Light emitting device and display apparatus including the same

Abstract

A light-emitting device and a display device are provided. The light-emitting device includes: a reflective layer comprising a plurality of nanostructures arranged in a regular periodic structure in two dimensions; a first electrode disposed on the plurality of nanostructures of the reflective layer; an organic emitting layer disposed on the first electrode; and a second electrode disposed on the organic emitting layer. The spacing between adjacent nanostructures in the central portion of the reflective layer or the spacing between adjacent nanostructures in the peripheral portion surrounding the central portion of the reflective layer is equal to or less than 70 nanometers.

Description

[0001] Cross-reference to related applications

[0002] This application is based on and claims priority to Korean Patent Application No. 10-2021-0025958, filed on February 25, 2021, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to a light-emitting device and a display device including the light-emitting device, and more specifically, to an organic light-emitting device and an organic light-emitting display device that have high color purity even without the use of a color filter. Background Technology

[0004] Organic light-emitting diodes (OLEDs) are display devices that form images when holes injected from the anode and electrons injected from the cathode combine in an organic emitting layer to emit light. OLEDs have excellent display characteristics, such as wide viewing angles, fast response times, thinness, low manufacturing costs, and high contrast.

[0005] Furthermore, OLEDs can emit desired colors by selecting appropriate materials as the organic emitting layer. Based on this principle, OLEDs can be used to implement color display devices. For example, the organic emitting layer of blue pixels can be formed from organic materials that produce blue light, the organic emitting layer of green pixels can be formed from organic materials that produce green light, and the organic emitting layer of red pixels can be formed from organic materials that produce red light. Moreover, white OLEDs can be implemented by arranging multiple organic materials that produce blue, green, and red light respectively in a single organic emitting layer, or by arranging pairs of organic materials of two or more types that are complementary to each other. Summary of the Invention

[0006] An organic light-emitting device and an organic light-emitting display device are provided that have high color purity even without the use of color filters.

[0007] It provides submicron-sized organic light-emitting devices.

[0008] An ultra-high resolution organic light-emitting display device with submicron pixels is provided.

[0009] Additional aspects will be set forth in part in the description which follows, and will become apparent in part from the description itself, or may be learned by practice of the embodiments presented.

[0010] According to one aspect of this disclosure, a light-emitting device is provided including a reflective layer comprising a plurality of nanostructures arranged in a regular periodic structure in two dimensions; a first electrode disposed on the plurality of nanostructures of the reflective layer; an organic emitting layer disposed on the first electrode; and a second electrode disposed on the organic emitting layer, wherein the reflective layer and the second electrode form a microcavity having a resonant wavelength, the resonant wavelength of the microcavity being based on the width of each of the plurality of nanostructures, the height of each of the plurality of nanostructures, the spacing between adjacent nanostructures of the plurality of nanostructures, and the period of the plurality of nanostructures, and wherein the spacing between adjacent nanostructures in the central portion of the reflective layer or the spacing between adjacent nanostructures in the peripheral portion surrounding the central portion of the reflective layer is equal to or less than 70 nanometers.

[0011] The width of each of the multiple nanostructures in the reflective layer, the height of each of the multiple nanostructures, the spacing between adjacent nanostructures, and the period of the multiple nanostructures are configured such that the resonant wavelength of the microcavity matches the emission wavelength of the light-emitting device.

[0012] The period of multiple nanostructures is smaller than the emission wavelength of the light-emitting device.

[0013] The periods of multiple nanostructures range from about 70 nanometers to about 300 nanometers.

[0014] Each of the multiple nanostructures has a height equal to or less than 200 nanometers, and each of the multiple nanostructures of the reflective layer has the same height.

[0015] The width of each of the multiple nanostructures in the reflective layer ranges from about 50 nanometers to about 200 nanometers.

[0016] The spacing between adjacent nanostructures in the central portion of the reflective layer or between adjacent nanostructures in the peripheral portion of the reflective layer ranges from about 10 nanometers to about 70 nanometers.

[0017] The width of the light-emitting device is equal to or less than 2 micrometers.

[0018] The reflective layer includes a plurality of first nanostructures disposed in the central portion of the reflective layer and a plurality of second nanostructures disposed in the peripheral portion of the reflective layer, wherein a first interval between two adjacent nanostructures in the plurality of first nanostructures is smaller than a second interval between two adjacent nanostructures in the plurality of second nanostructures.

[0019] The first width of each of the plurality of first nanostructures is the same as the second width of each of the plurality of second nanostructures.

[0020] The reflective layer includes a plurality of first nanostructures disposed in the central portion of the reflective layer and a plurality of second nanostructures disposed in the peripheral portion of the reflective layer, wherein a first interval between two adjacent nanostructures in the plurality of second nanostructures is smaller than a second interval between two adjacent nanostructures in the plurality of first nanostructures.

[0021] The reflective layer includes a plurality of first nanostructures and a plurality of second nanostructures arranged in the central portion of the reflective layer and a plurality of third nanostructures arranged in the peripheral portion of the reflective layer, wherein a first interval between two adjacent nanostructures in the plurality of first nanostructures is different from a second interval between two adjacent nanostructures in the plurality of second nanostructures, and a second interval between two adjacent nanostructures in the plurality of second nanostructures is different from a third interval between two adjacent nanostructures in the plurality of third nanostructures.

[0022] The first period of multiple first nanostructures is the same as the second period of multiple second nanostructures.

[0023] The first width of each of the plurality of first nanostructures is different from the second width of each of the plurality of second nanostructures, while the second width of each of the plurality of second nanostructures is the same as the third width of each of the plurality of third nanostructures.

[0024] Multiple first nanostructures are arranged together with multiple second nanostructures in the central part of the reflective layer.

[0025] Multiple second nanostructures are arranged in portions surrounding multiple first nanostructures, and multiple third nanostructures are arranged in portions surrounding multiple second nanostructures.

[0026] The second interval between two adjacent nanostructures in the plurality of second nanostructures is smaller than the third interval between two adjacent nanostructures in the plurality of third nanostructures, and the first period of the plurality of first nanostructures is smaller than the third period of the plurality of third nanostructures, and the second period of the plurality of second nanostructures is smaller than the third period of the plurality of third nanostructures.

[0027] The first interval between two adjacent nanostructures in the plurality of first nanostructures is smaller than the second interval between two adjacent nanostructures in the plurality of second nanostructures, and the second interval between two adjacent nanostructures in the plurality of second nanostructures is smaller than the third interval between two adjacent nanostructures in the plurality of third nanostructures.

[0028] The spacing between adjacent nanostructures is the same throughout the entire reflective layer.

[0029] According to another aspect of this disclosure, a display device is provided, including a first pixel configured to emit light of a first wavelength band; and a second pixel configured to emit light of a second wavelength band different from the first wavelength band, wherein the first pixel includes: a reflective layer including a plurality of nanostructures arranged in a regular periodic structure in a two-dimensional manner; a first electrode disposed on the plurality of nanostructures of the reflective layer; an organic emitting layer disposed on the first electrode; and a second electrode disposed on the organic emitting layer, wherein the reflective layer and the second electrode form a microcavity having a resonant wavelength, the resonant wavelength of the microcavity being based on the width of each of the plurality of nanostructures, the height of each of the plurality of nanostructures, the spacing between adjacent nanostructures of the plurality of nanostructures, and the period of the plurality of nanostructures, and wherein the spacing between adjacent nanostructures in the central portion of the reflective layer or the spacing between adjacent nanostructures in the peripheral portion surrounding the central portion of the reflective layer is equal to or less than 70 nanometers.

[0030] The reflective layer includes a plurality of first nanostructures disposed in the central portion of the reflective layer and a plurality of second nanostructures disposed in the peripheral portion of the reflective layer, wherein a first interval between two adjacent nanostructures in the plurality of first nanostructures is smaller than a second interval between two adjacent nanostructures in the plurality of second nanostructures.

[0031] The reflective layer includes a plurality of first nanostructures disposed in the central portion of the reflective layer and a plurality of second nanostructures disposed in the peripheral portion of the reflective layer, wherein a first interval between two adjacent nanostructures in the plurality of second nanostructures is smaller than a second interval between two adjacent nanostructures in the plurality of first nanostructures.

[0032] The reflective layer includes a plurality of first nanostructures and a plurality of second nanostructures arranged in the central portion of the reflective layer and a plurality of third nanostructures arranged in the peripheral portion of the reflective layer, wherein a first interval between two adjacent nanostructures in the plurality of first nanostructures is different from a second interval between two adjacent nanostructures in the plurality of second nanostructures, and a second interval between two adjacent nanostructures in the plurality of second nanostructures is different from a third interval between two adjacent nanostructures in the plurality of third nanostructures.

[0033] The spacing between adjacent nanostructures is the same throughout the entire reflective layer.

[0034] The width of each of the first and second pixels is equal to or less than 2 micrometers.

[0035] The width of each nanostructure is the diameter of each nanostructure.

[0036] According to another aspect of this disclosure, a light-emitting device including a reflective layer is provided, the reflective layer comprising: a plurality of nanostructures arranged in two dimensions; a first electrode disposed on the plurality of nanostructures of the reflective layer; an organic emitting layer disposed on the first electrode; and a second electrode disposed on the organic emitting layer, wherein the reflective layer and the second electrode form a microcavity having a resonant wavelength, and wherein the spacing between adjacent nanostructures in the central portion of the reflective layer or the spacing between adjacent nanostructures in the peripheral portion surrounding the central portion of the reflective layer is equal to or less than 70 nanometers.

[0037] According to another aspect of this disclosure, a light-emitting device including a reflective layer is provided, the reflective layer comprising: a plurality of nanostructures arranged in two dimensions; a first electrode disposed on the plurality of nanostructures of the reflective layer; an organic emitting layer disposed on the first electrode; and a second electrode disposed on the organic emitting layer, wherein the reflective layer and the second electrode form a microcavity having a resonant wavelength, and wherein a first spacing between a plurality of adjacent nanostructures in a central portion of the reflective layer is different from a second spacing between a plurality of adjacent nanostructures in a peripheral portion surrounding the central portion of the reflective layer. Attached Figure Description

[0038] The above and other aspects, features, and advantages of particular embodiments will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0039] Figure 1 This is a cross-sectional view showing the structure of a light-emitting device according to an example embodiment;

[0040] Figure 2 This illustrates an example embodiment. Figure 1 Detailed cross-sectional view of the structure of the organic emission layer;

[0041] Figure 3 This illustrates an embodiment according to another example. Figure 1 Detailed cross-sectional view of the structure of the organic emission layer;

[0042] Figure 4A It shows Figure 1 A plan view of the arrangement of multiple nanostructures in the reflective layer;

[0043] Figure 4B It shows Figure 1 A perspective view of the arrangement of multiple nanostructures in the reflective layer;

[0044] Figure 5 It is a graph showing the emission characteristics of a light-emitting device based on the size of the light-emitting device and the spacing between two adjacent nanostructures;

[0045] Figure 6This is a plan view illustrating the arrangement of multiple nanostructures in a reflective layer according to an example embodiment;

[0046] Figure 7 This is a plan view showing the arrangement of multiple nanostructures in a reflective layer according to another example embodiment;

[0047] Figure 8 It shows including Figure 6 and Figure 7 A graph showing the emission characteristics of the light-emitting device, including the reflective layer.

[0048] Figure 9A It shows including Figure 6 A view of the emission area and emission intensity inside the organic emission layer of a light-emitting device, including the reflective layer;

[0049] Figure 9B and Figure 9C Each of these is a view showing the emission area and emission intensity inside the organic emission layer of a light-emitting device according to a comparative scale;

[0050] Figure 10 This is a plan view showing the arrangement of multiple nanostructures in a reflective layer according to another example embodiment;

[0051] Figure 11 It shows including Figure 10 A graph showing the emission characteristics of the light-emitting device, including the reflective layer.

[0052] Figure 12A It shows including Figure 10 A view of the emission area and emission intensity inside the organic emission layer of a light-emitting device, including the reflective layer;

[0053] Figure 12B This is a view showing the emission area and emission intensity inside the organic emission layer of a light-emitting device according to a comparative example;

[0054] Figure 13 This is a plan view showing the arrangement of multiple nanostructures in a reflective layer according to another example embodiment;

[0055] Figure 14 This is a plan view showing the arrangement of multiple nanostructures in a reflective layer according to another example embodiment;

[0056] Figure 15 It shows including Figure 13 and Figure 14 A graph showing the emission characteristics of the light-emitting device, including the reflective layer.

[0057] Figure 16 This is a cross-sectional view showing the structure of a light-emitting device according to another example embodiment;

[0058] Figure 17 This is a cross-sectional view showing the structure of a display device according to an example embodiment; and

[0059] Figure 18 This is a cross-sectional view showing the structure of a display device according to another example embodiment. Detailed Implementation

[0060] Referring now to the embodiments, examples of which are illustrated in the accompanying drawings, wherein similar reference numerals throughout the drawings denote similar elements. In this respect, embodiments may take different forms and should not be construed as limited to the description set forth herein. Therefore, exemplary embodiments are described below only with reference to the accompanying drawings to explain various aspects. The term “and / or” as used herein includes any and all combinations of one or more of the related listed items. Expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than modifying individual elements in the list.

[0061] In the following, a light-emitting device and a display device including the light-emitting device will be described in detail with reference to the accompanying drawings. The same reference numerals always denote the same elements, and the dimensions of the elements may be enlarged in the drawings for clarity and ease of explanation. Furthermore, the exemplary embodiments described below are merely illustrative, and various modifications can be made based on these exemplary embodiments.

[0062] It will be understood that when referring to an element "on" another element, the element may be directly on the other element, or there may be an intermediate element in between. The singular forms "a," "an," and "described" are intended to also include the plural forms, unless the context clearly indicates otherwise. Throughout the specification, when a part "includes" an element, it may also include another element, without excluding the presence of the other element, unless otherwise stated.

[0063] In the context of describing this disclosure, the terms “a,” “an,” and “the,” and similar pronouns, should be interpreted to cover both singular and plural cases. Unless otherwise stated herein or clearly contradicted by the context, the steps of all methods described herein may be performed in any suitable order, and are not limited to the order described.

[0064] Terms such as “unit” and “module” refer to a unit used to perform at least one function or operation, and these units can be implemented as hardware or software or a combination of hardware and software.

[0065] Furthermore, the lines or components connecting the elements shown in the accompanying drawings only illustrate functional connections and / or physical or electrical connections. In actual devices, connections between components can be represented by a variety of replaceable or addable functional, physical, or electrical connections.

[0066] Unless otherwise required, any and all examples or language used herein are intended only to better describe this disclosure and do not impose any limitation on the scope of this disclosure.

[0067] Figure 1 This is a cross-sectional view showing the structure of a light-emitting device according to an example embodiment. (Refer to...) Figure 1 The light-emitting device 100 may include a reflective layer 110 (the reflective layer 110 includes a plurality of nanostructures 111 arranged in a regular periodic structure in two dimensions), a first electrode 121 disposed on the reflective layer 110, an organic emission layer 130 disposed on the first electrode 121, and a second electrode 122 disposed on the organic emission layer 130.

[0068] The light-emitting device 100 may further include a transparent passivation layer 140 disposed on the second electrode 122. According to an example embodiment, the passivation layer 140 can protect the second electrode 122. Furthermore, the light-emitting device 100 may also include a planarization layer 115 disposed between the reflective layer 110 and the first electrode 121 to planarize the bottom surface of the first electrode 121. Each of the planarization layer 115 and the passivation layer 140 may be formed of a material that allows light generated by the organic emitting layer 130 to pass through. The planarization layer 115 may be disposed on the reflective layer 110 to contact all the nanostructures 111 of the reflective layer 110. For this purpose, the bottom surface of the planarization layer 115 may fill between the nanostructures 111 and may have a shape complementary to the shape of the nanostructures 111 formed on the top surface of the reflective layer 110. The top surface of the planarization layer 115 is flat, and the first electrode 121 is disposed on the top surface of the planarization layer 115.

[0069] The light-emitting device 100 can be an organic light-emitting diode (OLED). For example, Figure 2 This illustrates an example embodiment. Figure 1 A detailed cross-sectional view of the structure of the organic emitter layer 130. (Refer to...) Figure 2 The organic emitting layer 130 may include a hole injection layer 132 disposed on the top surface of the first electrode 121, an organic emitting material layer 131 disposed on the hole injection layer 132, and an electron injection layer 133 disposed on the organic emitting material layer 131. In this structure, light is generated by the recombination of holes injected by the hole injection layer 132 and electrons injected by the electron injection layer 133 in the organic emitting material layer 131. The wavelength of the generated light can be determined by the band gap of the emitting material of the organic emitting material layer 131.

[0070] Furthermore, the organic emission layer 130 may also include a hole transport layer 134 disposed between the hole injection layer 132 and the organic emission material layer 131 to facilitate hole transport. Additionally, the organic emission layer 130 may also include an electron transport layer 135 disposed between the electron injection layer 133 and the organic emission material layer 131 to facilitate electron transport. Furthermore, according to another example embodiment, the organic emission layer 130 may include various additional layers if necessary. For example, the organic emission layer 130 may also include an electron blocking layer between the hole transport layer 134 and the organic emission material layer 131, and may also include a hole blocking layer between the organic emission material layer 131 and the electron transport layer 135.

[0071] The organic emitting material layer 131 can be configured to emit visible light. For example, the organic emitting material layer 131 can be configured to emit light corresponding to any one of the wavelengths corresponding to red light, green light, and blue light. Alternatively, the organic emitting material layer 131 can be configured to emit white visible light including all red, green, and blue light.

[0072] For example, Figure 3 This illustrates an embodiment according to another example. Figure 1 A detailed cross-sectional view of the structure of the organic emitter layer 130. (Refer to...) Figure 3 The organic emitting material layer 131 may include a first organic emitting material layer 131a emitting red light, a second organic emitting material layer 131b emitting green light, and a third organic emitting material layer 131c emitting blue light. Furthermore, according to an example embodiment, one or more exciton blocking layers 136 may be disposed within the organic emitting layer 130. For example, the exciton blocking layer 136 may be disposed between the first organic emitting material layer 131a and the second organic emitting material layer 131b, and between the second organic emitting material layer 131b and the third organic emitting material layer 131c. In this case, the organic emitting layer 130 can emit white light. However, the structure of the organic emitting layer 130 emitting white light is not limited to this. As an alternative to including three organic emitting material layers (i.e., the first to third organic emitting material layers 131a, 131b, and 131c), the organic emitting layer 130 may include two organic emitting material layers with complementary colors.

[0073] According to an exemplary embodiment, a first electrode 121 disposed on the bottom surface of the organic emitting layer 130 can be used as an anode providing holes. According to an exemplary embodiment, a second electrode 122 disposed on the top surface of the organic emitting layer 130 can be used as a cathode providing electrons. According to an exemplary embodiment, the first electrode 121 can be formed of a material with a relatively high work function, and the second electrode 122 can be formed of a material with a relatively low work function.

[0074] Furthermore, the first electrode 121 may be a transparent electrode that allows light (e.g., visible light) to pass through. For example, the first electrode 121 may include a transparent conductive oxide, such as indium tin oxide (ITO), indium zinc oxide (IZO), or aluminum zinc oxide (AZO).

[0075] The second electrode can be a semi-transmissive electrode that reflects a portion of the light and transmits another portion. For this purpose, the second electrode 122 can comprise a very thin reflective metal. For example, the second electrode 122 can be formed of silver (Ag), aluminum (Al), gold (Au), nickel (Ni), or alloys thereof, or can have a two-layer structure comprising silver (Ag) and magnesium (Mg) or a two-layer structure comprising aluminum (Al) and lithium (Li). The total thickness of the second electrode 122 can range from about 10 nanometers to about 50 nanometers. Because the second electrode 122 is very thin, some light can pass through the reflective metal.

[0076] The reflective layer 110 can be configured to reflect light generated by the organic emitting layer 130 and transmitted through the first electrode 121. Furthermore, the reflective layer 110 can be formed of a conductive material. For this purpose, the reflective layer 110 can be formed of silver (Ag), gold (Au), aluminum (Al), nickel (Ni), or alloys thereof. However, this disclosure is not limited thereto, and the reflective layer 110 can include other reflective materials, provided that the reflective layer 110 has high reflectivity and high conductivity.

[0077] The reflective layer 110 and the second electrode 122 can form a microcavity. In other words, a microcavity can be formed between the reflective layer 110 and the second electrode 122 of the light-emitting device 100. For example, light generated by the organic emitting layer 130 can reciprocate and resonate between the reflective layer 110 and the second electrode 122, and then light corresponding to the resonant wavelength of the microcavity can be emitted to the outside through the second electrode 122.

[0078] The resonant wavelength of the microcavity formed between the reflective layer 110 and the second electrode 122 can be determined by the optical length L of the microcavity. For example, when the resonant wavelength of the microcavity is λ, the optical length of the microcavity can be nλ / 2 (n is a natural number). The optical length L of the microcavity can be determined by the sum of the optical thicknesses of the layers constituting the microcavity between the reflective layer 110 and the second electrode 122, the phase retardation of the second electrode 122, and the phase shift (e.g., phase retardation) of the reflective layer 110. Here, the optical thickness of the layers constituting the microcavity between the reflective layer 110 and the second electrode 122 is not a simple physical thickness, but a thickness that takes into account the refractive index of the material constituting the microcavity. For example, the optical thickness of the layers constituting the microcavity can be the sum of the optical thickness of the planarization layer 115, the optical thickness of the first electrode 121, and the optical thickness of the organic emitting layer 130.

[0079] According to an example embodiment, the optical length L or resonant wavelength of the microcavity can be adjusted by regulating only the phase shift caused by the reflective layer 110 while fixing the optical thickness of the layers constituting the microcavity and the phase delay caused by the second electrode 122. To adjust the phase shift via the reflective layer 110, a phase modulation surface is formed on the reflective surface of the reflective layer 110 facing the first electrode 121. The phase modulation surface can include very small nanostructures. For example, the phase modulation surface of the reflective layer 110 can have a metastructure in which nanostructures with dimensions smaller than the wavelength of visible light are periodically arranged.

[0080] Return to reference Figure 1 The reflective layer 110 may include a phase modulation surface having a metastructure formed on its top surface facing the first electrode 121. The phase modulation surface of the reflective layer 110 may include a plurality of nanostructures 111 arranged regularly and periodically on the top surface of the reflective layer 110. The plurality of nanostructures 111 may have a columnar shape protruding from the top surface toward the first electrode 121. For example, each of the plurality of nanostructures 111 may have a cylindrical shape or a polygonal prism shape. The plurality of nanostructures 111 may be integrally formed with the reflective layer 110 on its top surface.

[0081] For example, when each nanostructure 111 has a cylindrical shape, the optical properties of the phase modulation surface (e.g., the phase delay of reflected light) can be determined by the diameter of each nanostructure 111, the height H of each nanostructure 111, the spacing S between two adjacent nanostructures 111, and the spacing or period P of the plurality of nanostructures 111. When each nanostructure 111 has a polygonal prism shape, the optical properties of the phase modulation surface can be determined by the maximum width of each nanostructure 111, the height H of each nanostructure 111, the spacing S between two adjacent nanostructures, and the spacing or period P of the plurality of nanostructures 111. Hereinafter, the diameter or maximum width of each nanostructure 111 is referred to as the width dimension WD of the nanostructure 111.

[0082] When the size of each nanostructure 111 on the phase modulation surface is smaller than the resonant wavelength, the incident light resonates in the peripheral portion of the nanostructure 111 to form multiple nano-optical resonant structures. Specifically, the electric field component of the incident light does not penetrate into the space between the nanostructures 111, and only the magnetic field component resonates in the peripheral portion of the nanostructures 111. Therefore, the multiple nano-optical resonant structures formed in the space between the nanostructures 111 are cylindrical magnetic resonators, wherein the magnetic field component of the incident light resonates in the peripheral portion of the nanostructures 111. Furthermore, phase modulation occurs due to the combination of the nano-optical resonance of a single nanostructure 111 and the collective plasmonic resonance of multiple nanostructures 111. As a result, a phase shift larger than that caused by a simple phase shift due to the effective optical distance (H×n) may occur on the phase modulation surface of the reflective layer 110, where the effective optical distance (H×n) is determined as the product of the height H of the nanostructure 111 and the refractive index n of the nanostructure 111.

[0083] Therefore, the resonant wavelength of the microcavity can be determined by the width dimension WD of each nanostructure 111 of the phase modulation surface, the height H of each nanostructure 111, the spacing S between two adjacent nanostructures 111, and the period P of the multiple nanostructures 111. In other words, the width dimension WD of each nanostructure 111 of the phase modulation surface, the height H of each nanostructure 111, the spacing S between two adjacent nanostructures 111, and the period P of the multiple nanostructures 111 can be selected such that when the resonant wavelength of the microcavity is λ, the optical length L of the microcavity satisfies nλ / 2 (n is a natural number).

[0084] Therefore, the resonant wavelength of the microcavity can be easily matched with the emission wavelength or emission color of the light-emitting device 100. In this case, the reflective layer 110 can have the highest reflectivity for light emitting in the emission band of the light-emitting device 100. For example, when the light-emitting device 100 is a red light-emitting device, the width dimension WD of each nanostructure 111 of the phase modulation surface, the height H of each nanostructure 111, the spacing S between two adjacent nanostructures 111, and the period P of the multiple nanostructures 111 can be selected such that the resonant wavelength of the microcavity corresponds to the red band. In this way, the emission wavelength of the light-emitting device 100 can be determined using only the structure of the phase modulation surface of the reflective layer 110.

[0085] For example, Figure 4A It shows Figure 1 A plan view of the arrangement of multiple nanostructures 111 of the reflective layer 110. Figure 4B It shows Figure 1 A perspective view of the arrangement of multiple nanostructures 111 of the reflective layer 110. (Refer to...) Figure 4A and Figure 4BMultiple nanostructures 111, each with a cylindrical shape, can be arranged in a two-dimensional, regular square array. Although the nanostructures 111... Figure 4A and Figure 4B While the nanostructure 111 has a cylindrical shape, its shape is not limited to this. The nanostructure 111 can have any of a variety of cross-sectional shapes with double symmetry. For example, the nanostructure 111 can have a cylindrical shape, an elliptical cylinder shape, a polygonal prism shape such as a pentagonal prism, or a cross prism shape.

[0086] Furthermore, to prevent the microcavity from exhibiting polarization dependence, multiple nanostructures 111 can be arranged regularly and periodically with four-fold symmetry. When the microcavity exhibits polarization dependence, only light with specific polarization components will resonate, thereby reducing the luminous efficiency of the light-emitting device 100. Figure 4A and Figure 4B In the original text, the nanostructures 111 are arranged in a regular square array. However, the nanostructures 111 can be arranged in any other array, as long as they possess fourfold symmetry. For example, multiple nanostructures 111 can be arranged in a two-dimensional hexagonal array or a two-dimensional body-centered square array.

[0087] In another example embodiment, the arrangement of the plurality of nanostructures 111 can be designed differently from 4-fold symmetry, such that the light-emitting device 100 is intended to emit light with only a specific polarization component. For example, the plurality of nanostructures 111 can be arranged in a one-dimensional array pattern.

[0088] To apply the light-emitting device 100 to an ultra-high resolution display device with 10,000 pixels per inch (PPI), the light-emitting device 100 can have a small size, such as a submicron size. For example, the width W of the light-emitting device 100 can be equal to or less than 4 micrometers, equal to or less than 2 micrometers, or equal to or less than 1 micrometer. As the size of the light-emitting device 100 decreases, the number of nanostructures 111 disposed in the reflective layer 110 decreases. In this case, the collective characteristics due to the periodicity of the multiple nanostructures 111 decrease, thereby reducing the luminous efficiency. Therefore, to achieve a light-emitting device 100 with a small size, such as a submicron size, the spacing S between two adjacent nanostructures 111 can be reduced.

[0089] Figure 5 This is a graph showing the emission characteristics of the light-emitting device 100 according to the size of the light-emitting device 100 and the spacing between two adjacent nanostructures 111. The organic emitting layer 130 of the light-emitting device 100 is configured to emit white light, and the height and period of the nanostructures 111 of the reflective layer 110 are selected such that the resonant wavelength of the microcavity corresponds to the red band.

[0090] First, it can be seen that when the width of each nanostructure 111 is 160 nm and the spacing between two adjacent nanostructures 111 is 80 nm, the luminous efficiency of the light-emitting device 100 decreases rapidly as the width of the light-emitting device 100 decreases to 4 μm, 2 μm, and 1 μm. The height of all nanostructures 111 is 50 nm. Furthermore, ultraviolet or blue light in the microcavity can cause the light-emitting device 100 to emit a third-order resonance, and the peak value of the ultraviolet or blue band is similar to that of the red band.

[0091] Conversely, reducing the spacing between two nanostructures 111 can improve the luminous efficiency of the light-emitting device 100. For example, when the width of each nanostructure 111 is 140 nanometers and the spacing between two adjacent nanostructures 111 is 35 nanometers, the luminous efficiency of the light-emitting device 100 in the red band is significantly improved. Moreover, even when the width of the light-emitting device 100 is reduced to 4 micrometers, 2 micrometers, and 1 micrometer, the luminous efficiency does not decrease rapidly. The luminous efficiency of the light-emitting device 100 with a spacing of 35 nanometers between two adjacent nanostructures 111 and a width of 1 micrometer is higher than that of the light-emitting device 100 with a spacing of 80 nanometers between two adjacent nanostructures 111 and a width of 4 micrometers.

[0092] Furthermore, as the spacing between the two nanostructures 111 decreases, the peak value of the non-red band generated in the microcavity of the light-emitting device 100 shifts to shorter wavelengths. For example, the peak value of the blue band may shift to the ultraviolet region and may be invisible to the human eye. (Refer to...) Figure 5 It can be seen that when the spacing between two nanostructures 111 is reduced to 35 nanometers, the intensity of the blue wavelength of approximately 450 nanometers visible to the human eye is significantly reduced. Therefore, when the size of the light-emitting device 100 is reduced, the efficiency and color purity of the light-emitting device 100 can be prevented from decreasing by reducing the spacing between two adjacent nanostructures 111. For example, the spacing between two adjacent nanostructures 111 in the entire portion of the reflective layer 110 can be equal to or less than 70 nanometers, and the spacing, width dimension WD, period, and height of the nanostructures 111 can be the same throughout the entire portion of the reflective layer 110.

[0093] Collective plasmon resonance primarily occurs in the central portion of the phase modulation surface of the reflective layer 110. According to an example embodiment, plasmon resonance occurs in the gap spaces between nanostructures 111. According to an example embodiment, plasmon resonance typically occurs in the gap spaces between nanostructures 111 (except for the outermost gap). The outermost gap can be the gap between the outermost nanostructure 111 and its adjacent nanostructure 111. The range of plasmon resonance occurring in the gap spaces between nanostructures 111 varies depending on the number of structures (i.e., gap structures) and arrays. However, this disclosure is not limited thereto. As the size of the light-emitting device 100 decreases, the proportion of the edge portion increases relatively, and the resonant area for the target wavelength decreases. Moreover, when the spacing between nanostructures 111 throughout the reflective layer 110 decreases to improve luminous efficiency, the phase shift increases, the resonant wavelength of the microcavity shifts to longer wavelengths, and color reproduction decreases. Taking these points into consideration, a phase modulation surface with heterogeneous nanostructures can be designed. For example, when the period of multiple nanostructures 111 or the spacing between two adjacent nanostructures 111 is reduced to 70 nanometers or less only in the central part of the reflective layer 110, or when the period of multiple nanostructures 111 or the spacing between two adjacent nanostructures 111 is reduced to 70 nanometers or less only in the edge part of the reflective layer 110, the shift of the resonant wavelength can be minimized and the luminous efficiency of the target wavelength can be improved.

[0094] Figure 6 This is a plan view illustrating the arrangement of multiple nanostructures in a reflective layer according to an example embodiment. (Refer to...) Figure 6 The reflective layer 110a may include a plurality of first nanostructures 111a disposed in a central portion and a plurality of second nanostructures 112a disposed in a peripheral portion surrounding the central portion. The second nanostructures 112a disposed in the peripheral portion of the reflective layer 110a may be arranged such that the resonant wavelength of the microcavity corresponds to the green band, and the first nanostructures 111a disposed in the central portion may be disposed more densely than the second nanostructures to improve luminous efficiency.

[0095] Therefore, the spacing between two adjacent nanostructures 111a in the plurality of first nanostructures 111a arranged in the central portion can be smaller than the spacing between two adjacent nanostructures 112a in the plurality of second nanostructures 112a arranged in the peripheral portion. Furthermore, the period of the plurality of first nanostructures 111a arranged in the central portion can be smaller than the period of the plurality of second nanostructures 112a arranged in the peripheral portion. The width dimension of the nanostructures in the entire portion of the reflective layer 110a can be the same. In other words, the width dimension of each nanostructure in the plurality of first nanostructures 111a can be the same as the width dimension of each nanostructure in the plurality of second nanostructures 112a. However, this disclosure is not limited thereto; according to the design, the width dimension of each nanostructure in the first nanostructure 111a can be slightly different from the width dimension of each nanostructure in the plurality of second nanostructures 112a.

[0096] For example, in Figure 6 In the reflective layer 110a, the width of the light-emitting device can be 1 micrometer, the width of the first nanostructure 111a can be 80 nanometers, and the spacing between the first nanostructures 111a can be 50 nanometers. Furthermore, the width of the second nanostructure 112a can be 80 nanometers, and the spacing between the second nanostructures 112a can also be 80 nanometers. The height of both the first nanostructure 111a and the second nanostructure 112a can be 50 nanometers. Therefore, the period of the first nanostructure 111a and the period of the second nanostructure 112a are smaller than the emission wavelength of the light-emitting device.

[0097] Figure 7 This is a plan view illustrating the arrangement of multiple nanostructures in a reflective layer according to another example embodiment. (Refer to...) Figure 7 The reflective layer 110b may include a plurality of first nanostructures 111b arranged in a central portion and a plurality of second nanostructures 112b arranged in a peripheral portion surrounding the central portion. The first nanostructures 111b arranged in the central portion of the reflective layer 110b may be arranged such that the resonant wavelength of the microcavity corresponds to the green band, and the second nanostructures 112b arranged in the peripheral portion may be arranged more densely than the first nanostructures 111b to improve luminous efficiency.

[0098] Therefore, the spacing between two adjacent nanostructures in the plurality of second nanostructures 112b arranged in the peripheral portion can be smaller than the spacing between two adjacent nanostructures in the plurality of first nanostructures 111b arranged in the central portion. Furthermore, the period of the plurality of second nanostructures 112b arranged in the peripheral portion can be smaller than the period of the plurality of first nanostructures 111b arranged in the central portion. The width dimensions of the nanostructures throughout the entire portion of the reflective layer 110b can be the same or slightly different.

[0099] For example, in Figure 7 In the reflective layer 110b, the width of the light-emitting device can be 1 micrometer, the width of the first nanostructure 111b can be 80 nanometers, and the spacing between the first nanostructures 111b can be 80 nanometers. Furthermore, the width of the second nanostructure 112b can be 80 nanometers, and the spacing between the second nanostructures 112b can be 50 nanometers. The height of both the first nanostructure 111b and the second nanostructure 112b can be 50 nanometers.

[0100] Figure 8 It shows including Figure 6 and Figure 7 The graph shows the emission characteristics of the light-emitting device, including the reflective layer. To compare with... Figure 6 Example 1-1 of the example embodiments shows a light-emitting device including a reflective layer 110a and according to Figure 7 The example embodiments shown in the text compare the emission characteristics of Example 1-2, which includes a reflective layer 110b, with those of Comparative Example 1-1, which includes a reflective layer (the entire width of which is 80 nanometers and the spacing between the nanostructures is 80 nanometers), and Comparative Example 1-2, which also includes a reflective layer (the entire width of which is 80 nanometers and the spacing between the nanostructures is 70 nanometers). The width of the light-emitting devices in Comparative Example 1-1 and Comparative Example 1-2 is 1 micrometer.

[0101] Reference Figure 8 It can be seen that in the green band of approximately 550 nm, the luminous efficiency of Example 1-1 is higher than that of Comparative Example 1-1 and Comparative Example 1-2. For example, in the green band, the emission peak of Example 1-1 is about 20% higher than that of Comparative Example 1-1. Furthermore, compared to the emission wavelength of Comparative Example 1-1, the emission wavelength of Example 1-1 is shifted to a longer wavelength by about 3 nm. Although the luminous efficiency of Comparative Example 1-2 is slightly higher than that of Comparative Example 1-1, and the emission peak of Comparative Example 1-2 in the green band is shifted to a slightly longer wavelength than that of Comparative Example 1-1, the difference between Comparative Example 1-2 and 1-1 is not significant. Furthermore, in the green band, the luminous efficiency of Example 1-2 is higher than that of Example 1-1. Therefore, Example 1-2 has the highest luminous efficiency in the green band. Additionally, in the green band, compared to Example 1-1, the emission peak of Example 1-2 is shifted to a slightly longer wavelength.

[0102] When comparing the light intensity in the blue wavelength band of approximately 450 nm, the light intensity of the blue wavelength in Example 1-1 is approximately 64% lower than that in Comparative Example 1-1, and the light intensity of the blue wavelength in Example 1-2 is slightly lower than that in Example 1-1. That is, compared to Example 1-1, the peak blue wavelength at the target green pixel in Example 1-2 is reduced. Therefore, when the width of the light-emitting device is as small as 1 micrometer, the luminous efficiency and color purity of Example 1-1 are higher than those of Comparative Example 1-1, and the luminous efficiency and color purity of Example 1-2 are higher than those of Example 1-1. The light intensity of the blue wavelength at 450 nm in Comparative Example 1-2 is similar to that in Comparative Example 1-1.

[0103] Figure 9A It shows including Figure 6 A view of the emission area and emission intensity inside the organic emission layer of the light-emitting device, including the reflective layer 110a. Figure 9B and Figure 9C Each of these is a view showing the emission area and emission intensity inside the organic emitting layer of the light-emitting device according to Comparative Examples 1-1 and 1-2. Figures 9A to 9C As shown, it can be seen that the emission area and emission intensity increase in the organic emission layer according to Example 1-1. Therefore, when the emission area in the organic emission layer increases, the organic emission material in the organic emission layer is used more uniformly, thus increasing the lifetime of the organic emission material (i.e., the lifetime of the light-emitting device).

[0104] Figure 10 This is a plan view illustrating the arrangement of multiple nanostructures in a reflective layer according to another example embodiment. (Refer to...) Figure 10 The reflective layer 110c may include a plurality of first nanostructures 111c disposed in a central portion and a plurality of second nanostructures 112c disposed in a peripheral portion surrounding the central portion. The second nanostructures 112c disposed in the peripheral portion of the reflective layer 110c may be arranged such that the resonant wavelength of the microcavity corresponds to the red band. The first nanostructures 111c disposed in the central portion may be arranged more densely than the second nanostructures 112c to improve luminous efficiency. The width dimensions of the first nanostructures 111c and the second nanostructures 112c may be the same, and the period and spacing of the first nanostructures 111c may be smaller than the period and spacing of the second nanostructures 112c. However, in another example embodiment, the width dimensions of the first nanostructures 111c and the second nanostructures 112c may be different from each other.

[0105] Because the phase modulation of the reflective layer 110c is greater when the target wavelength is red than when the target wavelength is green, the width dimensions of the first nanostructure 111c and the second nanostructure 112c are increased. Therefore, the number of the first nanostructure 111c and the second nanostructure 112c arranged in the reflective layer 110c can be less than the number of the first nanostructures 111a and 111b and the second nanostructures 112a and 112b arranged in the reflective layers 110a and 110b.

[0106] For example, in Figure 10 In the reflective layer 110c, the width of the light-emitting device is 1.2 micrometers, the width of the first nanostructure 111c is 160 nanometers, and the spacing between the first nanostructures 111c is 50 nanometers. Furthermore, the width of the second nanostructure 112c is 160 nanometers, and the spacing between the second nanostructures 112c is 80 nanometers. The height of both the first nanostructure 111c and the second nanostructure 112c is 50 nanometers.

[0107] Figure 11 It shows including Figure 10 The graph shows the emission characteristics of the light-emitting device, including the reflective layer 110c. To compare with... Figure 10 The example embodiments shown in the text illustrate a comparison with Example 2, which includes a light-emitting device with a reflective layer 110c. The optical properties of Comparative Example 2, which includes a reflective layer (the entire width of which is 160 nanometers and the spacing between nanostructures is 80 nanometers), are also shown. The light-emitting device of Comparative Example 2 has a width of 1 micrometer.

[0108] Reference Figure 11 As can be seen, in the red band at approximately 650 nm, the luminous efficiency of Example 2 is higher than that of Comparative Example 2. For example, in the red band, the emission peak of Example 2 is approximately 50% higher than that of Comparative Example 2. Furthermore, compared to the emission wavelength of Comparative Example 2, the emission wavelength of Example 2 is shifted to a longer wavelength by approximately 3 nm. Moreover, when comparing the light intensity at a blue wavelength of 450 nm, the light intensity of the blue wavelength in Example 2 is approximately 62% lower than that in Comparative Example 2.

[0109] Figure 12A It shows including Figure 10 A view of the emission area and emission intensity inside the organic emission layer of the light-emitting device, including the reflective layer 110c. Figure 12B This is a view showing the emission area and emission intensity inside the organic emission layer of the light-emitting device in Comparative Example 2. (See diagram below.) Figure 12A and Figure 12BAs shown, it can be seen that the emission area and emission intensity of the organic emission layer in Example 2 are higher than those of the organic emission layer in Comparative Example 2. Furthermore, it can be seen that the overall emission intensity in the organic emission layer of Example 2 is uniform.

[0110] although Figure 6 , Figure 7 and Figure 10 The width of the light-emitting device in the image is 1 micrometer and 1.2 micrometers, but the size of the light-emitting device can be larger or smaller than 1 micrometer and 1.2 micrometers. For example, the width of the light-emitting device can be equal to or less than 2 micrometers. When the width of the light-emitting device is 2 micrometers, more first nanostructures and second nanostructures can be set in the reflective layer.

[0111] Figure 13 This is a plan view illustrating the arrangement of multiple nanostructures in a reflective layer according to another example embodiment. (Refer to...) Figure 13 The reflective layer 110d may include a plurality of first nanostructures 111d arranged in a central portion and a plurality of second nanostructures 112d arranged in a peripheral portion surrounding the central portion. The second nanostructures 112d arranged in the peripheral portion of the reflective layer 110d may be arranged such that the resonant wavelength of the microcavity corresponds to the green band, and the first nanostructures 111d arranged in the central portion may be arranged more densely than the second nanostructures 112d to improve luminous efficiency.

[0112] For example, in including according to Figure 13 In Example 3-1, which illustrates the reflective layer 110d in the exemplary embodiment, the width of the light-emitting device is 2 micrometers, the width of the first nanostructure 111d is 80 nanometers, and the spacing between the first nanostructures 111d is 50 nanometers. Furthermore, the width of the second nanostructure 112d is 80 nanometers, and the spacing between the second nanostructures 112d is 80 nanometers. The height of both the first nanostructure 111d and the second nanostructure 112d is 50 nanometers.

[0113] Despite Figure 6 , Figure 7 , Figure 10 and Figure 13 The intermediate reflective layer comprises two different arrangements of nanostructures, but the reflective layer may include three or more different arrangements of nanostructures.

[0114] Figure 14 This is a plan view illustrating the arrangement of multiple nanostructures in a reflective layer according to another example embodiment. (Refer to...) Figure 14The reflective layer 110e may include a third nanostructure 113e disposed in the outermost portion of the reflective layer 110e and a first nanostructure 111e and a second nanostructure 112e disposed in a portion further inward than the third nanostructure 113e. For example, the reflective layer 110e may include a plurality of first nanostructures 111e disposed in the central portion, a plurality of second nanostructures 112e disposed in the first peripheral portion directly surrounding the central portion, and a plurality of third nanostructures 113e disposed in the second peripheral portion directly surrounding the first peripheral portion. The third nanostructure 113e disposed in the second peripheral portion, which is the outermost portion of the reflective layer 110e, may be arranged such that the resonant wavelength of the microcavity corresponds to the green band, and the first nanostructures 111e and 112e disposed in the central portion and the first peripheral portion, respectively, may be disposed more densely than the third nanostructure 113e to improve luminous efficiency. Furthermore, the first nanostructures 111e disposed in the central portion may be disposed at a narrower interval than the second nanostructures 112e disposed in the first peripheral portion.

[0115] For example, in including according to Figure 14 In Example 3-2 of the exemplary embodiment showing the reflective layer 110e, the width of the light-emitting device is 2 micrometers. The width of the first nanostructure 111e is 90 nanometers, the spacing between the first nanostructures 111e is 40 nanometers, the width of the second nanostructure 112e is 80 nanometers, the spacing between the second nanostructures 112e is 50 nanometers, and the width of the third nanostructure 113e is 80 nanometers, and the spacing between the third nanostructures 113e is 80 nanometers. The height of the first nanostructure 111e, the second nanostructure 112e, and the third nanostructure 113e is 50 nanometers. Therefore, the period of the second nanostructure 112e is less than the period of the third nanostructure 113e, and the period of the first nanostructure 111e is the same as the period of the second nanostructure 112e. Furthermore, the width of the first nanostructure 111e is greater than the width of the second nanostructure 112e, and the width of the second nanostructure 112e is the same as the width of the third nanostructure 113e. The spacing between the first nanostructures 111e is smaller than the spacing between the second nanostructures 112e, and the spacing between the second nanostructures 112e is smaller than the spacing between the third nanostructures 113e.

[0116] Figure 15 It shows including Figure 13 and Figure 14 The graph shows the emission characteristics of the light-emitting device, including the reflective layers 110d and 110e. (To be consistent with...) Figure 13 Example 3-1 and the reflective layer 110d Figure 14Compared to Example 3-2 with reflective layer 110e, the emission characteristics of Comparative Example 3, which includes a reflective layer (the entire width of which is 80 nanometers and the spacing between the nanostructures is 80 nanometers), are also shown. The light-emitting device of Comparative Example 3 has a width of 2 micrometers.

[0117] Reference Figure 15 In the green band, the emission peak values ​​of Examples 3-1 and 3-2 are approximately 10% to approximately 12% higher than that of Comparative Example 3. Furthermore, compared to the emission wavelength of Comparative Example 3, the emission wavelengths of Examples 3-1 and 3-2 are shifted to longer wavelengths by approximately 6 nanometers. Additionally, when comparing the light intensity at a blue wavelength of 450 nanometers, the light intensity at the blue wavelength of Examples 3-1 and 3-2 is approximately 73% lower than that of Comparative Example 3. Examples 3-1 and 3-2 exhibit nearly similar emission characteristics.

[0118] Figure 13 and Figure 14 The structures of reflective layers 110d and 110e can be applied to light-emitting devices with red emission wavelengths, and in this case, the dimensions associated with the nanostructures can vary according to the red emission wavelength. Furthermore, the structures of reflective layers 110a, 110b, 110c, 110d, and 100e can be applied to light-emitting devices with blue emission wavelengths, and the dimensions associated with the nanostructures can vary according to the blue emission wavelength. For example, the spacing between adjacent nanostructures in the central portion of the reflective layer can be equal to or less than 70 nanometers. The spacing between adjacent nanostructures in the central portion of the reflective layer can be selected in the range of about 10 nanometers to about 70 nanometers. Furthermore, the spacing between adjacent nanostructures in the peripheral portion surrounding the central portion of the reflective layer can be equal to or less than 80 nanometers. The spacing between adjacent nanostructures in the peripheral portion surrounding the central portion of the reflective layer can be selected in the range of about 30 nanometers to about 80 nanometers. Conversely, the spacing between adjacent nanostructures in the peripheral portion of the reflective layer can be equal to or less than 70 nanometers, and the spacing between adjacent nanostructures in the central portion of the reflective layer can be equal to or less than 80 nanometers. Furthermore, the width of each nanostructure can be selected in the range of approximately 50 nanometers to approximately 200 nanometers, and the period of multiple nanostructures can be selected in the range of approximately 70 nanometers to approximately 300 nanometers. Although the height of each nanostructure is 50 nanometers in the example embodiment above, the height of each nanostructure can be selected to be 200 nanometers or less.

[0119] Although Figure 14In this embodiment, a first nanostructure 111e is disposed in the central portion of the reflective layer 110e, a second nanostructure 112e is disposed in the first peripheral portion surrounding the central portion, and a third nanostructure 113e is disposed in the second peripheral portion surrounding the first peripheral portion. However, this is merely an example, and the disclosure is not limited thereto. For example, the third nanostructure 113e may be disposed in the outermost portion of the reflective layer 110e, while the first nanostructure 111e and the second nanostructure 112e may be disposed together in the central portion of the reflective layer 110e. Furthermore, additional nanostructures arranged at intervals different from the intervals between the first nanostructures 111e and the second nanostructure 112e may be disposed in a portion further inward than the third nanostructure 113e. The arrangement intervals of the additional nanostructures disposed in the portion further inward than the third nanostructure 113e may differ from the arrangement intervals of the third nanostructure 113e. Alternatively, the spacing between the first nanostructures 111e in the central portion of the reflective layer 110e can be maximized, while the spacing between the third nanostructures 113e in the outermost portion of the reflective layer 110e can be minimized. Furthermore, the width dimensions of the first nanostructure 111e, the second nanostructure 112e, and the third nanostructure 113e can be selected differently from the parameters described above, depending on design conditions (e.g., the emission wavelength of the light-emitting device and the width of the emitting device).

[0120] Figure 16 This is a cross-sectional view showing the structure of a light-emitting device according to another example embodiment. (Refer to...) Figure 16 The light-emitting device 100a may further include a dielectric 125 filled in the spaces between the nanostructures 111. The dielectric 125, which is an insulating material transparent to visible light, may include, for example, inorganic materials (such as SiO2, SiN...). x The resonant wavelength of the microcavity can be finely tuned according to the refractive index of the dielectric 125. The height of the top surface of the dielectric 125 can be the same as the height of the top surface of the nanostructure 111. In this case, the bottom surface of the first electrode 121 can be flat.

[0121] As described above, when using a reflective layer 110 comprising multiple nanostructures 111, the emission wavelength of the light-emitting device can be determined by adjusting the optical length L of the microcavity. In this case, while fixing the physical length of the microcavity, the emission wavelength of the light-emitting device can be determined using only the dimensions associated with the multiple nanostructures 111. Therefore, when the light-emitting device according to the example embodiment is applied to the RGB subpixels of a display device, the manufacturing process of the display device is simplified. Furthermore, when different types of nanostructures 111 are arranged in the central and peripheral portions of the reflective layer 110, high luminous efficiency and high color purity can be achieved even in submicron-sized organic light-emitting devices. Therefore, an ultra-high resolution display device with submicron pixels and a resolution of 10,000 PPI can be provided.

[0122] Figure 17 This is a cross-sectional view showing the structure of a display device according to an example embodiment. (Refer to...) Figure 17 The display device 200 according to an example embodiment may include a display substrate 201 and a first pixel 100B, a second pixel 100G, and a third pixel 100R arranged on the display substrate 201. Figure 17 In the middle, although each of the first to third pixels 100B, 100G and 100R has the same... Figure 1 The light-emitting device 100 has the same structure as the first to third pixels 100B, 100G and 100R, but each of them may have the following characteristics: Figure 16 The structure of the light-emitting device 100a. Furthermore, although for ease of explanation, in Figure 17 Only one first pixel 100B, one second pixel 100G, and one third pixel 100R are shown, but in reality, a large number of first to third pixels 100B, 100G, and 100R can be arranged repeatedly.

[0123] The first to third pixels 100B, 100G, and 100R may include reflective layers 110B, 110G, and 110R (each of which comprises a plurality of two-dimensionally arranged nanostructures 111B, 111G, and 111R), a planarization layer 115 disposed on the reflective layers 110B, 110G, and 110R, a first electrode 121 disposed on the planarization layer 115, an organic emission layer 130 disposed on the first electrode 121, and a second electrode 122 disposed on the organic emission layer 130. Furthermore, the first to third pixels 100B, 100G, and 100R may also include a transparent passivation layer 140 disposed on the second electrode 122 to protect the second electrode 122.

[0124] The first to third pixels 100B, 100G, and 100R can be configured to emit light of different wavelengths. For example, the first pixel 100B can be configured to emit blue light (B), the second pixel 100G can be configured to emit green light (G), and the third pixel 100R can be configured to emit red light (R). Therefore, the reflective layers 110B, 110G, and 110R of the first to third pixels 100B, 100G, and 100R can each include nanostructures 111B, 111G, and 111R with different sizes.

[0125] For example, the spacing between adjacent nanostructures 111B, 111G, and 111R in the central portions of the reflective layers 110B, 110G, and 110R of the first to third pixels 100B, 100G, and 100R can be different from the spacing between adjacent nanostructures 111B, 111G, and 111R in the peripheral portions. Specifically, either the spacing between adjacent nanostructures 111B, 111G, and 111R in the central portions of the reflective layers 110B, 110G, and 110R, or the spacing between adjacent nanostructures 111B, 111G, and 111R in the peripheral portions of the reflective layers 110B, 110G, and 110R, can be equal to or less than 70 nanometers. Alternatively, the spacing between adjacent nanostructures 111B and 111G in the central portions of the reflective layers 110B and 110G of the first pixel 100B and the second pixel 100G can be different from the spacing between adjacent nanostructures 111B and 111G in the peripheral portions surrounding the central portions, and the spacing between adjacent nanostructures 111R in the entire portion of the reflective layer 110R of the third pixel 100R can be equal to or less than 70 nanometers. When the spacing between adjacent nanostructures 111R in the entire portion of the reflective layer 110R decreases uniformly, the emission wavelength shifts relatively significantly to longer wavelengths, which can be beneficial for the third pixel 100R to emit red light. Furthermore, the period and width dimensions of the nanostructure 111B of the reflective layer 110B of the first pixel 100B can be smaller than the period and width dimensions of the nanostructure 111G of the reflective layer 110G of the second pixel 100G, and the period and width dimensions of the nanostructure 111G of the reflective layer 110G of the second pixel 100G can be smaller than the period and width dimensions of the nanostructure 111R of the reflective layer 110R of the third pixel 100R.

[0126] The physical lengths of the microcavities in the first to third pixels 100B, 100G, and 100R can be the same, and the emission wavelengths of the first to third pixels 100B, 100G, and 100R can be determined solely by using the dimensions of the nanostructures 111B, 111G, and 111R in the reflective layers 110B, 110G, and 110R. Furthermore, in the first to third pixels 100B, 100G, and 100R, the components other than the reflective layers 110B, 110G, and 110R (e.g., the first electrode 121, the organic emitting layer 130, and the second electrode 122) can have the same composition and the same thickness. As a result, the physical thicknesses of the first to third pixels 100B, 100G, and 100R can be the same. Therefore, the method of manufacturing the display device 200 can be simplified, and manufacturing costs can be reduced.

[0127] Figure 18 This is a cross-sectional view showing the structure of a display device according to another example embodiment. Figure 18 In the display device 300, the reflective layers 110G and 110R of the second pixel 100G and the third pixel 100R respectively include nanostructures 111G and 111R, but the reflective layer 110B of the first pixel 100B that emits blue light may not include nanostructures. In this case, in the first pixel 100B, the optical length of the microcavity can be determined such that the resonant wavelength of the microcavity corresponds to the blue band. For example, the optical length of the microcavity of the first pixel 100B can be determined as the sum of the optical lengths of the materials disposed between the reflective layer 110B and the second electrode 122.

[0128] In the second pixel 100G and the third pixel 100R, the resonant wavelength of the microcavity can be adjusted by using nanostructures 111G and 111R through phase shift of the reflected light. According to an example embodiment, the spacing between adjacent nanostructures 111G and 111R in the central portions of the reflective layers 110G and 110R of the second pixel 100G and the third pixel 100R can be different from the spacing between adjacent nanostructures 111G and 111R in the peripheral portions. According to another example embodiment, the spacing between adjacent nanostructures 111G in the central portion of the reflective layer 110G of the second pixel 100G can be different from the spacing between adjacent nanostructures 111G in the peripheral portions surrounding the central portion, and the spacing between adjacent nanostructures 111R in the entire portion of the reflective layer 110R of the third pixel 100R that emits red light can be equal to or less than 70 nanometers.

[0129] It should be understood that the exemplary embodiments described herein should be considered descriptive only and not for limiting purposes. The description of features or aspects in each exemplary embodiment should typically be interpreted as other similar features or aspects that may be used in other exemplary embodiments. Although one or more exemplary embodiments have been described with reference to the accompanying drawings, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope defined by the appended claims.

Claims

1. A light-emitting device, comprising: The reflective layer comprises multiple nanostructures arranged in a regular, periodic two-dimensional structure; The first electrode is disposed on the plurality of nanostructures of the reflective layer; An organic emission layer is disposed on the first electrode; as well as The second electrode is disposed on the organic emission layer. The reflective layer and the second electrode form a microcavity with a resonant wavelength, the resonant wavelength of which is based on the width of each of the plurality of nanostructures, the height of each of the plurality of nanostructures, the spacing between adjacent nanostructures, and the period of the plurality of nanostructures. Wherein, the spacing between adjacent nanostructures in the central portion of the reflective layer or the spacing between adjacent nanostructures in the peripheral portion of the reflective layer surrounding the central portion is equal to or less than 70 nanometers. The reflective layer includes a plurality of first nanostructures disposed in the central portion of the reflective layer and a plurality of second nanostructures disposed in the peripheral portion of the reflective layer. Wherein, the interval between any two adjacent nanostructures in the plurality of first nanostructures is a first interval, the interval between any two adjacent nanostructures in the plurality of second nanostructures is a second interval, and the first interval is smaller than the second interval.

2. The light-emitting device according to claim 1, wherein, The width of each of the plurality of nanostructures in the reflective layer, the height of each of the plurality of nanostructures, the spacing between adjacent nanostructures, and the period of the plurality of nanostructures are configured such that the resonant wavelength of the microcavity matches the emission wavelength of the light-emitting device.

3. The light-emitting device according to claim 1, wherein, The period of the plurality of nanostructures is smaller than the emission wavelength of the light-emitting device.

4. The light-emitting device according to claim 3, wherein, The period of the multiple nanostructures ranges from 70 nanometers to 300 nanometers.

5. The light-emitting device according to claim 1, wherein, The height of each of the plurality of nanostructures is equal to or less than 200 nanometers, and Each of the plurality of nanostructures in the reflective layer has the same height.

6. The light-emitting device according to claim 1, wherein, The width of each of the plurality of nanostructures in the reflective layer is in the range of 50 nanometers to 200 nanometers.

7. The light-emitting device according to claim 1, wherein, The spacing between adjacent nanostructures in the central portion of the reflective layer or between adjacent nanostructures in the peripheral portion of the reflective layer is in the range of 10 nanometers to 70 nanometers.

8. The light-emitting device according to claim 1, wherein, The width of the light-emitting device is equal to or less than 2 micrometers.

9. The light-emitting device according to claim 1, wherein, The first width of each of the plurality of first nanostructures is the same as the second width of each of the plurality of second nanostructures.

10. The light-emitting device according to claim 1, wherein, The reflective layer further includes a plurality of additional nanostructures disposed in the central portion of the reflective layer and surrounding the plurality of first nanostructures, and the plurality of second nanostructures are arranged around the plurality of additional nanostructures. Wherein, the first interval between every two adjacent nanostructures in the plurality of first nanostructures is different from the interval between every two adjacent nanostructures in the plurality of additional nanostructures, and the interval between every two adjacent nanostructures in the plurality of additional nanostructures is different from the second interval between every two adjacent nanostructures in the plurality of second nanostructures.

11. The light-emitting device according to claim 10, wherein, The period of the plurality of first nanostructures is the same as the period of the plurality of additional nanostructures.

12. The light-emitting device according to claim 10, wherein, The first width of each of the plurality of first nanostructures is different from the width of each of the plurality of additional nanostructures, while the width of each of the plurality of additional nanostructures is the same as the second width of each of the plurality of second nanostructures.

13. The light-emitting device according to claim 10, wherein, The interval between any two adjacent nanostructures in the plurality of additional nanostructures is smaller than the second interval between any two adjacent nanostructures in the plurality of second nanostructures, the period of the plurality of first nanostructures is smaller than the period of the plurality of second nanostructures, and the period of the plurality of additional nanostructures is smaller than the period of the plurality of second nanostructures.

14. The light-emitting device according to claim 10, wherein, The first interval between any two adjacent nanostructures in the plurality of first nanostructures is smaller than the interval between any two adjacent nanostructures in the plurality of additional nanostructures, and the interval between any two adjacent nanostructures in the plurality of additional nanostructures is smaller than the second interval between any two adjacent nanostructures in the plurality of second nanostructures.

15. A display device, comprising: The first pixel includes a light-emitting device according to any one of claims 1 to 14 and is configured to emit light in a first wavelength band; as well as The second pixel is configured to emit light in a second band that is different from the first band.

16. The display device according to claim 15, wherein, The width of each of the first pixel and the second pixel is equal to or less than 2 micrometers.

17. The display device according to claim 15, wherein, The width of each nanostructure is the diameter of that nanostructure.

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