A method for improving the response performance of electrochromic colloidal photonic crystals by electrode surface microstructure modification

Abstract

This invention discloses a novel method for improving the response performance of electrochromic colloidal photonic crystals by modifying the microstructure of the electrode surface. The electrode surface is modified into a non-planar structure with numerous tiny protrusions through methods such as sputtering and depositing metal nanoparticles or coating and depositing semiconductor nanoparticles. These protruding, pointed structures increase charge injection and enhance the local electric field, thereby improving multiple response properties of the electrochromic photonic crystal. Compared with electrochromic photonic crystals encapsulated with ordinary electrodes, the photonic crystal with modified electrode encapsulation proposed in this invention exhibits lower operating voltage, higher structural color saturation, and better electrical response reversibility and stability, providing a new path for the development of photonic crystal color electrophoretic display technology.

Description

Technical Field

[0001] This invention belongs to the fields of photonic crystal materials and electrophoretic display screen applications, and specifically relates to a method for improving the response performance of electrochromic colloidal photonic crystals by modifying the microstructure of the electrode surface. Background Technology

[0002] Electrophoretic displays offer energy-saving and eye-friendly advantages, making them widely used in e-readers, electronic tags, smartphones, and bus stop displays. Electroresponsive colloidal photonic crystals are a novel type of electrochromic material characterized by low driving voltage, color saturation, adjustable color, and compatibility with existing technologies, making them a promising new material for manufacturing color electrophoretic displays. When a DC voltage is applied, the colloidal particles constituting the photonic crystal migrate electrophoretically towards the electrodes with opposite charges under the influence of Coulomb forces. This causes the photonic crystal lattice to shrink, resulting in a blue shift of the reflected signal and a corresponding change in structural color. Based on this working principle, key performance indicators for evaluating such electrochromic photonic crystal materials can be summarized, including operating voltage, structural color (reflection wavelength) modulation range, structural color saturation, response stability, response reversibility, and response speed.

[0003] Since South Korean scientists reported the first such material in 2010, research has been conducted on various aspects, including colloids, dispersion media, and electrodes, actively exploring various methods to improve the performance of electrochromic photonic crystals, and some progress has been made. However, considering the technical requirements of display devices, the electroresponse performance of this material is still unsatisfactory, and many key problems remain to be solved. Among them, the high driving voltage of around 1.0V to 4V is the core issue affecting performance. Numerous studies have shown that charged particles and colloidal photonic crystals usually need to be realized in polar media, which strongly shields the Coulomb effect, forcing these materials to operate at high voltages. Excessively high voltages first interfere with the self-assembly of the colloid, leading to a decrease in the orderliness and reflection intensity of the photonic crystal, thus significantly reducing the saturation of the structural color. In addition, since the lattice compression state of the photonic crystal and the corresponding structural color must be maintained by continuously applying an electric field, such a high driving voltage will inevitably induce electrochemical reactions on the electrode surface, changing the external electric field conditions of particle electrophoresis, thereby destroying the stability and reversibility of the electroresponse and reducing the modulation range of the structural color.

[0004] In recent years, research has reported on constructing electrochromic colloidal photonic crystals using hydrophobic particles and weakly polar dielectrics to address the aforementioned "high voltage" problem. The weakly polar dielectrics, with their minimal Coulomb effect shielding, significantly reduce the driving voltage of the material. However, this unconventional weakly polar electrochromic photonic crystal design places limitations or higher demands on the selection of raw materials, synthesis, and assembly processes. Therefore, there is an urgent need to find a universal method to improve the performance of colloidal photonic crystals, independent of their material composition. This would undoubtedly have a positive impact on promoting the practical application of electrochromic photonic crystals. Summary of the Invention

[0005] This invention addresses the performance issues of traditional electrochromic photonic crystals, such as high driving voltage, large attenuation of structural color saturation, and poor electrical response stability and reversibility. It provides a novel method to improve the response performance of electrochromic colloidal photonic crystals by modifying the microstructure of the electrode surface. By sputtering and depositing metal and semiconductor nanoparticles, the surface roughness of the electrodes is increased, enhancing the local electric field strength and the sensitivity of the electrochromic photonic crystal response, thereby effectively reducing the driving voltage of the material. The lower operating voltage also allows the electrochromic photonic crystal to exhibit excellent resistance to attenuation of structural color saturation and good reversibility and stability, providing a universally applicable new method for improving the performance of this type of material.

[0006] This invention proposes a method for improving the response performance of electrochromic colloidal photonic crystals by modifying the electrode surface, specifically including the following steps:

[0007] (1) Modify the surface microstructure of the conductive surface of the transparent electrode;

[0008] (2) A colloidal photonic crystal with electrochromic effect is encapsulated between a conventional transparent electrode and a transparent electrode modified in step (1), with double-sided adhesive used as electrode spacer and encapsulation bonding material around the perimeter to obtain a photonic crystal electrophoresis device.

[0009] In step (1), the transparent electrode includes: ITO, FTO conductive glass, flexible ITO, FTO conductive film, etc.

[0010] In step (1), the modification of the electrode surface includes, but is not limited to, ion sputtering of metal nanoparticles; the metal includes gold, platinum, copper, etc.

[0011] The ion sputtering time is typically 5-80 seconds; preferably, gold plating is 20 seconds and copper plating is 80 seconds.

[0012] The ion sputtering refers to placing a cleaned transparent electrode (with a bare conductive surface of 1.2cm*1.2cm) in an ion sputtering instrument equipped with a metal target, evacuating to a vacuum level of 9Pa / mmHg, and sputtering for different times under a sputtering current of 2mA to obtain different transparent electrodes.

[0013] In step (1), the modification of the electrode surface includes, but is not limited to, coating with metal oxide nanoparticles; the metal oxide includes Cu2O, TiO2, etc.

[0014] The coating method involves dispersing 10 mg of pre-prepared metal oxide nanoparticles in a mixed solution of 0.75 mL isopropanol and 0.25 mL deionized water. This colloidal dispersion is then drop-coated onto a cleaned transparent electrode (with a 1.2 cm x 1.2 cm exposed conductive surface), and dried at room temperature to obtain a transparent electrode modified with metal oxide nanoparticles.

[0015] In step (2), the electrochromic effect refers to the effect of the material exhibiting different spectral colors such as red, orange, yellow, green, and blue under different DC voltage conditions.

[0016] In step (2), the colloidal photonic crystal with electrochromic effect includes, but is not limited to: liquid colloidal photonic crystals such as SiO2 / PCb, SiO2 / EG, SiO2 / IPA, SiO2 / ANI, SiO2 / DMF, and SiO2 / (PCb-EG); preferably, it is SiO2 / (PCb-EG).

[0017] In step (2), the volume fraction of SiO2 particles in the colloidal photonic crystal is 15%-25%; preferably, the volume fraction is 22.5%.

[0018] In step (2), the volume fraction of solvent in the colloidal photonic crystal is 75%-85%; preferably, the volume fraction is 77.5%.

[0019] In step (2), if the encapsulated electrochromic photonic crystal is composed of negatively charged particles, the modified transparent electrode is placed at the positive electrode; if the photonic crystal is composed of positively charged particles, the modified transparent electrode is placed at the negative electrode.

[0020] In step (2), the double-sided adhesive for encapsulation includes, but is not limited to, epoxy double-sided adhesive, UV-curable adhesive, hot melt adhesive, etc.; preferably, hot melt adhesive is used.

[0021] In step (2), the thickness of the double-sided adhesive used for encapsulation, i.e. the spacing between the electrode plates after encapsulation, is 30-200 micrometers; preferably, the spacing is 50 micrometers.

[0022] Furthermore, the method of the present invention includes step (3): connecting it to an external DC power supply and adjusting the voltage value to achieve an electrochromic effect and an electrical response performance superior to that of traditional electrochromic photonic crystal devices.

[0023] In step (3), the DC voltage modulation range is 0–3.0V.

[0024] In step (3), the conventional electrochromic photonic crystal device refers to an electrophoretic device packaged with unmodified ordinary transparent electrodes.

[0025] In step (3), the superior electrical response performance compared to traditional electrochromic photonic crystal devices includes lower operating voltage (1.3V, blue shift 120 nm), wider structural color chromaticity range (red to lake blue), higher structural color saturation, higher response stability (1.3V, 30 minutes) and reversibility (0V-1.3V, 30 cycles).

[0026] The principle behind the method of this invention for improving material properties is explained as follows: Figure 1 As shown, discontinuous island-like deposition films can be formed on the surface of ITO transparent electrodes using methods such as ion sputtering of Au nanoparticles, ion sputtering of Cu nanoparticles, and coating with Cu2O nanoparticles. This modification of the electrode surface microstructure does not affect the conductivity of the ITO film; however, the micro-protrusion structure introduced by the nanoparticles leads to a tip discharge effect, increasing the local charge density and local electric field strength on the electrode surface. Therefore, the colloidal photonic crystal near the modified electrode experiences a stronger local electric field, resulting in greater lattice contraction under the same voltage conditions, a larger blue shift in the reflected wavelength, and a correspondingly greater change in structural color. In other words, the driving voltage required to achieve the same lattice contraction and structural color change is reduced. The lower the voltage required to maintain a specific structural color, the less interference it causes with crystal order, and the higher the structural color saturation, thus effectively avoiding a significant decrease in structural color saturation during lattice contraction. A lower operating voltage also helps to avoid electrochemical reactions on the electrode surface, thereby improving the stability and reversibility of the electrochromic photonic crystal's electrical response.

[0027] Compared with existing technologies, the advantages of this invention are: 1) The technical method for improving the performance of electrochromic colloidal photonic crystals based on electrode surface microstructure modification described in this invention simultaneously achieves low voltage, high saturation structural color, and excellent stability and reversibility. This method is proposed for the first time and has not been reported before. It is fundamentally different from technical methods based on the control of colloidal photonic crystal material composition. 2) The performance improvement method described in this invention has no specific requirements on the composition of photonic crystal materials and has an improving effect on electrochromic photonic crystals with various formulations. The SiO2 / (PCb-EG) used in the embodiments of this invention is a common electrochromic colloidal photonic crystal. Attached Figure Description

[0028] Figure 1 Taking the gold plating treatment on the surface of ITO electrodes as an example, this paper explains the basic principle of improving the response performance of electrochromic photonic crystals based on electrode surface modification.

[0029] Figure 2 In the figure, Figures a, b, and c are digital photographs, optical microscope photographs, and scanning electron microscope images of the SiO2 / (PCb-EG) electrochromic photonic crystal, respectively; Figure d is a scanning electron microscope image of the ITO electrode after gold plating treatment for different durations; Figures e and f are the structural color changes of the SiO2 / (PCb-EG) photonic crystal packaged in ordinary ITO cathode and gold-plated ITO cathode at different voltages, respectively.

[0030] Figure 3 In the figure, Figures a and b show the reflection spectra of SiO2 / (PCb-EG) photonic crystals under different voltages when packaged with ordinary ITO cathode and gold-plated ITO cathode, respectively; Figure c shows the relationship between driving voltage and lattice compression ratio in the above two cases; Figure d shows the relationship between reflection intensity attenuation and lattice compression ratio in the above two cases.

[0031] Figure 4 In the figures, Figures a and b show the variation trends of the reflected wavelength of SiO2 / (PCb-EG) photonic crystals under repeated "voltage application-voltage removal" tests when the SiO2 / (PCb-EG) photonic crystals are packaged with ordinary ITO positive electrodes and gold-plated ITO positive electrodes, respectively. Figures c and d show the variation trends of the reflected wavelength of the two photonic crystals when SiO2 / (PCb-EG) photonic crystals are packaged with ordinary ITO positive electrodes and gold-plated ITO positive electrodes, respectively, and when 2.3V and 1.3V voltages are continuously applied for 30 minutes to achieve the same lattice compression, respectively.

[0032] Figure 5In the figure, Figure a shows the comparison of the changes in the reflected wavelength of the SiO2 / (PCb-EG) photonic crystal under different voltages when packaged with ordinary ITO cathode and copper-plated ITO cathode; Figure b shows the comparison of the changes in the reflected wavelength of the SiO2 / (PCb-EG) photonic crystal under different voltages when packaged with ordinary ITO cathode and copper oxide-plated ITO cathode. Detailed Implementation

[0033] The present invention will be further described below through specific embodiments:

[0034] Example 1. Preparation of SiO2 / (PCb-EG) electrochromic colloidal photonic crystal

[0035] First, adopt Monodisperse SiO2 colloidal particles with an average particle size of 167 nm were prepared by a method, and then washed with ethanol for later use. The particles had a volume of 22.5 × 10⁻⁶. -3 cm -3 SiO2 colloidal particles were dispersed in 1.1 mL of ethanol and then ultrasonically mixed with 62.5 μL of propylene carbonate (PCb) and 15 μL of ethylene glycol (EG) to form a homogeneous solution. The solution was then heated in a 90°C oven for 2 hours to evaporate and remove the ethanol, yielding a 100 μL SiO2 / (PCb-EG) colloidal photonic crystal with electrochromic properties. Figure 2 As shown in a-2c, this colloidal photonic crystal has a liquid appearance and can spontaneously precipitate to form colloidal microcrystals with a red structural color without any electric field. These colloidal microcrystals can be directly observed in optical microscope images, and scanning electron microscope images after the sample is dried can directly prove that these colloidal crystals are crystal structures formed by the orderly stacking of SiO2 colloidal particles.

[0036] Example 2. Gold plating, copper plating, and cuprous oxide nanoparticle coating on the surface of an ITO transparent electrode.

[0037] The "electrode surface microstructure modification" described in this invention refers to depositing nanoparticles of a certain composition on the electrode surface, including ion-sputtered Au nanoparticles, ion-sputtered Cu nanoparticles, and coated Cu2O nanoparticles, forming discontinuous island-like nanoparticle deposition, thereby enhancing the local electric field strength on the electrode surface. Specifically, the gold plating process involves placing a cleaned ITO electrode in an ion sputtering apparatus equipped with a gold target, evacuating to a vacuum level of 9 Pa / mmHg, and sputtering for 5-50 seconds at a sputtering current of 2 mA to obtain ITO electrodes with different Au plating levels, such as... Figure 2As shown in d. Copper plating refers to placing the cleaned ITO electrode in an ion sputtering instrument equipped with a copper target, evacuating to a vacuum degree of 9 Pa / mmHg, and sputtering for 80 s at a sputtering current of 2 mA to obtain ITO electrodes with different Cu plating. Coating with cuprous oxide nanoparticles refers to dispersing 10 mg of pre-prepared Cu2O nanoparticles in a mixed solution of 0.75 mL isopropanol and 0.25 mL deionized water. The above colloidal dispersion is drop-coated onto the cleaned ITO electrode, and after drying at room temperature, an ITO electrode modified with Cu2O nanoparticles is obtained.

[0038] Example 3. Packaging of photonic crystals and fabrication of electrochromic electrophoresis devices

[0039] For traditional electrochromic electrophoretic devices without electrode surface modification, the SiO2 / (PCb-EG) colloidal photonic crystal described in Example 1 of this invention can be encapsulated between two untreated ITO conductive glasses (i.e., positive and negative transparent electrodes). The two electrodes are bonded together with 50-micrometer-thick double-sided adhesive or thermosetting adhesive, which also prevents solvent evaporation from the photonic crystal and ensures that the two electrodes are 50 micrometers apart to avoid short circuits. By connecting the two electrodes to an external DC power supply and applying a specific DC voltage, the electrochromic effect of the colloidal photonic crystal can be achieved.

[0040] For electrochromic electrophoretic devices with modified electrode surfaces, only the ITO positive electrode needs to be replaced with the modified electrode described in Example 2 of this invention; the rest of the process remains unchanged to prepare the corresponding device. It should be noted that the electrode modifications used in the embodiments of this invention are all modifications to the ITO positive electrode. This is because the colloidal crystal used in the embodiments is composed of negatively charged SiO2 particles. When an external voltage is applied, the particles electrophore towards the positive electrode, causing lattice contraction and structural color changes. Modification of the positive electrode is necessary to effectively enhance the electrochromic sensitivity. If the photonic crystal is composed of positively charged particles, then the ITO negative electrode needs to be modified.

[0041] Example 4. Electrochromic effect of colloidal photonic crystals

[0042] To demonstrate the electrochromic effect, the two electrophoretic devices described in Embodiment 3 of this invention were connected to an external DC power supply, and different DC voltages were applied. For example... Figure 2 As shown in e and 2f, regardless of whether the SiO2 / (PCb-EG) photonic crystal is packaged with a conventional ITO cathode or a gold-plated ITO cathode, it exhibits a significant electrochromic effect. In the absence of an electric field, both exhibit a highly saturated red structural color. With gradually increasing external voltage, both photonic crystals undergo lattice compression, resulting in a blue shift in the reflected wavelength, and the structural color gradually changes from red to orange, green, turquoise, and finally blue.

[0043] Example 5. Reducing the operating voltage of electrochromic photonic crystals using gold plating on ITO cathodes.

[0044] To compare the effect of electrode surface modification on the operating voltage of electrochromic photonic crystals, the two electrophoretic devices described in Embodiment 3 of this invention were connected to an external DC power supply and different DC voltages were applied. Figure 2 e, 2f and Figure 3 Images a and 3b record the structural color and reflection spectrum changes of two types of packaged photonic crystals during voltage rise. The difference lies in the voltage required for the structural color of the photonic crystal with a standard ITO cathode to change from red to orange, green, turquoise, and blue: 1.5V, 1.8V, 2.3V, and 3V, respectively. In contrast, the gold-plated ITO cathode-packaged photonic crystal achieves the same color change at voltages of 0.8V, 1V, 1.3V, and 2V, indicating a significant reduction in driving voltage. Calculations can convert the reflection wavelength change into lattice contraction rate, thus yielding... Figure 3 c, the "operating voltage-lattice shrinkage rate" relationship graph. This graph more clearly demonstrates the above conclusion: to achieve the same lattice shrinkage (i.e., the same structural color change), the driving voltage required by using a gold-plated ITO positive electrode package is lower than that required by using a regular ITO positive electrode package.

[0045] Example 6. Improving the structural color attenuation resistance of electrochromic photonic crystals by using gold plating on ITO cathodes.

[0046] To compare the effect of electrode surface modification on the color saturation of electrochromic photonic crystal structures, the two electrophoretic devices described in Embodiment 3 of this invention were connected to an external DC power supply and different DC voltages were applied. Figure 3 Figures a and 3b record the changes in the reflection spectrum of the two types of packaged photonic crystals during voltage rise. The reflection intensity values ​​at each voltage are extracted from the figures, and the reflection intensity retention ratio is calculated, thus yielding... Figure 3 d represents the relationship between "reflection intensity retention ratio and lattice contraction rate". The saturation of the structural color of a photonic crystal is mainly determined by its reflection intensity. Therefore, this figure clearly demonstrates that, when achieving the same lattice contraction (i.e., the same structural color change), the photonic crystal with gold-plated ITO cathode packaging has higher structural color saturation and stronger resistance to structural color attenuation than the one with ordinary ITO cathode packaging.

[0047] Example 7. Improving the reversibility of the electro-response of electrochromic photonic crystals using gold plating on ITO cathodes.

[0048] To compare the effect of electrode surface modification on the reversibility of the electrochromic photonic crystal's electrical response, the photonic crystal with a common ITO positive electrode package as described in Example 3 of this invention was connected to an external DC power supply, and a DC voltage of "2.3V-0V" was applied alternately multiple times; simultaneously, a photonic crystal with a gold-plated ITO positive electrode package was applied alternately with a DC voltage of "1.3V-0V", and the reflected wavelength value after the electric field switching was recorded. The reversibility comparison experiment design was based on the experimental results in Example 5. The two types of packaged photonic crystals have the same red structural color at 0V, and also have similar lake blue structural colors at 2.3V and 1.3V. Figure 4 As shown in a and 4b, under the premise of achieving the same reflection wavelength shift and the same structural color change in each switch, the reflection wavelength modulation range of the photonic crystal with ordinary ITO positive electrode packaging is greatly reduced after 4 switches; while the reflection wavelength modulation range of the photonic crystal with gold-plated ITO positive electrode packaging remains basically unchanged after 30 switches, showing better electrical response reversibility.

[0049] Example 8. Improving the electroresponse stability of electrochromic photonic crystals using gold plating on ITO cathodes.

[0050] To compare the effect of electrode surface modification on the electrical response stability of electrochromic photonic crystals, a photonic crystal with a conventional ITO positive electrode package as described in Example 3 of this invention was externally charged with a 2.3V voltage, while a photonic crystal with a gold-plated ITO positive electrode package was externally charged with a 1.3V voltage. These voltages were applied continuously for 30 minutes, and the changes in reflected wavelength were recorded during this period. Applying 2.3V and 1.3V voltages to the two photonic crystals respectively is based on the experimental results in Example 5, where the structural color changes of both are the same. Figure 4 As shown in c and 4d, under the premise of achieving the same reflection wavelength shift, i.e., the same structural color change, the photonic crystal with ordinary ITO positive electrode packaging rapidly increases its reflection wavelength after a continuous application of 2.3V for 2 minutes, and stabilizes at the median value after 10 minutes, indicating that the photonic crystal cannot display the same structural color for a long time. In contrast, the photonic crystal with gold-plated ITO positive electrode packaging consistently exhibits a similar reflection wavelength and structural color when a continuous application of 1.3V for 30 minutes is applied, demonstrating superior electrical response stability.

[0051] Example 9. Improving the performance of electrochromic colloidal crystals by plating Cu on the surface of ITO electrodes

[0052] To demonstrate that Cu plating on the surface of ITO electrodes can also improve the performance of electrochromic photonic crystals, referring to the method in Example 3 of this invention, SiO2 / (PCb-EG) colloidal photonic crystals were encapsulated between ordinary ITO positive and negative electrodes, or between ordinary ITO negative electrodes and Cu-plated positive electrodes; the resulting electrophoretic devices were connected to an external DC power supply, and different DC voltages were applied, and the reflection wavelengths of the two were recorded, thereby comparing their performance differences in terms of operating voltage. Figure 5 The results show that, compared with electrochromic photonic crystals using ordinary ITO cathode packaging, photonic crystals using Cu-plated ITO cathode packaging require a lower driving voltage to achieve the same structural color change (i.e., the same amount of reflection wavelength change).

[0053] Example 10. Improving the performance of electrochromic colloidal crystals by depositing Cu2O nanoparticles on the surface of an ITO electrode.

[0054] To demonstrate that depositing Cu2O nanoparticles on the surface of an ITO electrode can also improve the performance of electrochromic photonic crystals, referring to the method in Example 3 of this invention, a SiO2 / (PCb-EG) colloidal photonic crystal was encapsulated between ordinary ITO positive and negative electrodes, or encapsulated between an ordinary ITO negative electrode and a Cu2O-plated positive electrode; the resulting electrophoretic device was connected to an external DC power supply, and different DC voltages were applied, and the reflection wavelengths of the two were recorded, thereby comparing their performance differences in terms of operating voltage. Figure 5 The results show that, compared with electrochromic photonic crystals using ordinary ITO cathode packaging, photonic crystals using Cu2O-plated ITO cathode packaging require a lower driving voltage to achieve the same structural color change (i.e., the same amount of reflection wavelength change).

[0055] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for improving the response performance of electrochromic colloidal photonic crystals by modifying the microstructure of the electrode surface, characterized in that, The specific implementation steps are as follows: (1) Modify the surface microstructure of the conductive surface of the transparent electrode. The electrode surface modification includes ion sputtering of metal nanoparticles, coating of metal oxide nanoparticles, and forming discontinuous island-shaped nanoparticle deposition; (2) Encapsulate a colloidal photonic crystal with electrochromic effect between a conventional transparent electrode and a transparent electrode modified in step (1). Double-sided adhesive is used as electrode spacer and encapsulation bonding material around the perimeter to obtain a simple photonic crystal electrophoresis device.

2. The method of claim 1, wherein, In step (1), the transparent electrode includes: ITO, FTO conductive glass, flexible ITO, and FTO conductive film.

3. The method as described in claim 1, characterized in that, In step (2), the electrochromic effect refers to the effect of the material exhibiting different spectral colors of red, orange, yellow, green and blue under different DC voltage conditions; and / or, colloidal photonic crystals with electrochromic effects include SiO2 / PCb, SiO2 / EG, SiO2 / IPA, SiO2 / ANI, SiO2 / DMF, and SiO2 / (PCb-EG) liquid colloidal photonic crystals.

4. The method as described in claim 1, characterized in that, In step (2), the volume fraction of colloidal particles in the electrochromic colloidal photonic crystal is 15%-25%, and the volume fraction of solvent is 75%-85%.

5. The method as described in claim 1, characterized in that, In step (2), when the electrochromic photonic crystal is composed of negatively charged colloidal particles, the modified transparent electrode needs to be placed at the positive electrode; when the photonic crystal is composed of positively charged colloidal particles, the modified transparent electrode needs to be placed at the negative electrode.

6. The method as described in claim 1, characterized in that, In step (2), the double-sided adhesive for encapsulation includes epoxy double-sided adhesive, UV curing adhesive, and hot melt adhesive.

7. The method as described in claim 1, characterized in that, The method includes step (3): connecting it to an external DC power supply and adjusting the voltage value to achieve an electrochromic effect and an electrical response performance superior to that of traditional electrochromic photonic crystal devices.

8. The method as described in claim 7, characterized in that, The DC voltage modulation range is 0-3.0 V.

9. The method as described in claim 7, characterized in that, The conventional electrochromic photonic crystal device refers to an electrophoretic device encapsulated with unmodified ordinary transparent electrodes.

10. The method as described in claim 7, characterized in that, The superior electro-response performance compared to traditional electrochromic photonic crystal devices is characterized by one or more of the following indicators: operating voltage as low as 1.3V, blue shift of 120 nm, structural color chromaticity range from red to lake blue, increased structural color saturation, response stability up to 1.3V for 30 minutes, and reversibility of 0V-1.3V for 30 cycles.