;

[0012] The first dimension is the maximum dimension in which the charges in the N-type charge generation layer and the P-type charge generation layer can move along the second direction, the first direction is a direction perpendicular to the plane where the light-emitting layer is located, and the first direction and the second direction intersect.

[0013] Optionally, the molecular dipole moment of the polarizable electron transport layer is greater than 2 Debye, and the molecular dipole moment of the polarizable hole transport layer is greater than 2 Debye.

[0014] Optionally, a dimension of the polarized electron transport layer in a first direction is between 5 nanometers and 30 nanometers, wherein the first direction is a direction perpendicular to the plane where the light-emitting layer is located.

[0015] And / or, a dimension of the polarized hole transport layer in a first direction is between 10 nanometers and 50 nanometers, wherein the first direction is a direction perpendicular to the plane where the light-emitting layer is located.

[0016] Optionally, the N-type charge generation layer is a host-guest doped structure, including a first host material and a first guest material, and the proportion of the first guest material in the N-type charge generation layer is between 0.2% and 3%.

[0017] Optionally, a dimension of the N-type charge generation layer in a first direction is between 10 nanometers and 30 nanometers, wherein the first direction is a direction perpendicular to the plane where the light-emitting layer is located.

[0018] Optionally, the P-type charge generation layer is a host-guest doped structure, including a second host material and a second guest material, and the proportion of the second guest material in the P-type charge generation layer is between 1% and 10%.

[0019] Optionally, a dimension of the P-type charge generation layer in a first direction is between 5 nanometers and 20 nanometers, wherein the first direction is a direction perpendicular to the plane where the light-emitting layer is located.

[0020] In a second aspect, an embodiment of the present application provides a display substrate, comprising:

[0021] substrate;

[0022] The stacked light-emitting device as described in any one of the first aspects above;

[0023] a plurality of pixel driving circuits configured to drive the at least one stacked light-emitting device to emit light;

[0024] a packaging layer configured to package the plurality of stacked light-emitting devices and the plurality of pixel driving circuits.

[0025] Optionally, the display substrate comprises pixel regions and non-pixel regions arranged alternately.

[0026] The overlap between 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 a first polarization layer.

[0027] The overlap between 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 is a second polarization layer.

[0028] The size of the first polarization layer in a 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 on which the substrate layer is located.

[0029] In a third aspect, an embodiment of the present application provides a display device, which comprises the display substrate of any one of the second aspect.

[0030] In the embodiment of the present application, since at least two light-emitting units are stacked between the first electrode and the second electrode, the stacking connection layer is arranged between the electron transport layer included in one light-emitting unit of every two adjacent light-emitting units and the hole transport layer included in the other light-emitting unit. Therefore, every two adjacent light-emitting units in the at least two light-emitting units between the first electrode and the second electrode are connected by a stacking connection layer, so that at least two light-emitting units can emit light at the same time, thereby improving the luminous efficiency of the stacked light-emitting device D. Since the light-emitting unit includes a stacked electron transport layer, a light-emitting layer and a hole transport layer, the stacked connecting layer includes a stacked N-type charge generation layer and a P-type charge generation layer, the N-type charge generation layer is stacked on the electron transport layer included in one of the two adjacent light-emitting units, and the hole transport layer included in the other of the two adjacent light-emitting units is stacked on the P-type charge generation layer. Therefore, the free electrons in the N-type charge generation layer are majority carriers, and the holes are almost zero, called minority carriers, while the holes in the P-type charge generation layer are majority carriers and the free electrons are minority carriers. A concentration difference between electrons and holes appears at their junction, and some electrons diffuse from the N-type charge generation layer to the P-type charge generation layer, and some holes diffuse from the P-type charge generation layer to the N-type charge generation layer. As a result of their diffusion, the P-type charge generation layer loses holes on one side, leaving negatively charged impurity ions, and the N-type charge generation layer loses electrons on one side, leaving positively charged impurity ions, forming a space charge region, that is, a depletion region. , and the conductivity of the space charge region decreases significantly due to the decrease in the concentration of movable electrons, which prevents the lateral transmission of charges. This plays a positive role in improving the lateral crosstalk between the N-type charge generation layer and the P-type charge generation layer in the stacked light-emitting device D and other stacked light-emitting devices D. In addition, 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, so that a polarized electric field is generated between the electron transport layer of one light-emitting unit and the hole transport layer of the other light-emitting unit in every two adjacent light-emitting units. The built-in electric field is also generated in the N-type charge generation layer and the P-type charge generation layer due to the movement of electrons and holes. The direction of the polarized 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 movable free charges. Therefore, after the stacked light-emitting device D is applied to the display substrate, the lateral crosstalk in the display substrate can be improved. That is, in the embodiment of the present 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 each two adjacent light-emitting units 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 movable free charges, thereby effectively reducing the lateral crosstalk between the stacked light-emitting devices D. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 A schematic diagram showing the cross-sectional structure of a stacked light-emitting device in the related art;

[0033] Figure 2 A schematic diagram showing a stacked light-emitting device provided in an embodiment of the present application;

[0034] Figure 3 A schematic diagram showing the cross-sectional structure of a stacked light-emitting device provided in an embodiment of the present application;

[0035] Figure 4 A schematic diagram showing a display substrate provided in an embodiment of the present application;

[0036] Figure 5 One of the schematic diagrams showing a display device provided in an embodiment of the present application;

[0037] Figure 6 A second schematic diagram showing a display device provided in an embodiment of the present application.

[0038] Reference numerals:

[0039] D: stacked light-emitting device; 10: first electrode; 20: second electrode; 30: light-emitting unit; 31: electron transport layer; 32: light-emitting layer; 33: hole transport layer; 40: stacked connection layer; 41: N-type charge generation layer; 42: P-type charge generation layer; 111: display substrate; 112: flexible circuit board; 1: substrate; 4: encapsulation layer; 1110: pixel defining layer; 100: display device; 110: display module; X: first direction; Y: second direction; M: third direction; N: fourth direction. DETAILED DESCRIPTION

[0040] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present application. Obviously, the embodiments described are only some embodiments of the present application, not all embodiments. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0041] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and its other forms, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open and inclusive, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" are intended to indicate that the specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present application. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0042] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, unless otherwise specified, "plurality" means two or more.

[0043] When describing some embodiments, the term "electrically connected" and its derivatives may be used. For example, when describing some embodiments, the term "electrically connected" may be used to indicate that two or more components are in direct physical or electrical contact with each other.

[0044] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0045] The use of "configured to" herein is intended to be open and inclusive language that does not exclude devices adapted or configured to perform additional tasks or steps.

[0046] As used herein, “approximately” includes the stated value and an average value that is within an acceptable range of deviation from the particular value, where the acceptable range of deviation is determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0047] Exemplary embodiments are described herein with reference to cross-sectional and / or plan view illustrations that are schematic and are not intended to be drawn to scale. Specifically, the dimensions of the various features in the drawings can be exaggerated relative to other dimensions to help improve understanding of embodiments of the present teachings. Similarly, like reference numerals can be used to denote like structures throughout the specification and the figures. As used herein, the term "or" as used herein, without further qualification, can be used to describe either a selective exclusive "or" where the first condition is exclusive of the second, or a non-exclusive "or" where at least one of the conditions is satisfied but both can be satisfied. Further, unless otherwise clear from the context, the use herein of the term "just one of' will be understood as meaning 'exactly one of'.

[0048] Before the stacked light-emitting device provided by the embodiments of the present application is explained, the application scenario of the stacked light-emitting device provided by the embodiments of the present application is described in detail as follows: as shown in the figure, in the related art, the stacked light-emitting device includes at least two light-emitting units, and two adjacent light-emitting units are connected through a stacked connection layer. The stacked connection layer 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, so that the stacked light-emitting device is prone to lateral movement of charges, and charge crosstalk is formed. Figure 1

[0049] As shown in the figure, in the embodiments of the present application, the stacked light-emitting device D includes: a first electrode 10; a second electrode 20; at least two light-emitting units 30, the at least two light-emitting units 30 being stacked and arranged between the first electrode 10 and the second electrode 20, and each light-emitting unit 30 including an electron transport layer 31, a light-emitting layer 32 and a hole transport layer 33 which are stacked and arranged; and at least one stacked connection layer 40, the stacked connection layer 40 being arranged between the electron transport layer 31 included in one of the two adjacent light-emitting units 30 and the hole transport layer 33 included in the other light-emitting unit 30, and the stacked connection layer 40 including an N-type charge generation layer 41 and a P-type charge generation layer 42 which are stacked and arranged. The N-type charge generation layer 41 is stacked and arranged on the electron transport layer 31 included in one of the two adjacent light-emitting units 30, and the hole transport layer 33 included in the other light-emitting unit 30 is stacked and arranged on the P-type charge generation layer 42. Wherein, the electron transport layer 31 stacked and arranged with the N-type charge generation layer 41 is a polarized electron transport layer, and the hole transport layer 33 stacked and arranged with the P-type charge generation layer 42 is a polarized hole transport layer, and a polarization electric field is formed between the polarized electron transport layer and the polarized hole transport layer. Figure 2

[0050] ​​In the embodiment of the present application, since at least two light-emitting units 30 are stacked between the first electrode 10 and the second electrode 20, the stacking connection layer 40 is arranged between the electron transport layer 31 included in one light-emitting unit 30 of every two adjacent light-emitting units 30 and the hole transport layer 33 included in the other light-emitting unit 30. Therefore, every two adjacent light-emitting units 30 in the at least two light-emitting units 30 between the first electrode 10 and the second electrode 20 are connected by a stacking connection layer 40, so that at least two light-emitting units 30 can emit light at the same time, thereby improving the luminous efficiency of the stacked light-emitting device D. Since the light-emitting unit 30 includes an electron transport layer 31, a light-emitting layer 32 and a hole transport layer 33 which are stacked, the stacked connecting layer 40 includes an N-type charge generation layer 41 and a P-type charge generation layer 42 which are stacked, the N-type charge generation layer 41 is stacked on the electron transport layer 31 included in one of the two adjacent light-emitting units 30, and the hole transport layer 33 included in the other of the two adjacent light-emitting units 30 is stacked on the P-type charge generation layer 42, therefore, the free electrons in the N-type charge generation layer 41 are majority carriers and the holes are few. The concentration difference between electrons and holes appears at their junction, and 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. As a result of their diffusion, the P-type charge generation layer 42 loses holes and leaves negatively charged impurity ions, while the N-type charge generation layer 41 loses electrons and leaves positively charged impurity ions, forming a space charge region. The space charge region forms a depletion region, and the conductivity of the space charge region decreases significantly due to the decrease in the concentration of movable electrons, which prevents the lateral transmission of charges. This plays a positive role in improving the 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. 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, thereby A polarization electric field will be 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, and a 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 movable free charges. Therefore, 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 embodiment of the present 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 movable free charges, thereby effectively reducing the lateral crosstalk between the stacked light-emitting devices D.

[0051] It should be noted that the first electrode 10 can be an anode or a cathode; correspondingly, the second electrode 20 can be a cathode or an anode.

[0052] In some examples, the material of the first electrode 10 is metal. For example, the material of the first electrode 10 can 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).

[0053] In some examples, the material of the second electrode 20 is a metal material or a metal compound. For example, when the material of the second electrode 20 is a metal, 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 a metal compound inorganic material, the material of the second electrode 20 can be lithium oxide (Li2O), calcium oxide (CaO), lithium fluoride (LiF), or magnesium fluoride (MgF2).

[0054] It should also be noted that in the embodiment of the present application, the polarized electron transport layer and the polarized hole transport layer are polarized film layers, and the polarized film layers are film layers with added polarized materials. Since the atomic directions in the film layers with added polarized materials are spontaneously and disorderly arranged, when a voltage is applied to the polarized film layers, the atoms in the polarized film layers are arranged according to the electric field direction of the applied voltage, that is, the polarization direction of the polarized film layers is the direction of the electric field.

[0055] In addition, in some embodiments, under the polarization action of the polarized electron transport layer and the polarized hole transport layer, a polarization layer is generated between the N-type charge generation layer 41 and the P-type charge generation layer 42, wherein the size of the polarization layer in the first direction X is greater than or equal to the first size; wherein the first size is the maximum size that the charges 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, and the first direction X and the second direction Y intersect.

[0056] Since the size of the polarization layer in the first direction X is greater than or equal to the first size, it can ensure that the charges in the N-type charge generation layer 41 and the P-type charge generation layer 42 move in the depletion region as much as possible when moving, 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.

[0057] 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 92°. It is sufficient that 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 this embodiment of the present application.

[0058] Additionally, in some embodiments, the molecular dipole moment of the polarizable electron transport layer is greater than 2 Debye, and the molecular dipole moment of the polarizable hole transport layer is greater than 2 Debye.

[0059] This arrangement 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 light-emitting unit 30 in each pair of adjacent light-emitting units 30, the width of the depletion region is sufficiently large. This effectively increases the width of the depletion region, thereby effectively avoiding the problem of potential lateral crosstalk 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 and the molecular dipole moment of the polarized hole transport layer to be greater than 2 debye, the probability of potential lateral crosstalk between the stacked light-emitting units 30 can be effectively reduced.

[0060] It should be noted that the molecular dipole moment of the polarizable electron transport layer can be any value greater than 2 debye, for example, the molecular dipole moment of the polarizable electron transport layer is 3 debye, as another example, the molecular dipole moment of the polarizable electron transport layer is 2.5 debye, as another example, the molecular dipole moment of the polarizable electron transport layer is 2.8 debye. The molecular dipole moment of the polarizable hole transport layer can be any value greater than 2 debye, for example, the molecular dipole moment of the polarizable hole transport layer is 3 debye, as another example, the molecular dipole moment of the polarizable hole transport layer is 2.5 debye, as another example, the molecular dipole moment of the polarizable hole transport layer is 3.5 debye.

[0061] In addition, in some embodiments, the dimension 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.

[0062] Since the intensity of the polarization electric field is proportional to the thickness of the film layer, by setting the size of the polarized electron transport layer in the first direction X between 5 nanometers and 30 nanometers, the thickness of the polarized electron transport layer can be made larger, which is beneficial for the polarization electric field intensity generated by the polarized electron transport layer after the electron transport layer 31 forms the polarized electron transport layer, and thus is beneficial for improving the lateral crosstalk between the stacked light-emitting devices D.

[0063] 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. For another example, the size of the polarized electron transport layer in the first direction X can be 10 nanometers. For another example, the size of the polarized electron transport layer in the first direction X can be 20 nanometers. For another example, the size of the polarized electron transport layer in the first direction X can be 25 nanometers. For another example, the size of the polarized electron transport layer in the first direction X can be 30 nanometers.

[0064] In addition, in some embodiments, the dimension 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.

[0065] Since the intensity of the polarization electric field is proportional to the thickness of the film layer, by setting the size of the polarized hole transport layer in the first direction X between 10 nanometers and 50 nanometers, the thickness of the polarized hole transport layer can be made larger, which is beneficial for the hole transport layer 33 to form the polarized hole transport layer. After that, the polarized electric field intensity generated by the polarized hole transport layer is larger, which is beneficial to improving the lateral crosstalk between the stacked light-emitting devices D.

[0066] 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. For another example, the size of the polarized hole transport layer in the first direction X can be 15 nanometers. For another example, the size of the polarized hole transport layer in the first direction X can be 20 nanometers. For another example, the size of the polarized hole transport layer in the first direction X can be 25 nanometers. For another example, the size of the polarized hole transport layer in the first direction X can be 30 nanometers. For another example, the size of the polarized hole transport layer in the first direction X can be 40 nanometers. For another example, the size of the polarized hole transport layer in the first direction X can be 50 nanometers.

[0067] 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, and the proportion of the first guest material in the N-type charge generation layer 41 is between 0.2% and 3%.

[0068] Through the arrangement, the N-type charge generation layer 41 can effectively form the stack connection layer 40, which is conducive to the subsequent stack connection layer 40 connecting the two adjacent light emitting units 30.

[0069] The first host material can be an organic material with electron transport performance, and the first guest material can be a reactive metal such as magnesium or ytterbium.

[0070] 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 is 0.2%, for example, the proportion of the first guest material in the N-type charge generation layer 41 can be 1%, for example, the proportion of the first guest material in the N-type charge generation layer 41 can be 2%, for example, the proportion of the first guest material in the N-type charge generation layer 41 can be 2.5%, for example, the proportion of the first guest material in the N-type charge generation layer 41 can be 3%.

[0071] 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.

[0072] Through the arrangement, the thickness of the N-type charge generation layer 41 is moderate, which can facilitate the formation of the stack connection layer 40, thereby ensuring that every two adjacent light emitting units 30 in the stack light emitting unit 30 can be effectively connected.

[0073] 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, for example, the size of the N-type charge generation layer 41 in the first direction X is 15 nanometers, for example, the size of the N-type charge generation layer 41 in the first direction X is 20 nanometers, for example, the size of the N-type charge generation layer 41 in the first direction X is 25 nanometers, for example, the size of the N-type charge generation layer 41 in the first direction X is 30 nanometers.

[0074] In addition, in some embodiments, the P-type charge generation layer 42 is a host-guest doped structure, which includes a second host material and a second guest material, and the proportion of the second guest material in the P-type charge generation layer 42 is between 1% and 10%.

[0075] Through the arrangement, the P-type charge generation layer 42 can effectively form the stack connection layer 40, which is conducive to the subsequent stack connection layer 40 connecting the two adjacent light emitting units 30.

[0076] The second host material may be an organic material having hole transport properties, and the second guest material may be a metal oxide such as molybdenum trioxide, tungsten trioxide, or F4-TCNQ.

[0077] 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 is 1%. For another example, the proportion of the second guest material in the P-type charge generation layer 42 can be 3%. For another example, the proportion of the second guest material in the P-type charge generation layer 42 can be 5%. For another example, the proportion of the second guest material in the P-type charge generation layer 42 can be 8%. For another example, the proportion of the second guest material in the P-type charge generation layer 42 can be 10%.

[0078] In addition, in some embodiments, the dimension of the P-type charge generation 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.

[0079] Through such a configuration, the thickness of the P-type charge generation layer 42 can be made moderate, which can facilitate the formation of the stacked connection layer 40 and further ensure that every two adjacent light-emitting units 30 in the stacked light-emitting unit 30 can be effectively connected.

[0080] 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. For another example, the size of the P-type charge generation layer 42 in the first direction X is 10 nanometers. For another example, the size of the P-type charge generation layer 42 in the first direction X is 15 nanometers. For another example, the size of the P-type charge generation layer 42 in the first direction X is 20 nanometers.

[0081] In the embodiment of the present application, since the at least two light-emitting units 30 are stacked between the first electrode 10 and the second electrode 20, and the stack connecting layer 40 is arranged between the electron transport layer 31 included in one of the two adjacent light-emitting units 30 and the hole transport layer 33 included in the other light-emitting unit 30, each two adjacent light-emitting units 30 among the at least two light-emitting units 30 between the first electrode 10 and the second electrode 20 is connected by one stack connecting layer 40, so that the at least two light-emitting units 30 can emit light at the same time, thereby improving the light-emitting efficiency of the stack light-emitting device D. Since the light-emitting unit 30 includes the electron transport layer 31, the light-emitting layer 32 and the hole transport layer 33 stacked, the stack connecting layer 40 includes the N-type charge generation layer 41 and the P-type charge generation layer 42 stacked, the N-type charge generation layer 41 is stacked on the electron transport layer 31 included in one of the two adjacent light-emitting units 30, and the hole transport layer 33 included in the other light-emitting unit 30 is stacked on the P-type charge generation layer 42, therefore, the free electrons in the N-type charge generation layer 41 are majority carriers, and the holes are almost zero, which are minority carriers, while the holes in the P-type charge generation layer 42 are majority carriers, and the free electrons are minority carriers, and a concentration difference of the electrons and the holes occurs at the interface between them, and some electrons diffuse from the N-type charge generation layer 41 to the P-type charge generation layer 42, and some holes also diffuse from the P-type charge generation layer 42 to the N-type charge generation layer 41, and the diffusion results in that the P-type charge generation layer 42 loses holes on one side, leaving negatively charged impurity ions, and the N-type charge generation layer 41 loses electrons on one side, leaving positively charged impurity ions, forming a space charge region, i.e. a depletion region. The space charge region has a greatly reduced conductivity due to the reduced concentration of mobile electrons, which prevents lateral charge transport. It plays a positive role in improving the lateral crosstalk between the N-type charge generation layer 41 and the P-type charge generation layer 42 in the stack light-emitting device D and other stack light-emitting devices D. In addition, 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 polarization electric field is formed between the polarized electron transport layer and the polarized hole transport layer, so that a polarization electric field is generated 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, and a built-in electric field is generated between 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, so that the width of the depletion region increases, and the concentration of mobile free charges decreases, thereby improving the lateral crosstalk in the display substrate 111 after the stack light-emitting device D is applied to the display substrate 111.That is, in the embodiment of the present 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 movable free charges, thereby effectively reducing the lateral crosstalk between the stacked light-emitting devices D.

[0082] like Figure 6 As shown, some embodiments of the present application provide a display device 100, which can be any device that displays images, whether in motion (e.g., video) or fixed (e.g., still images), and whether text or images. More specifically, it is expected that some embodiments of the present application can be implemented in or associated with a variety of electronic devices. The various electronic devices can be, for example (but 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, video cameras, game consoles, watches, clocks, calculators, television monitors, flat-panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigation systems, cockpit controls 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.

[0083] In some embodiments, please refer to Figure 6 The display device 100 includes a display module 110 and a housing 120 .

[0084] In some examples, such as Figure 5 As shown, the display module 110 includes a display substrate 111 , a flexible circuit board 112 and other electronic components.

[0085] It should be noted that the display substrate 111 may be of various types and may be selected according to actual needs.

[0086] Exemplarily, the above-mentioned display substrate 111 can be an electroluminescent display substrate, for example, an organic light emitting diode (OLED) display substrate, a quantum dot light emitting diode (QLED) display substrate, etc., and the embodiments of the present application do not make specific limitations on this.

[0087] Hereinafter, some embodiments of the present application will be exemplarily described taking the above-mentioned display substrate 111 as an OLED display substrate as an example.

[0088] In some embodiments, as shown in Figure 5 The display substrate 111 can have a display area A located in the dashed box and a peripheral area B located outside the dashed box. The display area A is the area of the display substrate 111 for displaying images, and the peripheral area B is the area for not displaying images, which is configured to set display driving circuits, such as gate driving circuits and source driving circuits.

[0089] It should be noted that the present application does not limit the setting position of the peripheral area B. For example, the peripheral area B can be located on one side, two sides or three sides of the display area A. For another example, the peripheral area B can also surround the display area A. Figure 2 The peripheral area B surrounding the display area A will be exemplarily described.

[0090] In some examples, as shown in Figure 5 The display substrate 111 includes a plurality of sub-pixels P arranged 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 (such as red, green and blue).

[0091] The plurality of sub-pixels P are arranged in a plurality of rows and a plurality of columns, each row includes a plurality of sub-pixels P arranged along a third direction, and each column includes a plurality of sub-pixels P arranged along a fourth direction. The plurality of sub-pixels P arranged in a row along the third direction can be referred to as the same row of sub-pixels P, and the plurality of sub-pixels P arranged in a column along the fourth direction can be referred to as the same column of sub-pixels P.

[0092] Here, the third direction and the fourth direction intersect each other. The included angle between the third direction and the fourth direction can be selected according to actual needs. Exemplarily, the included angle between the third direction and the fourth direction can be 85°, 89° or 90°, etc.

[0093] In some embodiments, as shown in Figure 5 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 arranged on the substrate 1, and includes a plurality of pixel driving circuits including a plurality of transistors. The light-emitting structure layer is arranged on the side of the circuit structure layer away from the substrate 1, and includes a plurality of stacked light-emitting devices D. One stacked light-emitting device D is connected to one pixel driving circuit. The encapsulation layer 4 is arranged 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.

[0094] It should be noted that the transistors included in the pixel driving circuit may be of various types. For example, each transistor included in the pixel driving circuit may be a bottom-gate thin film transistor or a top-gate thin film transistor.

[0095] In some examples, the pixel driving circuit includes a plurality of transistors, including a driving transistor, which is electrically connected to the stacked light-emitting device D.

[0096] It should be noted that the driving transistor and the stacked light-emitting device D may be directly or indirectly electrically connected.

[0097] It should be noted that the first electrodes of the above-mentioned 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.

[0098] It should be noted that the first electrode layer may be a block structure, for example; the second electrode layer may be a full-surface structure, and cover the entire display area A; in addition, the organic light-emitting layer may be a full-surface structure, or a block structure, for example.

[0099] The first electrode may be an anode or a cathode; correspondingly, the second electrode may be a cathode or an anode.

[0100] In some examples, the first electrode 10 is an anode, and the first electrode layer is an anode layer; correspondingly, the second electrode 20 is a cathode, and the second electrode layer is a cathode layer. In this case, the stacked light-emitting device D is an upright top-emitting light-emitting device. In this case, because the first electrode 10 is opaque and the second electrode 20 is transparent or translucent, 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.

[0101] It should be understood that the following embodiments are all described by taking the first electrode 10 as the anode and the second electrode 20 as the cathode as an example.

[0102] In some examples, the encapsulation layer 4 may be an encapsulation film or an encapsulation cover.

[0103] In some examples, such as Figure 4 As shown, the display substrate 111 further includes a pixel defining layer 1110. The pixel defining layer 1110 includes multiple openings, and a stacked light-emitting device D is disposed in one of the openings. 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.

[0104] 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. In other words, the light-emitting unit 30 of the stacked light-emitting device D does not need to be additionally provided with an electron injection layer, and the light-emitting unit 30 does not need to be additionally provided with a hole injection layer.

[0105] In addition, in some embodiments, the display substrate 111 may further include pixel regions and non-pixel regions that are alternately arranged; wherein 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 41 and the P-type charge generation layer 42 is a first polarization layer. wherein 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 41 and the P-type charge generation layer 42 is a second polarization layer; the dimension of the first polarization layer in a 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.

[0106] Since an external electric field is usually set in the pixel area, the pixel area emits light, and the polarization electric field is relatively weak and can be ignored relative to the external electric field. Therefore, the polarization electric field has little effect on the charge transfer of the stacked light-emitting device D. The non-pixel area has no anode, that is, there is no external electric field, and the polarization electric field has a greater effect on the charge transfer of the stacked light-emitting device D. Therefore, the second polarization layer formed by the overlapping part of the positive projection of the non-pixel area and the positive 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 increasing the width of the depletion region, and thereby effectively reducing the lateral crosstalk of the charge of the stacked light-emitting device D.

[0107] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0108] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A stacked light emitting device, characterized in that: The stacked light emitting device comprises: a first electrode; a second electrode; At least two light-emitting units, wherein the at least two light-emitting units are stacked between the first electrode and the second electrode, and the light-emitting units include an electron transport layer, a light-emitting layer, and a hole transport layer stacked; at least one stacked connecting layer, the stacked connecting layer being disposed between the electron transport layer included in one of the two adjacent light-emitting units and the hole transport layer included in the other light-emitting unit; The stacked connection layer includes an N-type charge generation layer and a P-type charge generation layer stacked, the N-type charge generation layer is stacked on the electron transport layer included in one of the two adjacent light-emitting units, and the hole transport layer included in the other of the two adjacent light-emitting units is stacked on the P-type charge generation layer; Among them, 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, and 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 action of the polarized electron transport layer 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; The first dimension is the maximum dimension in which the charges in the N-type charge generation layer and the P-type charge generation layer can move along the second direction, the first direction is a 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 polarizable electron transport layer is greater than 2 Debye, and the molecular dipole moment of the polarizable hole transport layer is greater than 2 Debye.

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

5. The stacked light emitting device according to claim 1, wherein: The N-type charge generation layer is a host-guest doped structure, including a first host material and a first guest material. 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, characterized in that: The size of the N-type charge generation layer in a first direction is between 10 nanometers and 30 nanometers, wherein the first direction is a direction perpendicular to the plane where the light-emitting layer is located.

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

8. The stacked light emitting device according to claim 7, wherein: The size of the P-type charge generation layer in a first direction is between 5 nanometers and 20 nanometers, wherein the first direction is a direction perpendicular to the plane where the light-emitting layer is located.

9. A display substrate, characterized in that: The display substrate comprises: substrate; The stacked light emitting device according to any one of claims 1 to 8; A plurality of pixel driving circuits, configured to drive at least one of the stacked light-emitting devices to emit light; The encapsulation layer is used to encapsulate the plurality of stacked light-emitting devices and the plurality of pixel driving circuits.

10. The display substrate according to claim 9, wherein: The display substrate includes pixel areas and non-pixel areas arranged alternately; 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 and the P-type charge generation layer is the first polarization layer; Wherein, 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 and the P-type charge generation layer is the second polarization layer; A size of the first polarization layer in a first direction is smaller than a size of the second polarization layer in the first direction, wherein the first direction is a direction perpendicular to a plane where the substrate layer is located. 11 . A display device comprising the display substrate according to claim 9 .

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