An integrated dual-band electrochromic smart window and a preparation method thereof

Abstract

This invention relates to an integrated dual-band electrochromic smart window and its fabrication method. The method includes coating an electrochromic electrolyte onto a conductive substrate, covering it with another conductive substrate, and assembling the device under pressure to obtain the integrated dual-band electrochromic smart window. This invention utilizes the characteristic of this nanomaterial being easily dispersed in electrolyte solvents to prepare an integrated electrochromic electrolyte with excellent cycling and color-changing capabilities. Under low-voltage driving conditions, it can effectively regulate visible-near-infrared radiation energy, achieving dynamic adjustment of indoor temperature. This reduces the frequency of use of traditional high-power indoor temperature control facilities such as air conditioners, and has positive significance for reducing energy consumption in buildings and automobiles.

Description

Technical Field

[0001] This invention belongs to the field of smart windows, and specifically relates to an integrated dual-band electrochromic smart window and its preparation method. Background Technology

[0002] With energy shortages and environmental problems becoming increasingly prominent, energy conservation and emission reduction are imperative. The low-carbon transformation of the building and transportation sectors is a crucial link in achieving the strategic goal of carbon neutrality. Glass doors and windows, as an important component of buildings and automobiles, are vital media for the exchange of light, heat, and gases between buildings / automobiles and the external environment. While existing building and automotive windows utilize mature Low-E glass that can reduce heat exchange between buildings / automobiles and the environment, achieving insulation in winter and heat insulation in summer, it primarily addresses radiation energy in the mid-infrared region. Solar radiation energy is mainly concentrated in the visible light (~42%) and near-infrared (~49%) bands, which are the main sources of heat causing increased interior temperatures in buildings and automobiles. Therefore, there is a need to further develop intelligent windows capable of achieving efficient dynamic adjustment in both the visible and near-infrared bands.

[0003] The visible-near-infrared dual-band smart window technology based on electrochromic technology can dynamically adjust the optical properties of the window according to the user's needs. It has the advantages of strong controllability, large adjustment range and low energy consumption, and shows great application prospects in aerospace, construction and transportation, defense and military industries. In recent years, dual-band electrochromic smart windows have developed rapidly. They mainly adjust the optical properties of the visible-near-infrared region through transition metal nano-oxides, conjugated organic compounds or multi-component composites. However, there are still some problems: (1) Most organic compounds are difficult to achieve wide spectrum adjustment capability of visible-near-infrared and exhibit poor environmental stability (ultraviolet, high and low temperature); (2) Transition metal nano-oxides are traditional multilayer structures with complex interface reactions and structural design requirements. Frequent ion insertion / extraction will inevitably lead to the destruction and shedding of the crystal structure, and the processing technology is often complicated and cumbersome. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the technical problem this invention aims to solve is to provide an integrated dual-band electrochromic smart window and its fabrication method. This method employs an integrated structural design, overcoming the defects of interface structure collapse and complex device fabrication methods inherent in traditional layered devices during use. Furthermore, the electrochromic electrolyte prepared by this method exhibits strong optical control capabilities in the visible-near-infrared region, long cycle life, and excellent service performance. Moreover, the fabrication conditions are mild, facilitating large-area device fabrication and flexible design.

[0005] The present invention discloses a method for fabricating an integrated dual-band electrochromic smart window, comprising:

[0006] (1) Electrochromic nanomaterials, oxidant and solvent are mixed to obtain a homogeneous and stable precursor solution;

[0007] (2) The polymer and precursor solution are mixed and stirred to obtain a dual-band electrochromic electrolyte.

[0008] (3) Coat the electrochromic electrolyte of step (2) onto the first conductive substrate, and then cover it with the second conductive substrate. Apply pressure to assemble the device to obtain an integrated dual-band electrochromic smart window.

[0009] Preferably, in step (1), the electrochromic nanomaterial is one or more of transition metal oxides and noble metal materials; the morphology of the electrochromic nanomaterial is at least one of nanocrystals, nanosheets, nanoclusters, and nanowires; the oxidant is one or more of hydrogen peroxide (H2O2), piperidine, piperidine derivatives, cyclopentadiene, cyclopentadiene derivatives, bromides, and iodides; and the solvent is one or more of water (H2O), N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), propylene carbonate (PC), ethylene carbonate (EC), and dimethyl carbonate (DMC).

[0010] Furthermore, the electrochromic nanomaterial is one or more of the following: tungsten-oxygen nanocrystals, molybdenum-oxygen nanowires, vanadium-oxygen nanocrystals, tungsten-oxygen nanoclusters, titanium-oxygen nanosheets, and polyacid and polyacid salt nanoclusters.

[0011] More preferably, the electrochromic nanomaterial is WO3 nanocrystals, W... 0.71 Mo 0.29 O3 nanocrystals, K6P2W 18 O 62 K3PMo 12 O 40 Na6V 10 O 28 One or more of TiO2 nanocrystals; electrochromic nanomaterials can be synthesized by conventional solution methods or obtained directly from the market, and there is no limitation on the electrochromic gel.

[0012] The oxidant is one or more of hydrogen peroxide (H2O2), tetramethylpiperidine oxide, TEMPO, cyclopentadienyl iron, ferrocene, lithium bromide, and lithium iodide.

[0013] Preferably, in step (1), the concentration of the electrochromic nanomaterial in the precursor solution is 1–1000 mM; and the concentration of the oxidant is 1–2000 mM.

[0014] More preferably, the concentration of the electrochromic nanomaterial in the precursor solution is 10-50 mM; and the concentration of the oxidant is 150-200 mM.

[0015] In step (2), the polymer is an organic resin, which may be one or more of polyvinylidene fluoride-hexafluoropropylene PVDF-HFP, polyethylene oxide PEO, polyvinyl butyral PVB, and polymethyl methacrylate PMMA; the mass ratio of the polymer to the precursor solution is 0-100 wt%; and the stirring temperature is 10-150℃.

[0016] More preferably, the mass ratio of the polymer to the precursor solution is 5 wt% to 30 wt%.

[0017] In step (3), tape is applied around the first or second conductive substrate, or an annular tape is applied to the first or second conductive substrate.

[0018] Preferably, the pressure applied in step (3) to assemble the device specifically involves applying pressure to firmly bond the first conductive substrate and the second conductive substrate together with adhesive tape, and filling the space between the conductive substrates with electrochromic electrolyte.

[0019] The thickness of the tape can be 0.01 to 100 mm; the conductive substrate can be rigid or flexible.

[0020] Preferably, in step (3), the thickness between the first conductive substrate and the second conductive substrate is 0.01 to 100 mm; the conductive layer of the conductive substrate is a metal or a transparent conductive oxide, and the support layer is glass or a flexible polymer film; the coating is done by scraping or spin coating; wherein the auxiliary heating temperature during the scraping of the conductive substrate is 25 to 300°C.

[0021] Furthermore, the conductive substrate is one or more of FTO-glass, ITO-glass, Ag-glass, and ITO-PET; the first conductive substrate may be the same as or different from the second conductive substrate.

[0022] Preferably, the pressure applied in step (3) is cold pressing, hot pressing, or vacuum pressing; the process parameters for applying the pressure are a pressure of 0 to 5 MPa and a temperature of 0 to 500°C during the pressing process.

[0023] The device area can be 0.2 cm². 2 ~2m 2 .

[0024] An integrated dual-band electrochromic smart window prepared by the method described in this invention.

[0025] The present invention relates to the application of the integrated dual-band electrochromic smart window in the fields of aerospace, construction and transportation, and national defense and military industries.

[0026] This invention provides a method for fabricating a large-area visible-near-infrared dual-band smart window based on an integrated device structure. This method is simple, utilizing a mild liquid-phase processing platform to achieve large-area, large-scale fabrication of the smart window. The resulting electrochromic smart window can achieve >50% modulation of radiation energy in the visible-near-infrared region, exhibiting excellent cycling performance and service stability.

[0027] This invention utilizes electrochromic nanomaterials, which possess structural stability and exhibit excellent cycling performance, making them a highly promising electrochromic material. This invention disperses nanomaterials in an electrolyte solvent to prepare an integrated electrochromic electrolyte with excellent cycling and color-changing capabilities. Under low-voltage driving conditions, it can effectively regulate visible-near-infrared radiation energy, enabling dynamic adjustment of indoor temperature. This reduces the frequency of use of traditional high-power indoor temperature control facilities such as air conditioners, and has positive implications for reducing energy consumption in buildings and automobiles.

[0028] This invention utilizes a mild liquid-phase processing method to prepare an integrated electrochromic smart window using a nanomaterial-based electrolyte. The nanomaterials in the electrolyte exhibit structural stability during the color-changing process and demonstrate strong optical control capabilities in the visible-near-infrared region. This invention achieves the fabrication of an integrated dual-band electrochromic smart window with strong optical control capabilities, long cycle life, and excellent service performance, showing broad application prospects in aerospace, construction and transportation, and defense industries.

[0029] Beneficial effects

[0030] (1) The method for preparing the electrochromic electrolyte of the present invention is simple, does not involve high temperature, high pressure and vacuum conditions, and is suitable for large-scale production;

[0031] (2) The present invention uses an electrochromic electrolyte as the color-changing active material, and the integrated structure device avoids the crystal structure collapse problem caused by ion implantation / extraction in the traditional layered transition metal oxide device.

[0032] (3) The present invention adopts an integrated device structure, which avoids the problem of interface stability decline caused by interface stress mismatch during long-term use of layered structure devices;

[0033] (4) The present invention uses an electrochromic electrolyte based on nanomaterials. The nanoscale electrochromic material endows the electrochromic electrolyte with excellent dual-band modulation effect and cycle stability in the visible-near infrared region, which solves the problem of poor near-infrared modulation effect of traditional organic small molecule color-changing material integrated devices.

[0034] (5) This invention can regulate the light and heat exchange process between buildings, vehicles and the external environment through electrochromic effects, exhibiting strong optical regulation effect, long cycle life and excellent service stability, which makes it show great application prospects in aerospace, construction and transportation, defense and military industries. Attached Figure Description

[0035] Figure 1 Example 1: Schematic diagram of the fabrication method and device structure of an integrated dual-band electrochromic smart window using nanomaterial electrochromic electrolyte;

[0036] Figure 2 Example 1: Visible-near-infrared spectra at different voltages;

[0037] Figure 3 Example 1: Transmittance versus time curves of an integrated dual-band electrochromic smart window at 600 nm under different cycles of applied step voltages for coloring (-1.5V) and fading (0.1V);

[0038] Figure 4 Example 1: Photograph of an integrated dual-band electrochromic smart window;

[0039] Figure 5 Example 1: Solar energy spectrum and solar energy spectrum transmitted through the smart window at different voltages. Detailed Implementation

[0040] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0041] Example 1

[0042] 4.9g of tungsten oxide nanoclusters (K6P2W) 18 O 62Add 100 ml of dimethyl carbonate (DMC) and stir to dissolve at room temperature to obtain a clear solution. Then add 1.86 g of ferrocene (Fc) and continue stirring to dissolve at room temperature to obtain a precursor. Add 12 g of polyethylene oxide (PEO) powder to the precursor solution and heat and stir at 60 °C until the powder is completely dispersed to obtain a nanomaterial-based electrochromic electrolyte. Place conductive ITO glass on a 50 °C hot stage. Apply 0.2 mm thick adhesive tape to the conductive substrate to form an annular insulating layer and an adhesive layer. Pour the nanomaterial-based electrochromic electrolyte onto the conductive electrode and use a doctor blade to spread the electrolyte to form a 0.2 mm thick electrolyte electrode. Transfer the conductive electrode with the electrochromic electrolyte to a room temperature platform. Cover the conductive glass with another piece of conductive glass and cold press it with a pressure of 0.1 MPa to obtain an integrated dual-band electrochromic smart window. The fabrication process flow diagram and device structure diagram are shown below. Figure 1 As shown. Figure 2 The visible-near-infrared spectra of the dimming smart window at different voltages show that the visible electrochromic electrolyte exhibits a large optical modulation range; for example... Figure 3 The transmittance versus time curves of the dimming smart window at 600 nm under step voltages of coloring (-1.5V) and fading (0V) applied before and after 3000 cycles are shown. Figure 4 This is a photograph of an electrochromic smart window. Figure 5 This is a solar energy spectrum of the electrochromic smart window transmitted through the device at different voltages.

[0043] By applying voltages of -1.5V / 0V, the dimming smart window prepared above can achieve a coloring / fading transition. At 600nm, it can achieve optical modulation from 97% transmittance in the faded state (0V) to 5% in the colored state (-1.5V). In the near-infrared region at 1200nm, it can achieve optical modulation from 98% transmittance in the faded state (0V) to 6% in the colored state (-1.5V). It exhibits a modulation capability of >50% of solar irradiance energy in the visible-near-infrared region, and after 3000 cycles, the optical modulation range and the ability to retain more than 90% of the initial state are maintained.

[0044] In this example, the dimethyl carbonate, ferrocene, and polyethylene oxide used to prepare the electrochromic gel were all purchased from Sinopharm Group and were not purified before use. The large-area conductive glass was purchased from Luoyang Guluo Glass (7-10 Ω / sq).

[0045] Example 2

[0046] 2.88 g of potassium dodecyl molybdate nanoclusters were added to 100 ml of dimethyl carbonate (DMC) and stirred at room temperature to dissolve, obtaining a clear solution. Then, 1.86 g of ferrocene (Fc) was added and stirred at room temperature to dissolve, yielding a precursor. No polymer powder was added, resulting in a nanomaterial-based electrochromic electrolyte. Adhesive tape was applied to a conductive substrate to form an annular insulating and adhesive layer. The nanomaterial-based electrochromic electrolyte was poured onto conductive glass and spin-coated at 100 r / min to obtain a 0.2 mm thick electrolyte electrode. The conductive electrode coated with the electrochromic electrolyte was transferred to a room temperature platform. Another piece of conductive glass was placed over the spin-coated conductive glass and cold-pressed at 0.1 MPa to obtain an integrated dual-band electrochromic smart window.

[0047] In this example, potassium dodecyl molybdate phosphate, dimethyl carbonate, and ferrocene were all purchased from Sinopharm Group and were not purified before use. The conductive glass was purchased from Luoyang Guluo Glass (7-10 Ω / sq).

[0048] Example 3

[0049] 6.3g Na6V 10 O 28 Nanocluster materials were added to 100 ml of dimethyl carbonate (DMC) and dissolved by stirring at room temperature to obtain a clear solution. Then, 2.79 g of ferrocene (Fc) was added and stirred at room temperature to dissolve, yielding a precursor. 12 g of polyethylene oxide (PEO) powder was added to the precursor solution and dispersed to obtain a nanomaterial-based electrochromic electrolyte. Two conductive substrates were placed together in a vacuum pressurization device, and vacuum pressurization was applied to tightly bond the conductive glass and the electrochromic electrolyte layer, forming an electrochromic smart window. The conductive ITO glass was placed on a 50°C hot stage. A 0.2 mm thick adhesive tape was applied to the conductive substrate to form a ring-shaped insulating layer and an adhesive layer. The nanomaterial-based electrochromic electrolyte was poured onto the conductive electrode, and a scraper was used to spread the electrolyte, forming a 0.2 mm thick electrolyte electrode. The conductive electrode with the electrochromic electrolyte was then transferred to a room temperature platform. Another piece of conductive glass is placed on top of the conductive glass coated with electrochromic electrolyte, and then cold-pressed for 30 seconds using a pressure of 0.1 MPa to obtain an integrated dual-band electrochromic smart window.

[0050] In this example, the dimethyl carbonate, ferrocene, and ethylene oxide used to prepare the electrochromic gel were all purchased from Sinopharm Group and were not purified before use. The conductive glass was purchased from Luoyang Guluo Glass (7-10 Ω / sq).

[0051] Example 4

[0052] 4.9g of tungsten oxide nanoclusters (K6P2W) 18 O 62Add 100 ml of propylene carbonate (PC) and stir to dissolve at room temperature to obtain a clear solution. Then add 1.56 g of 2,2,6,6-tetramethylpiperidine-1-oxygen radical (TEMPO) and continue stirring to dissolve at room temperature to obtain a precursor. Add 12 g of polymethyl methacrylate (PMMA) powder to the precursor solution and heat and stir at 60 °C until the powder is completely dispersed to obtain a nanomaterial-based electrochromic electrolyte. Place conductive ITO glass on a 50 °C hot stage. Apply a 0.2 mm thick and 1 cm wide 3M film to the conductive substrate to form a ring-shaped insulating layer and an adhesive layer. Pour the nanomaterial-based electrochromic electrolyte onto the conductive electrode and use a spatula to spread the electrolyte to form a 0.2 mm thick electrolyte electrode. Transfer the conductive electrode with the electrochromic electrolyte to a room temperature platform. Cover the conductive glass with another piece of conductive glass with the electrochromic electrolyte and cold press it under a pressure of 0.1 MPa to obtain an integrated dual-band electrochromic smart window.

[0053] In this example, the propylene carbonate, 2,2,6,6-tetramethylpiperidine-1-oxygen radical, and polymethyl methacrylate used in the preparation of the electrochromic gel were all purchased from Sinopharm Group and were not purified before use. The conductive glass was purchased from Luoyang Guluo Glass (7-10 Ω / sq).

[0054] Example 5

[0055] 4.9 g of titanium oxide nanosheets were added to 100 ml of dimethyl carbonate (DMC) and dissolved by stirring at room temperature to obtain a clear solution. Then, 1.86 g of ferrocene (Fc) was added and stirred at room temperature to dissolve. Finally, 10.6 g of anhydrous LiClO4 was added and dissolved to obtain a precursor. 12 g of polyvinylidene fluoride (PVDF) powder was added to the precursor solution and stirred at room temperature until the powder was completely dispersed to obtain a nanomaterial-based electrochromic electrolyte. A 0.2 mm thick adhesive tape was applied to a flexible ITO conductive substrate to form an annular insulating layer and an adhesive layer. The nanomaterial-based electrochromic electrolyte was poured onto a conductive electrode, and the electrolyte was coated with a scraper to form a 0.2 mm thick electrolyte electrode. The conductive electrode coated with the electrochromic electrolyte was transferred to a room temperature platform. Another flexible ITO conductive substrate was placed on top of the conductive glass coated with the electrochromic electrolyte, and hot-pressed at 90 °C under a pressure of 0.1 MPa to obtain an integrated dual-band electrochromic smart window.

[0056] In this example, the dimethyl carbonate, ferrocene, anhydrous LiClO4, and ethylene oxide used in the synthesis of the electrochromic gel were all purchased from Sinopharm Group and were not purified before use. The conductive glass was purchased from Luoyang Guluo Glass (7-10 Ω / sq).

Claims

1. A method for fabricating an integrated dual-band electrochromic smart window, comprising the following steps: (1) Mix electrochromic nanomaterials, oxidant and solvent to obtain precursor solution; The electrochromic nanomaterials mentioned therein are one or more of the following: tungsten oxide nanocrystals, molybdenum oxide nanowires, vanadium oxide nanocrystals, tungsten oxide nanoclusters, titanium oxide nanosheets, and polyacid and polyacid salt nanoclusters; wherein the tungsten oxide nanoclusters are K6P2W. 18 O 62 Polyacid and polyacid salt nanoclusters include potassium dodecyl molybdate phosphate nanoclusters and Na6V. 10 O 28 One or more of the nanoclusters; The oxidant is one or more of hydrogen peroxide (H2O2), piperidine, piperidine derivatives, cyclopentadiene, cyclopentadiene derivatives, bromides, and iodides; wherein the concentration of the electrochromic nanomaterial in the precursor solution is 1~1000 mM; and the concentration of the oxidant is 1~2000 mM. (2) The polymer and the precursor solution are mixed and stirred to obtain an electrochromic electrolyte; the polymer is one or more of polyvinylidene fluoride-hexafluoropropylene PVDF-HFP, polyethylene oxide PEO, polyvinyl butyral PVB, and polymethyl methacrylate PMMA; the mass ratio of the polymer to the precursor solution is 0~100 wt%; the stirring temperature is 10-150℃; (3) Coat the electrochromic electrolyte of step (2) on the first conductive substrate, and then cover it with the second conductive substrate. Apply pressure to assemble and obtain an integrated dual-band electrochromic smart window.

2. The preparation method according to claim 1, characterized in that, The solvent in step (1) is one or more of water (H2O), N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), propylene carbonate (PC), ethylene carbonate (EC), and dimethyl carbonate (DMC).

3. The preparation method according to claim 1, characterized in that, In step (1), the oxidant is replaced by one or more of tetramethylpiperidine oxide, TEMPO, cyclopentadienyl iron, ferrocene, lithium bromide, and lithium iodide, with a concentration of 1~1000mM.

4. The preparation method according to claim 1, characterized in that, The pressure assembly in step (3) specifically involves applying pressure to firmly bond the first conductive substrate and the second conductive substrate together with adhesive tape, and filling the space between the conductive substrates with electrochromic electrolyte.

5. The preparation method according to claim 1, characterized in that, In step (3), the thickness between the first conductive substrate and the second conductive substrate is 0.01~100 mm; the conductive layer of the first conductive substrate and the second conductive substrate is metal or transparent conductive oxide, and the support layer is glass or flexible polymer film; the coating is applied by scraping or spin coating.

6. The preparation method according to claim 1, characterized in that, In step (3), the pressure applied is either cold pressing / hot pressing or vacuum pressing; the process parameters for applying the pressure are a pressure of 0~5 MPa and a temperature of 0~500℃.

7. An integrated dual-band electrochromic smart window prepared by the method of claim 1.

8. The application of the integrated dual-band electrochromic smart window as described in claim 7 in the fields of aerospace, construction and transportation, and national defense and military industries.

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