Light emitting element and display device including the same and method of manufacturing the display device

Abstract

A light emitting element, a display device, and a method of manufacturing a display device according to an embodiment are provided. The light emitting element includes a main body including a semiconductor layer and an active layer, and a ligand including a head portion, an end portion, and a chain portion, the head portion being bonded to a surface of the main body, the end portion being spaced apart from the main body and having a positive charge or a negative charge, the chain portion connecting the head portion and the end portion.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2019-0094379, filed on August 2, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a light-emitting element having improved manufacturing yield and reliability, a display device including the light-emitting element, and a method for manufacturing the display device. Background Technology

[0004] Light-emitting diodes (LEDs), which utilize the properties of compound semiconductors to convert electrical signals into light such as infrared or visible light, are used in household appliances, remote controls, electronic display panels, and various automation devices. As demonstrated by their applications in a wide range of electronic devices, from small handheld electronic devices to large display devices, LEDs are being used even more extensively.

[0005] As part of research utilizing light-emitting diodes (LEDs), a technique for manufacturing ultra-small LEDs at the micrometer or nanometer scale is being developed. For example, rod-shaped LEDs can be manufactured in small sizes to fit into pixels in self-emissive display panels. Summary of the Invention

[0006] This disclosure provides a light-emitting element that has remodeled surface properties by applying charged ligands to the surface of the light-emitting element body.

[0007] This disclosure also provides a display device with improved reliability and manufacturing yield, and a method for manufacturing the display device, the display device including a light-emitting element with remodeled surface properties.

[0008] Embodiments of this disclosure provide a light-emitting element comprising: a body including a semiconductor layer and an active layer; and a ligand including a head portion, an end portion and a chain portion, wherein the head portion is bonded to the surface of the body, the end portion is spaced apart from the body and has a positive or negative charge, and the chain portion connects the head portion and the end portion.

[0009] The semiconductor layer may include a first semiconductor layer and a second semiconductor layer, the second semiconductor layer being spaced apart from the first semiconductor layer, and the active layer being located between the first semiconductor layer and the second semiconductor layer.

[0010] The main body may also include a first contact electrode adjacent to the first semiconductor layer and a second contact electrode adjacent to the second semiconductor layer.

[0011] The body may also include a side surface covering the semiconductor layer and the active layer and an insulating film including a metal oxide.

[0012] The ligand can bind to the insulating membrane.

[0013] The ligand may include a first ligand and a second ligand, the first ligand including a first end portion having a positive charge and the second ligand including a second end portion having a negative charge.

[0014] The body may include a first side surface with a first ligand bonded thereto and a second side surface facing the first side surface with a second ligand bonded thereto.

[0015] The head portion may include at least one of a hydroxyl group, a thiol group, a catechol group, and a carboxyl group.

[0016] The chain portion may include substituted or unsubstituted alkyl groups, substituted or unsubstituted amine groups, substituted or unsubstituted oxy groups, substituted or unsubstituted thiol groups, substituted or unsubstituted ester groups, or substituted or unsubstituted amide groups.

[0017] The length of the main body can range from about 1 μm to about 100 μm.

[0018] In other embodiments of this disclosure, the display device includes: a pixel circuit; an insulating layer covering the pixel circuit; a first electrode located on the insulating layer and electrically connected to the pixel circuit; a second electrode located on the insulating layer and spaced apart from the first electrode; and a plurality of light-emitting elements electrically connected to the first and second electrodes, each of the plurality of light-emitting elements including: a body; and a ligand including a head portion, an end portion, and a chain portion, the head portion being bonded to a surface of the body, the end portion being spaced apart from the body and having a positive or negative charge, and the chain portion connecting the head portion and the end portion.

[0019] The main body may include a first contact electrode electrically connected to a first electrode, a first semiconductor layer on the first contact electrode, an active layer on the first semiconductor layer, a second semiconductor layer spaced apart from the first semiconductor layer and the active layer located between the first semiconductor layer and the second semiconductor layer, and a second contact electrode on the second semiconductor layer and electrically connected to the second electrode.

[0020] Each of the plurality of light-emitting elements may further include an insulating film covering the side surfaces of the first semiconductor layer, the active layer, and the second semiconductor layer and comprising a metal oxide.

[0021] The light-emitting element may include a first light-emitting element and a second light-emitting element, wherein the first light-emitting element includes a first ligand having a positive charge, and the second light-emitting element is adjacent to the first light-emitting element and includes a second ligand having a negative charge.

[0022] The first ligand may include a first end portion having a positive charge, the second ligand may include a second end portion having a negative charge, and the first end portion and the second end portion may be electrostatically bonded to each other.

[0023] In yet another embodiment of this disclosure, a method of manufacturing a display device includes: forming a circuit layer on a base layer; forming a first electrode and a second electrode on the circuit layer; providing a solution containing a plurality of light-emitting elements and a solvent on the first electrode and the second electrode; and evaporating the solvent, wherein each of the plurality of light-emitting elements includes a body and a ligand, the ligand including a head portion, an end portion and a chain portion, the head portion being bonded to a surface of the body, the end portion being spaced apart from the body and having a positive or negative charge, and the chain portion connecting the head portion and the end portion.

[0024] The light-emitting element may include a first light-emitting element and a second light-emitting element. The first light-emitting element includes a first ligand with a positive charge, and the second light-emitting element is adjacent to the first light-emitting element and includes a second ligand with a negative charge. The second ligand is electrostatically bonded to the first ligand.

[0025] During solvent evaporation, multiple light-emitting elements can be aligned by electrostatically binding the first and second ligands in the solution.

[0026] The solvent can be water-soluble.

[0027] The chain portion may be a substituted or unsubstituted alkyl group, a substituted or unsubstituted amine group, a substituted or unsubstituted oxy group, a substituted or unsubstituted thiol group, a substituted or unsubstituted ester group, or a substituted or unsubstituted amide group. Attached Figure Description

[0028] The accompanying drawings are included to provide a further understanding of this disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present disclosure and, together with the description, serve to explain aspects of the disclosure. In the drawings:

[0029] Figure 1 This is a perspective view of a display device according to an embodiment of the present disclosure;

[0030] Figure 2 This is a block diagram of a display device according to an embodiment of the present disclosure;

[0031] Figure 3 This is a perspective view showing a portion of a light-emitting element according to an embodiment of the present disclosure;

[0032] Figures 4A to 4C This is a cross-sectional view showing a portion of a light-emitting element according to an embodiment of the present disclosure;

[0033] Figure 5A and Figure 5B This is a cross-sectional view of a light-emitting element according to an embodiment of the present disclosure;

[0034] Figure 6 This is a cross-sectional view of a display panel according to an embodiment of the present disclosure;

[0035] Figure 7 This is a cross-sectional view showing a portion of a method for manufacturing a display device according to an embodiment of the present disclosure;

[0036] Figure 8A It is shown Figure 7 A diagram showing some enlarged parts of the configuration;

[0037] Figure 8B To show in more detail Figure 8A A partial schematic diagram; and

[0038] Figure 9A and Figure 9B This is a plan view showing a portion of a display panel according to an embodiment of the present disclosure. Detailed Implementation

[0039] The features of the inventive concept and methods for implementing it can be more readily understood by referring to the detailed description of the embodiments and the accompanying drawings. Hereinafter, embodiments will be described in more detail with reference to the accompanying drawings. However, the described embodiments may be implemented in various different forms and should not be construed as limited to the embodiments shown herein. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey to those skilled in the art aspects and features of the inventive concept. Therefore, processes, elements, and techniques that are not essential for those skilled in the art to fully understand the aspects and features of the inventive concept are not described.

[0040] Unless otherwise stated, the same reference numerals denote the same elements throughout the drawings and written description, and therefore, descriptions of the same elements will not be repeated. Furthermore, portions irrelevant to the description of the embodiments may be omitted to make the description clear. In the drawings, the relative dimensions of elements, layers, and regions may be exaggerated for clarity.

[0041] Various embodiments are described herein with reference to cross-sectional views that serve as schematic diagrams of implementations and / or intermediate structures. Thus, variations in the shapes shown in the figures should be anticipated, for example, due to manufacturing techniques and / or tolerances. Furthermore, the specific structural or functional descriptions disclosed herein are merely illustrative for the purpose of describing embodiments according to the concept of this disclosure. Therefore, the embodiments disclosed herein should not be construed as limited to the shapes of the specifically shown areas, but should include, for example, deviations in shape due to manufacturing processes.

[0042] For example, an implantation region shown as rectangular will typically have rounded or curved features at its edges and / or a gradient of implantation concentration, rather than a binary change from an implantation region to a non-implantation region. Similarly, the implantation region formed by implantation may result in some implantation in the area between the implantation region and the surface through which the implantation occurs. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to represent the actual shape of the areas of the device, nor are they intended to be limiting. Furthermore, as those skilled in the art will recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of this disclosure.

[0043] In the detailed description, numerous specific details are set forth for illustrative purposes to provide a thorough understanding of the various embodiments. However, it will be apparent that various embodiments can be practiced without these specific details or with one or more equivalent arrangements. In other instances, well-known structures and devices are shown in block diagram form to avoid unnecessarily obscuring the various embodiments.

[0044] It should be understood that although the terms “first,” “second,” “third,” etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Therefore, without departing from the spirit and scope of this disclosure, the first element, first component, first region, first layer, or first portion described below may be referred to as a second element, second component, second region, second layer, or second portion.

[0045] For ease of description, spatial relative terms such as “below,” “under,” “lower,” “below,” “above,” “upper,” etc., may be used herein to describe the relationship between one element or feature and another element (or feature) or feature (or feature) as shown in the figures. It should be understood that, in addition to the orientation depicted in the figures, spatial relative terms are intended to encompass different orientations of the device in use or operation. For example, if the device in the figures is flipped, the element described as “below,” “under,” or “below” other elements or features will consequently be oriented “above” other elements or features. Thus, the exemplary terms “below” and “below” can encompass both above and below orientations. The device may be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relative descriptive terms used herein should be interpreted accordingly. Similarly, when a first part is described as being arranged “on” a second part, this means that the first part is arranged above or below the second part, and not limited to the upper side of the second part based on the direction of gravity.

[0046] Furthermore, in this specification, the phrase "in a plane" or "plan view" refers to the target portion viewed from above, and the phrase "in a cross section" refers to a cross section formed by vertically cutting the target portion from the side.

[0047] It should be understood that when a component, layer, region, or assembly is referred to as being "on," "connected to," or "linked to" another component, layer, region, or assembly, it may be directly on, directly connected to, or directly linked to the other component, layer, region, or assembly, or there may be one or more intervening components, layers, regions, or assemblies. However, "direct connection / direct link" means that one component is directly connected to or directly linked to another component without any intermediate components. Similarly, other expressions describing relationships between components (such as "between," "directly between," or "proximately to" and "directly proximate to") can be interpreted similarly. Furthermore, it should be understood that when a component or layer is referred to as being "between" two components or layers, it may be the only component or layer between the two components or layers, or there may be one or more intervening components or layers.

[0048] For the purposes of this disclosure, when following an element of a list, expressions such as “at least one of…” or “one or more of…” modify the elements of the entire list without modifying any individual element in the list. For example, “at least one of X, Y, and Z” and “at least one of X, Y, and Z” can be interpreted as only X, only Y, only Z, or any combination of two or more of X, Y, and Z, such as, for example, XYZ, XYY, YZ, and ZZ. Throughout the text, the same numbers denote the same elements. As used herein, the term “and / or” includes any and all combinations of one or more of the related listed items.

[0049] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a” and “an” are intended to also include the plural forms unless the context clearly indicates otherwise. It will be further understood that, when used in this specification, the terms “comprises,” “comprising,” “have,” “having,” “includes,” and “including” specify the presence of the described features, integrals, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof.

[0050] As used herein, the terms “substantially,” “about,” “approximately,” and similar terms are used as approximate terms rather than as terms of degree and are intended to allow for inherent deviations in measured or calculated values ​​as would be recognized by one of ordinary skill in the art. As used herein, “about” or “approximately” includes the value as well as the average of the values ​​within an acceptable range of deviations from the particular value, as determined by one of ordinary skill in the art, taking into account the measurement in question and errors associated with the measurement of the particular quantity (i.e., limitations of the measurement system). For example, “about” may mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the value. Additionally, the word “may” as used in describing embodiments of this disclosure means “one or more embodiments of this disclosure.”

[0051] When a particular implementation can be carried out differently, a specific process sequence can be performed differently from the described sequence. For example, two consecutively described processes can be performed substantially simultaneously, or in the reverse order of the described sequence.

[0052] Furthermore, any numerical ranges disclosed and / or enumerated herein are intended to include all subranges with the same numerical precision contained within said range. For example, the range “1.0 to 10.0” is intended to include all subranges between the minimum value 1.0 and the maximum value 10.0 (and inclusive), i.e., a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit described herein is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification (including the claims) to expressly describe any subranges contained within the range expressly described herein.

[0053] The electronic or electrical devices and / or any other related devices or components described herein according to embodiments of this disclosure can be implemented using any suitable hardware, firmware (e.g., application-specific integrated circuits), software, or a combination of software, firmware, and hardware. For example, various components of these devices may be formed on a single integrated circuit (IC) chip or on separate IC chips. Additionally, various components of these devices may be implemented on a flexible printed circuit film, a tape-on-a-package (TCP), a printed circuit board (PCB), or formed on a substrate.

[0054] Furthermore, the various components of these devices can be processes or threads that run on one or more processors in one or more computing devices, execute computer program instructions, and interact with other system components for performing the various functions described herein. The computer program instructions are stored in memory implemented in the computing device using standard storage devices, such as, for example, random access memory (RAM). The computer program instructions may also be stored in other non-transitory computer-readable media, such as, for example, CD-ROMs, flash drives, etc. Additionally, those skilled in the art will recognize that, without departing from the spirit and scope of embodiments of this disclosure, the functions of various computing devices may be combined or integrated into a single computing device, or the functions of a particular computing device may be distributed across one or more other computing devices.

[0055] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concept pertains. It should also be understood that terms, such as those defined in common dictionaries, shall be interpreted as having the same meaning as they have in the relevant field and / or the context of this specification, and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0056] Figure 1 This is a perspective view of a display device according to an embodiment of the present disclosure.

[0057] Reference Figure 1 The display device DD can display images through the display area DA. Figure 1 The illustration shows a display area DA disposed on a surface defined by a first direction DR1 and a second direction DR2 intersecting the first direction DR1. However, in another embodiment of this disclosure, the display area DA of the display device DD may be disposed on a curved surface.

[0058] The thickness direction of the display device DD can be represented by the third direction DR3. The directions indicated by the first direction DR1, the second direction DR2, and the third direction DR3 are relative concepts and can be converted to other directions. As used herein, the term "when viewed on a plane" can refer to the view from the third direction DR3. Furthermore, "thickness direction" can refer to the third direction DR3.

[0059] Figure 1The display device DD shown is a television. However, the display device DD can be used not only for large electronic devices such as monitors or billboards, but also for small and medium-sized electronic devices such as personal computers, laptops, personal digital terminals, car navigation units, game consoles, smartphones, tablets, and cameras. Furthermore, these are given by way of example only, and of course, the display device DD can be used for other electronic devices without departing from this disclosure.

[0060] Figure 2 This is a block diagram of a display device according to an embodiment of the present disclosure.

[0061] Reference Figure 2 The display device DD may include a display panel DP, a signal controller TC or timing controller, a data driver DDV, and a scan driver GDV. Each of the signal controller TC, the data driver DDV, and the scan driver GDV may include circuitry.

[0062] Display panel DP can be an ultra-small light-emitting element display panel DP that includes ultra-small light-emitting elements. For example, display panel DP can be a micro LED display panel DP.

[0063] The display panel DP can include multiple scan lines SL1 to SLn, multiple data lines DL1 to DLm, and multiple pixels PX.

[0064] Multiple scan lines SL1 to SLn can extend along a first direction DR1 and can be arranged along a second direction DR2 that intersects the first direction DR1. Multiple data lines DL1 to DLm can extend along the second direction DR2 and can be arranged along the first direction DR1.

[0065] Each pixel PX may include a light-emitting element and pixel circuitry electrically connected to the light-emitting element. The pixel circuitry may include multiple transistors. A first power supply voltage ELVDD and a second power supply voltage ELVSS may be supplied to each pixel PX.

[0066] Pixels (PX) can be arranged on the plane of the display panel (DP) (e.g., according to predetermined rules or arrangements). Each pixel (PX) can display one of the primary colors or one of the mixed colors. Primary colors can include red, green, and blue, and mixed colors can include various colors such as yellow, cyan, magenta, and white. However, the colors displayed by the pixels (PX) are not limited to these.

[0067] The signal controller TC receives RGB image data that can be provided from an external source. The signal controller TC converts the RGB image data to conform to the operation of the display panel DP, thereby generating converted image data R'G'B', and outputs the converted image data R'G'B' to the data driver DDV.

[0068] In addition, the signal controller TC can receive control signals CS provided from external sources. The control signals CS may include a vertical synchronization signal, a horizontal synchronization signal, a master clock signal, and a data enable signal. The signal controller TC provides a first control signal CONT1 to the data driver DDV and a second control signal CONT2 to the scan driver GDV. The first control signal CONT1 is used to control the data driver DDV, and the second control signal CONT2 is used to control the scan driver GDV.

[0069] The data driver DDV can provide electrical signals to multiple data lines DL1 to DLm in response to the first control signal CONT1 received from the signal controller TC. The data driver DDV can be implemented as a standalone integrated circuit, electrically connected to one side of the display panel DP, or directly mounted on the display panel DP. Furthermore, the data driver DDV can be implemented as a single chip or can include multiple chips.

[0070] The scan driver GDV can provide electrical signals to scan lines SL1 to SLn in response to a second control signal CONT2 received from the signal controller TC. The scan driver GDV can be integrated into a region (e.g., a predetermined region) of the display panel DP. For example, the scan driver GDV may include multiple thin-film transistors formed using the same process (e.g., low-temperature polycrystalline silicon (LTPS) or low-temperature polycrystalline oxide (LTPO) process) as the driving circuitry of the pixels PX. Furthermore, in another embodiment of this disclosure, the scan driver GDV may be implemented as a separate integrated circuit chip electrically connected to one side of the display panel DP.

[0071] When a gate-on voltage is applied to one of the scan lines SL1 to SLn, the switching transistor of each pixel PX in the row connected to that scan line is turned on. In this case, the data driver DDV provides a data drive signal to the data lines DL1 to DLm. The data drive signal provided to the data lines DL1 to DLm is applied to the corresponding pixel PX through the turned-on switching transistor. The data drive signal can be an analog voltage corresponding to the grayscale values ​​of the RGB image data.

[0072] Figure 3 This is a perspective view of some components of a light-emitting element according to an embodiment of the present disclosure. Figures 4A to 4C This is a cross-sectional view of some components of a light-emitting element according to an embodiment of the present disclosure. Figure 3 and Figures 4A to 4C The structure of the main body EDM of the light-emitting element according to an embodiment is shown. Figures 4A to 4C It is along Figure 3 A sectional view taken from line I-I'.

[0073] The light-emitting element according to the embodiment can be an ultra-small LED element. An ultra-small LED element can be an LED element with a length between about a few nanometers and about several hundred micrometers. However, the length of an ultra-small LED element is described only as an example, and the length of an ultra-small LED element is not limited to the numerical range described above.

[0074] Reference Figure 3 The main body EDM of the light-emitting element according to the embodiment can have various shapes, such as a cylindrical shape or a polygonal column shape. Although Figure 3 The illustration shows a cylindrical LED element as the main body EDM, but this disclosure is not limited to this, and the main body EDM of the light-emitting element can have various polygonal cylindrical shapes, including cuboid shapes. The main body EDM can also have a long rod shape along the longitudinal direction.

[0075] Reference Figure 3 and Figure 4A In some embodiments, the main body EDM of the light-emitting element according to the embodiment includes semiconductor layers SCP and SCN, and an active layer AL. The main body EDM may include a first semiconductor layer SCN, a second semiconductor layer SCP, and an active layer AL. The active layer AL may be located between the first semiconductor layer SCN and the second semiconductor layer SCP. The main body EDM may also include an insulating film IL covering the sides of the core portion EDC, which includes semiconductor layers SCP and SCN, and the active layer AL.

[0076] The first semiconductor layer SCN can be an n-type semiconductor layer provided by doping the semiconductor layer with an n-type dopant. The second semiconductor layer SCP can be a p-type semiconductor layer provided by doping the semiconductor layer with a p-type dopant. The semiconductor layer can include a semiconductor material, and the semiconductor material can be, for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, or AlInN, but is not limited thereto. The n-type dopant can be silicon (Si), germanium (Ge), tin (Sn), selenium (Se), tellurium (Te), or combinations thereof, but is not limited thereto. The p-type dopant can be magnesium (Mg), zinc (Zn), calcium (Ca), strontium (Sr), or barium (Ba), or combinations thereof, but is not limited thereto.

[0077] The active layer AL can be formed from at least one of a single quantum well structure, a multiple quantum well structure, a quantum wire structure, and a quantum dot structure. The active layer AL can be a region in which electrons injected through the first semiconductor layer SCN recombine with holes injected through the second semiconductor layer SCP. The active layer AL is a layer that emits light with an energy determined by the intrinsic energy band of the material. The location of the active layer AL can be varied in various ways depending on the type of device.

[0078] The first semiconductor layer SCN can be connected to the first electrode E1 (see...). Figure 6 ) and the second electrode E2 (see Figure 6 One of the first electrodes E1 and the other of the second semiconductor layer E2.

[0079] The length LT of the main EDM can be between approximately several hundred nanometers and several hundred micrometers. The length LT of the main EDM can be, for example, between approximately 1 micrometer and approximately 100 micrometers.

[0080] The width DT of the main body EDM can be between a few nanometers and a few micrometers. The width DT of the main body EDM can be, for example, between about 100 nanometers and about 1 micrometer. The ratio of the length LT to the width DT of the main body EDM, i.e., the aspect ratio, can be between about 5:1 and about 10:1.

[0081] The insulating film IL can cover the sides of the first semiconductor layer SCN, the second semiconductor layer SCP, and the active layer AL, and can protect the outer surfaces of the first semiconductor layer SCN, the second semiconductor layer SCP, and the active layer AL. In another embodiment of this disclosure, the insulating film IL can cover only the active layer AL. The insulating film IL can include a metal oxide. For example, the insulating film IL can include one or more insulating materials selected from the group consisting of SiO2, Si3N4, Al2O3, and / or TiO2, but is not limited thereto.

[0082] Reference Figure 4B In some implementations, when with Figure 4A Compared to the main EDM, the main EDM-1 may also include a first contact electrode ECL1 and a second contact electrode ECL2. That is, the core part EDC-1 may include a first semiconductor layer SCN, an active layer AL, a second semiconductor layer SCP, a first contact electrode ECL1, and a second contact electrode ECL2.

[0083] The first contact electrode ECL1 may be adjacent to the first semiconductor layer SCN, and the second contact electrode ECL2 may be adjacent to the second semiconductor layer SCP. For example, the first contact electrode ECL1, the first semiconductor layer SCN, the active layer AL, the second semiconductor layer SCP, and the second contact electrode ECL2 may be positioned sequentially.

[0084] Each of the first contact electrode ECL1 and the second contact electrode ECL2 may be made of a metal or an alloy of metals. For example, each of the first contact electrode ECL1 and the second contact electrode ECL2 may comprise any metal or an alloy of metals selected from molybdenum (Mo), chromium (Cr), nickel (Ni), gold (Au), aluminum (Al), titanium (Ti), platinum (Pt), vanadium (V), tungsten (W), lead (Pd), copper (Cu), rhodium (Rh), and iridium (Ir). The first contact electrode ECL1 and the second contact electrode ECL2 may comprise the same material as each other, or they may comprise different materials. Each of the first contact electrode ECL1 and the second contact electrode ECL2 may be electrically connected to the first electrode E1 (see...). Figure 6 ) and the second electrode E2 (see Figure 6 One of the corresponding ones in ).

[0085] Reference Figure 4C In other embodiments, the main body EDM-2 may include an insulating film IL-1, which, when combined with... Figure 4B Compared to the insulating film IL of the body EDM-1 shown in the example, the insulating film IL-1 has a different shape.

[0086] The core component EDC-2 may include a first semiconductor layer SCN, an active layer AL, a second semiconductor layer SCP, a first contact electrode ECL1, and a second contact electrode ECL2. An insulating film IL-1 may cover the first semiconductor layer SCN, the second semiconductor layer SCP, and the active layer AL, but not the first contact electrode ECL1 or the second contact electrode ECL2. However, the disclosed embodiments are not limited thereto, and in other embodiments, the insulating film IL-1 may cover at least a portion of the first contact electrode ECL1 and the second contact electrode ECL2, or it may cover both the first contact electrode ECL1 and the second contact electrode ECL2.

[0087] Figure 5A This is a cross-sectional view of a light-emitting element according to an embodiment of the present disclosure. Figure 5B This is a cross-sectional view of a light-emitting element according to another embodiment of the present disclosure.

[0088] Reference Figure 5A According to an embodiment, the light-emitting element (ED) includes a body EDM and a ligand LD bonded to the surface of the body EDM. The body EDM may include a core portion EDC and an insulating film IL covering the sides of the core portion EDC. In the following description, the body EDM is equally applicable. Figures 4A to 4C The above embodiments are described in detail in the description of the main body EDM, EDM-1 and EDM-2.

[0089] The ligand LD can be bound to the surface of the body EDM of the light-emitting element ED, and for example, it can be bound to the surface of the insulating film IL. The ligand LD may include a head portion HD bound to the surface of the body EDM, an end portion TM spaced apart from the body EDM and having a charge, and a chain portion CP connecting the head portion HD and the end portion TM.

[0090] The head portion HD may include functional groups for bonding to the surface of the host EDM (e.g., to the surface of the insulating film IL). In one embodiment, the head portion HD may include at least one of a hydroxyl group, a thiol group, a catechol group, and a carboxyl group. The head portion HD may include at least one functional group for bonding to the surface of the insulating film IL. For example, the head portion HD may include one catechol group or a carboxyl group or two hydroxyl groups.

[0091] The end portion TM may include a positive charge or a negative charge. The end portion TM may include a functional group having a positive charge or a functional group having a negative charge. In one embodiment, the functional group having a positive charge may be an ammonium cation. In one embodiment, the functional group having a negative charge may be a sulfonate anion.

[0092] The chain portion CP can connect the head portion HD and the end portion TM, and can be selected to a suitable length so that the ligand LD can be formed to a suitable length. The chain portion CP can be, for example, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amine group, a substituted or unsubstituted oxygen group, a substituted or unsubstituted thiol group, a substituted or unsubstituted ester group, or a substituted or unsubstituted amide group. The chain portion CP can include functional groups such as amine groups, oxygen groups, and / or amide groups, such that the light-emitting element ED is uniformly dispersed in the solution INC described later (see [link to solution INC]). Figure 8A )middle.

[0093] Reference Figure 5B According to the embodiments, the light-emitting element ED' may include a first ligand LD1 and a second ligand LD2 that are different from each other. The first ligand LD1 is bound to a first side surface SS1 of the light-emitting element ED', and the second ligand LD2 is bound to a second side surface SS2 of the light-emitting element ED' that faces the first side surface SS1.

[0094] The first ligand LD1 may include a first head portion HD1, a first chain portion CP1, and a first end portion TM1. The second ligand LD2 may include a second head portion HD2, a second chain portion CP2, and a second end portion TM2.

[0095] The first end portion TM1 may include a positively charged functional group. For example, the first end portion TM1 may include a functional group having an ammonium cation. The second end portion TM2 may include a negatively charged functional group. For example, the second end portion TM2 may include a functional group having a sulfonate anion.

[0096] The first head portion HD1 and the first chain portion CP1 can be selected based on the characteristics of the first ligand LD1. The second head portion HD2 and the second chain portion CP2 can be selected based on the characteristics of the second ligand LD2. In an embodiment, the first head portion HD1 and the second head portion HD2 can be the same. The first chain portion CP1 and the second chain portion CP2 can be the same. That is, except for having end portions TM1 and TM2 containing different charges, the first ligand LD1 and the second ligand LD2 can be the same.

[0097] Figure 6 This is a cross-sectional view of a display panel according to an embodiment of the present disclosure. For ease of description, in Figure 6 The diagram shows the area corresponding to a pixel, while excluding some components.

[0098] Reference Figure 6 The first base layer BL1 and the second base layer BL2 can face each other. Each of the first base layer BL1 and the second base layer BL2 can be a stacked structure including a silicon substrate, a plastic substrate, a glass substrate, an insulating film and / or multiple insulating layers.

[0099] The circuit layer CCL can be located on the first base layer BL1. The circuit layer CCL can include a stacked structure comprising multiple insulating layers, multiple transistors, and multiple electrodes. For example, the circuit layer CCL can include a buffer layer BFL, a first insulating layer L1, a first thin-film transistor TR1, a second thin-film transistor TR2, a second insulating layer L2, a third insulating layer L3, a fourth insulating layer L4, a connection electrode CNE, and a fifth insulating layer L5.

[0100] The buffer layer BFL can be located on the first base layer BL1. The first thin-film transistor TR1 and the second thin-film transistor TR2 can be located on the buffer layer BFL.

[0101] The first thin-film transistor TR1 may include a first control electrode CE1, a first input electrode IE1, a first output electrode OE1, and a first semiconductor pattern SP1. The second thin-film transistor TR2 may include a second control electrode CE2, a second input electrode IE2, a second output electrode OE2, and a second semiconductor pattern SP2.

[0102] The first semiconductor pattern SP1 and the second semiconductor pattern SP2 can be located on the buffer layer BFL. The buffer layer BFL can provide a reformed surface for the first semiconductor pattern SP1 and the second semiconductor pattern SP2. In this case, the first semiconductor pattern SP1 and the second semiconductor pattern SP2 can have a higher adhesion to the buffer layer BFL compared to when they are formed directly on the first base layer BL1. Furthermore, the buffer layer BFL can be a barrier layer for protecting the lower surface of each of the first semiconductor pattern SP1 and the second semiconductor pattern SP2. In this case, the buffer layer BFL can reduce or prevent contaminants or moisture entering or passing through the first base layer BL1 from penetrating into the first semiconductor pattern SP1 and the second semiconductor pattern SP2.

[0103] The first insulating layer L1 may be located on the buffer layer BFL and may cover the first semiconductor pattern SP1 and the second semiconductor pattern SP2. The first insulating layer L1 may include an inorganic material. The inorganic material may be, for example, but not limited to, silicon nitride, silicon oxynitride, silicon oxide, titanium oxide and / or aluminum oxide.

[0104] The first control electrode CE1 and the second control electrode CE2 may be located on the first insulating layer L1. The second insulating layer L2 may be located on the first insulating layer L1 and may cover the first control electrode CE1 and the second control electrode CE2. The second insulating layer L2 may include inorganic material.

[0105] The capacitor may include a first cap electrode and a second cap electrode CPa. For example, the first cap electrode may branch from the second control electrode CE2, and the second cap electrode CPa may be located on the second insulating layer L2.

[0106] The third insulating layer L3 may be located on the second insulating layer L2 and may cover the second cap electrode CPa. The first input electrode IE1, the first output electrode OE1, the second input electrode IE2, and the second output electrode OE2 may be located on the third insulating layer L3. The first input electrode IE1 and the first output electrode OE1 may be connected to the first semiconductor pattern SP1 through vias passing through the first insulating layer L1, the second insulating layer L2, and the third insulating layer L3. The second input electrode IE2 and the second output electrode OE2 may be connected to the second semiconductor pattern SP2 through vias passing through the first insulating layer L1, the second insulating layer L2, and the third insulating layer L3. Not only may the first input electrode IE1, the first output electrode OE1, the second input electrode IE2, and the second output electrode OE2 be located on the third insulating layer L3, but signal wiring (e.g., at least some of each of scan lines and / or data lines) may also be located on the third insulating layer L3.

[0107] The fourth insulating layer L4 may be located on the third insulating layer L3 and may cover the first input electrode IE1, the first output electrode OE1, the second input electrode IE2, and the second output electrode OE2. The fourth insulating layer L4 may be a single layer or multiple layers, and the fourth insulating layer L4 may include organic materials and / or inorganic materials.

[0108] The connection electrode CNE can be located on the fourth insulating layer L4. Not only can the connection electrode CNE be located on the fourth insulating layer L4, but signal lines (e.g., at least some of the other scan lines and / or data lines) can also be located on the fourth insulating layer L4. The connection electrode CNE can be connected to the second output electrode OE2.

[0109] The fifth insulating layer L5 may be located on the fourth insulating layer L4 and may cover the connection electrode CNE. The fifth insulating layer L5 may include organic material. The fifth insulating layer L5 may cover the pixel circuitry located below and may provide a flat surface.

[0110] The first blocking portion BR1 and the second blocking portion BR2 are located on the fifth insulating layer L5. Each of the first blocking portion BR1 and the second blocking portion BR2 may extend in a first direction DR1. The second blocking portion BR2 may be spaced apart from the first blocking portion BR1 in a second direction DR2. The first blocking portion BR1 and the second blocking portion BR2 may comprise the same material. For example, the first blocking portion BR1 and the second blocking portion BR2 may comprise organic materials.

[0111] The first electrode E1 can be located on the first blocking portion BR1, and the second electrode E2 can be located on the second blocking portion BR2. The first electrode E1 can extend in the first direction DR1 and can cover the first blocking portion BR1, and the second electrode E2 can extend in the first direction DR1 and can cover the second blocking portion BR2. That is, the first blocking portion BR1 can be located between the first electrode E1 and the fifth insulating layer L5, and the second blocking portion BR2 can be located between the second electrode E2 and the fifth insulating layer L5.

[0112] A via can be provided in the fifth insulating layer L5, and the connection electrode CNE can be exposed through the via. The first electrode E1 can be electrically connected to the exposed connection electrode CNE. In other embodiments, the second electrode E2 can be electrically connected to a second power supply line. That is, the second power supply voltage ELVSS (see...) Figure 2 It can be provided to the second electrode E2.

[0113] Each of the first electrode E1 and the second electrode E2 may have a single-layer structure, or a multi-layer structure or a stacked structure. For example, in some embodiments, each of the first electrode E1 and the second electrode E2 may include a reflective electrode and a capping electrode located on the reflective electrode. The reflective electrode may have a single-layer structure or a multi-layer structure or a stacked structure. For example, the reflective electrode may have a structure in which indium tin oxide (ITO), silver (Ag), and indium tin oxide (ITO) are stacked sequentially. However, this is merely an example, and the present disclosure is not limited thereto. The capping electrode may cap the reflective electrode. The capping electrode may include at least one of indium zinc oxide (IZO), indium tin oxide (ITO), indium gallium oxide (IGO), indium gallium zinc oxide (IGZO), and mixtures / compounds thereof.

[0114] The light-emitting element ED can be located on the fifth insulating layer L5. Multiple light-emitting elements ED can be provided, and these multiple light-emitting elements ED can be connected in parallel. In some embodiments, an insulating pattern can be further located between the fifth insulating layer L5 and the light-emitting element ED. The light-emitting element ED can be electrically connected to the first electrode E1 and the second electrode E2.

[0115] The sixth insulating layer L6 or insulating pattern may be located on the light-emitting element ED. The sixth insulating layer L6 may cover at least a portion of the upper surface of the light-emitting element ED.

[0116] The light-emitting element ED can be electrically connected to the first electrode E1 through the first connecting electrode CNE1, and the light-emitting element ED can be electrically connected to the second electrode E2 through the second connecting electrode CNE2.

[0117] The second connecting electrode CNE2 can be located on the light-emitting element ED and the second electrode E2. The seventh insulating layer L7 can be located on the second connecting electrode CNE2. The first connecting electrode CNE1 can be located on the light-emitting element ED and the first electrode E1. Even if the length of the light-emitting element ED is about several hundred micrometers or less, the second connecting electrode CNE2 and the first connecting electrode CNE1 can be kept out of direct contact with each other due to the seventh insulating layer L7. However, this is only one embodiment of the present disclosure, and in another embodiment of the present disclosure, the first connecting electrode CNE1 and the second connecting electrode CNE2 can be formed simultaneously by the same process. In this embodiment, the seventh insulating layer L7 can be omitted.

[0118] The first connecting electrode CNE1 and the second connecting electrode CNE2 may include a conductive material. For example, the conductive material may include at least one of indium zinc oxide (IZO), indium tin oxide (ITO), indium gallium oxide (IGO), indium gallium zinc oxide (IGZO), and mixtures / compounds thereof. However, this disclosure is not limited thereto. For example, the conductive material may be a metallic material, and the metallic material may include, for example, molybdenum (Mo), silver (Ag), titanium (Ti), copper (Cu), aluminum (Al), and / or alloys thereof.

[0119] The eighth insulating layer L8 can be located on the first connecting electrode CNE1 and the seventh insulating layer L7. The eighth insulating layer L8 can be an encapsulation layer.

[0120] The light-blocking layer BM can be located on a surface of the second base layer BL2 facing the first base layer BL1. An opening can be provided in the light-blocking layer BM, and the wavelength converter CL can cover the opening. The area exposed by the opening can correspond to the pixel emission region PXA.

[0121] The wavelength converter CL may include a resin BR and a light emitter QD. The resin BR is the medium in which the light emitter QD is dispersed, and can be formed from various resin compositions, which are generally referred to as binders. However, this disclosure is not limited thereto, and the resin BR may be referred to as a base resin, regardless of its name, additional functions, materials, etc., as long as it is a medium capable of dispersing the light emitter QD. The base resin may be a polymer resin. For example, the base resin may be an acrylic resin, a polyurethane resin, a silicone resin, an epoxy resin, etc. The base resin may be a transparent resin.

[0122] A light emitter (QD) can absorb first light provided by a light-emitting element (ED) and can convert the wavelength of the first light to emit a second color light that is different from the first light. The light emitter (QD) can be, for example, a quantum dot. The first light can be blue light, and the second color light can be green or red light.

[0123] Quantum dots possess a crystal structure of a few nanometers in size, containing hundreds to thousands of atoms, and exhibit a quantum confinement effect, in which the band gap increases due to their small size. When light incident on a quantum dot has a wavelength with energy higher than the band gap, the quantum dot is excited by absorbing the light and simultaneously falls into its ground state while emitting light of a given wavelength. The emitted light at a specific wavelength has a value corresponding to the band gap. By adjusting the size and composition of the quantum dot, the luminescence properties caused by the quantum confinement effect can be controlled.

[0124] Quantum dots can have a core-shell structure, consisting of a core and a shell surrounding the core. Furthermore, quantum dots can have a core-shell structure where one quantum dot surrounds another. The interface between the core and shell can have a concentration gradient, where the concentration of elements in the shell decreases closer to the center.

[0125] Quantum dots can be particles with nanoscale dimensions. They can possess a full width at half maximum (FWHM) of light emission wavelengths of approximately 45 nm or smaller, approximately 40 nm or smaller, or approximately 30 nm or smaller, and can improve color purity or color reproducibility within these ranges. Furthermore, light emitted through such quantum dots is emitted in all directions, thereby improving wide viewing angles.

[0126] Furthermore, although there are no particular restrictions on the form of quantum dots, quantum dots can be used in the form of spheres, pyramids, multi-armed shapes, or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplate particles, etc.

[0127] In another embodiment of this disclosure, a color filter can be used instead of the wavelength converter CL. A color filter can achieve color by absorbing light of a specific wavelength. In another embodiment of this disclosure, the wavelength converter CL can be omitted. In this case, the light-emitting element ED can emit blue, green, or red light. Furthermore, in another embodiment of this disclosure, the display device DD may also include a color filter layer located between the wavelength converter CL and the second base layer BL2.

[0128] A ninth insulating layer L9 may be located between the wavelength converter CL and the eighth insulating layer L8. For example, a first base layer BL1 on which pixel circuitry and light-emitting elements ED are positioned, and a second base layer BL2 on which the wavelength converter CL and light-blocking layer BM are positioned, can be bonded through the ninth insulating layer L9. For example, the ninth insulating layer L9 may be a filler, an optically transparent adhesive film, an optically transparent resin, or a pressure-sensitive adhesive film. However, this is only one example, and in another embodiment of this disclosure, the ninth insulating layer L9 may be omitted. In this case, a cell gap may be provided between the wavelength converter CL and the eighth insulating layer L8.

[0129] Figure 7 This is a cross-sectional view illustrating some steps of a method for manufacturing a display device according to an embodiment of the present disclosure. Figure 8A It is shown Figure 7 The diagram shows some enlarged portions of the configuration. Figure 8B To show in more detail Figure 8A A schematic diagram of the part. Figure 8B It shows Figure 8A Region AA. In the following text, reference will be made to... Figure 7 , Figure 8A and Figure 8BA method for manufacturing a display device according to embodiments of the present disclosure is described. On the other hand, compared with the above... Figures 1 to 6 The same components shown are given the same reference numerals, and repeated descriptions thereof will be omitted.

[0130] The method for manufacturing a display device according to an embodiment includes positioning a circuit layer CCL (see embodiment) on a first base layer BL1. Figure 6 The method involves forming a first electrode E1 and a second electrode E2 on a circuit layer CCL. According to an embodiment, the method includes providing a solution INC comprising a plurality of light-emitting elements ED and a solvent SL on the formed first electrode E1 and second electrode E2. The plurality of light-emitting elements ED are included in the solution INC and provided on the first electrode E1 and second electrode E2, and then aligned to connect to the first electrode E1 and the second electrode E2 after the solvent SL evaporates. The method according to an embodiment may further include aligning the light-emitting elements ED by applying an electric current to the first electrode E1 and the second electrode E2 before the solvent SL evaporates. In the alignment process, an electric field is formed between the first electrode E1 and the second electrode E2, and the formed electric field induces bipolarity in the light-emitting elements ED, such that the light-emitting elements ED can be aligned between the first electrode E1 and the second electrode E2 by dielectric force.

[0131] Each of the plurality of light-emitting elements (EDs) according to the embodiments includes a host EDM and a ligand LD. In the following description of the light-emitting element ED, the description can be consistent with that described above. Figure 5A and Figure 5B The light-emitting elements ED and ED' described in the embodiments are identical.

[0132] The plurality of light-emitting elements ED contained in the solution INC may include a first light-emitting element ED1 and a second light-emitting element ED2. The first light-emitting element ED1 may include a first body EDM1 and a first ligand LD1 connected to the first body EDM1. The second light-emitting element ED2 may include a second body EDM2 and a second ligand LD2 connected to the second body EDM2. The first body EDM1 includes a first core portion EDC1, and the second body EDM2 includes a second core portion EDC2.

[0133] The first ligand LD1 included in the first light-emitting element ED1 may include a first end portion TM1 having a positive charge. The second ligand LD2 included in the second light-emitting element ED2 may include a second end portion TM2 having a negative charge. In an embodiment, the first end portion TM1 may include an ammonium cation, and the second end portion TM2 may include a sulfonate anion. However, this disclosure is not limited thereto. When the positively charged first end portion TM1 and the negatively charged second end portion TM2 are combined with each other by electrostatic attraction, multiple light-emitting elements ED can be aligned in a solution INC, such as... Figure 8A As shown in the image.

[0134] Figure 8B The first head portion HD1 and the second head portion HD2 are shown to include catechol groups, and the first chain portion CP1 and the second chain portion CP2 include amide groups. However, this disclosure is not limited thereto. The first head portion HD1 and the second head portion HD2 may include functional groups for bonding to the insulating films IL1 and IL2 of the bodies EDM1 and EDM2, and the first chain portion CP1 and the second chain portion CP2 may include functional groups to be dispersed in the water-soluble solvent SL of the solution INC. The first chain portion CP1 and the second chain portion CP2 may be formed to have selected lengths such that the first light-emitting element ED1 and the second light-emitting element ED2 are maintained at an appropriate interval.

[0135] The light-emitting element according to an embodiment of the present disclosure includes a body and a ligand bound to the body, and the ligand includes an end portion having a positive or negative charge located at an end. When the light-emitting element according to an embodiment of the present disclosure is dissolved in a water-soluble solvent and provided in solution on an electrode of a display device, the light-emitting element of the embodiment is uniformly dispersed in the solution because the dispersibility in the water-soluble solvent is increased through the charged end portion of the ligand.

[0136] Furthermore, the multiple light-emitting elements may include ligands having positively charged end portions and ligands having negatively charged end portions, such that the multiple light-emitting elements can be aligned in the solution by electrostatic bonding (e.g., at predetermined intervals) between the positively charged and negatively charged end portions. Therefore, after the solution comprising the multiple light-emitting elements is provided to the electrodes of the display device, the light-emitting elements aligned in the solution can be uniformly aligned in the electrodes, thereby improving the manufacturing yield and reliability of the display device.

[0137] Figure 9A and Figure 9B This is a plan view illustrating some components of a display panel according to an embodiment of the present disclosure. Figure 9A and Figure 9B The description, and in Figure 1Components identical to those described in Figure 5 are given the same reference numerals, and repeated descriptions thereof will be omitted. Figure 9A and Figure 9B The region corresponding to a pixel is shown, and some components are omitted in the description.

[0138] refer to Figure 9A and Figure 9B Each of the first electrode E1 and the second electrode E2 can be configured as multiple in a pixel area. Figure 9A and Figure 9B As an example, each of the first electrode E1 and the second electrode E2 is arranged in pairs, but this disclosure is not limited thereto. For example, only one first electrode E1 and one second electrode E2 may be located in a pixel region, and the number of each of the first electrode E1 and the second electrode E2 located in a pixel region may be three or more.

[0139] The first electrode E1 can be connected to the first connecting line CL1, and the second electrode E2 can be connected to the second connecting line CL2. The first connecting line CL1 and the first electrode E1 can be formed as a single unit, and the second connecting line CL2 and the second electrode E2 can be formed as a single unit. The first connecting line CL1 can electrically connect the first electrode E1 and the connecting electrode CNE (see [link to documentation]). Figure 6 Furthermore, the second connecting line CL2 can electrically connect the second electrode E2 and the power supply line. The first electrode E1 and the second electrode E2 can be spaced apart from each other. For example, the first electrode E1 and the second electrode E2 can be alternately arranged on the second direction DR2.

[0140] Figure 9B It is a plan view showing the first electrode E1 and the second electrode E2, and Figure 9B The diagram also shows a plan view of the light-emitting elements (EDs) electrically connected to the first electrode E1 and the second electrode E2. As described above, before the solution comprising multiple light-emitting elements (EDs) is provided to the first electrode E1 and the second electrode E2, the light-emitting elements (EDs) can be aligned in the solution by electrostatic bonding between ligands (LDs), allowing the light-emitting elements (EDs) to be aligned on the first electrode E1 and the second electrode E2 (e.g., at predetermined intervals), and the arrangement position can be controlled. Therefore, the reliability of display panels and display devices including light-emitting elements (EDs) can be improved.

[0141] According to embodiments of the present disclosure, ligands having positive or negative charges at their end portions can bind to the surface of the light-emitting element, and thus when the light-emitting element is applied to a display device, the alignment characteristics of the light-emitting element can be improved, thereby improving the reliability and manufacturing yield of the display device.

[0142] Although this disclosure has been described with reference to preferred embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made in this disclosure without departing from the spirit and scope thereof.

[0143] Therefore, the scope of this disclosure is not intended to be limited to what is set forth in the detailed description of the specification, but is intended to be defined by the appended claims, and their functional equivalents are considered to be included within the scope of this disclosure.

Claims

1. A light-emitting element comprising: a body including a semiconductor layer, an active layer, and an insulating film covering side surfaces of the semiconductor layer and the active layer and including a metal oxide; and a ligand including: a head portion bound to the insulating film at an outer surface of the body, the head portion including at least one of a hydroxyl group, a thiol group, a catechol group, and a carboxyl group, wherein the outer surface of the body is a surface defining an outermost surface of the body; an end portion spaced apart from the body and having a positive charge or a negative charge; and a chain portion connecting the head portion and the end portion. The ligand includes a first ligand including a first end portion having the positive charge and a second ligand including a second end portion having the negative charge.

2. The light-emitting element according to claim 1, wherein 3. A display device comprising: a pixel circuit; an insulating layer covering the pixel circuit; a first electrode on the insulating layer and electrically connected to the pixel circuit; a second electrode on the insulating layer and spaced apart from the first electrode; and a plurality of light-emitting elements electrically connected to the first electrode and the second electrode, each of the plurality of light-emitting elements including: a body including a semiconductor layer, an active layer, and an insulating film covering side surfaces of the semiconductor layer and the active layer and including a metal oxide; and a ligand including: a head portion bound to the insulating film at an outer surface of the body, the head portion including at least one of a hydroxyl group, a thiol group, a catechol group, and a carboxyl group, wherein the outer surface of the body is a surface defining an outermost surface of the body; an end portion spaced apart from the body and having a positive charge or a negative charge; and a chain portion connecting the head portion and the end portion. The body includes: a first contact electrode electrically connected to the first electrode; 4. The display device of claim 3, wherein, a first semiconductor layer on the first contact electrode; the active layer on the first semiconductor layer; a second semiconductor layer spaced apart from the first semiconductor layer with the active layer between the first semiconductor layer and the second semiconductor layer; and a second contact electrode on the second semiconductor layer and electrically connected to the second electrode. The light-emitting element includes a first light-emitting element including a first ligand having the positive charge and a second light-emitting element adjacent to the first light-emitting element and including a second ligand having the negative charge.

6. The display device according to claim 5, wherein:

5. The display device of claim 4, wherein, the first ligand includes a first end portion having the positive charge; the second ligand includes a second end portion having the negative charge; and the first end portion and the second end portion are electrostatically bound to each other.

7. A method for manufacturing a display device, the method comprising: forming a circuit layer on a base layer; forming a first electrode and a second electrode on the circuit layer; providing a solution containing a plurality of light-emitting elements and a solvent on the first electrode and the second electrode; and evaporating the solvent, ​ ​ ​ Each of the plurality of light emitting elements includes: a body including a semiconductor layer, an active layer, and an insulating film covering side surfaces of the semiconductor layer and the active layer and including a metal oxide; and a ligand including: a head portion bound to the insulating film at an outer surface of the body, the head portion including at least one of a hydroxyl group, a thiol group, a catechol group, and a carboxyl group, wherein the outer surface of the body is a surface defining an outermost surface of the body; a tail portion spaced apart from the body and having a positive charge or a negative charge; and a chain portion connecting the head portion and the tail portion.

8. The method of claim 7, wherein, The light emitting element includes: a first light emitting element including a first ligand having the positive charge; and a second light emitting element adjacent to the first light emitting element and including a second ligand having the negative charge, the second ligand electrostatically bound to the first ligand.

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