Unpolarized electrochemical structural color pixel

Abstract

The present application relates to an unpolarized electrochemical structural color pixel. According to embodiments of the present application, the unpolarized structural color pixel can dynamically express vivid and diverse colors without depending on specific polarization (that is, under non-polarizer conditions) by integration of an electrochemical deposition-dissolution technique of a metal and a nanohole metasurface of a dielectric layer.

Description

Non-polarized electrochemical structural color pixels

[0001] The present invention relates to a non-polarized electrochemical structural color pixel.

[0002] This patent is a result derived as part of the “Seoul Regional Innovation Center University Support System (RISE),” which was conducted with funding from the Ministry of Education and the Seoul Metropolitan Government and supported by the Seoul RISE Center in 2025. (2025-RISE-01-034-01)

[0003] Conventional color display technology is primarily based on dyes or pigments, which has resulted in limitations in color vividness and visibility. To overcome this, structural color technology, utilizing precisely designed nanostructures and patterns capable of inducing optical resonance within the visible light spectrum, is attracting attention. Such structural color can control hue or color intensity by adjusting the dielectric constant contrast between the structure and the surrounding medium, or by precisely controlling structural parameters.

[0004] In particular, diffraction grating structures are widely used in the design of color filters to enhance color reproduction by amplifying the resonance effect of light. However, these diffraction-based structural color pixels suffer from polarization dependency, where the color varies depending on the polarization state of most light; this poses a critical limitation in practical applications, particularly in display applications such as e-paper technology. The addition of a separate polarization layer complicates the device structure, increases manufacturing costs, and impairs energy efficiency.

[0005] Structural color using nanostructures has the property of being able to respond sensitively to external stimuli (e.g., electricity, heat, light, magnetic fields, etc.), so it can implement the function of dynamically controlling color according to external stimuli.

[0006] For applications in displays, sensors, and information transmission devices, low-power operation, fast switching response speeds, and characteristics independent of light polarization are required, and these characteristics can be effectively utilized in various fields. Furthermore, the advancement of this technology can significantly contribute to sustainable industrial development.

[0007] [Prior Art Literature]

[0008] [Patent Literature]

[0009] Republic of Korea Registered Patent Publication No. 2737909.

[0010] The present invention aims to provide a non-polarized electrochemical structural color pixel.

[0011] However, the problems that this invention seeks to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description below.

[0012] One aspect of the present invention provides a non-polarized structural color pixel comprising a reflective substrate, a dielectric layer having a nanohole array formed thereon, an electrolyte containing a metal salt, and a transparent electrode, wherein the nanoholes have a pillar-like structure and the metal of the metal salt is electrochemically deposited and dissolved inside the nanoholes.

[0013] The non-polarized structural color pixel according to the embodiments of the present invention integrates a nanohole metasurface of a dielectric layer and an electrochemical deposition-dissolution technique of a metal, thereby enabling the dynamic expression of vivid and diverse colors without dependence on specific polarization (i.e., non-polarized conditions).

[0014] The non-polarized structural color pixel according to the embodiments of the present invention can realize a desired reflected color by precisely controlling the characteristics of the nanohole array of the dielectric layer. In addition, the structure can be reversibly changed through the electrochemical deposition-dissolution of a metal, and the color and optical properties of the pixel can be changed.

[0015] The non-polarized structural color pixel according to the embodiments of the present invention has a low driving voltage of about 1.4 V or less and about 0.5 mW / cm² 2 Less than or about 0.3 mW / cm 2 Optical switching operates at the lower power density shown below, and dual stability characteristics can be achieved by applying a low voltage, thereby enabling implementation with very low energy consumption.

[0016] The non-polarized structural color pixels according to the embodiments of the present invention have a significantly shorter stripping time and can be usefully applied in displays (as a non-limiting example, electronic paper displays) and optical devices requiring a rapid response.

[0017] The non-polarized structural color pixel according to the embodiments of the present invention can provide stable reversible color change and optical characteristic switching functions even after driving for about 600 cycles or more.

[0018] The non-polarized structural color pixel according to the embodiments of the present invention is characterized by having a significantly high color reflectance of about 60% or more because it has no polarizer.

[0019] FIG. 1a and 1b each represent schematic diagrams of the driving of an unpolarized structural color pixel in one embodiment of the present invention.

[0020] FIGS. 2a and 2b show, in one embodiment of the present invention, (a) scanning electron microscope (SEM) images of the nanohole metasurface of an unpolarized structural color pixel before (top) and after (bottom) Cu electrodeposition; and (b) energy dispersive spectrometer (EDS) images of a pixel with a nanohole array period of 425 nm after Cu electrodeposition.

[0021] FIGS. 3a to 3c represent, in one embodiment of the present invention, (a) a color change according to the period of a nanohole array of an unpolarized structural color pixel; (b) a graph of applied voltage, corresponding current, and power density over time during a Cu electrochemical deposition-dissolution process; and (c) a graph of reflectance continuously measured during a Cu electrochemical deposition-dissolution process of an unpolarized structural color pixel.

[0022] FIGS. 4a and 4b, in one embodiment of the present invention, show (a) a change in wavelength according to the driving cycle of a pixel with a period of 425 nm of a nanohole array; and (b) an optical microscope image according to Cu deposition and dissolution.

[0023] FIG. 5a and 5b show, in one embodiment of the present invention, (a) a graph of the applied voltage and the corresponding current according to the Cu electrodeposition time and (b) a graph of the power density according to the Cu electrodeposition time.

[0024] Hereinafter, embodiments and examples of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments and examples described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0025] Throughout this specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "electrically connected" with other elements interposed between them.

[0026] Throughout this specification, when a component is described as being located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components.

[0027] Throughout this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0028] Terms of degree used in this specification, such as “about,” “substantially,” etc., are used to mean at or near the stated value when inherent manufacturing and material tolerances are presented in the stated meaning, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure in which precise or absolute values ​​are mentioned to aid in understanding the invention.

[0029] The terms “step of” or “step of” as used throughout this specification do not mean “step for”.

[0030] Throughout this specification, the term “combination(s) of these” included in the Markush-type expression means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expression, and means including one or more selected from the group consisting of said components.

[0031] Throughout this specification, the description of "A and / or B" means "A or B, or A and B".

[0032] Embodiments of the present invention have been described in detail below, but the present invention may not be limited thereto.

[0033] One aspect of the present invention provides a non-polarized structural color pixel comprising a reflective substrate, a dielectric layer having a nanohole array formed thereon, an electrolyte containing a metal salt, and a transparent electrode, wherein the nanoholes have a pillar-like structure and the metal of the metal salt is electrochemically deposited and dissolved inside the nanoholes.

[0034] In one embodiment of the present invention, the non-polarized structural color pixel integrates the nanohole metasurface of the dielectric layer and the electrochemical deposition-dissolution technique of the metal to dynamically display vivid and diverse colors without dependence on specific polarization (i.e., non-polarized conditions).

[0035] In one embodiment of the present invention, the reflective substrate may comprise one or more selected from Pt, Ag, Au, and Pd, but is not limited thereto.

[0036] The above-described reflective substrate contributes to the realization of structural color by reflecting incident light, and at the same time supplies electrons as a working electrode to enable the electrochemical deposition of metal on the reflective substrate within the nanohole. The above-described reflective substrate may have excellent chemical stability with respect to the electrolyte.

[0037] In one embodiment of the present invention, the thickness of the reflective substrate may be about 100 nm or more.

[0038] In one embodiment of the present invention, the dielectric layer may comprise one or more selected from TiO2, SiO2, Si, ZrO2, RuO2, IrO2, CaO, SrO, BaO, MnO, CuO, CuO2, Cu2O3, MoS2, TiN, and WO3, but is not limited thereto.

[0039] In one embodiment of the present invention, the thickness of the dielectric layer is about 10 nm to about 1,000 nm, about 10 nm to about 900 nm, about 10 nm to about 800 nm, about 10 nm to about 700 nm, about 10 nm to about 600 nm, about 10 nm to about 500 nm, about 10 nm to about 400 nm, about 10 nm to about 300 nm, about 10 nm to about 200 nm, about 10 nm to about 150 nm, about 10 nm to about 100 nm, about 50 nm to about 1,000 nm, about 50 nm to about 900 nm, about 50 nm to about 800 nm, about 50 nm to about 700 nm, about 50 nm to about 600 nm, about 50 nm to about 500 nm, about 50 nm to about It may be 400 nm, about 50 nm to about 300 nm, about 50 nm to about 200 nm, about 50 nm to about 150 nm, about 50 nm to about 100 nm, about 50 nm to about 80 nm, about 100 nm to about 1,000 nm, about 100 nm to about 900 nm, about 100 nm to about 800 nm, about 100 nm to about 700 nm, about 100 nm to about 600 nm, about 100 nm to about 500 nm, about 100 nm to about 400 nm, about 100 nm to about 300 nm, about 100 nm to about 200 nm, about 100 nm to about 150 nm, but is not limited thereto.

[0040] In one embodiment of the present invention, the thickness of the dielectric layer may mean the height of the nanohole.

[0041] In one embodiment of the present invention, the unpolarized structural color pixel can realize a passive reflective structural color due to the sophisticated optical properties appearing on the metasurface of the nanohole array. The passive reflective structural color may be a fixed property that appears due to the structural properties of the dielectric layer on which the nanohole array is formed. Various colors of passive reflective structural colors can be realized by adjusting the period of the nanohole array and the diameter and shape of the nanoholes.

[0042] In one embodiment of the present invention, the columnar structure of the nanohole may include one or more selected from a cylinder, a triangular prism, a square prism, a pentagonal prism, a hexagonal prism, and a star-shaped prism, but is not limited thereto.

[0043] In one embodiment of the present invention, the diameter of the nanohole may be about 100 nm to about 500 nm. In one embodiment of the present invention, the diameter of the nanohole may be 100+5l nm (nanometers) (where l is an integer from 0 to 80), which is about 100 nm or more to about 500 nm or less.

[0044] In one embodiment of the present invention, the period of the nanohole array may be about 200 nm to about 900 nm.

[0045] In one embodiment of the present invention, the period of the nanohole array may be 200+5k nm (nanometers), which is about 200 nm or more to about 900 nm or less (where k is an integer from 0 to 100).

[0046] In one embodiment of the present invention, the period of the nanohole array may be included in a first sub-period range of about 200 nm to about 500 nm; or a second sub-period range of about 500 nm to about 900 nm.

[0047] In one embodiment of the present invention, the period of the nanohole array is a key element determining the color of the passive reflective structural color and can be adjusted according to the color to be implemented.

[0048] In one embodiment of the present invention, the period of the nanohole array may be about 1.5 to about 2 times, about 1.5 to about 1.9 times, about 1.5 to about 1.8 times, about 1.5 to about 1.7 times, about 1.5 to about 1.6 times, about 1.6 to about 2 times, about 1.6 to about 1.9 times, about 1.6 to about 1.8 times, about 1.6 to about 1.7 times, about 1.7 to about 2 times, about 1.7 to about 1.9 times, or about 1.7 to about 1.8 times, but is not limited thereto.

[0049] In one embodiment of the present invention, the metal may comprise one or more selected from Cu, Ni, Ag, Zn, Pb, Bi, and Al, but is not limited thereto.

[0050] In one embodiment of the present invention, the metal salt may be dissociated within the electrolyte and exist in the form of metal ions and anions.

[0051] In one embodiment of the present invention, the metal salt may be a metal hydrate salt, a metal halide salt, or a combination of a metal ion and an organic ion.

[0052] In one embodiment of the present invention, the metal hydrate salt may be Cu(ClO4)26H2O or Cu(NO3)2·3H2O as a non-limiting example. The halide metal salt may be CuCl2 or CuBr2 as a non-limiting example.

[0053] In one embodiment of the present invention, the metal salt is ClO4 - , NO3 - , Cl - , Br -, and I - It may include, but is not limited to, one or more anions selected from. In particular, ClO4 as an anion - When using a metal salt containing the metal, the electrochemical deposition-dissolution time (i.e., stripping time) of the metal may be reduced.

[0054] In one embodiment of the present invention, the solvent of the electrolyte may be used without limitation as long as it is commonly used in electrochemical devices. As a non-limiting example, the solvent may be water, a buffer solution in which KOH or NaOH is dissolved, or sulfones such as sulfolane or dimethyl sulfoxide (DMSO).

[0055] In one embodiment of the present invention, the electrolyte may additionally include a polymer. In one embodiment of the present invention, the polymer may be polyvinyl butyral (PVB) or polyvinyl alcohol (PVA) as a non-limiting example. In one embodiment of the present invention, the polymer may be formed as a film on the reflective substrate to protect the reflective substrate and improve the dissociation rate of the metal.

[0056] In one embodiment of the present invention, the transparent electrode may comprise one or more selected from indium tin oxide (ITO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium zinc oxide (IZO), antimony-doped tin oxide (ATO), and indium gallium zinc oxide (IGZO), but is not limited thereto.

[0057] In one embodiment of the present invention, a color change can be achieved by controlling the electrochemical-deposited dissolution state of the metal.

[0058] In one embodiment of the present invention, the metal undergoes a structural change by electrochemical deposition-dissolution in the nanohole, thereby allowing the color to change reversibly.

[0059] In one embodiment of the present invention, the non-polarized structural color pixel enables the realization of a full-color reflective display without changing the characteristics of the nanohole array by controlling the electrochemical deposition-dissolution state of the metal while the structural characteristics of the nanohole array (period of the nanohole array, diameter and shape of the nanohole) are fixed.

[0060] In one embodiment of the present invention, the metal may be deposited over time from the reflective substrate in the height direction of the nanohole by electrochemical deposition. The electrochemical deposition state of the metal may include (1) no deposition, (2) the metal filling a portion of the nanohole, (3) the metal filling the entire nanohole, (4) the metal over-depositing to form a dome beyond the surface of the nanohole, or (5) the metal over-depositing to form a continuous thin film beyond the surface of the nanohole, and the color realized may differ depending on each state. In state (2), the height of the metal inside the nanohole may increase over time, and a color change may occur accordingly.

[0061] In one embodiment of the present invention, random (non-uniform) dissolution may occur during the process of dissolving the electrochemically deposited metal. As a result, disordered metal nanoparticles are formed, and a black color may be realized due to their broadband absorption.

[0062] In one embodiment of the present invention, the unpolarized structural color pixel may have different electrochemical deposition patterns of metal and corresponding color realization mechanisms depending on the period of the nanohole array. Specifically, when the period of the nanohole array falls within the first sub-period range, yellow, green, blue, pink, and red colors can be realized through shape changes of the metal deposited via over-deposition. When the period of the nanohole array falls within the second sub-period range, black, blue, green, and red colors can be realized over time of electrochemical deposition.

[0063] In one embodiment of the present invention, the electrochemical deposition of the metal can be performed by applying a (-) voltage to the working electrode.

[0064] In one embodiment of the present invention, the electrochemical dissolution of the metal can be performed by applying a (+) voltage to the working electrode.

[0065] In one embodiment of the present invention, the voltage difference of the voltage applied during the electrochemical deposition-dissolution process of the metal may be about 1.4 V or less, or about 0.1 V to about 1.4 V, but is not limited thereto.

[0066] In one embodiment of the present invention, the power density consumed during the electrochemical deposition-dissolution process of the metal is approximately 0.5 mW / cm² 2 Below, approximately 0.4 mW / cm² 2 Below, approximately 0.3 mW / cm² 2 Below, approximately 0.1 mW / cm² 2 Up to about 0.5 mW / cm 2 , approximately 0.1 mW / cm² 2 Up to about 0.4 mW / cm 2 , or about 0.1 mW / cm² 2 Up to about 0.3 mW / cm 2 It may be, but may not be limited to.

[0067] In one embodiment of the present invention, the non-polarized structural color pixel has a low driving voltage of about 1.4 V or less and about 0.5 mW / cm² 2 Less than or about 0.3 mW / cm 2 Optical switching operates at the lower power density below, and can have dual stability characteristics due to very low energy consumption.

[0068] In one embodiment of the present invention, the time required for the metal to be electrochemically deposited and for the electrochemically deposited metal to be completely dissolved (i.e., stripping time) may be about 1 second or less, about 0.001 seconds to about 1 second, about 0.001 seconds to about 0.1 seconds, about 0.001 seconds to about 0.01 seconds, or about 0.001 seconds to about 0.005 seconds, but may not be limited thereto.

[0069] In one embodiment of the present invention, the unpolarized structural color pixel has a significantly short stripping time and can be usefully applied to displays (e.g., electronic paper displays) and optical devices that require a rapid response.

[0070] In one embodiment of the present invention, the non-polarized structural color pixel can provide stable reversible color change and optical characteristic switching functions even after driving about 600 cycles or more.

[0071] In one embodiment of the present invention, the non-polarized structural color pixel is characterized by having a significantly high color reflectance of about 60% or more without a polarizer.

[0072] The present invention will be explained in more detail below using examples, but the following examples are merely illustrative to aid in understanding the present invention, and the content of the present invention is not limited to the following examples.

[0073] [Example]

[0074] Example 1: Preparation of a non-polarized structural color pixel

[0075] Pt reflective substrate, TiO2 dielectric with nanohole array formed via lithography process, Cu 2+A non-polarized structural color pixel was fabricated comprising an electrolyte containing [specific material] and an ITO (Indium Tin Oxide) transparent electrode as a counter electrode (Figs. 1a and 1b). The electrolyte was prepared by dissolving 0.9 M Cu(ClO4)26H2O and 0.1 M CuBr2 in a solvent mixed with DMSO (dimethyl sulfoxide) and water in an 80:20 wt% ratio. At this time, the electrolyte may additionally contain 0.05 wt% of a polymer material, such as PVB (polyvinyl butyral) or PVA (polyvinyl alcohol). The polymer material can be formed as a film on the reflective substrate to protect the reflective substrate and improve the dissociation rate of the metal. Figs. 1a and 1b are schematic diagrams of the non-polarized structural color pixel, showing the state in which Cu metal is dissolved in the electrolyte (non-deposited state) (top) and the state in which it is electrodeposited inside the nanohole (bottom). Figure 2a (top) is a scanning electron microscope (SEM) image of an unpolarized structural color pixel, showing a titanium dioxide (TiO2) nanohole metasurface with nanohole arrays formed at various periods (255 nm, 340 nm, 380 nm, 425 nm). The inset shows the reflected colors measured by an optical microscope. Figure 2a (bottom) shows the structure after Cu has been electrodeposited into the nanoholes. Similarly, the inset shows the reflected colors measured by an optical microscope, exhibiting blue-tinged colors at periods of 340 nm or higher. Figure 2b shows the energy dispersive spectrometer (EDS) measurement results for a nanohole array at a period of 425 nm, when Cu has been electrodeposited into the nanoholes to fill them.

[0076] A non-polarized structural color pixel was fabricated by controlling the period of the nanohole array within the range of 200 nm to 900 nm, and the color change according to the electrochemical deposition-dissolution process was measured (Fig. 3a). Fig. 3b is a graph showing the applied voltage, corresponding current, and power density over time during the electrochemical deposition-dissolution process. First, -0.65 V was applied for 3.2 seconds for the electrodeposition of metal (I, II). When a negative voltage is applied, electrons are injected into the reflective substrate, which is the working electrode, causing metal salts to be deposited as metal particles, resulting in a structural change. II shows the state where copper metal has been deposited in the nanoholes for 3.2 seconds, completely filling the interior. Subsequently, +0.7 V was applied for 13 seconds for the electrodissolution of metal (III, IV, V). When a positive voltage is applied, the metal particles deposited in the nanoholes react with anions (Br) at the counter electrode (ITO) and are converted back into metal salts. As a result, the metal inside the nanoholes dissociates and is restored to its original nanohole array form. At this time, copper metal can be completely dissolved in less than 1 second by applying +0.7 V. The voltage difference applied during the electrochemical deposition-dissolution process remains stable at 1.4 V or less. Furthermore, the power density used when changing the voltage is 0.271 mW / cm². 2 and 0.3055 mW / cm 2 (Average 0.3 mW / cm² 2 As such, it was confirmed that the electrochemical structural color pixel of the present invention can be driven with low power.

[0077] Figure 3c is a reflection graph continuously measured during the deposition (top) and dissolution (bottom) processes of unpolarized structural color pixels according to the period of the nanohole array. It can be seen that the reflection dip shifts to red as the period of the nanohole array increases. In addition, when comparing the reflection dips before and after copper metal deposition in each nanohole array, a wavelength change of more than 100 nm occurs after the metal is deposited. Furthermore, it was confirmed that each nanohole array has a high reflectance value, with an average reflectance value of more than 60%. Through metal deposition, it is possible to realize states such as (1) no deposition, (2) metal filling a part of the nanohole, (3) metal filling the entire nanohole, (4) metal over-depositing to form a dome beyond the surface of the nanohole, or (5) metal over-depositing to form a continuous thin film beyond the surface of the nanohole. When the period is relatively small (less than 500 nm), colors ranging from yellow, green, blue, pink, and red can be realized through shape changes of the metal deposited via over-deposition. In the case of a nanohole array with the smallest period (255 nm), red appeared because the Cu metal was over-deposited beyond the nanohole surface. Additionally, although omitted from the drawing, when the period is greater than 500 nm, full color including black can be realized in a single pixel via electro-deposition. By applying a fixed voltage (e.g., -0.65 V) to a single pixel and adjusting the voltage application time, various color changes ranging from black, blue, green, and red can be realized. In this case, if the metal nanoparticles deposited in the nanoholes dissociate in a disordered manner, black can be realized through the broadband absorption phenomenon of the disordered metal nanoparticle array.

[0078] The reflection spectrum wavelengths according to the repetition cycle were measured for a structural color pixel having a nanohole array with a period of 425 nm (Figs. 4a and 4b). Cu was deposited by applying -0.65 V for 1.6 seconds per cycle, and Cu was dissolved by applying 0.7 V for 0.012 seconds (i.e., 83 Hz). Referring to the optical microscope image of the pixel in Fig. 4a, the driving stability was confirmed as no color change was observed when comparing the reflection color after the first and 600 cycles.

[0079] Figure 5a is a graph showing the applied voltage and the corresponding current according to the electrodeposition time, and Figure 5b is a graph showing the change in power density according to the electrodeposition time. The optical photograph inserted in Figure 5b is an image taken at 0 seconds, 3.2 seconds, 60 seconds, and 70 seconds, visually demonstrating the maintenance and stability of the copper deposition color over time. As shown in Figures 5a and 5b, if a low voltage is applied to maintain the color, the color can be maintained for more than 60 seconds. At this time, since the power density consumed is low, it was confirmed that color maintenance is possible even with low power.

[0080] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical concept or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0081] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and the concept of equivalents thereof should be interpreted as being included within the scope of the present invention.

Claims

1. A non-polarized structural color pixel comprising a reflective substrate, a dielectric layer having a nanohole array formed thereon, an electrolyte containing a metal salt, and a transparent electrode, The above nanoholes have a pillar-like structure, and A non-polarized structural color pixel in which the metal of the above metal salt is electrochemically deposited and dissolved inside the nanohole.

2. In Paragraph 1, The above-mentioned reflective substrate comprises one or more selected from Pt, Ag, Au, and Pd, in a non-polarized structural color pixel.

3. In Paragraph 1, A non-polarized structural color pixel in which the dielectric layer comprises one or more selected from TiO2, SiO2, Si, ZrO2, RuO2, IrO2, CaO, SrO, BaO, MnO, CuO, CuO2, Cu2O3, MoS2, TiN, and WO3.

4. In Paragraph 1, A non-polarized structural color pixel having a dielectric layer thickness of 10 nm to 1,000 nm.

5. In Paragraph 1, A non-polarized structural color pixel in which the columnar structure of the above nanohole comprises one or more selected from a cylinder, a triangular prism, a square prism, a pentagonal prism, a hexagonal prism, and a star-shaped prism.

6. In Paragraph 1, A non-polarized structural color pixel having a diameter of 100 nm to 500 nm for the nanoholes.

7. In Paragraph 1, A non-polarized structural color pixel in which the period of the above nanohole array is 200 nm to 900 nm.

8. In Paragraph 7, A non-polarized structural color pixel in which the period of the above nanohole array is 200 nm to 500 nm.

9. In Paragraph 7, A non-polarized structural color pixel in which the period of the above nanohole array is 500 nm to 900 nm.

10. In Paragraph 1, A non-polarized structural color pixel in which the period of the nanohole array is 1.5 to 2 times the diameter of the nanohole.

11. In Paragraph 1, A non-polarized structural color pixel in which the above metal comprises one or more selected from Cu, Ni, Ag, Zn, Pb, Bi, and Al.

12. In Paragraph 1, The above metal salt is ClO4 - , NO3 - , Cl - , Br - , and I - A non-polarized structural color pixel comprising one or more anions selected from.

13. In Paragraph 1, The above electrolyte is a non-polarized structural color pixel that additionally includes a polymer.

14. In Paragraph 1, A non-polarized structural color pixel, wherein the transparent electrode comprises one or more selected from indium tin oxide (ITO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium-zinc oxide (IZO), antimony-doped tin oxide (ATO), and indium-gallium-zinc oxide (IGZO).

15. In Paragraph 1, A non-polarized structural color pixel that implements a color change by controlling the electrochemical deposition-dissolution state of the above metal.

16. In Paragraph 1, A non-polarized structural color pixel in which the voltage difference of the voltage applied during the electrochemical deposition-dissolution process of the above metal is 1.4 V or less.

17. In Paragraph 1, The power density consumed during the electrochemical deposition-dissolution process of the above metal is 0.5 mW / cm² 2 Non-polarized structural color pixel that is less than or equal to 18. In Paragraph 1, The above metal is electrochemically deposited, and A non-polarized structural color pixel in which the time required for the electrochemically deposited metal to completely dissolve is 1 second or less.

19. In Paragraph 1, A non-polarized structural color pixel having a color reflectance of 60% or more.

20. In Paragraph 1, Non-polarized structural color pixels used in electronic paper displays.

Images