Electro-thermotropic dual-response color-changing device and preparation method and application thereof

Abstract

The invention relates to the technical field of electrochromic materials and devices, and discloses an electrochromic-thermochromic device and a preparation method and application thereof. The electrochromic-thermochromic device comprises a first substrate, an electrochromic layer, a thermochromic electrolyte layer, an ion storage layer and a second substrate which are sequentially stacked, wherein the electrochromic layer is made of materials including titanium dioxide molecules and viologen molecules adsorbed on the surfaces of the titanium dioxide molecules, the thermochromic electrolyte layer is made of materials including one of zinc salt or aluminum salt and an OEGMAx-co-MEO2MAy copolymer, and x / y is one of 5 / 95, 10 / 90, 20 / 80, 30 / 70, 40 / 60 and 50 / 50. The electro-thermal dual-response color-changing device can realize near-zero light transmittance, realizes near-zero light transmittance in a wave band of 400-2500nm in a working state, and remarkably improves privacy protection and energy efficiency.

Description

Technical Field

[0001] This invention relates to the field of electrochromic materials and devices, and in particular to an electrochromic-thermochromic dual-response device, its preparation method, and its application. Background Technology

[0002] The escalating global energy crisis and climate change have increased the demand for energy-saving technologies for sustainable development. Notably, buildings consume over 40% of the world's energy, with windows accounting for nearly half of that energy loss. Traditional static windows cannot dynamically adapt to changing environmental conditions, leading to significant energy waste due to the overuse of heating, ventilation, and air conditioning systems. Against this backdrop, electrochromic (EC) smart windows, capable of dynamically adjusting solar transmittance under the influence of an electric field, offer a promising technological approach to addressing this issue. However, current EC smart windows still have significant limitations in terms of energy efficiency and privacy protection because they cannot achieve the near-zero transmittance required to completely block sunlight (400-2500nm).

[0003] Previous research has explored various methods to overcome this limitation. One strategy is to develop black electrochromic devices capable of fully absorbing the visible spectrum. This can be achieved by designing electrochromic copolymers with specific structures, integrating complementary electrode materials, and stacking multiple devices. However, these strategies primarily focus on modulating the visible (VIS) spectrum (380–780 nm), neglecting the crucial near-infrared (NIR) region (780–2500 nm). This limitation reduces their ability to block solar radiation, as studies have shown that 47% of solar energy reaching the Earth's surface falls within the NIR range, thus limiting their potential for smart window applications.

[0004] Viologen (N,N′-disubstituted-4,4′-bipyridine derivatives), as an important class of electrochromic materials, has shown great potential in near-infrared spectral modulation through rational molecular design. Upon electrochemical reduction with applied voltage, dicationic viologen undergoes a single-electron transfer process to form radical cations, accompanied by a significant color change. Due to their rich color states, rapid response speed, and high optical contrast, these compounds have become promising candidates for smart window applications. Recent studies have shown that strategically inserting π-bridged heterocycles containing chalcogenides (selenophene, thiophene, and furan) between pyridine rings induces a significant redshift in absorption peaks, producing distinct near-infrared absorption peaks at 1022 nm, 1060 nm, and 1128 nm, respectively. Furthermore, modification with these chromophores endows devices with vibrant color states, such as purple, pink, and red, enabling them to meet the requirements of smart windows in various application scenarios. However, this design strategy is still insufficient to achieve full-spectrum optical modulation across the entire solar radiation range (400-2500 nm). Furthermore, viologen is difficult to form into films and is usually fabricated into integrated structural devices. While this simplifies the manufacturing process, this structure lacks sufficient ion storage capacity, causing the device to spontaneously fade after voltage removal, making it unsuitable for smart windows that require persistent coloring.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide an electro-thermal dual-response color-changing device, its preparation method and application, aiming to solve the problem that existing color-changing devices are insufficient to achieve full-spectrum optical modulation of the entire solar radiation range (400-2500nm).

[0007] The technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides an electrochromic-thermochromic dual-response color-changing device, the electrochromic-thermochromic dual-response color-changing device comprising a first substrate, an electrochromic layer, a thermochromic electrolyte layer, an ion storage layer, and a second substrate, which are sequentially stacked.

[0009] The electrochromic layer is made of titanium dioxide molecules and viologen molecules adsorbed on the surface of the titanium dioxide molecules. The thermochromic electrolyte layer is made of one of zinc salts or aluminum salts, or OEGMA. x -co-MEO2MA y Copolymer, x is 5-50, y is 95-50.

[0010] Optionally, the structural formula of the viologen molecule is as follows:

[0011] R is selected from one or more of furan, thiophene, selenophene, ethylenedioxythiophene, and benzothiadiazole.

[0012] Optionally, the thickness of the electrochromic layer is 3-20 micrometers.

[0013] Optionally, the ion storage layer is made of zinc.

[0014] A second aspect of the present invention provides a method for fabricating an electro-thermal dual-response color-changing device, the method comprising the following steps:

[0015] Provide the first base;

[0016] A titanium dioxide slurry is coated on the surface of the first substrate and annealed to obtain a titanium dioxide film.

[0017] The first substrate covered with a titanium dioxide film was placed in a viologen solution, so that viologen molecules were adsorbed onto the surface of titanium dioxide molecules to obtain an electrochromic layer.

[0018] Mix one of the zinc salts or aluminum salts with OEGMA x -co-MEO2MA y The copolymer was dissolved in water to obtain a thermochromic electrolyte solution;

[0019] The thermochromic electrolyte solution is added to the surface of the electrochromic layer to form a thermochromic electrolyte layer;

[0020] The ion storage layer and the second substrate are then placed on the surface of the thermochromic electrolyte layer in sequence, and encapsulated with curing adhesive to obtain the electrochromic-thermochromic dual-response color-changing device.

[0021] Optionally, the annealing temperature is 450-600℃ and the annealing time is 0.5-3 hours.

[0022] Optionally, the zinc salt is one or more of zinc chloride, zinc bis(trifluoromethanesulfonyl)imide, zinc sulfate, and zinc carbonate, and the aluminum salt is one of aluminum chloride, aluminum bis(trifluoromethanesulfonyl)imide, aluminum sulfate, and aluminum carbonate.

[0023] Optionally, in the thermochromic electrolyte solution, OEGMA x -co-MEO2MA y The concentration of the copolymer is 10% to 50%.

[0024] Optionally, the concentration of zinc salt or aluminum salt in the thermochromic electrolyte solution is 0.1–2 mol / L.

[0025] A third aspect of the present invention provides an application of the above-described electro-thermal dual-response color-changing device in a smart window.

[0026] The present invention has the following beneficial effects:

[0027] This invention proposes an electro-thermal dual-response color-changing device, its preparation method, and its application. The electro-thermal dual-response color-changing device has two synergistic mechanisms: (1) an electrochromic layer developed by anchoring viologen molecules to TiO2 via Ti-OP multidentate coordination; (2) the addition of OEGMA x -co-MEO2MA y (abbreviated as O) x M y The thermochromic electrolyte layer of the copolymer undergoes a reversible transition from transparent to opaque through the formation or breaking of hydrogen bonds. Under operating conditions, it achieves near-zero transmittance (<1%) in the 400-2500 nm wavelength range, significantly improving privacy protection and energy efficiency. Furthermore, it allows for multi-functional control, enabling spectral modulation under different environmental conditions and user needs through dual temperature and voltage control. This electrochromic-thermochromic dual-response device provides a new approach to adaptive spectral control technology and holds promise for applications in smart buildings. Attached Figure Description

[0028] Figure 1 A schematic diagram of the structure of the electrochromic-thermochromic dual-response device prepared according to a preferred embodiment of the present invention;

[0029] Figure 2 This is a SEM microstructure characterization image of the electrochromic thin film in Embodiment 1 of the present invention;

[0030] Figure 3 The Fourier transform infrared spectra of the electrochromic thin film FPB molecules before and after adsorption in Example 1 of this invention;

[0031] Figure 4 The images show the cyclic voltammetry diagrams of the electrochromic thin film in Example 1 of this invention at different scan rates (100-400 mV / s).

[0032] Figure 5 O for different polymer monomer ratios x M y Temperature-dependent transmission spectrum of aqueous solution at 550 nm;

[0033] Figure 6 These are photographs of the electro-thermal dual-response color-changing device prepared in Example 1 of the present invention at different voltages;

[0034] Figure 7 The transmission spectra of the electro-thermal dual-response color-changing device prepared in Example 1 of this invention under different voltages are shown.

[0035] Figure 8These are photographs of the smart window prepared in Example 1 of the present invention under different working states;

[0036] Figure 9 The transmission spectra of the smart window prepared in Example 1 of this invention under different working conditions;

[0037] Figure 10 The temperature change curves of the interior over time for a conventional window and a smart window prepared using Example 1 of this invention under continuous solar radiation;

[0038] Figure 11 The changes in indoor illuminance of the smart window prepared in Example 1 of the present invention under four working modes. Detailed Implementation

[0039] This invention provides an electro-thermo-responsive color-changing device, its preparation method, and its application. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0041] This invention provides an electrochromic-thermochromic dual-response color-changing device, which includes a first substrate, an electrochromic layer, a thermochromic electrolyte layer, an ion storage layer, and a second substrate stacked sequentially.

[0042] The electrochromic layer is made of titanium dioxide molecules and viologen molecules adsorbed on the surface of the titanium dioxide molecules. The thermochromic electrolyte layer is made of one of zinc salts or aluminum salts, or OEGMA. x -co-MEO2MA y The copolymer, where x / y is one of 5 / 95, 10 / 90, 20 / 80, 30 / 70, 40 / 60, or 50 / 50.

[0043] In some embodiments, the first substrate is FTO conductive glass or ITO conductive glass, and the second substrate is FTO conductive glass or ITO conductive glass.

[0044] In some embodiments, the structural formula of the viologen molecule is as follows: R is selected from one or more of furan, thiophene, selenophene, ethylenedioxythiophene, and benzothiadiazole.

[0045] The electrochromic-thermochromic dual-response device provided in this embodiment of the invention has two synergistic mechanisms: (1) an electrochromic layer developed by anchoring viologen molecules to TiO2 through strong Ti-OP multidentate coordination; (2) the addition of OEGMA x -co-MEO2MA y (abbreviated as O) x M y The thermochromic electrolyte layer of the copolymer exhibits a reversible transition from transparent to opaque through the formation or breaking of hydrogen bonds, achieving near-zero transmittance. In operation, it achieves near-zero transmittance within the 400-2500 nm wavelength range, significantly improving privacy protection and energy efficiency. Furthermore, it allows for multi-functional control, enabling spectral modulation under varying environmental conditions and user needs through dual temperature and voltage control. This electrochromic-thermochromic dual-response device provides a novel approach to adaptive spectral control technology and holds promise for applications in smart buildings.

[0046] Specifically, the core of this invention lies in the design of the molecular structure, which introduces an electron donor unit (e.g., furan) between two electron-accepting pyridine rings, thereby forming an "ADA" (acceptor-donor-acceptor) chromophore. This design effectively narrows the band gap, causing a redshift in the absorption spectrum to the near-infrared region, achieving controllable visible-near-infrared spectral absorption. Furthermore, the chromophore is functionalized with a phosphate group, enabling stable chemisorption on TiO2 molecules, effectively preventing spontaneous ion release during the fading process and imparting a memory effect to the device.

[0047] To achieve near-zero transmittance in the 400-2500nm range, embodiments of the present invention further developed a method based on O x M y The copolymer utilizes a temperature-responsive thermochromic electrolyte to synergistically modulate optical blocking capabilities. Furthermore, the phase transition temperature of the copolymer exhibits excellent tunability through precise control of the OEGMA and MEO2MA monomer ratios. Below its LCST (lowest eutectic temperature), O... x M y Hydrogen bonds form between the ethoxy group (-CH2-CH2-O-) and water molecules, maintaining high transparency and allowing a large amount of solar radiation to pass through. When heated above the LCST, the hydrogen bonds in the polymer network gradually dissociate, water molecules are expelled, and the solution becomes opaque. Unlike absorption-based electrochromic layer mechanisms, this system forms aggregates in its opaque state, with sizes approaching or exceeding the wavelengths of visible and near-infrared radiation (400-2500 nm), thus inducing strong Mie scattering and hindering light transmission. Combining the electrochromic and thermochromic mechanisms can achieve zero transmittance in the 400-2500 nm range.

[0048] In some embodiments, the thickness of the electrochromic layer is 3-20 micrometers. The thickness of the electrochromic layer can be 3 micrometers, 5 micrometers, 8 micrometers, 10 micrometers, 13 micrometers, 15 micrometers, 17 micrometers, or 20 micrometers.

[0049] When the thickness of the electrochromic layer is less than 3 micrometers, the insufficient adsorption of active molecules leads to low optical contrast, failing to achieve the desired sunlight blocking effect. Conversely, when the thickness of the electrochromic layer exceeds 20 micrometers, it reduces the light transmittance of the device in its faded state, while also increasing material consumption and manufacturing costs.

[0050] In some preferred embodiments, the thickness of the electrochromic layer is 5 micrometers.

[0051] In some embodiments, the ion storage layer is made of zinc.

[0052] During the electrochromic process, the ion storage layer acts as the anode, undergoing an oxidation reaction that releases electrons and zinc ions, driving the electrochromic layer to undergo a reduction reaction and transform into a colored state. Simultaneously, during the fading process, metallic Zn is deposited to maintain charge balance.

[0053] A second aspect of the present invention provides a method for fabricating an electro-thermal dual-response color-changing device, the method comprising the following steps:

[0054] Provide the first base;

[0055] A titanium dioxide slurry is coated on the surface of the first substrate and annealed to obtain a titanium dioxide film.

[0056] The first substrate covered with a titanium dioxide film was placed in a viologen solution, so that viologen molecules were adsorbed onto the surface of titanium dioxide molecules to obtain an electrochromic layer.

[0057] Mix one of the zinc salts or aluminum salts with OEGMA x -co-MEO2MA y The copolymer was dissolved in water to obtain a thermochromic electrolyte solution;

[0058] The thermochromic electrolyte solution is added to the surface of the electrochromic layer to form a thermochromic electrolyte layer;

[0059] The ion storage layer and the second substrate are then placed on the surface of the thermochromic electrolyte layer in sequence, and encapsulated with curing adhesive to obtain the electrochromic-thermochromic dual-response color-changing device.

[0060] In some embodiments, the annealing temperature is 450-600°C, and the annealing time is 0.5-3 hours. The annealing temperature can be 450°C, 500°C, 550°C, or 600°C, and the annealing time can be 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, or 3 hours.

[0061] In some embodiments, the zinc salt is one or more of zinc chloride, zinc bis(trifluoromethanesulfonyl)imide, zinc sulfate, and zinc carbonate, and the aluminum salt is one of aluminum chloride, aluminum bis(trifluoromethanesulfonyl)imide, aluminum sulfate, and aluminum carbonate.

[0062] In some embodiments, the thermochromic electrolyte solution contains OEGMA x -co-MEO2MA y The concentration of the copolymer is 10% to 50%.

[0063] When the copolymer concentration is too high, it leads to a decrease in ion mobility and a slower response rate; when the concentration is too low, it causes uneven phase transition behavior. The latter is mainly due to the increased inter-aggregate spacing and the elongated diffusion path of water molecules under high water content. In addition, the differences in size, morphology and local water concentration of the aggregates result in non-uniformity in the spatiotemporal distribution of the dissolution process.

[0064] In some preferred embodiments, the thermochromic electrolyte solution contains OEGMA x -co-MEO2MA y The copolymer concentration is 33%.

[0065] In some embodiments, the concentration of zinc salt or aluminum salt in the thermochromic electrolyte solution is 0.1–2 mol / L.

[0066] When the concentration of zinc or aluminum salts is low (less than 0.1 mol / L), the ionic conductivity of the thermochromic electrolyte layer is insufficient, resulting in a slow electrochromic rate in the device. When the concentration of zinc or aluminum salts is too high (greater than 2 mol / L), salting out or crystallization may occur, increasing costs.

[0067] Zinc salts ionize in thermochromic electrolyte solutions to produce Zn 2+ These ions migrate between the cathode and anode under the influence of an electric field, achieving charge transport. Simultaneously, during the electrochromic process, Zn... 2+ It participates in redox reactions. At the cathode, Zn 2+ It can be reduced to metallic zinc and deposited, accompanied by a color change in the electrochromic material. The aluminum salts function similarly to the zinc salts.

[0068] In some preferred embodiments, the concentration of zinc salt or aluminum salt in the thermochromic electrolyte solution is 1 mol / L.

[0069] A third aspect of the present invention provides an application of the above-described electro-thermal dual-response color-changing device in a smart window.

[0070] The following detailed description uses specific examples.

[0071] Example 1

[0072] A method for fabricating an electro-thermal dual-response color-changing device includes the following steps:

[0073] The synthesis of S1.FPB molecules is as follows:

[0074]

[0075] Compound 2,5-dibromofuran (1.98 g, 8.85 mmol), pinacol 4-pyridineboronic acid (5 g, 24.5 mmol), tetrakis(triphenylphosphine)palladium (1.02 g, 0.88 mmol), and potassium phosphate (14.9 g, 70.5 mmol) were weighed into a 250 mL two-necked flask. Water and oxygen were removed, and then 10 mL of a mixed solution of 1,4-dioxane and N,N'-dimethylformamide (volume ratio 1:1) was added. The mixture was reacted at 130 °C for 72 hours, cooled to room temperature, filtered, and the precipitate was washed with chloroform. Column chromatography was used to separate the precipitate into a yellow solid, compound M1 (1.12 g, 5.15 mmol), with a yield of 57%.

[0076] Compound M1 (0.45 g, 2 mmol) and diethyl 2-bromoethylphosphonate (2.44 g, 10 mmol) were dissolved in 10 mL of DMF and heated at 90 °C for 72 h. After cooling to room temperature, the solvent was evaporated, and the product was recrystallized three times from methanol and diethyl ether (1:50). The resulting product was dissolved in 50 mL of concentrated hydrochloric acid and transferred to a 100 mL round-bottom flask. The reaction mixture was refluxed at 100 °C for 24 h. After cooling to room temperature, the solvent was removed under reduced pressure. The crude product was then purified by washing three times with anhydrous ethanol and dried under vacuum to give the target compound as a yellow solid (0.81 g, yield: 71%). 1 H NMR (400MHz, D2O) δ8.88–8.66(m,4H),8.42–8.19(m,4H),7.65(s,2H),2.26(dt,J=15.9,7.8Hz,4H). 31 P NMR (162MHz, D2O) δ 17.68.

[0077] S2. TiO2 slurry is coated onto the cleaned FTO conductive glass (first substrate) using a scraping method, and the coating thickness is controlled by the mask thickness and the number of scraping cycles.

[0078] S3. Place the coated TiO2 film in a muffle furnace and anneal it at 500℃ for 2 hours at a heating rate of 5℃ / min to obtain a TiO2 film with a thickness of 5.7μm.

[0079] S4. Place the TiO2 film in a 1×10 -4 TiO2-FPB electrochromic layer was prepared by immersing the above-prepared mol / L FPB aqueous solution in water for 12 hours.

[0080] S5. Synthesis O 10 M 90 Thermally responsive copolymers, with the following reaction formula:

[0081]

[0082] OEGMA (1 g, 2 mmol), MEO2MA (3.38 g, 18 mmol), and AIBN (6.5 mg, 0.04 mmol) were dissolved in DMF (20 mL). The reaction mixture was subjected to three freeze-drying cycles to remove dissolved oxygen, and the polymerization reaction was carried out at 70 °C for 24 hours. After cooling to room temperature, the reaction mixture was slowly precipitated into ice-cold diethyl ether. The product was further washed three times with ice-cold diethyl ether to obtain a colorless, transparent, viscous liquid of the target polymer in 82% yield.

[0083] S6. Mix 2 mmol ZnCl2 and 1 g O 10 M 90 Dissolve in 2g H2O and stir overnight to obtain a homogeneous and transparent thermochromic electrolyte solution.

[0084] S7. First, attach a 50μm thick double-sided adhesive tape along the edge of the TiO2-FPB film. Then, place a 50μm thick zinc foil on the tape as an ion storage layer. Drop the thermochromic electrolyte solution into the center of the TiO2-FPB film. Then, cover it with a glass substrate (second substrate) and seal the edge of the device with UV-curable adhesive to obtain the electrochromic-thermochromic dual-response color-changing device ETCD.

[0085] The structural diagram of the electro-thermal dual-response color-changing device obtained in Example 1 is shown below. Figure 1 As shown.

[0086] Example 2

[0087] Compared with Example 1, the difference in this example is that: O has been changed. x M y The monomer ratio of OEGMA and MEO2MA is 5 / 95.

[0088] Example 3

[0089] Compared with Example 1, the difference in this example is that: O has been changed. x M y The monomer ratio of OEGMA and MEO2MA is 20 / 80.

[0090] Example 4

[0091] Compared with Example 1, the difference in this example is that: O has been changed. x M y The monomer ratio of OEGMA and MEO2MA is 30 / 70.

[0092] Performance testing

[0093] Test Example 1: Structural and Morphological Characterization of the Electrochromic Layer

[0094] Specific testing steps: The morphology of the electrochromic film in Example 1 was analyzed using a TESCAN MIRA3 scanning electron microscope (SEM).

[0095] like Figure 2 As shown, scanning electron microscopy characterization revealed that the TiO2 film exhibited a loose porous structure with a thickness of 5.7 μm. This porous structure has a dual function: (1) the high surface area provides abundant active sites for FPB molecules to anchor on the TiO2 surface; (2) the interconnected porous network facilitates the insertion / extraction of electrolyte ions and charge transport during electrochemical cycling, thereby enhancing the coloring / bleaching kinetics of the device.

[0096] Test Example 2: Chemical Structure Characterization of the Electrochromic Layer

[0097] Specific testing steps: The chemical structure of the electrochromic layer in Example 1 was analyzed using a Bruker Vertex 70V Fourier transform infrared analyzer.

[0098] Figure 3 The Fourier transform infrared spectra of TiO2 nanoparticles before and after FPB adsorption are shown. At 1066 cm⁻¹... -1 A distinct vibrational band was observed, corresponding to the Ti-OP stretching vibration mode, which provides direct evidence for the successful chemical grafting of FPB onto the TiO2 surface.

[0099] Test Example 3 Cyclic Voltammetry Characterization

[0100] Specific test steps: In Example 1, the cyclic voltammogram of the electrochromic layer was measured using a three-electrode system in a 1M lithium perchlorate / propylene carbonate solution at a scan rate of 100-300 mV / s within a potential range of -2.0 to 0.5 V. The electrochemical workstation used was a CHI760e.

[0101] The cyclic voltammetry results of the TiO2-FPB layer are as follows: Figure 4 As shown, a distinct reduction peak appears at approximately -1.0 V. This peak corresponds to the electron transition from the dual-cation state (FPB). 2+ Towards the cation free radical state (FPB) +· The film undergoes a color change from pale yellow to red during the transfer of ) .

[0102] Test Example 4: Characterization of Phase Transition Temperatures with Different Proportions of Polymerizing Monomers

[0103] Specific testing steps: Using a UV-Vis spectrophotometer (PerkinElmerλ650s), the O2 content was measured at different temperatures. x M y The permeability of the aqueous solution.

[0104] Test results are as follows Figure 5 As shown. The results indicate that O5M 95 O 10 M 90 O 20 M 80 and O 30 M 70 The LCST values ​​were 32℃, 36℃, 48℃, and 58℃, respectively. This is because the longer ethylene glycol side chain enhances the O... x M y The intermolecular interactions between the polymer and water molecules cause the LCST to gradually increase with increasing OEGMA content. This adjustable phase transition temperature characteristic allows it to meet specific environmental conditions or user needs when applied to smart windows.

[0105] Test Example 5: Photographs and spectral characterization of the electro-thermal dual-response color-changing device prepared in Example 1 under different voltages.

[0106] Specific test steps: The transmission spectrum curve was measured by a combination of a UV-Vis-NIR spectrophotometer (ShimadzuUV-3600) and a signal generator (Rigol DG4102 Function / Arbitrary). The UV-Vis spectrophotometer was responsible for collecting spectral data, and the signal generator was used to apply voltage to the electrical components.

[0107] Test results are as follows Figure 6 and Figure 7 As shown. Under short-circuit conditions (0V), the device exhibits two characteristic absorption peaks at 510 and 574 nm, and simultaneously displays a deep red color. Furthermore, the device demonstrates excellent near-infrared modulation capabilities, exhibiting distinct absorption peaks at 968 nm and 1142 nm. After applying a positive bias potential (0.2V-0.6V), the viologen cation radical FPB... +·Single-electron electrochemical oxidation occurs, restoring FPB to a dual-cation state. 2+ This allows the device to switch to a bleaching state. Notably, the device exhibits an extremely low operating voltage, achieving complete bleaching at only 0.6V. This low operating voltage offers significant advantages in energy saving.

[0108] Test Example 6: Smart Window photographs (i.e., the electro-thermal dual-response color-changing device prepared in Example 1) and spectral characterization under different operating modes

[0109] Specific testing steps: The transmittance spectrum curves under different conditions were measured using a UV-Vis-NIR spectrophotometer (Shimadzu UV-3600).

[0110] like Figure 8 As shown, the smart window can operate in four different states: bleached, tinted, opaque, and tinted-opaque. This smart window employs a dual-control mechanism based on temperature and voltage: in cold winters, when the ambient temperature is below the LCST (Lower Limit Stability), the window maintains high transparency, allowing ample solar radiation into the interior space while meeting lighting and heating needs. Conversely, in hot summers, when the ambient temperature is above the LCST, the window automatically switches to an opaque state, effectively blocking heat transfer by scattering incident light, thereby reducing indoor temperature and minimizing cooling energy consumption. In addition to temperature control, users can also adjust the window to a visually comfortable red color at any time via voltage regulation, blocking some visible and near-infrared light, flexibly controlling indoor lighting intensity. Furthermore, when privacy is required, the window can be switched to an opaque state by adjusting the indoor temperature. Figure 8 The demonstration also showcased images captured by the smart window in these four modes. Clearly, when the smart window is in an opaque or color-opaque state, the external landscape is not clearly visible. This multi-functional control mechanism allows the smart window to adapt to various application scenarios and user requirements.

[0111] Figure 9 The visible-near-infrared transmission spectra of the smart window in these four operating states are presented. The device exhibits excellent solar light modulation capability, achieving near-zero transmittance in both opaque and colored opaque states.

[0112] Test Example 7: Smart Window Simulation Representation

[0113] Specific testing steps: Construct a miniature house model with a 7cm x 7cm window (dimensions: 27.2cm x 22.1cm x 23.0cm). Use an AM1.5 solar simulator to transmit solar radiation through the smart window into the interior space. Evaluate its light and heat regulation capabilities by monitoring changes in indoor temperature and illuminance.

[0114] like Figure 10As shown, after 30 minutes of sunlight exposure, the indoor temperature of a house with a traditional window gradually rises to 27.2℃, while the temperature of a house equipped with the smart window of this invention only reaches 22.2℃ during the same period. Compared to a traditional window, the smart window in operation reduces the indoor temperature by 5.0℃. Furthermore, changes in indoor illuminance were monitored under four operating modes (…). Figure 11 In the bleached state, the measured indoor illuminance was 12.93 klux, while in the colored opaque state, the indoor illuminance decreased to 1.41 klux.

[0115] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A dual-response electro-thermal color-changing device, characterized in that, The electrochromic-thermochromic dual-response color-changing device includes a first substrate, an electrochromic layer, a thermochromic electrolyte layer, an ion storage layer, and a second substrate, which are stacked sequentially. The electrochromic layer is made of titanium dioxide molecules and viologen molecules adsorbed on the surface of the titanium dioxide molecules. The thermochromic electrolyte layer is made of one of zinc salts or aluminum salts, or OEGMA. x -co-MEO2MA y Copolymer, x is 5-50, y is 95-50.

2. The electro-thermal dual-response color-changing device according to claim 1, characterized in that, The structural formula of the viologen molecule is as follows: R is selected from one or more of furan, thiophene, selenophene, ethylenedioxythiophene, and benzothiadiazole.

3. The electro-thermal dual-response color-changing device according to claim 1, characterized in that, The thickness of the electrochromic layer is 3-20 micrometers.

4. The electro-thermal dual-response color-changing device according to claim 1, characterized in that, The material of the ion storage layer is zinc.

5. A method for preparing the electro-thermal dual-response color-changing device according to claim 1, characterized in that, The preparation method includes the following steps: Provide the first base; A titanium dioxide slurry is coated on the surface of the first substrate and annealed to obtain a titanium dioxide film. The first substrate covered with a titanium dioxide film was placed in a viologen solution, so that viologen molecules were adsorbed onto the surface of titanium dioxide molecules, thus obtaining an electrochromic layer. Mix one of the zinc salts or aluminum salts with OEGMA x -co-MEO2MA y The copolymer was dissolved in water to obtain a thermochromic electrolyte solution; The thermochromic electrolyte solution is added to the surface of the electrochromic layer to form a thermochromic electrolyte layer; The ion storage layer and the second substrate are then placed on the surface of the thermochromic electrolyte layer in sequence, and encapsulated with curing adhesive to obtain the electrochromic-thermochromic dual-response color-changing device.

6. The method for fabricating the electro-thermal dual-response color-changing device according to claim 5, characterized in that, The annealing temperature is 450-600℃, and the annealing time is 0.5-3 hours.

7. The method for preparing the electro-thermal dual-response color-changing device according to claim 5, characterized in that, The zinc salt is one or more of zinc chloride, zinc bis(trifluoromethanesulfonyl)imide, zinc sulfate, and zinc carbonate, and the aluminum salt is one of aluminum chloride, aluminum bis(trifluoromethanesulfonyl)imide, aluminum sulfate, and aluminum carbonate.

8. The method for preparing the electro-thermal dual-response color-changing device according to claim 5, characterized in that, In the thermochromic electrolyte solution, OEGMA x -co-MEO2MA y The concentration of the copolymer is 10% to 50%.

9. The method for preparing the electro-thermal dual-response color-changing device according to claim 5, characterized in that, The concentration of zinc salt or aluminum salt in the thermochromic electrolyte solution is 0.1–2 mol / L.

10. The application of the electro-thermo-sensitive dual-response color-changing device according to any one of claims 1-4 in a smart window.

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