Patent Application
20230337457
This application claims priority to and benefits of Korean Patent Application No. 10-2022-0047113 under 35 U.S.C. § 119, filed on Apr. 15, 2022, in the Korean Intellectual Property Office (KIPO), the entire contents of which are incorporated herein by reference.
The disclosure herein relates to a method for manufacturing a transparent electrode that may be used as a stretchable electrode, a light emitting element, and a method for manufacturing the light emitting element.
There has been a continuous demand for flexible, readily deformable, and stretchable electronic element technologies lately, and the stretchable electronic element technologies are expected to be widely applicable to the technical fields such as wearable elements and robot sensor skin.
The stretchable electronic element technologies go beyond simply having excellent bendable or flexible properties, and require electrodes that exhibit high transmittance and have useful electrical and mechanical properties even when stretched or compressed.
It is to be understood that this background of the technology section is, in part, intended to provide useful background for understanding the technology. However, this background of the technology section may also include ideas, concepts, or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to a corresponding effective filing date of the subject matter disclosed herein.
The disclosure provides a method for manufacturing a transparent electrode having excellent optical properties and low sheet resistance.
The disclosure also provides a light emitting element including a transparent electrode with low resistance and high transmittance.
The disclosure also provides a method for manufacturing a light emitting element including a transparent electrode with low resistance and high transmittance.
An embodiment of the disclosure provides a light emitting element that may include a first electrode, a second electrode facing the first electrode, and a plurality of functional layers disposed between the first electrode and the second electrode. At least one of the first electrode and the second electrode may include a plurality of fibrous electrodes, which are randomly disposed. The plurality of fibrous electrodes may include a first fibrous electrode having a first width in a plan view, and a second fibrous electrode having a second width different from the first width in a plan view.
In an embodiment, the first fibrous electrode and the second fibrous electrode may be integral with each other.
In an embodiment, the first width of the first fibrous electrode may be in a range of about 300 nm to about 500 nm, and the second width of the second fibrous electrode may be in a range of about 2 μm to about 3 μm.
In an embodiment, each of the first fibrous electrode and the second fibrous electrode may have a thickness in a thickness direction of the first electrode or the second electrode, and the thickness of the first fibrous electrode may be substantially equal to the thickness of the second fibrous electrode in the thickness direction.
In an embodiment, the first fibrous electrode and the second fibrous electrode may each independently include silver (Ag), gold (Au), platinum (Pt), aluminum (Al), copper (Cu), tin (Sn), gallium (Ga), indium (In), nickel (Ni), or any combination thereof.
In an embodiment, at least one of the first electrode and the second electrode may further include a buffer layer disposed on the plurality of fibrous electrodes and including a transparent conductive oxide.
In an embodiment, the buffer layer may cover the plurality of fibrous electrodes.
In an embodiment, the buffer layer may have an upper surface parallel to an upper surface of the first electrode or the second electrode.
In an embodiment, the buffer layer may include indium zinc oxide.
In an embodiment, the buffer layer may include a first buffer layer disposed on the plurality of fibrous electrodes and including the transparent conductive oxide, and a second buffer layer disposed on the first buffer layer and including a conductive polymer.
In an embodiment, the plurality of functional layers may include a hole transport region disposed on the first electrode, an emission layer disposed on the hole transport region, and an electron transport region disposed on the emission layer.
In an embodiment of the disclosure, a method for manufacturing a transparent electrode may include forming an electrode layer on a substrate, disposing a first polymer fiber having a first diameter and a second polymer fiber having a second diameter different from the first diameter on the electrode layer, etching the electrode layer, using the first polymer fiber and the second polymer fiber as masks, and removing the first polymer fiber and the second polymer fiber.
In an embodiment, the first polymer fiber and the second polymer fiber may be randomly disposed on the electrode layer.
In an embodiment, the first diameter may be in a range of about 300 nm to about 500 nm, and the second diameter may be in a range of about 2 μm to about 3 μm.
In an embodiment, the disposing of the first polymer fiber and the second polymer fiber may include disposing the first polymer fiber on the electrode layer, and disposing the second polymer fiber on the electrode layer and the first polymer.
In an embodiment, the method may further include forming a buffer layer including a transparent conductive oxide on the substrate, after the removing of the first polymer fiber and the second polymer fiber.
In an embodiment, the forming of the buffer layer may include forming a first buffer layer including the transparent conductive oxide on the substrate, and forming a second buffer layer including a conductive polymer on the first buffer layer.
In an embodiment, the method may further include heat-treating the first polymer fiber and the second polymer fiber, after the disposing of the first polymer fiber and the second polymer fiber.
In an embodiment, the disposing of the first polymer fiber and the second polymer fiber may be performed by at least one of electro-spinning, melt-blowing, and flash-spinning.
In an embodiment of the disclosure, a method for manufacturing a light emitting element may include forming a first electrode, forming a plurality of functional layers on the first electrode, and forming a second electrode on the plurality of functional layers. The forming of the first electrode may include forming an electrode layer on a substrate, disposing a first polymer fiber having a first diameter and a second polymer fiber having a second diameter different from the first diameter on the electrode layer, etching the electrode layer, using the first polymer fiber and the second polymer fiber as masks, and removing the first polymer fiber and the second polymer fiber.
It is to be understood that the embodiments above are described in a generic and explanatory sense only and not for the purpose of limitation, and the disclosure is not limited to the embodiments described above.
The accompanying drawings are included to provide a further understanding of the embodiments, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and principles therefore. The above and other aspects and features of the disclosure will become more apparent by describing in detail embodiments thereof with reference to the accompanying drawings, in which:
Hereinafter, embodiments of the disclosure will be described with reference to the drawings.
The disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments are shown. This disclosure may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
In the description, it will be understood that when an element (or region, layer, part, etc.) is referred to as being “on”, “connected to”, or “coupled to” another element, it can be directly on, connected to, or coupled to the other element, or one or more intervening elements may be present therebetween. In a similar sense, when an element (or region, layer, part, etc.) is described as “covering” another element, it can directly cover the other element, or one or more intervening elements may be present therebetween.
Like numbers refer to like elements throughout. In the drawings, the thickness, the ratio, and the dimensions of elements may be exaggerated for an effective description of technical contents.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the teachings of the disclosure. The singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise.
The spatially relative terms “below”, “beneath”, “lower”, “above”, “upper”, or the like, may be used herein for ease of description to describe the relations between one element or component and another element or component as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, in the case where a device illustrated in the drawing is turned over, the device positioned “below” or “beneath” another device may be placed “above” another device. Accordingly, the illustrative term “below” may include both the lower and upper positions. The device may also be oriented in other directions and thus the spatially relative terms may be interpreted differently depending on the orientations.
The terms “about” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the recited value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the recited quantity (i.e., the limitations of the measurement system). For example, “about” may mean within one or more standard deviations, or within ±20%, +10%, or +5% of the stated value.
It should be understood that the terms “comprises,” “comprising,” “includes,” “including,” “have,” “having,” “contains,” “containing,” and the like are intended to specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof in the disclosure, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.
As used herein, being “disposed directly on” may mean that there is no additional layer, film, region, plate, or the like between a part and another part such as a layer, a film, a region, a plate, or the like. For example, being “disposed directly on” may mean that two layers or two members are disposed without using an additional member such as an adhesive member, therebetween.
As used herein, the expressions used in the singular such as “a,” “an,” and “the,” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
In the specification and the claims, the phrase “at least one of” is intended to include the meaning of “at least one selected from the group of” for the purpose of its meaning and interpretation. For example, “at least one of A and B” may be understood to mean “A, B, or A and B.” In the specification and the claims, the term “and/or” is intended to include any combination of the terms “and” and “or” for the purpose of its meaning and interpretation. For example, “A and/or B” may be understood to mean “A, B, or A and B.” The terms “and” and “or” may be used in the conjunctive or disjunctive sense and may be understood to be equivalent to “and/or.”
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Hereinafter, embodiments of the disclosure will be described with reference to the accompanying drawings.
The display device DD may include a display panel DP and an optical layer PP disposed on the display panel DP. The display panel DP may include light emitting elements ED-1, ED-2, and ED-3. The display device DD may include multiple light emitting elements ED-1, ED-2, and ED-3. The optical layer PP may be disposed on the display panel DP to control reflected light of external light in the display panel DP. The optical layer PP may include, for example, a polarizing layer or a color filter layer. Unlike what is shown in the drawings, the optical layer PP may be omitted in the display device DD of an embodiment.
A base substrate BL may be disposed on the optical layer PP. The base substrate BL may be a member providing a base surface on which the optical layer PP is disposed. The base substrate BL may be a glass substrate, a metal substrate, a plastic substrate, etc. However, the embodiment of the disclosure is not limited thereto, and the base substrate BL may be an inorganic layer, an organic layer, or a composite material layer. Unlike what is shown, the base substrate BL may be omitted in an embodiment.
The display device DD according to an embodiment may further include a filling layer (not shown). The filling layer (not shown) may be disposed between a display element layer DP-ED and the base substrate BL. The filling layer (not shown) may be an organic material layer. The filling layer (not shown) may include at least one of an acrylic resin, a silicone-based resin, and an epoxy-based resin.
The display panel DP may include a base layer BS, a circuit layer DP-CL provided on the base layer BS, and a display element layer DP-ED. The display element layer DP-ED may include pixel defining films PDL, multiple light emitting elements ED-1, ED-2, and ED-3 disposed between the pixel defining films PDL, and an encapsulation layer TFE disposed on the light emitting elements ED-1, ED-2, and ED-3.
The base layer BS may be a member providing a base surface in which the display element layer DP-ED is disposed. The base layer BS may be a glass substrate, a metal substrate, a plastic substrate, etc. However, the embodiment of the disclosure is not limited thereto, and the base layer BS may be an inorganic layer, an organic layer, or a composite material layer.
In an embodiment, the circuit layer DP-CL may be disposed on the base layer BS, and the circuit layer DP-CL may include multiple transistors (not shown). The transistors (not shown) may each include a control electrode, an input electrode, and an output electrode. For example, the circuit layer DP-CL may include a switching transistor and a driving transistor for driving the light emitting elements ED-1, ED-2, and ED-3 of the display element layer DP-ED.
The light emitting elements ED-1, ED-2, and ED-3 may each have a structure of a light emitting element ED according to an embodiment of
An encapsulation layer TFE may cover the light emitting elements ED-1, ED-2, and ED-3. The encapsulation layer TFE may seal the light emitting elements ED-1, ED-2, and ED-3. The encapsulation layer TFE may be a thin film encapsulation layer. The encapsulation layer TFE may be a single layer or a stack of multiple layers. The encapsulation layer TFE may include at least one insulating layer. The encapsulation layer TFE according to an embodiment may include at least one inorganic film (hereinafter, an encapsulation inorganic film). The encapsulation layer TFE according to an embodiment may include at least one organic film (hereinafter, an encapsulation organic film) and at least one encapsulation inorganic film.
The encapsulation inorganic film may protect the display element layer DP-ED from moisture/oxygen, and the encapsulation organic film may protect the display element layer DP-ED from foreign substances such as dust particles. The encapsulation inorganic film may include silicon nitride, silicon oxynitride, silicon oxide, titanium oxide, aluminum oxide, etc., but is not particularly limited thereto. The encapsulation organic layer may include an acrylic compound, an epoxy-based compound, etc. The encapsulation organic layer may include a photopolymerizable organic material, and is not particularly limited.
The encapsulation layer TFE may be disposed on the second electrode EL2, and may be disposed to fill the openings OH.
Referring to
The light emitting regions PXA-R, PXA-G, and PXA-B may each be a region separated by the pixel defining films PDL. The non-light emitting regions NPXA may be regions between neighboring light emitting regions PXA-R, PXA-G, and PXA-B, and may correspond to the pixel defining films PDL. In the description, the light emitting regions PXA-R, PXA-G, and PXA-B may each correspond to a pixel. The pixel defining films PDL may separate the light emitting elements ED-1, ED-2, and ED-3. The emission layers EML-R, EML-G, and EML-B of the light emitting elements ED-1, ED-2 and ED-3 may be disposed and separated in openings OH defined by the pixel defining films PDL.
The light emitting regions PXA-R, PXA-G, and PXA-B may be divided into multiple groups according to the color of light generated from the light emitting elements ED-1, ED-2, and ED-3. In the display device DD of an embodiment shown in
In the display device DD according to an embodiment, the light emitting elements ED-1, ED-2, and ED-3 may emit light having different wavelength ranges. For example, in an embodiment, the display device DD may include a first light emitting element ED-1 emitting red light, a second light emitting element ED-2 emitting green light, and a third light emitting element ED-3 emitting blue light. For example, the red light emitting region PXA-R, the green light emitting region PXA-G, and the blue light emitting region PXA-B of the display device DD may correspond to the first light emitting element ED-1, the second light emitting element ED-2, and the third light emitting element ED-3, respectively.
However, the embodiment of the disclosure is not limited thereto, and the first to third light emitting elements ED-1, ED-2 and ED-3 may emit light in the same wavelength range or emit light in at least one different wavelength range. For example, the first to third light emitting elements ED-1, ED-2, and ED-3 all may emit blue light.
The light emitting regions PXA-R, PXA-G, and PXA-B in the display device DD according to an embodiment may be arranged in the form of a stripe. Referring to
The arrangement of the light emitting regions PXA-R, PXA-G, and PXA-B is not limited to what is shown in
The areas of each of the light emitting regions PXA-R, PXA-G, and PXA-B may be different in size from one another. For example, in an embodiment, the green light emitting region PXA-G may be smaller than the blue light emitting region PXA-B in size, but the embodiment of the disclosure is not limited thereto.
Referring to
The first electrode EL1 may include multiple fibrous electrodes FE and a buffer layer BFL. The first electrode EL1 may include multiple fibrous electrodes FE disposed on the substrate RB and a buffer layer BFL disposed on the fibrous electrodes FE. The substrate RB may provide a reference surface on which the fibrous electrodes FE are formed. For example, the substrate RB may be a base layer BS or a circuit layer DP-CL, which is described in
Referring to
At least two or more of the fibrous electrodes FE on the substrate RB may be arranged to intersect each other. A portion in which at least two fibrous electrodes FE intersect each other in the fibrous electrodes FE herein may be referred to as an intersect portion. In the fibrous electrodes FE, an intersect portion where adjacent fibrous electrodes FE intersect each other and a portion where fibrous electrodes FE do not intersect may be substantially the same in a thickness direction or the third direction DR3.
The fibrous electrodes FE may have a straight line, a curved line, or a mixed form of a straight line and a curved line.
The fibrous electrodes FE may include a first fibrous electrode FE1 and a second fibrous electrode FE2. Each of the first fibrous electrode FE1 and the second fibrous electrode FE2 may be disposed on the substrate RB. The first fibrous electrode FE1 and the second fibrous electrode FE2 may be randomly disposed on the substrate RB. A direction in which the first fibrous electrode FE1 and the second fibrous electrode FE2 extend may be random. In an embodiment, the first fibrous electrode FE1 and the second fibrous electrode FE2 may be integral with each other. For example, the first fibrous electrode FE1 and the second fibrous electrode FE2 may be provided as a single body. The first fibrous electrode FE1 and the second fibrous electrode FE2 may be disposed on the substrate RB and may be integral with each other.
The first fibrous electrode FE1 and the second fibrous electrode FE2 may have different widths in a plan view. The first fibrous electrode FE1 may have a first width WT1 in a plan view. The second fibrous electrode FE2 may have a second width WT2 in a plan view.
The first width WT1 and the second width WT2 may be different from each other. The second width WT2 of the second fibrous electrode FE2 may be greater than the first width WT1 of the first fibrous electrode FE1.
The first width WT1 of the first fibrous electrode FE1 may have a nano-scale width. In an embodiment, the first width WT1 of the first fibrous electrode FE1 may be in a range of about 300 nm to about 500 nm. In case that the first width WT1 of the first fibrous electrode FE1 is less than about 300 nm, the first electrode EL1 may have deterioration in mechanical durability due to a small width, resulting in damage such as cracks. In case that the first width WT1 of the first fibrous electrode FE1 is greater than about 500 nm, an electrode satisfying a desired resistance value and light transmittance may be not achieved.
The second width WT2 of the second fibrous electrode FE2 may have a micro-scale width. In an embodiment, the second width WT2 of the second fibrous electrode FE2 may be in a range of about 2 μm to about 3 μm. In case that the second width WT2 of the second fibrous electrode FE2 is less than about 2 μm, the fibrous electrode FE may have a reduced area ratio, and the light emitting element ED may thus have deterioration in luminous efficiency. In case that the second width WT2 of the second fibrous electrode FE2 is greater than about 3 μm, a space through which light passes may be reduced due to a large width to cause a reduction in light transmittance. As used herein, “nano-scale” may be a value in the nanometer range of less than about 1 μm, and “micro-scale” may be a value in the micrometer range of about 1 μm to about 1 mm.
The first fibrous electrode FE1 and the second fibrous electrode FE2 may include a same material. The first fibrous electrode and the second fibrous electrode may each independently include silver (Ag), gold (Au), platinum (Pt), aluminum (Al), copper (Cu), tin (Sn), gallium (Ga), indium (In), nickel (Ni), or any combination thereof. The first fibrous electrode FE1 and the second fibrous electrode FE2 may each independently include silver (Ag), gold (Au), platinum (Pt), aluminum (Al), copper (Cu), tin (Sn), gallium (Ga), indium (In), or nickel (Ni), or the first fibrous electrode FE1 and the second fibrous electrode FE2 may each independently include a mixture of two or more materials selected from the group consisting of silver (Ag), gold (Au), platinum (Pt), aluminum (Al), copper (Cu), tin (Sn), gallium (Ga), indium (In), and nickel (Ni).
An electrode opening E-OP may be defined in the fibrous electrodes FE. The fibrous electrodes FE may include a lower surface adjacent to the substrate RB and an upper surface facing the lower surface. The fibrous electrodes FE may have openings defined from the upper surface of the fibrous electrodes FE to the lower surface of the fibrous electrodes FE as shown in
The electrode opening E-OP may have various shapes. As the fibrous electrodes FE are randomly disposed on the substrate RB, the electrode opening E-OP defined in the fibrous electrodes FE may have various shapes. For example, the electrode opening E-OP may have a polygonal shape or an irregular shape, but is not limited thereto.
The fibrous electrodes FE may have a first thickness h1. The first thickness h1 of the fibrous electrodes FE may be measured in the third direction DR3 which is a thickness direction. In an embodiment, the first thickness h1 may be in a range of about 20 nm to about 160 nm. For example, the first thickness h1 may be about 50 nm, but is not limited thereto. In case that the first thickness h1 of the fibrous electrodes FE satisfies the above-described range, the first electrode EL1 applied to the light emitting element ED may have a reduced sheet resistance and a greater transmittance, and may thus increase luminous efficiency. In case that the first thickness h1 of the fibrous electrodes FE is less than about 20 nm, the first electrode EL1 applied to the light emitting element ED may have a greater sheet resistance and a reduced transmittance, and may thus deteriorate luminous efficiency. In case that the first thickness h1 of the of fibrous electrodes FE is greater than about 160 nm, the fibrous electrodes FE may have a greater peak to valley, and may accordingly cause an electrical shortage and a current leakage. As used herein, “peak to valley” may be a maximum height from the lower surface to the upper surface of the fibrous electrodes FE.
Each of the first fibrous electrode FE1 and the second fibrous electrode FE2 may have a predetermined (or selectable) thickness in the third direction DR3. Each of the first fibrous electrode FE1 and the second fibrous electrode FE2 may have a first thickness h1. For example, the first fibrous electrode FE1 may have a thickness in the third direction DR3 which is substantially the same as a thickness of the second fibrous electrode FE2 in the third direction DR3. As used herein, it should be understood that “substantially the same” may indicate that numerical ranges such as width and thickness are the same, including not only a case in which numerical ranges such as width and thickness are physically the same, but also errors upon processes, that may generally occur.
The first electrode EL1 may include a buffer layer BFL. The buffer layer BFL may be disposed on the fibrous electrodes FE. The buffer layer BFL may be disposed on the first fibrous electrode FE1 and the second fibrous electrode FE2. The buffer layer BFL may cover the first fibrous electrode FE1 and the second fibrous electrode FE2. The buffer layer BFL may fill the electrode opening E-OP formed in the fibrous electrodes FE and may cover the entirety of the first fibrous electrode FE1 and the second fibrous electrode FE2. The buffer layer BFL may be disposed on the fibrous electrodes FE to form parallel resistance with the fibrous electrodes FE. The buffer layer BFL may serve to provide a uniform current supply to the light emitting element ED through the forming of parallel resistance with the fibrous electrodes FE. The buffer layer BFL may serve to protect the fibrous electrodes FE from an external environment. For example, the buffer layer BFL may prevent damage to the fibrous electrodes FE by external heat and protect the fibrous electrodes FE against strong acid/strong base and plasma environments.
An upper surface of the buffer layer BFL may be flat. The upper surface of the buffer layer BFL may be parallel to a plane defined by the first direction DR1 and the second direction DR2. A step may be formed between the upper surface of the substrate RB and the upper surface of the fibrous electrodes FE. For example, a step may be formed on the upper surface of the substrate RB by the first thickness h1 of the fibrous electrodes FE. The buffer layer BFL may remove steps formed by the fibrous electrodes FE and provide a flat reference surface to a member disposed on an upper side.
The buffer layer BFL may have a second thickness h2 in the third direction DR3. The second thickness h2 may be measured from the upper surface of the substrate RB to the upper surface of the buffer layer BFL in the third direction DR3. The second thickness h2 of the buffer layer BFL may be greater than the first thickness h1 of the fibrous electrodes FE.
In an embodiment, the second thickness h2 of the buffer layer BFL may be in a range of about 40 nm to about 240 nm. However, the embodiment of the disclosure is not limited thereto. In case that the second thickness h2 of the buffer layer BFL is less than about 40 nm, a difference in sheet resistance between the buffer layer BFL and the fibrous electrodes FE may increase, and the light emitting element ED may thus have deteriorated electrical properties. In case that the second thickness h2 of the buffer layer BFL is greater than about 240 nm, the light emitting element ED may have deteriorated durability and reduced light transmittance due to a large thickness, and may thus have a decrease in luminous efficiency. As the second thickness h2 of the buffer layer BFL satisfies the above-described range, the first electrode EL1 exhibiting both low sheet resistance and high light transmittance may be obtained, and in case that the first electrode EL1 is applied to the light emitting element ED, the light emitting element ED may have increased luminous efficiency.
The buffer layer BFL may include a transparent conductive oxide (TCO) and/or a conductive polymer. In an embodiment, the buffer layer BFL may include a transparent conductive oxide (TCO). The buffer layer BFL may include a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium tin zinc oxide (ITZO). In an embodiment, the buffer layer BFL may include indium zinc oxide (IZO). In another embodiment, the buffer layer BFL may include a conductive polymer such as a polythiophene-based compound, a polypyrrole-based compound, a polyaniline-based compound, a polyacetylene-based compound, a polyphenylene-based compound, and a mixture thereof. For example, the buffer layer BFL may include a PEDOT:PSS (Poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) compound.
Referring to
The first buffer layer BFL1 may be disposed on the fibrous electrodes FE. The first buffer layer BFL1 may cover the fibrous electrodes FE. The second buffer layer BFL2 may be disposed on the first buffer layer BFL1. The second buffer layer BFL2 may be directly disposed on the first buffer layer BFL1 to cover an upper surface of the first buffer layer BFL1. The first buffer layer BFL1 may fill the electrode opening E-OP formed in the fibrous electrodes FE and may cover the entirety of the fibrous electrodes FE.
In an embodiment, the second thickness h2 of the first buffer layer BFL1 may be in a range of about 40 nm to about 240 nm. In case that the second thickness h2 of the first buffer layer BFL1 is less than about 40 nm, a difference in sheet resistance between the first buffer layer BFL1 and the fibrous electrodes FE may increase, and the light emitting element ED-a may thus have deteriorated electrical properties. In case that the second thickness h2 of the first buffer layer BFL1 is greater than about 240 nm, the light emitting element ED-a may have deteriorated durability and reduced light transmittance due to a thick thickness, may thus have a decrease in luminous efficiency. As the second thickness h2 of the first buffer layer BFL1 satisfies the aforementioned range, the first electrode EL1 exhibiting both low sheet resistance and high light transmittance may be realized.
The first buffer layer BFL1 may include a transparent conductive oxide (TCO). The first buffer layer BFL1 may include a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium tin zinc oxide (ITZO). In an embodiment, the first buffer layer BFL1 may include indium zinc oxide (IZO).
The second buffer layer BFL2 may be disposed on the first buffer layer BFL1. The second buffer layer BFL2 may be directly disposed on the upper surface of the first buffer layer BFL1. The second buffer layer BFL2 may be spaced apart from the fibrous electrodes FE in the third direction DR3. The second buffer layer BFL2 may be disposed to be spaced apart from the fibrous electrodes FE with the first buffer layer BFL1 therebetween. An upper surface of the second buffer layer BFL2 may be flat. The upper surface of the second buffer layer BFL2 may be parallel to a plane defined by the first direction DR1 and the second direction DR2. As the second buffer layer BFL2 is disposed on the first buffer layer BFL1, the first electrode EL1 may have a reduction in overall surface roughness, and the light emitting element ED-a may thus have an increased durability. As used herein, the surface roughness may be an arithmetic mean roughness (Ra).
The second buffer layer BFL2 may have a third thickness h3 in the third direction DR3. In an embodiment, the third thickness h3 of the second buffer layer BFL2 may be in a range of about 100 nm to about 300 nm. In case that the third thickness h3 of the second buffer layer BFL2 is less than about 100 nm, the thin film may be too thin to serve as a flat film. In case that the third thickness h3 of the second buffer layer BFL2 is greater than about 300 nm, mechanical properties may be deteriorated, and light transmittance may be reduced due to the thick thin film.
The second buffer layer BFL2 may include a conductive polymer. Examples of the conductive polymer may include a polythiophene-based compound, a polypyrrole-based compound, a polyaniline-based compound, a polyacetylene-based compound, a polyphenylene-based compound, and a mixture thereof, and for example, polythiophene-based compounds or PEDOT:PSS(Poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) may be used for the second buffer layer BFL2.
The hole transport region HTR may be provided on the first electrode EL1. The hole transport region HTR may include at least one of a hole injection layer, a hole transport layer, a buffer layer or a light emitting auxiliary layer, and an electron blocking layer. The hole transport region HTR may have, for example, a thickness in a range of about 50 Å to about 15,000 Å.
The hole transport region HTR may be a layer formed of a single material, a layer formed of different materials, or a structure having multiple layers formed of different materials.
For example, the hole transport region HTR may have a single-layer structure formed of a hole injection layer or a hole transport layer, or a single-layer structure formed of a hole injection material or a hole transport material. The hole transport region HTR may have a single-layer structure formed of different materials, or a structure in which a hole injection layer/hole transport layer, a hole injection layer/hole transport layer/buffer layer, a hole injection layer/buffer layer, a hole transport layer/buffer layer, or a hole injection layer/hole transport layer/electron blocking layer are stacked in order from the first electrode EL1, but the embodiment of the disclosure is not limited thereto.
The hole transport region HTR may be formed using various methods such as a vacuum deposition method, a spin coating method, a cast method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, and a laser induced thermal imaging (LITI) method.
The hole transport region HTR may include a compound represented by Formula H-2 below.
In Formula H-2 above, L1 and L2 may each independently be a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. a and b may each independently be an integer of 0 to 10. In case that a or b is an integer of 2 or greater, multiple L1's and L2's may each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.
In Formula H-2, Ar1 and Ar2 may each independently be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. In Formula H-2, Ar3 may be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.
In an embodiment, the compound represented by Formula H-2 above may be a monoamine compound. In another embodiment, the compound represented by Formula H-2 may be a diamine compound in which at least one of Ar−1 to Ar3 includes an amine group as a substituent. In still another embodiment, the compound represented by Formula H-2 may be a carbazole-based compound wherein at least of Ar1 and Ar2 may include a substituted or unsubstituted carbazole group or a substituted or unsubstituted fluorene-based group.
The compound represented by Formula H-2 may be a compound selected from Compound Group H. However, the compounds listed in Compound Group H below are presented as an example, and the compound represented by Formula H-2 is not limited to the those listed in Compound Group H below.
The hole transport region HTR may include a phthalocyanine compound such as copper phthalocyanine, N1,N1′-([1,1′-biphenyl]-4,4′-diyl)bis(N1-phenyl-N4,N4-di-m-tolylbenzene-1,4-diamine) (DNTPD), 4,4′,4″-[tris(3-methylphenyl)phenyl amino]triphenylamine (m-MTDATA), 4,4′4″-tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4′,4″-tris[N(2-naphthyl)-N-phenylamino]-triphenylamine (2-TNATA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/Dodecylbenzenesulfonic acid (PANI/DBSA), polyaniline/camphor sulfonicacid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB), triphenylamine-containing polyetherketone (TPAPEK), 4-isopropyl-4′-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate, dipyrazino[2,3-f: 2′,3′-h] quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN), etc.
The hole transport region HTR may include carbazole-based derivatives such as N-phenyl carbazole and polyvinyl carbazole, fluorene-based derivatives, N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine (TPD), triphenylamine-based derivatives such as 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), N,N′-di(1-naphtalene-1-yl)-N,N′-diphenyl-benzidine (NPB), 4,4′-cyclohexylidene bis[N,N-bis(4-methylphenyl]benzenamine] (TAPC), 4,4′-bis[N,N′-(3-tolyl)amino]-3,3′-dimethylbiphenyl (HMTPD), 1,3-bis(N-carbazolyl)benzene (mCP), etc.
The hole transport region HTR may include 9-(4-tert-Butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi), 9-phenyl-9H-3,9′-bicarbazole (CCP), 1,3-bis(1,8-dimethyl-9H-carbazol-9-yl)benzene (mDCP), etc.
At least one of the hole injection layer, the hole transport layer, and the electron blocking layer (not shown) in the hole transport region HTR may include the compounds that may be included in the hole transport region described above.
The hole transport region HTR may have a thickness in a range of about 100 Å to about 10,000 Å. For example, the hole transport region HTR may have a thickness in a range of about 100 Å to about 5,000 Å. In case that the hole transport region HTR includes a hole injection layer, the hole injection layer may have a thickness in a range of, for example, about 30 Å to about 1,000 Å. In case that the hole transport region HTR includes a hole transport layer, the hole transport layer may have a thickness in a range of about 30 Å to about 1,000 Å. In case that the hole transport region HTR includes an electron blocking layer, the electron blocking layer may have a thickness in a range of, for example, about 10 Å to about 1,000 Å. In case that the thicknesses of the hole transport region HTR, the hole injection layer, the hole transport layer, and the electron blocking layer satisfy the above-described ranges, satisfactory hole transport properties may be obtained without a substantial increase in driving voltage.
The hole transport region HTR may further include a charge generation material to increase conductivity. The charge generation material may be uniformly or non-uniformly dispersed in the hole transport region HTR. The charge generation material may be, for example, a p-dopant. The p-dopant may include at least one of halogenated metal compounds, quinone derivatives, metal oxides, and cyano group-containing compounds, but is not limited thereto. For example, the p-dopant may include halogenated metal compounds such as CuI and RbI, quinone derivatives such as tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), metal oxides such as tungsten oxides and molybdenum oxides, cyano group-containing compounds such as dipyrazino[2,3-f. 2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HATCN) and 4-[[2,3-bis[cyano-(4-cyano-2,3,5,6-tetrafluorophenyl)methylidene]cyclopropylidene]-cyanomethyl]-2,3,5,6-tetrafluorobenzonitrile (NDP9), etc., but is not limited thereto.
As described above, the hole transport region HTR may further include at least one of a buffer layer or an electron blocking layer in addition to the hole injection layer and the hole transport layer. The buffer layer may compensate a resonance distance according to the wavelength of light emitted from an emission layer EML, and may thus increase luminous efficiency. Materials which may be included in the hole transport region HTR may be used as materials included in the buffer layer. The electron blocking layer may be a layer that serves to prevent electrons from being injected from the electron transport region ETR to the hole transport region HTR.
The emission layer EML may be provided on the hole transport region HTR. The emission layer EML may have, for example, a thickness in a range of about 100 Å to about 1,000 Å. For example, the emission layer EML may have a thickness in a range of about 100 Å to about 300 Å. The emission layer EML may be a layer formed of a single material, a layer formed of different materials, or a structure having multiple layers formed of different materials.
In the light emitting elements ED and ED-a according to an embodiment, the emission layer EML may include an anthracene derivative, a pyrene derivative, a fluoranthene derivative, a chrysene derivative, a dihydrobenzanthracene derivative, or a triphenylene derivative. For example, the emission layer EML may include an anthracene derivative or a pyrene derivative.
In the light emitting elements ED and ED-a according to the embodiment shown in
In Formula E-1, R31 to R40 may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted silyl group, a substituted or unsubstituted thio group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or may be bonded to an adjacent group to form a ring. R31 to R40 may be linked to an adjacent group to form a saturated hydrocarbon ring, an unsaturated hydrocarbon ring, a saturated heterocycle, or an unsaturated heterocycle.
In Formula E-1, c and d may each independently be an integer of 0 to 5.
The compound represented by Formula E-1 may be any one of Compounds E1 to E19 below.
In an embodiment, the emission layer EML may include a first compound represented by Formula E-1, and at least one of a second compound represented by Formula HT-1 below, a third compound represented by Formula ET-1 below, and a fourth compound represented by Formula M-b below.
In an embodiment, the second compound may be used as a hole transporting host of the emission layer EML.
In Formula HT-1, a4 may be an integer of 0 to 8. In case that a4 is an integer of 2 or greater, multiple R10's may all be the same or at least one R10 may be different from the others. R9 and R10 may each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted aryl group having 6 to 60 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 60 ring-forming carbon atoms. For example, R9 may be a substituted phenyl group, an unsubstituted dibenzofuran group, or a substituted fluorenyl group. R10 may be a substituted or unsubstituted carbazole group.
The second compound may be represented by one of Compound Group 2 below. In Compound Group 2 below, D represents a deuterium atom.
In an embodiment, the emission layer EML may include a third compound represented by Formula ET-1 below. For example, the third compound may be used as an electron transporting host of the emission layer EML.
In Formula ET-1, at least one of Y1 to Y3 may be N, and another may be C(Ra), and Ra may be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 60 ring-forming carbon atoms.
b1 to b3 may each independently be an integer of 0 to 10. L1 to L3 may each independently be a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.
Ar1 to Ar3 may each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. For example, Ar1 to Ar3 may a substituted or unsubstituted phenyl group or a substituted or unsubstituted carbazole group.
The third compound may be represented by one of Compound Group 3 below. The light emitting elements ED and ED-a according to an embodiment may include one of Compound Group 3 below. In Compound Group 3 below, D may be a deuterium atom.
In an embodiment, the emission layer EML may include a compound represented by Formula E-2a or Formula E-2b below. The compound represented by Formula E-2a or Formula E-2b may be used as a phosphorescent host.
In Formula E-2a, a may be an integer of 0 to 10, and La may be a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. In case that a is an integer of 2 or greater, multiple La's may each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.
In Formula E-2a, A1 to A5 may each independently be N or C(Ri). Ra to Ri may each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted amine group, a substituted or unsubstituted thio group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or one linked to an adjacent group to form a ring. Ra to Ri may be linked to an adjacent group to form a hydrocarbon ring or a heterocycle containing N, O, S, etc. as a ring-forming atom.
In Formula E-2a, two or three of A1 to A5 may be N, and the others may be Cri.
In Formula E-2b, Cbz1 and Cbz2 may each independently be an unsubstituted carbazole group or an aryl-substituted carbazole group having 6 to 30 ring-forming carbon atoms. Lb may be a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, and b may be an integer of 0 to 10, and in case that b is an integer of 2 or greater, multiple Lb's may each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.
The compound represented by Formula E-2a or Formula E-2b may be represented by one of Compound Group E-2 below. However, the compounds listed in Compound Group E-2 below are presented as an example, and the compound represented by Formula E-2a or Formula E-2b is not limited to those listed in Compound Group E-2 below.
The emission layer EML may further include a general material as a host. For example, the emission layer EML may include, as a host, at least one of bis(4-(9H-carbazol-9-yl)phenyl)diphenylsilane (BCPDS), (4-(1-(4-(diphenylamino)phenyl)cyclohexyl)phenyl)diphenyl-phosphine oxide (POPCPA), bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-bis(carbazolyl-9-yl)benzene (mCP), 2,8-bis(diphenylphosphoryl)dibenzofuran (PPF), 4,4′,4″-tris(carbazol-9-yl)-triphenylamine (TCTA), and 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi). However, the embodiment of the disclosure is not limited thereto, and for example, tris(8-hydroxyquinolino)aluminum (Alq3), 9,10-di(naphthalene-2-yl)anthracene (ADN), 3-tert-butyl-9,10-di(naphth-2-yl)anthracene (TBADN), distyrylarylene (DSA), 4,4′-bis(9-carbazolyl)-2,2′-dimethyl-biphenyl (CDBP), 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), hexaphenyl cyclotriphosphazene (CP1), 1,4-bis(triphenylsilyl)benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO3), octaphenylcyclotetrasiloxane (DPSiO4), etc. may be used as a host.
The emission layer EML may include a compound represented by Formula M-a or Formula M-b below. The compound represented by Formula M-a or Formula M-b below may be used as a phosphorescent dopant.
In Formula M-a above, Y1 to Y4, and Z1 to Z4 may each independently be CR1 or N, and R1 to R4 may each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted amine group, a substituted or unsubstituted thio group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or one bonded to an adjacent group to form a ring. In Formula M-a, m may be 0 or 1, and n may be 2 or 3. In Formula M-a, in case that m is 0, n may be 3, and in case that m is 1, n may be 2.
The compound represented by Formula M-a may be used as a phosphorescent dopant.
The compound represented by Formula M-a may be represented by one of compounds M-al to M-a25 below. However, the compounds M-al to M-a25 below are presented as an example, and the compound represented by Formula M-a is not limited to those of the compounds M-al to M-a25 below.
In Formula M-b, Q1 to Q4 may each independently be C or N, and C1 to C4 may each independently be a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring-forming carbon atoms or a substituted or unsubstituted heterocycle having 2 to 30 ring-forming carbon
a substituted or unsubstituted divalent alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, and e1 to e4 may each independently be 0 or 1. R31 to R39 may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or one bonded to an adjacent group to form a ring, and d1 to d4 may each independently be an integer of 0 to 4.
The compound represented by Formula M-b may be used as a blue phosphorescent dopant or a green phosphorescent dopant.
The compound represented by Formula M-b may be represented by any one of Compounds M-b-1 to M-b-11 below. However, Compounds M-b-1 to M-b-11 below are presented as examples, and the compound represented by Formula M-b is not limited to Compounds M-b-1 to M-b-11 below.
In Compounds M-b-1 to M-b-11 above, R, R38, R39 may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.
The emission layer EML may include a compound represented by one of Formulas F-a to F-c below. The compounds represented by Formulas F-a to F-c below may be used as a fluorescent dopant.
In Formula F-a above, two of Ra to Rj may each independently be substituted with ⋅—NAr1Ar2. The others of Ra to Rj which are not substituted with ⋅—NAr1Ar2 may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. In ⋅—NAr1Ar2, Ar1 and Ar2 may each independently be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. For example, at least one of An or Ar2 may be a heteroaryl group containing O or S as a ring-forming atom.
In Formula F-b above, Ra and Rb may each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or one linked to an adjacent group to form a ring. Ar1 to Ar4 may each independently be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.
In Formula F-b, U and V may each independently be a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring-forming carbon atoms or a substituted or unsubstituted heterocycle having 2 to 30 ring-forming carbon atoms.
In Formula F-b, the number of rings represented by U and V may each independently be 0 or 1. For example, In Formula F-b, in case that the number of U or V is 1, one ring may form a fused ring in a portion indicated by U or V, and in case that the number of U or V is 0, no ring indicated by U or V may present. For example, in case that the number of U is 0 and the number of V is 1, or in case that the number of U is 1 and the number of V is 0, a fused ring having a fluorene core of Formula F-b may be a cyclic compound having four rings. In case that both U and V are 0, the fused ring of Formula F-b may be a cyclic compound having three rings. In case that both U and V are 1, the fused ring having a fluorene core of Formula F-b may be a cyclic compound having five rings.
In Formula F-c, A1 and A2 may each independently be O, S, Se, or N(Rm), and Rm may be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. R1 to R11 may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted boryl group, a substituted or unsubstituted oxy group, a substituted or unsubstituted thio group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or one bonded to an adjacent group to form a ring.
In Formula F-c, A1 and A2 may each independently be bonded to substituents of neighboring rings to form a fused ring. For example, in case that A1 and A2 are each independently NRm, Ai may be bonded to R4 or R5 to form a ring. A2 may be bonded to R7 or R8 to form a ring.
The emission layer EML may include, as a dopant, styryl derivatives (e.g., 1,4-bis[2-(3-N-ethylcarbazoryl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4″-[(di-p-tolylamino)styryl]stilbene (DPAVB), and N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylbenzenamine (N-BDAVBi)), perylene and derivatives thereof (e.g., 2,5,8,11-tetra-t-butylperylene (TBP)), pyrene and derivatives thereof (e.g., 1,1-dipyrene, 1,4-dipyrenylbenzene, 1,4-bis(N,N-diphenylamino)pyrene), etc.
The emission layer EML may include a phosphorescent dopant. For example, as a phosphorescent dopant, a metal complex including iridium (Ir), platinum (Pt), osmium (Os), gold (Au), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), or thulium (Tm) may be used. For example, iridium(III) bis(4,6-difluorophenylpyridinato-N,C2′)picolinate (FIrpic), bis(2,4-difluorophenylpyridinato)-tetrakis(1-pyrazolyl)borate iridium(III) (Fir6), platinum octaethyl porphyrin (PtOEP), etc. may be used as a phosphorescent dopant.
However, the embodiment of the disclosure is not limited thereto.
The emission layer EML may include a quantum dot material. The core of a quantum dot may include a Group II-VI compound, a Group III-VI compound, a Group 1-II-VI compound, a Group III-V compound, a Group III-II-V compound, a Group IV-VI compound, a Group IV element, a Group IV compound, or a combination thereof.
The Group II-VI compound may be selected from the group consisting of a binary compound selected from the group consisting of CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and a mixture thereof, a ternary compound selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and a mixture thereof, and a quaternary compound selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and a mixture thereof.
The Group III-VI compound may include a binary compound such as In2S3 and In2Se3, a ternary compound such as InGaS3 and InGaSe3, or any combination thereof.
The Group 1-III-VI compound may include a ternary compound selected from the group consisting of AgInS, AgInS2, CuInS, CuInS2, AgGaS2, CuGaS2 CuGaO2, AgGaO2, AgAlO2, or any mixture thereof, or a quaternary compound such as AgInGaS2 and CuInGaS2.
The Group III-V compound may be selected from the group consisting of a binary compound selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and a mixture thereof, a ternary compound selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InAlP, InNP, InNAs, InNSb, InPAs, InPSb, and a mixture thereof, and a quaternary compound selected from the group consisting of GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and a mixture thereof. The Group III-V compound may further include a Group II metal. For example, InZnP, etc. may be selected as a Group III-II-V compound.
The Group IV-VI compound may be selected from the group consisting of a binary compound selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and a mixture thereof, a ternary compound selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and a mixture thereof, and a quaternary compound selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and a mixture thereof. The Group IV element may be selected from the group consisting of Si, Ge, and a mixture thereof. The Group IV compound may be a binary compound selected from the group consisting of SiC, SiGe, and a mixture thereof.
The binary compound, the ternary compound, or the quaternary compound may be present in particles having a uniform concentration distribution, or may be present in the same particles having a partially different concentration distribution. A core/shell structure in which one quantum dot surrounds another quantum dot may be present. The core/shell structure may have a concentration gradient in which the concentration of an element present in the shell becomes lower towards the core.
In embodiments, a quantum dot may have the core/shell structure including a core having nano-crystals, which are described above, and a shell surrounding the core. The shell of the quantum dot may serve as a protection layer to prevent the chemical deformation of the core so as to keep semiconductor properties, and/or a charging layer to impart electrophoresis properties to the quantum dot. The shell may be a single layer or may include multiple layers.
The shell of the quantum dot may include a metal or non-metal oxide, a semiconductor compound, or a combination thereof.
For example, the metal or non-metal oxide may be a binary compound such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, and NiO, or a ternary compound such as MgAl2O4, CoFe2O4, NiFe2O4, and CoMn2O4, but the embodiment of the disclosure is not limited thereto.
The semiconductor compound may be, for example, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, etc., but the embodiment of the disclosure is not limited thereto.
The quantum dot may have a full width at half maximum (FWHM) of an emission wavelength spectrum less than or equal to about 45 nm. For example, the quantum dot may have a FWHM of an emission wavelength spectrum less than or equal to about 40 nm. For example, the quantum dot may have a FWHM of an emission wavelength spectrum less than or equal to about 30 nm. Color purity or color reproducibility may be enhanced in the above ranges. Light emitted through such a quantum dot may be emitted in all directions, and thus a wide viewing angle may be achieved.
The form of a quantum dot is not particularly limited as long as it is a form commonly used in the art, for example, a quantum dot in the form of spherical, pyramidal, multi-arm, cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplatelets, etc. may be used.
The quantum dot may control the color of emitted light according to particle size thereof, and thus the quantum dot may have various colors of emitted light such as blue, red, green, etc.
In the light emitting elements ED and ED-a according to an embodiment shown in
The electron transport region ETR may be a layer formed of a single material, a layer formed of different materials, or a structure having multiple layers formed of different materials.
For example, the electron transport region ETR may have a single layer structure of an electron injection layer or an electron transport layer, and may have a single layer structure formed of an electron injection material and an electron transport material. The electron transport region ETR may have a single layer structure formed of different materials, or may have a structure in which an electron transport layer/electron injection layer, or a hole blocking layer/electron transport layer/electron injection layer are stacked in order from the emission layer EML, but is not limited thereto. The electron transport region ETR may have a thickness in a range of, for example, about 1,000 Å to about 1,500 Å.
The electron transport region ETR may be formed using various methods such as a vacuum deposition method, a spin coating method, a cast method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, a laser induced thermal imaging (LITI) method, etc.
The electron transport region ETR may include a compound represented by Formula ET-2 below.
In Formula ET-2, at least one of X1 to X3 may each be N and the remainder of X1 to X3 may each independently be C(Ra). Ra may be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. An to Ar3 may each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.
In Formula ET-2, a to c may each independently be an integer of 0 to 10. In Formula ET-2, L1 to L3 may each independently be a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. In case that a to c are an integer of 2 or greater, L1 to L3 may each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.
The electron transport region ETR may include an anthracene-based compound. However, the embodiment of the disclosure is not limited thereto, and the electron transport region ETR may include, for example, tris(8-hydroxyquinolinato)aluminum (Alq3), 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, 2,4,6-tris(3′-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzoimidazolyl-1-ylphenyl)-9,10-dinaphthylanthracene, 1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), 3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD), bis(2-methyl-8-quinolinolato-N1,08)-(1,1′-biphenyl-4-olato)aluminum (Balq), berylliumbis(benzoquinolin-10-olate (Bebg2), 9,10-di(naphthalene-2-yl)anthracene (ADN), 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene (BmPyPhB), or a mixture thereof.
The electron transport region ETR may include at least one of Compounds ET1 to ET36 below.
The electron transport region ETR may include halogenated metals such as LiF, NaCl, CsF, RbCl, RbI, CuI, and KI, lanthanide metals such as Yb, or co-deposition materials of a halogenated metal and a lanthanide metal. For example, the electron transport region ETR may include K:Yb, RbI:Yb, LiF:Yb, etc. as a co-deposition material. For the electron transport region ETR, a metal oxide such as Li2O and BaO, 8-hydroxyl-lithium quinolate (Liq), etc. may be used, but the embodiment of the disclosure is limited thereto. The electron transport region ETR may be formed of a mixture material of an electron transport material and an insulating organo-metal salt. The organo-metal salt may be a material having an energy band gap of greater than or equal to about 4 eV. For example, the organo-metal salt may include, for example, metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, or metal stearates.
The electron transport region ETR may further include, for example, at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide (TSPO1), and 4,7-diphenyl-1,10-phenanthroline (Bphen) in addition to the materials described above, but the embodiment of the disclosure is not limited thereto.
At least one of the electron injection layer, the electron transport layer, and the hole blocking layer of the electron transport region ETR may include the compounds that may be included in the electron transport region described above.
In case that the electron transport region ETR includes the electron transport layer, the electron transport layer may have a thickness in a range of about 100 Å to about 1,000 Å. For example, the electron transport layer may have a thickness in a range of about 150 Å to about 500 Å. In case that the thickness of the electron transport layer satisfies the above-described range, satisfactory electron transport properties may be obtained without a substantial increase in driving voltage. In case that the electron transport region ETR includes the electron injection layer, the electron injection layer may have a thickness in a range of about 1 Å to about 100 Å. For example, the electron injection layer may have a thickness in a range of about 3 Å to about 90 Å. In case that the thickness of the electron injection layer satisfies the above-described range, satisfactory electron injection properties may be obtained without a substantial increase in driving voltage.
The second electrode EL2 may be provided on the electron transport region ETR. The second electrode EL2 may be a common electrode. The second electrode EL2 may be a cathode or an anode but the embodiment of the disclosure is not limited thereto. For example, in case that the first electrode EL1 is an anode, the second electrode EL2 may be a cathode, and in case that the first electrode EL1 is a cathode, the second electrode EL2 may be an anode. The second electrode may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, W, In, Sn, and Zn, an oxide thereof, a compound thereof, or a mixture thereof.
The second electrode EL2 may be a transmissive electrode, a transflective electrode, or a reflective electrode. In case that the second electrode EL2 is a transmissive electrode, the second electrode EL2 may be formed of a transparent metal oxide, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc.
In case that the second electrode EL2 is a transflective electrode or a reflective electrode, the second electrode EL2 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, L1, Ca, LiF/Ca, LiF/Al, Mo, Ti, Yb, W, a compound thereof, or a mixture thereof (e.g., AgMg, AgYb, or MgYb). In another embodiment, the second electrode EL2 may have a multilayer structure including a reflective film or a transflective film formed of the above-described materials, and a transparent conductive film formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. For example, the second electrode EL2 may include the above-described metal materials, a combination of two or more metal materials selected from the above-described metal materials, or oxides of the above-described metal materials.
Although not shown, the second electrode EL2 may be electrically connected with an auxiliary electrode. In case that the second electrode EL2 is electrically connected with the auxiliary electrode, the resistance of the second electrode EL2 may decrease.
A capping layer (not shown) may be further disposed on the second electrode EL2 of the light emitting elements ED and ED-a according to an embodiment. The capping layer may be a multilayer or a single layer.
In an embodiment, the capping layer may be an organic layer or an inorganic layer. For example, in case that the capping layer includes an inorganic material, the inorganic material may include an alkali metal compound such as LiF, or an alkaline earth metal compound such as MgF2, SiON, SiNx, SiOy, etc.
For example, in case that the capping layer includes an organic material, the organic material may include α-NPD, NPB, TPD, m-MTDATA, Alq3 CuPc, N4,N4,N4′,N4′-tetra(biphenyl-4-yl) biphenyl-4,4′-diamine (TPD15), 4,4′,4″-tris(carbazol sol-9-yl)triphenylamine (TCTA), etc., or may include epoxy resins or acrylates such as methacrylates. However, the embodiment of the disclosure is not limited thereto, and the capping layer may include compounds P1 to P5 below.
The capping layer may have a refractive index of greater than or equal to about 1.6. For example, the capping layer may have a refractive index of greater than or equal to about 1.6 in a wavelength range of about 550 nm to about 660 nm.
Referring to
Referring to
Referring to
Referring to
The electrode layer PEL may include silver (Ag), gold (Au), platinum (Pt), aluminum (Al), copper (Cu), tin (Sn), gallium (Ga), indium (In), nickel (Ni), or any combination thereof. The electrode layer PEL may include a metal material made of silver (Ag), gold (Au), platinum (Pt), aluminum (Al), copper (Cu), tin (Sn), gallium (Ga), indium (In), or nickel (Ni), or the electrode layer PEL may include a metal material made of a combination of two or more of silver (Ag), gold (Au), platinum (Pt), aluminum (Al), copper (Cu), tin (Sn), gallium (Ga), indium (In), and nickel (Ni).
Referring to
The electro-spinning device may include a spinning nozzle ESD, a collector CT, and a power supply unit (not shown). The electro-spinning device may further include a storage tank (not shown) for supplying a polymer solution to the spinning nozzle ESD. Components included in the electro-spinning device are not limited to the components described above. At least some of the components described above may be omitted, and other components may be added.
The spinning nozzle ESD may spin a polymer solution supplied from the storage tank (not shown). The spinning nozzle ESD may spin the polymer solution by a voltage applied from the power supply unit (not shown). As used herein, the “polymer solution” may be a polymer material that is dissolved in a solvent. The solvent is not particularly limited as long as the polymer material used may be dissolved therein.
The collector CT may collect the polymer solution spun from the spinning nozzle ESD. The collector CT may have a voltage opposite to that of the spinning nozzle ESD. A predetermined (or selectable) voltage may be applied to the spinning nozzle ESD and the collector CT from the power supply unit (not shown), and a voltage difference between the spinning nozzle ESD and the collector CT may cause the polymer solution to be spun in the form of fibers from the spinning nozzle ESD and thus to be collected in the collector CT. The solvent included in the polymer solution may be vaporized upon the spinning, and the dried polymer fibers may be collected in the collector CT.
The collector CT may be variously shaped and provided. In
Referring to
The first polymer fiber PF1 may be in the form of a nano-scale fiber. The first polymer fiber PF1 may have a first diameter (or a first width). In an embodiment, the first diameter may be in a range of about 300 nm to about 500 nm.
The type of the first polymer fiber PF1 is not particularly limited, and for example, the first polymer fiber PF1 may include at least one selected from the group consisting of polyvinyl acetate, polyurethane, polyurethane copolymer, cellulose derivative, polymethyl methacrylate (PMMA), polymethyl acrylate (PMA), polyacrylic copolymer, polyvinyl acetate copolymer, polyvinyl alcohol (PVA), polyfurfuryl alcohol (PPFA), polystyrene (PS), polystyrene copolymer, polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene oxide copolymer, polypropylene oxide copolymer, polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone, polyvinylpyrrolidone (PVP), polyvinylfluoride, polyvinylidenefluoride copolymer, and polyamide. However, the material of the first polymer fiber PF1 is not limited thereto.
The first polymer fibers PF1 may be randomly disposed on the electrode layer PEL. The first polymer fiber PF1 may have an arbitrary pattern that is not repeated on the electrode layer PEL. The first polymer fiber PF1 may extend in an arbitrary direction on the substrate RB. The first polymer fibers PF1 may extend in a random direction on the substrate RB. The distance between the adjacent first polymer fibers PF1 may be different.
At least two or more of the first polymer fibers PF1 may be arranged to intersect each other on the substrate RB.
Referring to
The second polymer fiber PF2 may be in the form of a micro-scale fiber. The second polymer fiber PF2 may have a second diameter (or a second width). The second diameter of the second polymer fiber PF2 may be different from the first diameter of the first polymer fiber PF1. The second diameter of the second polymer fiber PF2 may be greater than the first diameter of the first polymer fiber PF1. In an embodiment, the second diameter may be in a range of about 2 μm to about 3 μm.
The type of the second polymer fiber PF2 is not particularly limited, and for example, the second polymer fiber PF2 may include at least one selected from the group consisting of polyvinyl acetate, polyurethane, polyurethane copolymer, cellulose derivative, polymethyl methacrylate (PMMA), polymethyl acrylate (PMA), polyacrylic copolymer, polyvinyl acetate copolymer, polyvinyl alcohol (PVA), polyfurfuryl alcohol (PPFA), polystyrene (PS), polystyrene copolymer, polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene oxide copolymer, polypropylene oxide copolymer, polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone, polyvinylpyrrolidone (PVP), polyvinylfluoride, polyvinylidenefluoride copolymer, and polyamide. However, the material of the second polymer fiber PF2 is not limited thereto.
The second polymer fiber PF2 and the first polymer fiber PF1 may include a same material. However, the embodiment of the disclosure is not limited thereto, and the first polymer fiber PF1 and the second polymer fiber PF2 may include different materials.
The second polymer fibers PF2 may be randomly disposed on the electrode layer PEL. The second polymer fiber PE2 may have an arbitrary pattern that is not repeated on the electrode layer PEL. The second polymer fiber PF2 may extend in an arbitrary direction on the substrate RB. The second polymer fibers PF2 may extend in a random direction on the substrate RB. The distance between the adjacent second polymer fibers PF2 may be different.
The second polymer fiber PF2 may be disposed on the electrode layer PEL, and arranged to intersect at least one of the adjacent first polymer fiber PF1 or the adjacent second polymer fiber PF2.
Although not shown, after the disposing of the first polymer fiber PF1 and the second polymer fiber PF2 on the electrode layer PEL, heat-treating the first polymer fiber PF1 and the second polymer fiber PF2 may be performed. The heat-treating of the first polymer fiber PF1 and the second polymer fiber PF2 may increase adhesion between the electrode layer PEL and the first and second polymer fibers PF1 and PF2. The heat-treating of the first polymer fiber PF1 and the second polymer fiber PF2 may include cross-linking of the first polymer fiber PF1 and the second polymer fiber PF2. Accordingly, the adhesion between the electrode layer PEL and the first and second polymer fibers PF1 and PF2 may be increased.
The heat-treating may include exposing the first polymer fiber PF1 and the second polymer fiber PF2 to a first temperature condition. The first temperature may be above the glass transition temperature and below the melting point of each of the first polymer fiber PF1 and the second polymer fiber PF2. The first temperature is not particularly limited as long as the temperature is less than the melting point of each of the first polymer fiber PF1 and the second polymer fiber PF2, and, for example, the first temperature may be in a range of about 80° C. to about 150° C. The first temperature in the heat-treating may be appropriately set according to the type and capacity of the first polymer fiber PF1 and the second polymer fiber PF2. As used herein, the glass transition temperature and melting point of each of the first polymer fiber PF1 and the second polymer fiber PF2 may indicate one measured through differential scanning calorimetry (DSC).
As shown in
Referring to
The electrode layer PEL may be divided into a first portion overlapping the first polymer fiber PF1 and the second polymer fiber PF2 in the third direction DR3, and a second portion that is not overlapping the first polymer fiber PF1 and the second polymer fiber PF2 in the third direction DR3. The first portion of the electrode layer PEL may not be removed after the etching of the electrode layer PEL and may remain to form multiple fibrous electrodes FE. The second portion of the electrode layer PEL may be a portion that is removed after the etching of the electrode layer PEL.
The etching of the electrode layer PEL may include dry etching and/or wet etching.
In an embodiment, in the etching of the electrode layer PEL, dry etching and wet etching may be sequentially performed.
For the dry etching, at least one of plasma etching, reactive ion etching (RIE), and reactive ion beam etching may be used. In the dry etching, at least one gas selected from the group consisting of SiF4, CF4, C3F8, C2F6, CHF3, CClF3, O2, NF3, and SF6 may be used as a process gas. The process gas may further include an inert gas such as Ar or N2 which is not directly involved in the etching reaction so as to increase etching reactivity or to increase etching uniformity.
The wet etching may include an isotropic etching process. An etchant used for wet etching is not particularly limited, and for example, may include at least one of hydrofluoric acid (HF), hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4), phosphoric acid (H3PO4), oxalic acid, buffered oxide etchant (BOE), sodium hydroxide (NaOH), hydroxide potassium (KOH), hydrogen peroxide (H2O2), acetone, tetramethyl ammonium hydroxide (TMAH), ethylenediamine, pyrocatechol, hydrazine chelating amine, 1,2-diaminoethane, N, N-dimethylacetamide, and water, or a mixed solution by a combination thereof.
Referring to
Multiple fibrous electrodes FE may be formed after the etching of the electrode layer PEL, using the first polymer fiber PF1 and the second polymer fiber PF2 as masks. A first fibrous electrode FE1 may be formed in the portion in which the first polymer fiber PF1 is disposed in the electrode layer PEL. A second fibrous electrode FE2 may be formed in the portion in which the second polymer fiber PF2 is disposed in the electrode layer PEL. The formed first fibrous electrode FE1 and the second fibrous electrode FE2 may have different widths. The width of each of the first fibrous electrode FE1 and the second fibrous electrode FE2 may be controlled by altering the diameters of the first polymer fiber PF1 and the second polymer fiber PF2, respectively.
Referring to
Referring to
The method for manufacturing a light emitting element according to an embodiment may indicate manufacturing light emitting elements ED and ED-a of an embodiment described in
Referring to
Referring to
Referring to
Referring to
Referring to
In the describing of the method for manufacturing a light emitting element according to an embodiment with reference to
Hereinafter, a transparent electrode according to an embodiment of the disclosure will be described in detail with reference to evaluation results of transparent electrodes of Example and Comparative Examples. Example shown below are presented only for the understanding of the disclosure, and the scope of the disclosure is not limited thereto.
A polyethylene naphthalate (PEN) substrate was cut to a size of about 2.5 cm×2.5 cm and subjected to UV—O3 washing for about 10 minutes. An electrode layer having a thickness of about 40 nm was formed using Ag through thermal evaporation.
400 mg of polystyrene was dissolved in a mixed solution of 2 ml of acetone and 1 ml of dimethylformamide to prepare a polymer solution. Thereafter, the prepared polymer solution was electro-spun using an electro-spinning device to form a first polymer fiber having a diameter of about 300 nm to about 500 nm and a second polymer fiber having a diameter of about 2 μm to about 3 μm on the electrode layer.
The first and second polymer fibers were heat-treated at 130° C. for about 10 minutes. Thereafter, the resulting product was oxygen plasma treated, and immersed using H2O2 as an etchant to etch the electrode layer. The first and second polymer fibers were dissolved and removed using chloroform. Thereafter, a buffer layer having a thickness of about 240 nm was formed using IZO.
In Comparative Example 1, a transparent electrode was manufactured under the same conditions as in Example, except that a second polymer fiber was used alone as compared with Example above.
In Comparative Example 2, a transparent electrode was manufactured under the same conditions as in Example, except that a first polymer fiber was used alone as compared with Example above.
In Comparative Example 3, a transparent electrode having a single-layer structure in which only an electrode layer having a thickness of about 40 nm was formed using Ag on a polyethylene naphthalate substrate was manufactured.
In Comparative Example 4, a transparent electrode was manufactured by applying silver nanowires onto a polyethylene naphthalate substrate.
In
Referring to
Accordingly, it is believed that light emitting elements ED and ED-a may exhibit excellent electrical properties in case that the transparent electrode of Example is applied.
In
Referring to
On the other hand, it is seen that the light transmittance of the transparent electrodes of Comparative Examples 1 and 2 in the wavelength range of about 400 nm to about 500 nm is at a level corresponding to the light transmittance of the transparent electrode of Example, but the light transmittance of the transparent electrodes of Comparative Examples 1 and 2 in the wavelength range of about 500 nm to about 800 nm is lower than that of the transparent electrode of Example. It is also seen that Comparative Examples 1 and 2 have increased haze as compared with Example.
Surface coverage of the polymer fiber may increase with longer spinning time. As used herein, the “surface coverage” may be the area ratio of a polymer fiber with respect to the entire area of an electrode layer after electro-spinning. In case that the surface coverage of the polymer fiber increases, the area ratio of a fibrous electrode formed may increase.
Referring to
According to the method for manufacturing a transparent electrode according to an embodiment of the disclosure, a transparent electrode that satisfies both low electrical resistance and high light transmittance may be obtainable by using the nano-scale first polymer fiber and the micro-scale second polymer fiber together and controlling the spinning time of the first polymer fiber and the second polymer fiber. Referring back to
In
According to a method for manufacturing a transparent electrode according to an embodiment of the disclosure, a transparent electrode having excellent electrical, optical, and mechanical properties may be manufactured.
A light emitting element according to an embodiment of the disclosure may include a transparent electrode having a first fibrous electrode and a second fibrous electrode, which have different widths in a plan view, and thus may have excellent electrical, optical, and mechanical properties.
According to a method for manufacturing a light emitting element according to an embodiment of the disclosure, a light emitting element having excellent electrical, optical, and mechanical properties may be manufactured.
Embodiments have been disclosed herein, and although terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent by one of ordinary skill in the art, features, characteristics, and/or elements described in connection with an embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the disclosure as set forth in the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0047113 | Apr 2022 | KR | national |
