Zirconium oxide nanostructure realizing structural color and preparation method and application thereof

Abstract

The application provides a zirconium oxide nanostructure realizing structural color and a preparation method and application thereof. The preparation method of the zirconium oxide nanostructure realizing structural color comprises the following steps: coating a zirconium oxide photoresist solution on a substrate surface to form a film, and obtaining an inorganic zirconium oxide film through calcination; sputtering a conductive layer on the surface of the inorganic zirconium oxide film, and then performing focused ion beam etching to obtain the zirconium oxide nanostructure. The preparation method is simple, the structural color of the obtained nanostructure in a visible light band exhibits a wide color gamut, high resolution, high saturation and brightness, and has wide application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of structural color super surface, and particularly relates to a zirconium oxide nanostructure for realizing structural color and a preparation method and application thereof. BACKGROUND

[0002] Color plays a vital role in our world, and is the basis for humans to perceive and identify nature in daily life. However, it shows limited stability, poor resolution, and environmental pollution, and is not suitable for emerging display devices that require extremely high resolution. Structural color, which is different from the color determined by chemical composition, is generated by the reflection and diffraction of light on the special arrangement of microstructures on the surface of an object, and is ubiquitous in nature, such as butterfly wings, fish scales, pearls, and the like, which all exhibit beautiful and colorful structural color.

[0003] Based on plasmonic metal (such as gold or silver, etc.) super surface, extremely high resolution structural coloring can be realized beyond the diffraction limit. However, the inherent ohmic loss caused by the response of free electrons in metal materials affects the color purity and efficiency of structural color, and the incompatibility with the complementary metal oxide semiconductor (CMOS) manufacturing process also limits its application in optical devices.

[0004] All-dielectric resonators have emerged as a potential alternative solution. All-dielectric super surfaces are composed of dielectric materials with high refractive index and low loss, such as silicon (YANG W, XIAO S, SONG Q, et al. All-dielectric metasurface for high-performance structural color [J]. Nature Communications, 2020, 11(1): 1864.), titanium oxide (Sun S, Zhou Z, Zhang C, et al. All-dielectric full-color printing with TiO2 metasurfaces [J]. ACS nano, 2017, 11(5): 4445-4452.), etc., which can support electric and magnetic field multipole modes based on Mie resonance theory, and are used to realize high-performance structural color and improve diffraction limit resolution. Compared with the inherent ohmic loss of metal materials, which limits the color purity and efficiency of plasmonic structural color, all-dielectric super surface materials have the advantages of low loss, high resolution, stability, and tunability, making them a better candidate material in the field of structural color.

[0005] However, the high-order Mie resonance of the existing full dielectric material such as silicon will produce unnecessary sub-peak, seriously affect the monochromaticity of color, reduce the efficiency, and be limited to the problems of poor etching resistance, unstable properties and large light absorption coefficient of silicon. Zirconium oxide is a high refractive index metal oxide material, which has high refractive index, high transparency, CMOS compatibility and other characteristics. In the visible light band, it has a high refractive index of 2.0-2.2, an absorption coefficient close to 0, and can scatter and diffract incident light through microstructure, thereby producing specific color reflection or transmission effect. And because zirconium oxide is an inorganic material, it has strong corrosion resistance and wear resistance, and can well protect the original color and luster in structural color. For example, Chinese patent document CN104071839A discloses a preparation method of green zirconium oxide superstructure color agent. The method uses microemulsion method to prepare polymethyl methacrylate colloidal spheres with a diameter of 410±10nm, and self-assembles to obtain a face-centered cubic structure of polymethyl methacrylate template. 6g of zirconium acetate and 6g of methanol are mixed and stirred in a glass bottle to obtain a precursor mixture, which is infiltrated into the gap of the template and solidified. Then, it is placed in a quartz tube furnace and calcined in a reducing atmosphere at 450-500℃ for 2h, with a temperature rising rate of 2-4℃ / min and a nitrogen inflow amount of 0.6L / min. A beautiful single green zirconium oxide superstructure color agent is obtained, which has the characteristics of non-toxicity, high saturation, high brightness and never fading, and is an environmentally friendly new color agent. However, the color of the zirconium oxide superstructure color agent prepared by the invention is single, in addition, the preparation process of the zirconium oxide superstructure color agent is complex, the polymer template needs to be sacrificed, and finally carbon doping is needed.

[0006] Currently, the research of zirconium oxide in the field of structural color is limited to the deep ultraviolet region for holograms (Kim J, Kim W, Oh D K, et al. One-step printable platform for high-efficiency metasurfaces down to the deep-ultraviolet region[J]. Light: Science & Applications, 2023, 12(1): 68. Kang H, Kim H, Kim K, et al. Printable Spin-Multiplexed Metasurfaces for Ultraviolet Holographic Displays[J]. ACS nano, 2024, 18(32): 21504-21511.), and there are few studies in the visible light band. The construction of structural color super surface mostly uses electron beam evaporation, atomic layer deposition and magnetron sputtering to produce thin films, and is assisted by polymer photoresist as a mask plate, and needs stripping and other processes in the later stage, which has limitations in practical application.

[0007] Therefore, it is of great significance to develop a nano structure with simple preparation method, which realizes structural color in the visible light band with wide color gamut, high resolution, high saturation and brightness. SUMMARY

[0008] In view of the deficiencies of the prior art, the present application provides a zirconium oxide nano structure realizing structural color and a preparation method and application thereof. The present application coats a metal oxide photoresist on a substrate to form a film, calcines it in one step to form an oxide film, and combines focused ion beam technology to etch a periodic structure on the film to realize structural color. The preparation method of the present application is simple, and the structural color of the obtained nano structure in the visible light band exhibits wide color gamut, high resolution, high saturation and brightness, and has wide application value.

[0009] The technical scheme of the present application is as follows:

[0010] A preparation method of a zirconium oxide nano structure realizing structural color, comprising the steps of:

[0011] (1) coating a zirconium oxide photoresist solution on the surface of a substrate to form a film, and obtaining an inorganic zirconium oxide film by calcination;

[0012] (2) sputtering a conductive layer on the surface of the inorganic zirconium oxide film, and then etching by focused ion beam to obtain a zirconium oxide nano structure.

[0013] According to the application, preferably, in step (1), the zirconium oxide photoresist is selected from a zirconium oxide nanoparticle photoresist with benzoic acid and methacrylic acid as ligands or Zr6O4(OH)4(OMc) 12 one or both of the photoresists, Zr6O4(OH)4(OMc) 12 in the photoresist, the group OMc is CH2=CH(CH3)COO - Zr6O4(OH)4(OMc) 12 The synthesis method of the photoresist can refer to the literature "Wang Q, Cui H, Wang X, et al. Exceptional light sensitivity by thiol-ene clicklithography [J]. Journal of the American Chemical Society, 2023, 145(5): 3064-3074."

[0014] Preferably, the preparation method of the zirconium oxide nanoparticle photoresist with benzoic acid and methacrylic acid as ligands is as follows:

[0015] The n-butanol solution of zirconium n-butoxide or the n-propanol solution of zirconium n-propoxide and tetrahydrofuran are uniformly mixed to obtain solution A; benzoic acid, methacrylic acid, triethylamine, and tetrahydrofuran are uniformly mixed to obtain solution B; solution B and solution A are uniformly mixed, reacted, and rotary evaporated to obtain the zirconium oxide nanoparticle photoresist with benzoic acid and methacrylic acid as ligands.

[0016] Further preferably, the concentration of the n-butanol solution of zirconium n-butoxide is 80wt%, the concentration of the n-propanol solution of zirconium n-propoxide is 70wt%; the mass ratio of the n-butanol solution of zirconium n-butoxide or the n-propanol solution of zirconium n-propoxide to tetrahydrofuran is 1-3:1; the molar ratio of benzoic acid, methacrylic acid, and triethylamine is 1:1:0.1-0.3, the mass ratio of benzoic acid to tetrahydrofuran is 1:1-2; the molar ratio of zirconium n-butoxide or zirconium n-propoxide to benzoic acid is 1:1-2; the reaction temperature is 50-60℃, and the reaction time is 20-30h, and the reaction is carried out under stirring and reflux conditions.

[0017] According to the application, preferably, in step (1), the concentration of the zirconium oxide photoresist solution is 10wt%-80wt%, preferably 60wt%.

[0018] According to the application, preferably, in step (1), the solvent used in the zirconium oxide photoresist solution is selected from one or a combination of two or more of propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether (PM), ethyl lactate, butyl lactate, dimethyl sulfoxide, or tetrahydrofuran.

[0019] According to the application, preferably, in step (1), the substrate is silicon dioxide, ITO glass or aluminum oxide. Preferably, the substrate is silicon dioxide.

[0020] According to the application, preferably, in step (1), the coating method is spin coating, the spin coating speed is 800-1200 rpm / min, and the spin coating time is 40-80 s.

[0021] According to the application, preferably, in step (1), the film forming temperature is 60-100℃, and the film forming time is 5-15 min.

[0022] According to the application, preferably, in step (1), the calcination temperature is 520-800℃, the calcination time is 2-12 h, and the calcination atmosphere is air. Preferably, the calcination temperature is 500-600℃.

[0023] According to the application, preferably, in step (1), the thickness of the inorganic zirconium oxide film is 0.2-0.5 μm.

[0024] According to the application, preferably, in step (2), the conductive layer material is one of chromium, gold or ITO; the thickness of the conductive layer is 10 nm-60 nm; and the sputtering method is magnetron sputtering or ion sputtering.

[0025] According to the application, preferably, in step (2), the etching is performed using a scanning electron microscope-focussed ion beam (SEM-FIB), the etching voltage is 30 KV, the etching current is 7.7 pA-0.23 nA, and the ion beam injection time is 200 ns-10.0 μs. Preferably, the etching current is 24 pA-0.23 nA, and the ion beam injection time is 1.0 μs.

[0026] According to the application, preferably, in step (2), the etching period p is 300 nm, 320 nm, 350 nm, 380 nm or 400 nm, the width w of the retained line is 150 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm or 260 nm; the length of the retained line is greater than 300 nm; and the number of the retained lines is greater than or equal to 2. Preferably, the width w of the retained line is 150 nm, 170 nm, 180 nm, 210 nm or 220 nm. The retained line refers to the protruding line left after etching on both sides, and the etching period is the sum of the width of one retained line and the width of one adjacent etched line.

[0027] According to the application, preferably, in step (2), the etching depth is 200-600 nm.

[0028] According to the application, preferably, in step (2), the color of the structural color in the visible light band is regulated by regulating the etching current or / and the etching period or / and the width of the reserved line or / and the etching depth.

[0029] A zirconium oxide nanostructure realizing structural color is prepared by the method.

[0030] Application of the above-mentioned zirconium oxide nanostructure realizing structural color in a structural color device in the visible light band.

[0031] The technical features and advantages of the application are as follows:

[0032] 1. The zirconium oxide photoresist is coated on a substrate to form a film, and a zirconium oxide thin film is formed by one-step calcination, wherein the zirconium oxide thin film has high thermal stability and good film forming quality.

[0033] 2. According to the design period plate, etching is performed on the zirconium oxide thin film, that is, the etching is performed in a cycle of reserved line-etching line-reserved line-etching line to realize the periodic arrangement of the reserved line.

[0034] 3. The nanostructure can realize structural color with a small number of reserved lines (as few as 2) and a small length of the reserved line (as small as 300 nanometers), which indicates that the nanostructure has high resolution in the visible light band.

[0035] 4. In the application, a small etching current can obtain a periodic zirconium oxide grating with high precision, and a wide color gamut of structural color can be obtained, while a large etching current can reduce the color gamut of the structural color. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1is a thermogravimetric spectrum of ZrO2-MAA / BA obtained in Example 1 under nitrogen and air atmosphere.

[0037] Figure 2 is a particle size analysis spectrum of ZrO2-MAA / BA obtained in Example 1.

[0038] Figure 3 is a topography image of photoresist film (a) and zirconia film (b) obtained in Example 1 under atomic force microscope.

[0039] Figure 4 is a plot of film thickness vs. calcination temperature of photoresist film obtained in the method of Example 1 calcined at different temperatures for 2h.

[0040] Figure 5 is a plot of refractive index n vs. calcination temperature of photoresist film obtained in the method of Example 1 calcined at different temperatures for 2h, wavelength range 400-800nm.

[0041] Figure 6 is a scanning electron microscope image of zirconia nanostructure prepared in Examples 1-15 and the corresponding experimental structure color in reflected cross-polarization mode under polarizing microscope.

[0042] Figure 7 is a scanning electron microscope image of zirconia nanostructure prepared in Examples 16-25 and the corresponding experimental structure color in reflected cross-polarization mode under polarizing microscope.

[0043] Figure 8 is a plot of actual line width vs. etching depth in Test Example 4.

[0044] Figure 9 is a chromaticity diagram (CIE 1931) of experimental structure color of zirconia nanostructure in Test Example 5. Etching depth is 400nm, triangle is standard sRGB color gamut. DETAILED DESCRIPTION

[0045] The present application is further illustrated by the following specific examples, in which the starting materials are commercially available. It should be understood that the following examples are merely illustrative and explanatory of the present application and do not limit the scope of the present application.

[0046] Example 1

[0047] A method for preparing a zirconia nanostructure realizing structural color, comprising the steps of:

[0048] (1) 10.0 g of 80 wt% n-butanol zirconium (0.021 mol) solution in n-butanol and 5 g of tetrahydrofuran were mixed uniformly to form solution A; 3.91 g of benzoic acid (0.032 mol), 2.75 g of methacrylic acid (0.032 mol), 0.71 g of triethylamine (0.007 mol), 5 g of tetrahydrofuran were mixed uniformly to form solution B; solution B was mixed uniformly with solution A, under oil bath conditions, the reflux temperature was set to 60°C, the reflux time was 24 h, and the stirring reaction was carried out, after the reaction was completed, it was naturally lowered to room temperature, then rotary evaporation was carried out at 50-55°C for 30 min to remove the solvent, a white transparent liquid was obtained, named ZrO2-MAA / BA.

[0049] Thermal analysis was performed on the product ZrO2-MAA / BA. Thermal analysis (Netzsch, model STA449F3): under nitrogen or air environment, the temperature was raised at a rate of 10°C / min, from 25°C to 800°C. The obtained thermal analysis curve is shown in Figure 1 From the figure, it can be seen that the ZrO2-MAA / BA material contains 26.4 wt% of inorganic zirconium oxide component.

[0050] Particle size analysis was performed on the product ZrO2-MAA / BA. Dynamic light scattering instrument (Anton Paar, model: Litesizer500): ZrO2-MAA / BA was prepared at a concentration of 15 wt% with PGMEA as solvent. The obtained particle size distribution curve is shown in Figure 2 From the figure, it can be seen that the average particle size of ZrO2-MAA / BA is small and uniformly distributed.

[0051] (2) Preparation of zirconium oxide film, the product ZrO2-MAA / BA was dissolved in PGMEA, the mass ratio of ZrO2-MAA / BA and PGMEA was 3:2, filtered with a polytetrafluoroethylene filter membrane with a pore size of 0.22 μm to obtain a photoresist solution. A 2*2 cm 2 quartz piece was adsorbed on a spin coater and spin-coated at a speed of 1000 rpm / min for 60 s, then baked on a heating plate at 80°C for 10 min to obtain a photoresist film. Then it was placed in a muffle furnace, heated at 600°C for 2 h in air atmosphere, the heating rate was 10°C / min -1 , further removing the organic matter to obtain an inorganic zirconium oxide film with a thickness of 0.3 μm.

[0052] Atomic force microscopy (AFM) (Germany, model: Bruker Dimension Icon) was used to collect the surface morphology of the spin-coated photoresist film and the film calcined at 600°C for 2 h in light touch mode, the collection area was set to 3 μm*3 μm. The surface morphology of the photoresist film and the zirconium oxide film is shown in Figure 3The root mean square roughness (Rq) of a and b is 0.23 nm and 0.18 nm respectively, indicating that the surface of the zirconia film is smooth and flat.

[0053] (3) A 60 nm thick chromium layer is deposited on the surface of the inorganic zirconia film by magnetron sputtering of a chromium target. According to the design pattern, etching is performed on the zirconia film using a scanning electron microscope-focussed ion beam (SEM-FIB) (USA, model: Helios 5CX, Thermo Fisher Scientific). The basic conditions are an etching voltage of 30 KV, an etching current of 24 pA, an ion beam injection time of 1.0 μs, an etching period p of 300 nm, a width w of the retained line of 150 nm (referred to as p300w150), a length of the retained line of 3 μm, a number of retained lines of 9, and an etching depth of 400 nm. The retained line refers to the raised line left on both sides after etching. The etching period is the sum of the width of one retained line and the width of one adjacent etched line. Thus, a zirconia nanostructure is obtained.

[0054] Example 2

[0055] A method for preparing a zirconia nanostructure with structural color, as described in Example 1, except that in step (3), the etching current is 80 pA; the other steps and conditions are the same as in Example 1.

[0056] Example 3

[0057] A method for preparing a zirconia nanostructure with structural color, as described in Example 1, except that in step (3), the etching current is 0.23 nA; the other steps and conditions are the same as in Example 1.

[0058] Example 4

[0059] A method for preparing a zirconia nanostructure with structural color, as described in Example 1, except that in step (3), the etching period p is 320 nm, and the width w of the retained line is 170 nm (referred to as p320w170); the other steps and conditions are the same as in Example 1.

[0060] Example 5

[0061] A method for preparing a zirconia nanostructure with structural color, as described in Example 4, except that in step (3), the etching current is 80 pA; the other steps and conditions are the same as in Example 1.

[0062] Example 6

[0063] A method for preparing a zirconia nanostructure with structural color, as described in Example 1, except that in step (3), the etching period p is 350 nm and the width w of the retained lines is 180 nm (referred to as p350w180); and other steps and conditions are the same as in Example 1.

[0064] Example 7

[0065] A method for preparing a zirconia nanostructure with structural color, as described in Example 7, except that in step (3), the etching current is 80 pA; and other steps and conditions are the same as in Example 1.

[0066] Example 8

[0067] A method for preparing a zirconia nanostructure with structural color, as described in Example 7, except that in step (3), the etching current is 0.23 nA; and other steps and conditions are the same as in Example 1.

[0068] Example 9

[0069] A method for preparing a zirconia nanostructure with structural color, as described in Example 7, except that in step (3), the etching current is 0.23 nA; and other steps and conditions are the same as in Example 1.

[0070] Example 10

[0071] A method for preparing a zirconia nanostructure with structural color, as described in Example 1, except that in step (3), the etching period p is 380 nm and the width w of the retained lines is 210 nm (referred to as p380w210); and other steps and conditions are the same as in Example 1.

[0072] Example 11

[0073] A method for preparing a zirconia nanostructure with structural color, as described in Example 10, except that in step (3), the etching current is 80 pA; and other steps and conditions are the same as in Example 1.

[0074] Example 12

[0075] A method for preparing a zirconia nanostructure with structural color, as described in Example 10, except that in step (3), the etching current is 0.23 nA; and other steps and conditions are the same as in Example 1.

[0076] Example 13

[0077] A method for preparing a zirconia nanostructure realizing structural color, as described in Example 1, except that in step (3), the etching period p is 400 nm, and the width w of the reserved line is 220 nm (referred to as p400w220); the other steps and conditions are the same as in Example 1.

[0078] Example 14

[0079] A method for preparing a zirconia nanostructure realizing structural color, as described in Example 13, except that in step (3), the etching current is 80 pA; the other steps and conditions are the same as in Example 1.

[0080] Example 15

[0081] A method for preparing a zirconia nanostructure realizing structural color, as described in Example 13, except that in step (3), the etching current is 0.23 nA; the other steps and conditions are the same as in Example 1.

[0082] Example 16

[0083] A method for preparing a zirconia nanostructure realizing structural color, as described in Example 1, except that in step (3), the etching depth is 600 nm; the other steps and conditions are the same as in Example 1.

[0084] Example 17

[0085] A method for preparing a zirconia nanostructure realizing structural color, as described in Example 1, except that in step (3), the etching depth is 500 nm; the other steps and conditions are the same as in Example 1.

[0086] Example 18

[0087] A method for preparing a zirconia nanostructure realizing structural color, as described in Example 4, except that in step (3), the etching depth is 600 nm; the other steps and conditions are the same as in Example 1.

[0088] Example 19

[0089] A method for preparing a zirconia nanostructure realizing structural color, as described in Example 4, except that in step (3), the etching depth is 500 nm; the other steps and conditions are the same as in Example 1.

[0090] Example 20

[0091] A method for preparing a zirconia nanostructure realizing structural color, as described in Example 7, except that in step (3), the etching depth is 600 nm; the other steps and conditions are the same as in Example 1.

[0092] Example 21

[0093] A method for preparing a zirconia nanostructure with structural color, as described in Example 7, except that in step (3), the etching depth is 500 nm; other steps and conditions are the same as in Example 1.

[0094] Example 22

[0095] A method for preparing a zirconia nanostructure with structural color, as described in Example 10, except that in step (3), the etching depth is 600 nm; other steps and conditions are the same as in Example 1.

[0096] Example 23

[0097] A method for preparing a zirconia nanostructure with structural color, as described in Example 10, except that in step (3), the etching depth is 500 nm; other steps and conditions are the same as in Example 1.

[0098] Example 24

[0099] A method for preparing a zirconia nanostructure with structural color, as described in Example 13, except that in step (3), the etching depth is 600 nm; other steps and conditions are the same as in Example 1.

[0100] Example 25

[0101] A method for preparing a zirconia nanostructure with structural color, as described in Example 13, except that in step (3), the etching depth is 500 nm; other steps and conditions are the same as in Example 1.

[0102] Test Example 1

[0103] The photoresist film prepared by the method of Example 1, step (2) was calcined in air at 100°C, 200°C, 300°C, 400°C, 500°C, and 600°C for 2 h, with a heating rate of 10°C / min. -1 .

[0104] The relationship between the thickness of the film and the calcination temperature was analyzed using an ellipsometer (U.S.A., model: M-2000v) in the wavelength range of 400-800 nm, as shown in Figure 4 With the gradual increase of the calcination temperature, the thickness of the film gradually decreased. The thickness of the film before calcination was 1.8 μm, and the thickness of the film after calcination at 600°C was 0.3 μm.

[0105] The relationship between the refractive index of the film and the calcination temperature was analyzed using an ellipsometer (U.S.A., model: M-2000v) in the wavelength range of 400-800 nm, as shown in Figure 5The results show that with the increase of calcination temperature, the organic components are gradually removed, and the refractive index of the zirconia film gradually increases. When calcined at 600℃ for 2h, the refractive index of the film at a wavelength of 400nm can reach above 2.0, and the film has the characteristics of high refractive index, which is helpful to the realization of structural color.

[0106] Test Example 2

[0107] The etching patterns of the zirconia nanostructures prepared in Examples 1-15 were characterized by the scanning electron microscope imaging function of the scanning electron microscope-focused ion beam (SEM-FIB) system, and the structural color was obtained in the reflection orthogonal polarization mode by using a polarizing microscope (Germany, model: AxioScope AI, ZEISS), as shown in Figure 6 The etching patterns can exhibit blue, dark green, light green, orange, and red structural colors, proving that the zirconia nanostructures have good structural color performance. The etching precision of the etching current of 24pA is the highest.

[0108] Test Example 3

[0109] The etching patterns of the zirconia nanostructures prepared in Examples 16-25 were characterized by the scanning electron microscope imaging function of the scanning electron microscope-focused ion beam (SEM-FIB) system, and the structural color was obtained in the reflection orthogonal polarization mode by using a polarizing microscope (Germany, model: AxioScope AI, ZEISS), as shown in Figure 7 The overall exhibits purple, blue, green, orange, and red structural colors.

[0110] Test Example 4

[0111] According to the zirconia nanostructures obtained in Examples 1-25, the relationship between the actual line width and the etching depth of etching was obtained, as shown in Figure 8 The results show that as the etching depth increases, the actual obtained line width will gradually shorten, and different presentations of structural color can be obtained by controlling the etching depth.

[0112] Test Example 5

[0113] According to the zirconia nanostructures obtained in Examples, the structural colors obtained at an etching current of 24pA and etching depths of 400nm, 500nm, and 600nm were plotted into a chromaticity diagram (CIE 1931), as shown in Figure 9 The results show that the color gamut area of the experimental structural color of the zirconia nanostructures is close to sRGB, proving that the zirconia nanostructures have good structural color ability in the visible light band.

Claims

1. A method for preparing a zirconium oxide nanostructure to achieve structural color, comprising the steps of: (1) Coating a zirconium oxide photoresist solution on the substrate surface to form a film, and then calcining to obtain an inorganic zirconium oxide thin film; the calcination temperature is 520-800°C; (2) A conductive layer is sputtered on the surface of the inorganic zirconium oxide film, and then focused ion beam etching is performed to obtain a zirconium oxide nanostructure; the etching current is 7.7pA-0.23nA; the etching period p is 300nm, 320nm, 350nm, 380nm or 400nm, and the retained line width w is 150nm, 170nm, 180nm, 190nm, 200nm, 210nm, 220nm, 230nm, 240nm, 250nm or 260nm; the etching depth is 200-600nm.

2. The method for preparing a zirconium oxide nanostructure for achieving structural color according to claim 1, characterized in that: In step (1), the zirconium oxide photoresist is selected from zirconium oxide nanoparticle photoresist with benzoic acid and methacrylic acid as ligands or Zr6O4(OH)4(OMc) 12 One or both of the photoresists, Zr6O4(OH)4(OMc) 12 In photoresist, the group OMc is CH2=CH(CH3)COO-.

3. The method for preparing a zirconium oxide nanostructure for achieving structural color according to claim 2, characterized in that: The preparation method of zirconium oxide nanoparticle photoresist with benzoic acid and methacrylic acid as ligands is as follows: A n-butanol solution of zirconium n-butoxide or a n-propanol solution of zirconium n-propoxide and tetrahydrofuran are uniformly mixed to obtain solution A; benzoic acid, methacrylic acid, triethylamine and tetrahydrofuran are uniformly mixed to obtain solution B; solution B and solution A are uniformly mixed, reacted, and rotary evaporated to obtain zirconium oxide nanoparticle photoresist with benzoic acid and methacrylic acid as ligands.

4. The method for preparing a zirconium oxide nanostructure for achieving structural color according to claim 3, characterized in that: The concentration of the zirconium n-butoxide n-butanol solution is 80wt%, and the concentration of the zirconium n-propoxide n-propanol solution is 70wt%; the mass ratio of the zirconium n-butoxide n-butanol solution or the zirconium n-propoxide n-propanol solution to tetrahydrofuran is 1-3:1; the molar ratio of benzoic acid, methacrylic acid, and triethylamine is 1:1:0.1-0.3, and the mass ratio of benzoic acid to tetrahydrofuran is 1:1-2; the molar ratio of the zirconium n-butoxide or the zirconium n-propoxide to benzoic acid is 1:1-2; the reaction temperature is 50-60°C, the reaction time is 20-30h, and the reaction is carried out under stirring and reflux conditions.

5. The method for preparing a zirconium oxide nanostructure for achieving structural color according to claim 1, characterized in that: In step (1), one or more of the following conditions are included: i. The concentration of the zirconium oxide photoresist solution is 10wt%-80wt%; ii. The solvent used in the zirconium oxide photoresist solution is selected from one or a combination of two or more of propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether (PM), ethyl lactate, butyl lactate, dimethyl sulfoxide or tetrahydrofuran; iii. The substrate is silicon dioxide, ITO glass or alumina; iv. The coating method is spin coating, the spin coating speed is 800-1200 rpm / min, and the spin coating time is 40-80 s; v. Film forming temperature is 60-100°C and film forming time is 5-15min; vi. Calcination time is 2-12h, and the calcination atmosphere is air; vii. The thickness of the inorganic zirconium oxide film is 0.2-0.5 μm.

6. The method for preparing a zirconium oxide nanostructure for achieving structural color according to claim 1, characterized in that: In step (1), the calcination temperature is 500-600°C.

7. The method for preparing a zirconium oxide nanostructure for achieving structural color according to claim 1, characterized in that: In step (2), the conductive layer material is one of chromium, gold or ITO; the thickness of the conductive layer is 10nm-60nm.

8. The method for preparing a zirconium oxide nanostructure for achieving structural color according to claim 1, characterized in that: In step (2), a scanning electron microscope-focused ion beam (SEM-FIB) is used for etching, the etching voltage is 30 kV, and the ion beam injection time is 200 ns-10.0 μs.

9. The method for preparing a zirconium oxide nanostructure for achieving structural color according to claim 1, characterized in that: In step (2), the etching current is 24pA-0.23nA, and the ion beam injection time is 1.0μs.

10. The method for preparing a zirconium oxide nanostructure for achieving structural color according to claim 1, characterized in that: In step (2), the length of the retained lines is greater than 300 nm; and the number of retained lines is greater than or equal to 2.

11. The method for preparing a zirconium oxide nanostructure for achieving structural color according to claim 1, characterized in that: In step (2), the width w of the retained line is 150 nm, 170 nm, 180 nm, 210 nm or 220 nm.

12. The method for preparing a zirconium oxide nanostructure for achieving structural color according to claim 1, characterized in that: In step (2), the structural color is regulated in the visible light band by regulating the etching current and / or the etching period and / or the width of the retained line and / or the etching depth.

13. A zirconium oxide nanostructure that realizes structural color, prepared by the method according to any one of claims 1 to 12.

14. Use of the zirconium oxide nanostructure for achieving structural color as claimed in claim 13 in a structural color device in the visible light band.

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