Molybdenum-based multiband regulation and control electrochromic device as well as preparation method and application thereof

Abstract

The invention provides a molybdenum-based multiband regulation and control electrochromic device and a preparation method and application thereof, and belongs to the technical field of electrochromic materials. According to the molybdenum-based multiband regulation and control electrochromic device provided by the invention, when forward voltage is applied, H < + > migrates to the molybdenum oxide electrochromic layer from the electrolyte layer and is subjected to a reduction reaction with MoO3-x, so that absorption of visible light bands is enhanced, and the device is colored; when reverse voltage is applied, H < + > is separated from the electrochromic layer and returns to the electrolyte layer, MoO < 3-x > recovers the oxidation state, and the device fades; regulation and control of the near-infrared band are achieved by adjusting the oxygen vacancy concentration. High driving voltage promotes the plasma resonance effect, and near-infrared absorption is enhanced. The ion implantation discoloration mechanism is dominant under low driving voltage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochromic materials, and particularly relates to a molybdenum-based multi-band regulation electrochromic device and a preparation method and application thereof. BACKGROUND

[0002] Electrochromic devices (ECDs) are intelligent materials that can adjust optical properties through an applied electric field, and are widely used in smart windows, display devices and energy-saving fields. In the prior art, materials such as tungsten oxide (WO3) have electrochromic properties, but their spectral regulation range is limited, and it is difficult to achieve multi-band dynamic regulation. In addition, traditional electrochromic devices have problems such as slow response speed, insufficient cycle stability, complex preparation process and high environmental pollution risk.

[0003] Molybdenum oxide (MoO3) is a transition metal oxide that has high electrical conductivity, good optical transparency and fast charge transfer capability, but the existing technology mainly focuses on single-band regulation of molybdenum oxide in electrochromic devices, which is difficult to meet the needs of complex application scenarios. Therefore, it is urgent to provide a multi-band regulation electrochromic device based on molybdenum oxide to solve the limitations of the prior art. SUMMARY

[0004] The present application provides a molybdenum-based multi-band regulation electrochromic device and a preparation method and application thereof. The molybdenum-based multi-band regulation electrochromic device provided by the present application has high efficient optical regulation performance and environmental friendliness, and can realize multi-band regulation.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] The present application provides a molybdenum-based multi-band regulation electrochromic device, which comprises, from bottom to top, a first transparent conductive layer, a molybdenum oxide electrochromic layer, an electrolyte layer and a second transparent conductive layer.

[0007] The molybdenum oxide electrochromic layer is MoO 3-x thin film with adjustable oxygen vacancies.

[0008] The preparation method of the molybdenum oxide electrochromic layer comprises the following steps:

[0009] (1) mixing molybdenum powder, hydrogen peroxide solution and water under the condition of ice water bath, and then standing to obtain MoO 3-x sol precursor;

[0010] (2) coating and drying the MoO 3-x sol precursor obtained in step (1) to obtain MoO 3-xThe sol precursor film is subjected to annealing treatment to obtain the molybdenum oxide electrochromic layer.

[0011] (3) annealing the MoO 3-x The sol precursor film is subjected to annealing treatment to obtain the molybdenum oxide electrochromic layer.

[0012] Preferably, the first transparent conductive layer and the second transparent conductive layer are independently fluorine-doped tin oxide film or indium tin oxide film; the thickness of the first transparent conductive layer and the second transparent conductive layer is independently 100-500 nm.

[0013] Preferably, the mass of the molybdenum powder and the ratio of the volume of the hydrogen peroxide solution to water in step (1) is 1 g:(3.75-7.5) mL.

[0014] Preferably, the standing time in step (1) is 48-108 h, the standing temperature is room temperature, and the standing pressure is normal pressure.

[0015] Preferably, the MoO 3-x The amount of the sol precursor is 5-10 μL / cm 2 .

[0016] Preferably, the annealing temperature in step (3) is 300-500 ℃, the annealing time is 0.5-5 h, and the annealing atmosphere is air.

[0017] Preferably, the thickness of the molybdenum oxide electrochromic layer is 50-300 nm.

[0018] Preferably, the electrolyte layer comprises Nafion proton exchange membrane, and the thickness of the electrolyte layer is 50-200 μm.

[0019] The present application provides a preparation method of the molybdenum-based multi-band regulation electrochromic device, comprising the following steps:

[0020] 1) coating MoO 3-x sol precursor on the surface of the first transparent conductive layer, and then drying to obtain a MoO 3-x sol precursor film, and then performing annealing treatment to obtain a molybdenum oxide electrochromic layer;

[0021] 2) covering an electrolyte layer on the surface of the molybdenum oxide electrochromic layer obtained in step 1);

[0022] 3) covering a second transparent conductive layer on the surface of the electrolyte layer obtained in step 2) to obtain a molybdenum-based multi-band regulation electrochromic device.

[0023] The present invention provides the application of the molybdenum-based multi-band controllable electrochromic device described in the above technical solution or the molybdenum-based multi-band controllable electrochromic device prepared by the preparation method described in the above technical solution in smart window systems, adaptive display devices and military dynamic camouflage systems.

[0024] The present invention provides a molybdenum-based multi-band controllable electrochromic device, which comprises, from bottom to top, a first transparent conductive layer, a molybdenum oxide electrochromic layer, an electrolyte layer, and a second transparent conductive layer; the molybdenum oxide electrochromic layer is MoO with controllable oxygen vacancies. 3-x The preparation method of the molybdenum oxide electrochromic layer comprises the following steps: (1) mixing molybdenum powder, hydrogen peroxide solution and water in an ice water bath, and then allowing to stand to obtain MoO 3-x Sol precursor; (2) the MoO obtained in step (1) 3-x The sol precursor is coated and dried in sequence to obtain MoO 3-x Sol precursor film; (3) the MoO obtained in step (2) 3-x The sol precursor film is annealed to obtain a molybdenum oxide electrochromic layer. The transparent conductive layer of the present invention has excellent light transmittance and will not affect the display performance of other materials. It also has excellent conductivity and is suitable for transmitting current or signals, achieving a unique balance between transparency and conductivity. By regulating oxygen vacancies to form a dual color change mechanism of ion injection and plasma resonance, multi-spectral regulation of dynamic transmittance can be achieved in the visible light and near-infrared bands by adjusting the voltage, thereby achieving multi-band response and regulation capabilities. No harmful gases are released during the preparation of the molybdenum oxide electrochromic layer, and the raw materials can be recycled and reused, thereby having a good environmental effect and complying with the principles of green chemistry. By regulating MoO 3-x The sol precursor film is annealed to make the amorphous MoO 3-x Transformed into a crystalline structure, the annealing temperature is lower than that of MoO 3-x Standard crystallization temperature can form more oxygen vacancy defects, and this process can significantly reduce energy consumption while also avoiding high-temperature pollution.

[0025] The molybdenum-based multi-band control electrochromic device provided by the present invention, when a forward voltage is applied, hydrogen ions (H + ) migrates from the electrolyte layer to the molybdenum oxide electrochromic layer and reacts with MoO 3-x Reduction reaction occurs (Mo 6+ →Mo 5+ ), resulting in enhanced absorption in the visible light band (400-700nm) and device coloring; when a reverse voltage is applied, H + Detached from the electrochromic layer and returned to the electrolyte layer, MoO 3-x Restore oxidation state (Mo 5+ →Mo6+ ), device fade; near-infrared band (700-1000 nm) is regulated by adjusting the oxygen vacancy concentration: high driving voltage generates plasmonic resonance effect, enhances near-infrared absorption; ion implantation-dependent color change mechanism under low driving voltage. The transmittance difference ΔT% of the molybdenum-based multi-band regulation electrochromic device provided by the application in the visible light band of 400-700 nm and the near-infrared band of 700-1000 nm is 26.26-42.93% and 43.26-52.39%, respectively. The molybdenum-based multi-band regulation electrochromic device provided by the application has high efficient optical regulation performance and environmental friendly characteristics. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The thickness of the molybdenum oxide electrochromic layer in the molybdenum-based multi-band regulation electrochromic device provided for Example 1;

[0027] Figure 2 The structure schematic diagram of the molybdenum-based multi-band regulation electrochromic device provided for Example 2;

[0028] Figure 3 The transmittance-wavelength curve of the molybdenum-based multi-band regulation electrochromic device annealed at 300℃ provided for Example 3 under different voltages;

[0029] Figure 4 The transmittance-wavelength curve of the molybdenum-based multi-band regulation electrochromic device annealed at 400℃ provided for Example 4 under different voltages;

[0030] Figure 5 The transmittance-wavelength curve of the molybdenum-based multi-band regulation electrochromic device annealed at 500℃ provided for Example 5 under different voltages;

[0031] Figure 6 The transmittance-wavelength curve of the molybdenum-based multi-band regulation electrochromic device based on lithium ion electrolyte provided for Comparative Example 1 under different voltages. DETAILED DESCRIPTION

[0032] The application provides a molybdenum-based multi-band regulation electrochromic device, which comprises, from bottom to top, a first transparent conductive layer, a molybdenum oxide electrochromic layer, an electrolyte layer and a second transparent conductive layer;

[0033] The molybdenum oxide electrochromic layer is MoO 3-x thin film;

[0034] The preparation method of the molybdenum oxide electrochromic layer comprises the following steps:

[0035] (1) mixing molybdenum powder, hydrogen peroxide solution and water under the condition of ice water bath, and then standing to obtain MoO3-x sol-gel precursor;

[0036] (2) MoOxof step (1) is coated and dried in sequence to obtain MoOx 3-x sol-gel precursor; 3-x sol-gel precursor film;

[0037] (3) MoOxof step (2) is coated and dried in sequence to obtain MoOx 3-x sol-gel precursor film is annealed to obtain a molybdenum oxide electrochromic layer.

[0038] In the present application, the multi-band electrochromic device preferably further comprises a substrate layer; the substrate layer is preferably located at the bottom of the second transparent conductive layer. In the present application, the substrate layer preferably comprises a transparent glass substrate or a flexible polymer substrate. The present application does not have special limitations on the specific composition of the transparent glass substrate and the flexible polymer substrate, and commercially available transparent glass substrates or flexible polymer substrates well known to those skilled in the art can be used. The use of the above-mentioned substrate layer can not only be used to support the device structure, but also the substrate layer material can be recycled and reused, thereby reducing resource waste and reducing solid waste, which has good environmental protection effect.

[0039] In the present application, the first transparent conductive layer is a fluorine-doped tin oxide (FTO) film or an indium tin oxide (ITO) film; the thickness of the first transparent conductive layer is preferably 100-500 nm. As an embodiment of the present application, the thickness of the first transparent conductive layer can be 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm or 450 nm. By using a fluorine-doped tin oxide (FTO) film or an indium tin oxide (ITO) film as the first transparent conductive layer, the present application has excellent light transmittance and does not affect the display performance of other materials, while having excellent electrical conductivity, suitable for transmitting current or signal, and achieving a unique balance between transparency and electrical conductivity.

[0040] In the present application, the first transparent conductive layer is preferably pretreated; the pretreatment is preferably ultrasonic cleaning with acetone, ethanol and deionized water in sequence, and then dried and treated with ultraviolet ozone. In the present application, the time for ultrasonic cleaning with acetone, ethanol and deionized water is independently preferably 5-20 min, more preferably 10-15 min; the time for ultraviolet ozone treatment is preferably 3-10 min, more preferably 5-8 min. The present application does not have special limitations on the temperature and time of drying, which can remove the residual deionized water. By using acetone, ethanol and deionized water for ultrasonic cleaning, the present application can remove impurities remaining on the surface of the first transparent conductive layer, and by ultraviolet ozone treatment, the hydrophilicity can be enhanced.

[0041] In the present application, the molybdenum oxide electrochromic layer is MoO 3-x thin film. The present application forms an ion injection and plasma resonance dual-chromic mechanism by regulating oxygen vacancies, and can realize multi-spectrum regulation of dynamic transmittance in the visible and near-infrared wave bands by adjusting voltage, thereby realizing multi-band response and regulation capability.

[0042] In the present application, the preparation method of the molybdenum oxide electrochromic layer comprises the following steps:

[0043] (1) mixing molybdenum powder, hydrogen peroxide solution and water under the condition of an ice water bath, then standing to obtain MoO 3-x sol precursor;

[0044] (2) coating and drying the MoO 3-x sol precursor obtained in the step (1) in sequence to obtain a MoO 3-x sol precursor thin film;

[0045] (3) annealing the MoO 3-x sol precursor thin film obtained in the step (2) to obtain a molybdenum oxide electrochromic layer.

[0046] In the present application, molybdenum powder, hydrogen peroxide solution and water are mixed under the condition of an ice water bath, then standing to obtain MoO 3-x sol precursor. The present application prepares the MoO 3-x sol precursor by using the above-mentioned method, and no harmful gas is released in the reaction process, thereby having a good environmental protection effect.

[0047] In the present application, the ratio of the mass of the molybdenum powder to the total volume of the hydrogen peroxide solution and water is preferably 1 g: (3.75-7.5) mL; the water is preferably deionized water or pure water; the mass concentration of the hydrogen peroxide solution is preferably 10%; and the volume ratio of the hydrogen peroxide solution to water is preferably 1: (0.5-2). As an embodiment of the present application, the ratio of the mass of the molybdenum powder to the total volume of the hydrogen peroxide solution and water can be 1 g: 4 mL, 1 g: 4.25 mL, 1 g: 4.5 mL, 1 g: 4.75 mL, 1 g: 5 mL, 1 g: 5.25 mL, 1 g: 5.5 mL, 1 g: 5.75 mL, 1 g: 6 mL, 1 g: 6.25 mL, 1 g: 6.5 mL, 1 g: 6.75 mL, 1 g: 7 mL, or 1 g: 7.25 mL; and the volume ratio of the hydrogen peroxide solution to water can be 1: 0.6, 1: 0.8, 1: 1, 1: 1.2, 1: 1.4, 1: 1.5, 1: 1.6, or 1: 1.8. The present application can improve the reaction efficiency by controlling the amount of raw materials, thereby improving the purity of molybdenum oxide in the molybdenum oxide electrochromic layer; and the use of hydrogen peroxide solution as raw material can decompose into water and oxygen in the subsequent process without generating other pollutants, while the molybdenum powder can be recycled, which conforms to the principle of green chemistry.

[0048] In the present application, the mixing method of the molybdenum powder, the hydrogen peroxide solution, and the water in the ice-water bath is preferably as follows: the hydrogen peroxide solution and the water are mixed, then placed in an ice-water bath, and the molybdenum powder is slowly added under stirring. The present application does not have special limitations on the specific operation of the slow addition, which can be determined according to the technical common sense of those skilled in the art, as long as it can avoid splashing caused by violent reaction. The present application does not have special limitations on the method and rate of stirring, which can be determined according to the technical common sense of those skilled in the art, such as glass rod stirring, as long as it can avoid splashing of the solution. The present application can control the reaction temperature ≤ 30°C by mixing in the ice-water bath, thereby avoiding splashing of the solution caused by high temperature during the reaction.

[0049] The present application does not have special limitations on the specific time of the ice-water bath reaction, which can be determined according to the technical common sense of those skilled in the art, as long as the molybdenum powder is completely added to the hydrogen peroxide solution.

[0050] In the present application, the standing time is preferably 48-108 h; the standing temperature is preferably room temperature; and the standing pressure is preferably atmospheric pressure. As an embodiment of the present application, the standing time can be 54 h, 60 h, 66 h, 72 h, 78 h, 84 h, 90 h, 96 h, or 102 h. The present application can fully oxidize and dissolve the molybdenum powder in the hydrogen peroxide solution by standing and controlling the standing time; and the use of normal temperature and pressure conditions for standing can reduce energy consumption and environmental pressure without high temperature and pressure conditions.

[0051] After the standing, the application preferably further comprises separating the standing product. In the application, the separating method is preferably filtering. Through filtering, the application can remove the unreacted molybdenum powder.

[0052] obtains MoO 3-x After the sol precursor, the application coats and dries the MoO 3-x sol precursor in turn, to obtain MoO 3-x sol precursor film.

[0053] In the application, the coating method is preferably dropping the MoO 3-x sol precursor uniformly on the surface of the first transparent conductive layer, and then spin coating. In the application, the amount of MoO 3-x sol precursor used when coating is preferably 5-10 μL / cm 2 ; the spin coating rate is preferably 2000-5000 rpm; and the spin coating time is preferably 10-60 s. As an embodiment of the application, the amount of MoO 3-x sol precursor used when coating can be 6 μL / cm 2 , 7 μL / cm 2 , 8 μL / cm 2 or 9 μL / cm 2 ; the spin coating rate can be 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm or 4500 rpm; and the spin coating time can be 20 s, 30 s, 40 s or 50 s. Through spin coating, the application can obtain a MoO 3-x sol precursor film with uniform thickness.

[0054] In the application, the drying temperature is preferably 200-400°C; and the drying time is preferably 5-20 min. As an embodiment of the application, the drying temperature can be 250°C, 300°C or 350°C; and the drying time can be 8 min, 10 min, 12 min, 15 min or 18 min. Through drying, the application can remove the moisture and hydrogen peroxide in the MoO 3-x sol precursor film, to promote gelation.

[0055] In the application, when the thickness of the MoO 3-x sol precursor film obtained after coating and drying does not meet the requirements, the application preferably further comprises repeating the coating and drying operations until the thickness of the MoO 3-x sol precursor film meets the requirements. As an embodiment of the application, the number of times of repeating the coating and drying can be 2-5, and can also be 3-4.

[0056] MoO 3-x After the sol precursor film is prepared, the MoO 3-x The sol precursor film is annealed to obtain the molybdenum oxide electrochromic layer.

[0057] In the present application, the annealing temperature is preferably 300-500℃, the annealing time is preferably 0.5-5h, the annealing atmosphere is preferably air, and the heating rate to the annealing temperature is preferably 3-8℃ / min. As an embodiment of the present application, the annealing temperature can be 320℃, 340℃, 360℃, 380℃, 400℃, 420℃, 440℃, 460℃ or 480℃, the annealing time can be 0.8h, 1h, 2h, 3h or 4h, and the heating rate to the annealing temperature can be 4℃ / min, 5℃ / min, 6℃ / min or 7℃ / min. The present application can convert the amorphous MoO 3-x The sol precursor film is annealed to convert the amorphous MoO 3-x into a crystalline structure, and the annealing temperature is lower than the standard crystallization temperature of MoO 3-x , so that more oxygen vacancy defects can be formed, and the process can significantly reduce energy consumption and avoid high-temperature pollution.

[0058] In the present application, the thickness of the molybdenum oxide electrochromic layer is preferably 50-300nm. As an embodiment of the present application, the thickness of the molybdenum oxide electrochromic layer can be 80nm, 100nm, 120nm, 150nm, 180nm, 200nm, 220nm, 240nm or 280nm.

[0059] The present application can prepare the molybdenum oxide electrochromic layer by the sol-gel method, which can prepare the film at low temperature, ensure the high quality of the film, and reduce the production cost and environmental pollution. The coloring efficiency of the molybdenum oxide electrochromic layer provided by the present application is 10-37cm 2 / C, the response time is ≤10s, and the cycle stability is ≥100 times.

[0060] In the present application, the electrolyte layer is preferably a Nafion proton exchange membrane, and more preferably a DuPont N117 proton exchange membrane. In the present application, the Nafion proton exchange membrane is preferably pretreated; the pretreatment is preferably immersion treatment of the Nafion 117 proton exchange membrane with hydrogen peroxide aqueous solution, dilute sulfuric acid and water in sequence; the mass concentration of the hydrogen peroxide aqueous solution is preferably 5-10%; the immersion temperature of the hydrogen peroxide aqueous solution is preferably 60-90°C; the immersion time of the hydrogen peroxide aqueous solution is preferably 0.5-2h; the mass concentration of the dilute sulfuric acid is preferably 5-10%; the immersion temperature of the dilute sulfuric acid is preferably 60-90°C; the immersion time of the dilute sulfuric acid is preferably 0.5-2h; the water is preferably deionized water or pure water; the immersion temperature of the water is preferably room temperature; and the immersion time of the water is preferably 0.5-1h. In the present application, the thickness of the electrolyte layer is preferably 50-200μm. As an embodiment of the present application, the mass concentration of the hydrogen peroxide aqueous solution can be 6%, 7%, 8% or 9%; the immersion temperature of the hydrogen peroxide aqueous solution can be 70-80°C; the immersion time of the hydrogen peroxide aqueous solution can be 1-1.5h; the mass concentration of the dilute sulfuric acid is preferably 6%, 7%, 8% or 9%; the immersion temperature of the dilute sulfuric acid is preferably 70-80°C; the immersion time of the dilute sulfuric acid can be 1-1.5h; and the thickness of the electrolyte layer can be 60μm, 80μm, 100μm, 120μm, 140μm, 150μm, 160μm or 180μm. The present application does not have special limitations on the specific manner of immersion of the Nafion proton exchange membrane, and it can be fully soaked. The solvent selected in the pretreatment of the proton exchange membrane in the present application is an environmentally friendly solvent, which can reduce environmental pollution and meet environmental protection requirements.

[0061] In the present application, the second transparent conductive layer preferably comprises an FTO thin film or an ITO thin film; and the thickness of the second transparent conductive layer is preferably 100-500nm. As an embodiment of the present application, the thickness of the second transparent conductive layer can be 150nm, 200nm, 250nm, 300nm, 350nm, 400nm or 450nm. The present application adopts an FTO thin film or an ITO thin film as the second transparent conductive layer, which has excellent light transmittance and does not affect the display performance of other materials, and at the same time has excellent conductivity, is suitable for transmitting current or signals, and realizes a unique balance between transparency and conductivity.

[0062] In the present application, the second transparent conductive layer is preferably pretreated; the pretreatment is preferably ultrasonic cleaning with acetone, ethanol and deionized water in turn, and then dried and treated with ultraviolet ozone. In the present application, the time for ultrasonic cleaning with acetone, ethanol and deionized water is preferably independently 5-20 min, more preferably 10-15 min; the time for ultraviolet ozone treatment is preferably 3-10 min, more preferably 5-8 min. The present application does not have special limitations on the temperature and time for drying, which can only remove the residual deionized water. In the present application, ultrasonic cleaning with acetone, ethanol and deionized water can remove impurities remaining on the surface of the first transparent conductive layer, and ultraviolet ozone treatment can enhance hydrophilicity.

[0063] In the present application, the multi-band regulated electrochromic device preferably further comprises an encapsulation layer; the encapsulation layer is preferably used to encapsulate the edges of the multi-band regulated electrochromic device; the thickness of the encapsulation layer is preferably 50-100 μm, more preferably 60-80 μm. In the present application, the encapsulation layer is preferably silicone, transparent epoxy resin or polyethylene terephthalate (PET). In the present application, the encapsulation layer is used to seal the device to prevent external moisture or air from entering; the raw material used is a degradable or easily recyclable material, which can reduce waste generation.

[0064] In the present application, the multi-band regulated electrochromic device preferably further comprises an external power supply; the external power supply is preferably a direct current power supply; the voltage of the external power supply is preferably 1.5-4.0 V, more preferably 2.0-3.5 V, and further preferably 2.5-3.5 V; the positive and negative poles of the external power supply are preferably connected to the first transparent conductive layer and the second transparent conductive layer in the multi-band regulated electrochromic device.

[0065] In the present application, FTO film or ITO film is used as the transparent conductive layer, which has excellent light transmittance and does not affect the display performance of other materials, and also has excellent conductivity, suitable for transmitting current or signal, achieving a unique balance between transparency and conductivity; by regulating the oxygen vacancy formation ion injection and plasma resonance dual color mechanism, the dynamic transmittance can be multi-spectrally regulated in the visible and near-infrared bands by adjusting the voltage, thereby realizing multi-band response and regulation capability; in the process of preparing the molybdenum oxide electrochromic layer, no harmful gas is released, and the raw material can be recycled, thereby having good environmental protection effect and meeting the principle of green chemistry; by annealing the sol precursor film, the amorphous MoO 3-x is converted into a crystalline structure, the annealing temperature is lower than the standard crystallization temperature of MoO 3-x , more oxygen vacancy defects can be formed, and this process can significantly reduce energy consumption while avoiding high-temperature pollution. 3-x ​

[0066] The molybdenum-based multi-band control electrochromic device provided by the present invention, when a forward voltage is applied, hydrogen ions (H + ) migrates from the electrolyte layer to the molybdenum oxide electrochromic layer and reacts with MoO 3-x Reduction reaction occurs (Mo 6+ →Mo 5+ ), resulting in enhanced absorption in the visible light band (400-700nm) and device coloring; when a reverse voltage is applied, H + Detached from the electrochromic layer and returned to the electrolyte layer, MoO 3-x Restore oxidation state (Mo 5+ →Mo 6+ ), the device fades; the regulation of the near-infrared band (700-1000nm) is achieved by adjusting the oxygen vacancy concentration: high voltage promotes the plasma resonance effect and enhances near-infrared absorption; low voltage relies on the ion injection color change mechanism. The molybdenum-based multi-band regulated electrochromic device provided by the present invention has a transmittance difference ΔT% of 26.26-42.93% in the visible light band of 400-700nm and 43.26-52.39% in the near-infrared band of 700-1000nm. The molybdenum-based multi-band regulated electrochromic device provided by the present invention is used for application, which combines high-efficiency optical regulation performance with environmental friendliness.

[0067] The present invention also provides a method for preparing the molybdenum-based multi-band controllable electrochromic device described in the above technical solution, comprising the following steps:

[0068] 1) Coating MoO on the surface of the first transparent conductive layer 3-x Sol precursor, and then dried to obtain MoO 3-x The sol precursor film is then annealed to obtain a molybdenum oxide electrochromic layer;

[0069] 2) covering the surface of the molybdenum oxide electrochromic layer obtained in step 1) with an electrolyte layer;

[0070] 3) Covering the surface of the electrolyte layer obtained in step 2) with a second transparent conductive layer to obtain a molybdenum-based multi-band controllable electrochromic device.

[0071] The present invention coats MoO on the surface of the first transparent conductive layer. 3-x Sol precursor, and then dried to obtain MoO 3-x The sol precursor film is then annealed to obtain a molybdenum oxide electrochromic layer.

[0072] In the present invention, the process parameters for preparing the molybdenum oxide electrochromic layer are preferably the same as those described above and will not be described in detail herein.

[0073] After the molybdenum oxide electrochromic layer is obtained, the electrolyte layer is covered on the surface of the molybdenum oxide electrochromic layer.

[0074] In the present application, the covering method is preferably drop coating. The present application does not have special limitations on the specific operation and dosage of the drop coating, which can be determined according to the technical knowledge of those skilled in the art, as long as the thickness of the electrolyte layer meets the requirements.

[0075] After the electrolyte layer is obtained, the second transparent conductive layer is covered on the surface of the electrolyte layer to obtain the molybdenum-based multi-band regulation electrochromic device.

[0076] In the present application, the composition of the second transparent conductive layer is preferably the same as the aforementioned, which will not be repeated here.

[0077] The present application does not have special limitations on the specific operation of covering the second transparent conductive layer, which can be covered in a manner known to those skilled in the art.

[0078] In the present application, when the multi-band regulation electrochromic device includes a packaging layer, the present application preferably further includes packaging the edges of the multi-band regulation electrochromic device with the packaging layer. The present application does not have special limitations on the specific operation of the packaging, which can be packaged in a manner known to those skilled in the art.

[0079] In the present application, when the multi-band regulation electrochromic device includes an external power supply, the present application preferably connects the positive and negative electrodes of the external power supply to the first transparent conductive layer and the second transparent conductive layer in the multi-band regulation electrochromic device. The present application does not have special limitations on the specific method of the connection, which can be connected in a manner known to those skilled in the art (such as conductive connection).

[0080] The preparation method provided by the present application is environmentally friendly, low-cost and simple in preparation process, is suitable for large-scale production, and is conducive to promoting the application of the molybdenum-based multi-band regulation electrochromic device.

[0081] The present application also provides the application of the molybdenum-based multi-band regulation electrochromic device in the intelligent window system, the self-adaptive display device and the military dynamic camouflage system.

[0082] The present application does not have special limitations on the specific method of the intelligent window system and the military dynamic camouflage system, which can be applied in a manner known to those skilled in the art. The molybdenum-based multi-band regulation electrochromic device provided by the present application can significantly improve the light and heat management efficiency and user experience.

[0083] In the present application, the smart window system preferably comprises a molybdenum-based multi-band regulation electrochromic device, a voltage control system and a light intensity sensor. The present application does not have special limitations on the specific arrangement of the molybdenum-based multi-band regulation electrochromic device, the voltage control system and the light intensity sensor, and they can be arranged according to the technical knowledge of those skilled in the art. The present application adjusts the voltage amplitude and direction to switch the coloring state and bleaching state of the molybdenum-based multi-band regulation electrochromic device through the voltage control system; the light intensity sensor monitors the ambient light intensity in real time and feeds back to the control system, realizing adaptive light and heat management, reducing air conditioning and lighting energy consumption, and improving building energy efficiency.

[0084] In the present application, the smart window system preferably integrates a flexible display module. The present application does not have special limitations on the specific way of the integrated flexible display module, which can be determined according to the technical knowledge of those skilled in the art. The present application supports foldable or curved form applications by integrating a flexible display module, uses degradable packaging materials, and reduces electronic waste pollution.

[0085] In the present application, when the molybdenum-based multi-band regulation electrochromic device is applied to a military dynamic camouflage system, the reflectivity and transmittance of the device are dynamically adjusted by matching the environmental spectrum through multi-band regulation, so that the reflectivity matching error is ≤5%, thereby achieving the effect of camouflage.

[0086] The present application optimizes the material ratio, structure and preparation process of the molybdenum-based multi-band regulation electrochromic device, realizes dynamic adjustment from visible light to near-infrared band, and improves the response speed, stability and coloring efficiency of the device.

[0087] The technical solutions in the present application will be described clearly and completely below in combination with the embodiments in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0088] Embodiment 1

[0089] A molybdenum-based multi-band regulation electrochromic device, from bottom to top, comprises a first transparent conductive layer, a molybdenum oxide electrochromic layer, an electrolyte layer and a second transparent conductive layer;

[0090] The preparation method of the molybdenum-based multi-band regulation electrochromic device comprises the following steps:

[0091] (1) The FTO film is sequentially ultrasonically cleaned with acetone, ethanol and deionized water for 10 min, dried and then treated with ultraviolet ozone for 5 min to obtain the first transparent conductive layer; the thickness of the first transparent conductive layer is 300 nm, and the length and width are both 2 cm;

[0092] (2) mixing hydrogen peroxide solution and deionized water, then placing in ice water bath, slowly adding molybdenum powder under the condition of glass rod stirring, controlling the reaction temperature ≤ 30℃, then standing at normal temperature and pressure for 72h, finally filtering, obtaining dark blue MoO 3-x sol precursor; the mass of the molybdenum powder and the total volume of the hydrogen peroxide solution and deionized water are 1g:7.5mL; the mass concentration of the hydrogen peroxide solution is 10%; the volume ratio of the hydrogen peroxide solution and deionized water is 1:0.5;

[0093] (3) annealing the MoO 3-x sol precursor obtained in the step (2) at 300℃ for 1h in air atmosphere, obtaining a molybdenum oxide electrochromic layer with a thickness of 246nm; 2 sol precursor obtained in the step (2) at 300℃ for 1h in air atmosphere, obtaining a molybdenum oxide electrochromic layer with a thickness of 246nm; 3-x sol precursor film;

[0094] (4) covering the MoO 3-x sol precursor film obtained in the step (3) with a proton exchange membrane with a thickness of 175μm on the surface of the MoO

[0095] (5) covering the molybdenum oxide electrochromic layer obtained in the step (4) with a proton exchange membrane with a thickness of 175μm on the surface of the molybdenum oxide electrochromic layer, obtaining an electrolyte layer with a thickness of 175μm; the proton exchange membrane is pretreated by sequentially immersing Nafion117 proton exchange membrane in hydrogen peroxide aqueous solution, dilute sulfuric acid and water; the mass concentration of the hydrogen peroxide aqueous solution is 5%, the immersion temperature is 80℃, and the immersion time is 1h; the mass concentration of the dilute sulfuric acid is 5%, the immersion temperature is 80℃, and the immersion time is 1h; the water is deionized water, the immersion temperature is room temperature, and the immersion time is 0.5h;

[0096] (6) covering the electrolyte layer obtained in the step (5) with an FTO film on the surface of the electrolyte layer, forming a second transparent conductive layer with a thickness of 300nm, obtaining a molybdenum-based multi-band regulation electrochromic device; the FTO film is pretreated by sequentially ultrasonic cleaning with acetone, ethanol and deionized water for 10min, and then drying and treating with ultraviolet ozone for 5min; the length and width of the FTO film are both 2cm, and the FTO film is misaligned with the first transparent conductive layer.

[0097] Figure 1 is a cross-sectional view of the molybdenum oxide electrochromic layer in the molybdenum-based multi-band regulation electrochromic device provided in Example 1. Figure 1It can be seen that the thickness of the molybdenum oxide electrochromic layer provided by the application is 246 nm.

[0098] Example 2

[0099] A molybdenum-based multi-band regulation electrochromic device, from bottom to top, is sequentially a first transparent conductive layer, a molybdenum oxide electrochromic layer, an electrolyte layer and a second transparent conductive layer;

[0100] The preparation method of the molybdenum-based multi-band regulation electrochromic device is the following steps:

[0101] (1) The FTO film is sequentially ultrasonically cleaned with acetone, ethanol and deionized water for 10 min, dried and then treated with ultraviolet ozone for 5 min to obtain a first transparent conductive layer; the thickness of the first transparent conductive layer is 300 nm, and the length and width are both 2 cm;

[0102] (2) The hydrogen peroxide solution and deionized water are mixed, then placed in an ice water bath, and the molybdenum powder is slowly added under the condition of glass rod stirring, the reaction temperature is controlled to be ≤30℃, then it is left to stand at room temperature and normal pressure for 72 h, and finally filtered to obtain a deep blue MoO 3-x sol precursor; the mass of the molybdenum powder and the total volume of the hydrogen peroxide solution and deionized water are in a ratio of 1g:7.5mL; the mass concentration of the hydrogen peroxide solution is 10%; the volume ratio of the hydrogen peroxide solution and deionized water is 1:0.5;

[0103] (3) The MoO 3-x sol precursor obtained in the step (2) is uniformly dropped on the surface of the first transparent conductive layer of the step (1) with a dosage of 5μL / cm 2 , then spin-coated at a speed of 4000rpm for 30s, and finally dried at 300℃ for 10min, and the above operation is repeated 5 times to obtain a MoO 3-x sol precursor film;

[0104] (4) The MoO 3-x sol precursor film obtained in the step (3) is annealed at a temperature rising rate of 5℃ / min to 300℃ for 1h in an air atmosphere to obtain a molybdenum oxide electrochromic layer with a thickness of 246nm;

[0105] (5) covering the surface of the molybdenum oxide electrochromic layer obtained in the step (4) with a proton exchange membrane with a thickness of 175 μm to obtain an electrolyte layer with a thickness of 175 μm; the proton exchange membrane is pretreated by sequentially immersing a Nafion 117 proton exchange membrane in a hydrogen peroxide aqueous solution, dilute sulfuric acid and water; the hydrogen peroxide aqueous solution has a mass concentration of 5%, an immersion temperature of 80℃ and an immersion time of 1 h; the dilute sulfuric acid has a mass concentration of 5%, an immersion temperature of 80℃ and an immersion time of 1 h; the water is deionized water, and the immersion time is 0.5 h at room temperature;

[0106] (6) covering the surface of the electrolyte layer obtained in the step (5) with an FTO film to form a second transparent conductive layer with a thickness of 300 nm, connecting the first transparent conductive layer and the second transparent conductive layer with a copper tape, connecting an external direct current power source with the copper tape, and obtaining a molybdenum-based multi-band regulation electrochromic device; the FTO film is pretreated by sequentially ultrasonic cleaning with acetone, ethanol and deionized water for 10 min, drying and then treating with ultraviolet ozone for 5 min; the length and width of the FTO film are both 2 cm, and the FTO film is misaligned with the first transparent conductive layer.

[0107] Figure 2 A structure diagram of the molybdenum-based multi-band regulation electrochromic device provided for the embodiment 2 is shown in FIG. 2. Figure 2 As can be seen, the molybdenum-based multi-band regulation electrochromic device provided by the present application sequentially comprises a first transparent conductive layer, a molybdenum oxide electrochromic layer, an electrolyte layer and a second transparent conductive layer from bottom to top, and the first transparent conductive layer and the second transparent conductive layer are connected with an external power source through a wire.

[0108] Embodiment 3

[0109] A molybdenum-based multi-band regulation electrochromic device sequentially comprises a first transparent conductive layer, a molybdenum oxide electrochromic layer, an electrolyte layer, a second transparent conductive layer and a packaging layer from bottom to top.

[0110] A preparation method of the molybdenum-based multi-band regulation electrochromic device comprises the following steps:

[0111] (1) sequentially ultrasonic cleaning an FTO film with acetone, ethanol and deionized water for 10 min, drying and then treating with ultraviolet ozone for 5 min to obtain a first transparent conductive layer; the thickness of the first transparent conductive layer is 300 nm, and the length and width are both 2 cm;

[0112] (2) mixing a hydrogen peroxide solution and deionized water, then placing in an ice water bath, slowly adding molybdenum powder under the condition of glass rod stirring, controlling the reaction temperature ≤ 30℃, then standing at normal temperature and normal pressure for 72 h, and finally filtering to obtain deep blue MoO 3-xThe mass of the molybdenum powder and the total volume of the hydrogen peroxide solution and deionized water are 1 g: 7.5 mL; the mass concentration of the hydrogen peroxide solution is 10%; and the volume ratio of the hydrogen peroxide solution and deionized water is 1:0.5;

[0113] (3) The MoO 3-x The sol precursor is uniformly dropped on the surface of the first transparent conductive layer of step (1) at a dosage of 5 μL / cm 2 , and then spin-coated at a speed of 4000 rpm for 30 s, and finally dried at 300 ℃ for 10 min. The above operation is repeated 5 times to obtain a MoO 3-x sol precursor film;

[0114] (4) The MoO 3-x The sol precursor film is annealed at 300 ℃ for 1 h at a temperature increasing rate of 5 ℃ / min to obtain a molybdenum oxide electrochromic layer with a thickness of 246 nm;

[0115] (5) A proton exchange film with a thickness of 175 μm is coated on the surface of the molybdenum oxide electrochromic layer obtained in step (4) to obtain an electrolyte layer with a thickness of 175 μm; the proton exchange film is pretreated by sequentially immersing a Nafion 117 proton exchange film in a hydrogen peroxide aqueous solution, dilute sulfuric acid and water; the mass concentration of the hydrogen peroxide aqueous solution is 5%, the immersion temperature is 80 ℃, and the immersion time is 1 h; the mass concentration of the dilute sulfuric acid is 5%, the immersion temperature is 80 ℃, and the immersion time is 1 h; the water is deionized water, the immersion temperature is room temperature, and the immersion time is 0.5 h;

[0116] (6) An FTO film is coated on the surface of the electrolyte layer obtained in step (5) to form a second transparent conductive layer with a thickness of 300 nm, and finally sealed with a silicone frame with a thickness of 100 μm at the edge; the FTO film is pretreated by sequentially ultrasonic cleaning with acetone, ethanol and deionized water for 10 min, and then dried and treated with ultraviolet ozone for 5 min; the length and width of the FTO film are both 2 cm, and the FTO film is misaligned with the first transparent conductive layer;

[0117] (7) The first transparent conductive layer and the second transparent conductive layer in step (6) are connected by a copper tape, and then connected to an external direct current power supply to obtain a molybdenum-based multi-band modulation electrochromic device.

[0118] The voltage of the external direct current power supply is controlled to be 0, 2.5 V and 3.5 V, respectively, and then the transmittance-wavelength of the molybdenum-based multi-band modulation electrochromic device is tested, and the obtained results are shown in Figure 3 . As shown inFigure 3 It can be seen that when a voltage of 2.5V is applied, the molybdenum-based multi-band modulation electrochromic device enhances the absorption in the visible light band (400-700nm), and the device is colored; when a voltage of 3.5V is applied, the molybdenum-based multi-band modulation electrochromic device enhances the absorption in the visible light band (700-1000nm); the transmittance difference ΔT% of the molybdenum-based multi-band modulation electrochromic device in the visible light band of 400-700nm and the near-infrared band of 700-1000nm is 34.85% and 50.53%, respectively.

[0119] Example 4

[0120] A molybdenum-based multi-band modulation electrochromic device, from bottom to top, is sequentially a first transparent conductive layer, a molybdenum oxide electrochromic layer, an electrolyte layer, a second transparent conductive layer, and a packaging layer.

[0121] The preparation method of the molybdenum-based multi-band modulation electrochromic device is the following steps:

[0122] (1) The FTO film is sequentially ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes, dried, and then treated with ultraviolet ozone for 5 minutes to obtain a first transparent conductive layer; the thickness of the first transparent conductive layer is 300nm, and the length and width are both 2cm;

[0123] (2) The hydrogen peroxide solution and deionized water are mixed, then placed in an ice water bath, and molybdenum powder is slowly added under the condition of glass rod stirring, controlling the reaction temperature ≤30℃, then standing at room temperature and normal pressure for 72h, and finally filtering to obtain a deep blue MoO 3-x sol precursor; the mass of the molybdenum powder and the total volume of the hydrogen peroxide solution and deionized water are in a ratio of 1g:7.5mL; the mass concentration of the hydrogen peroxide solution is 10%; the volume ratio of the hydrogen peroxide solution and deionized water is 1:0.5;

[0124] (3) The MoO 3-x sol precursor obtained in step (2) is uniformly dropped on the surface of the first transparent conductive layer of step (1) at a dosage of 5μL / cm 2 , then spin-coated at a rate of 4000rpm for 30s, and finally dried at 300℃ for 10min, repeating the above operation 5 times to obtain a MoO 3-x sol precursor film;

[0125] (4) The MoO 3-x sol precursor film obtained in step (3) is annealed at 400℃ for 1h at a temperature rising rate of 5℃ / min in an air atmosphere to obtain a molybdenum oxide electrochromic layer with a thickness of 246nm;

[0126] (5) covering the surface of the molybdenum oxide electrochromic layer obtained in the step (4) with a proton exchange membrane with a thickness of 175 μm to obtain an electrolyte layer with a thickness of 175 μm; the proton exchange membrane is pretreated by sequentially immersing a Nafion 117 proton exchange membrane in a hydrogen peroxide aqueous solution, dilute sulfuric acid and water; the hydrogen peroxide aqueous solution has a mass concentration of 5%, an immersion temperature of 80°C and an immersion time of 1 h; the dilute sulfuric acid has a mass concentration of 5%, an immersion temperature of 80°C and an immersion time of 1 h; the water is deionized water, an immersion temperature of room temperature and an immersion time of 0.5 h;

[0127] (6) covering the surface of the electrolyte layer obtained in the step (5) with an FTO film to form a second transparent conductive layer with a thickness of 300 nm, and finally sealing the edge with a silicone frame with a thickness of 100 μm; the FTO film is pretreated by sequentially ultrasonic cleaning with acetone, ethanol and deionized water for 10 min, drying and then treating with ultraviolet ozone for 5 min; the length and width of the FTO film are both 2 cm, and the FTO film is misaligned with the first transparent conductive layer;

[0128] (7) connecting the first transparent conductive layer and the second transparent conductive layer in the step (6) with a copper tape, and then connecting an external direct current power supply to obtain a molybdenum-based multi-band modulation electrochromic device.

[0129] The transmittance-wavelength of the molybdenum-based multi-band modulation electrochromic device is tested by controlling the voltage of the external direct current power supply to be 0, 3 V and 4 V respectively, and the obtained results are shown in Figure 4 As can be seen from Figure 4 , when a voltage of 3 V is applied, the molybdenum-based multi-band modulation electrochromic device has enhanced absorption in the visible light band (400-700 nm) and the device is colored; when a voltage of 4 V is applied, the molybdenum-based multi-band modulation electrochromic device has enhanced absorption in the visible light band (700-1000 nm); the difference in transmittance ΔT% of the molybdenum-based multi-band modulation electrochromic device in the visible light band (400-700 nm) and the near-infrared band (700-1000 nm) is 26.26% and 43.26%, respectively.

[0130] Example 5

[0131] A molybdenum-based multi-band modulation electrochromic device, from bottom to top, comprises a first transparent conductive layer, a molybdenum oxide electrochromic layer, an electrolyte layer, a second transparent conductive layer and an encapsulation layer.

[0132] A preparation method of the molybdenum-based multi-band modulation electrochromic device comprises the following steps:

[0133] (1) The FTO film was sequentially cleaned with acetone, ethanol and deionized water for 10 min by ultrasonic, dried and treated with ultraviolet ozone for 5 min to obtain a first transparent conductive layer; the thickness of the first transparent conductive layer was 300 nm, and the length and width were both 2 cm;

[0134] (2) The hydrogen peroxide solution and deionized water were mixed, then placed in an ice water bath, and molybdenum powder was slowly added under the condition of glass rod stirring, the reaction temperature was controlled to be ≤30℃, then it was left to stand at room temperature and normal pressure for 72 h, and finally filtered to obtain a deep blue MoO 3-x sol precursor; the mass of the molybdenum powder and the total volume ratio of the hydrogen peroxide solution and deionized water were 1 g:7.5 mL; the mass concentration of the hydrogen peroxide solution was 10%; the volume ratio of the hydrogen peroxide solution and deionized water was 1:0.5;

[0135] (3) The MoO 3-x sol precursor obtained in step (2) was uniformly dropped on the surface of the first transparent conductive layer of step (1) at a dosage of 5 μL / cm 2 , then spin-coated at a speed of 4000 rpm for 30 s, and finally dried at 300℃ for 10 min, and the above operation was repeated 5 times to obtain a MoO 3-x sol precursor film;

[0136] (4) The MoO 3-x sol precursor film obtained in step (3) was annealed at 500℃ for 1 h at a temperature rising rate of 5℃ / min in an air atmosphere to obtain a molybdenum oxide electrochromic layer with a thickness of 246 nm;

[0137] (5) A proton exchange membrane with a thickness of 175 μm was covered on the surface of the molybdenum oxide electrochromic layer obtained in step (4) to obtain an electrolyte layer with a thickness of 175 μm; the proton exchange membrane was pretreated by sequentially immersing Nafion117 proton exchange membrane in hydrogen peroxide aqueous solution, dilute sulfuric acid and water; the mass concentration of the hydrogen peroxide aqueous solution was 5%, the immersion temperature was 80℃, and the immersion time was 1 h; the mass concentration of the dilute sulfuric acid was 5%, the immersion temperature was 80℃, and the immersion time was 1 h; the water was deionized water, the immersion temperature was room temperature, and the immersion time was 0.5 h;

[0138] (6) The surface of the electrolyte layer obtained in step (5) is covered with an FTO film to form a second transparent conductive layer with a thickness of 300 nm, and finally sealed with a silica gel frame with a thickness of 100 μm at the edge; the FTO film is pretreated by sequentially ultrasonic cleaning with acetone, ethanol and deionized water for 10 min, dried and then treated with ultraviolet ozone for 5 min; the length and width of the FTO film are both 2 cm, and misaligned with the first transparent conductive layer;

[0139] (7) The first transparent conductive layer and the second transparent conductive layer in step (6) are connected with a copper adhesive tape, followed by connecting an external direct current power source to obtain a molybdenum-based multi-band regulated electrochromic device.

[0140] The transmittance-wavelength of the molybdenum-based multi-band regulated electrochromic device is tested by controlling the voltage of the external direct current power source to be 0, 2.5 V and 3.5 V, respectively, and the results are shown in Figure 5 As shown in Figure 5 It can be seen that when a voltage of 2.5 V is applied, the molybdenum-based multi-band regulated electrochromic device has enhanced absorption in the visible light band (400-700 nm) and the device is colored; when a voltage of 3.5 V is applied, the molybdenum-based multi-band regulated electrochromic device has enhanced absorption in the visible light band (700-1000 nm); the transmittance difference ΔT% of the molybdenum-based multi-band regulated electrochromic device in the 400-700 nm visible light band and the 700-1000 nm near-infrared band is 42.93% and 52.39%, respectively.

[0141] Comparative Example 1

[0142] An electrochromic device, from bottom to top, comprises a first transparent conductive layer, a molybdenum oxide electrochromic layer, an electrolyte layer, a second transparent conductive layer and an encapsulation layer;

[0143] The preparation method of the molybdenum-based multi-band regulated electrochromic device comprises the following steps:

[0144] (1) The FTO film is sequentially ultrasonic cleaned with acetone, ethanol and deionized water for 10 min, dried and then treated with ultraviolet ozone for 5 min to obtain a first transparent conductive layer; the thickness of the first transparent conductive layer is 300 nm, and the length and width are both 2 cm;

[0145] (2) Hydrogen peroxide solution and deionized water are mixed, then placed in an ice water bath, and molybdenum powder is slowly added under the condition of glass rod stirring, the reaction temperature is controlled to be ≤30 ℃, then left at room temperature and normal pressure for 72 h, and finally filtered to obtain deep blue MoO 3-xThe sol precursor; the mass of the molybdenum powder and the total volume of the hydrogen peroxide solution and deionized water are 1 g:7.5 mL; the mass concentration of the hydrogen peroxide solution is 10%; the volume ratio of the hydrogen peroxide solution and deionized water is 1:0.5;

[0146] (3) annealing the MoO 3-x The sol precursor is uniformly dropped on the surface of the first transparent conductive layer of step (1) at a dosage of 5 μL / cm 2 , and then spin-coated at a speed of 4000 rpm for 30 s, and finally dried at 300 ℃ for 10 min. The above operation is repeated 5 times to obtain a MoO 3-x sol precursor film;

[0147] (4) annealing the MoO 3-x sol precursor film at a temperature increasing rate of 5 ℃ / min to 300 ℃ for 1 h to obtain a molybdenum oxide electrochromic layer with a thickness of 246 nm;

[0148] (5) dropping a lithium ion electrolyte with a concentration of 1 mol / L on the surface of the tungsten oxide electrochromic layer obtained in step (4) to obtain an electrolyte layer with a thickness of 50 μm; the lithium ion gel electrolyte is prepared by dissolving LiClO4 in propylene carbonate;

[0149] (6) covering the electrolyte layer obtained in step (5) with an FTO film to form a second transparent conductive layer with a thickness of 300 nm, and finally sealing the edge with a silicone frame with a thickness of 100 μm; the FTO film is pretreated by sequentially ultrasonic cleaning with acetone, ethanol and deionized water for 10 min, and then dried and treated with ultraviolet ozone for 5 min; the length and width of the FTO film are both 2 cm, and the first transparent conductive layer is misaligned with the FTO film;

[0150] (7) connecting the first transparent conductive layer and the second transparent conductive layer in step (6) with a copper tape, and then connecting an external direct current power supply to obtain an electrochromic device.

[0151] The transmittance-wavelength of the molybdenum-based multi-band modulation electrochromic device is tested by controlling the voltage of the external direct current power supply to be 0, 2.5 V and 3.5 V, respectively, and the results are shown in Figure 6 . As can be seen from Figure 6 , when the voltage is increased from 0 V to 2.5 V and 3.5 V, there is no obvious band spectrum modulation characteristic.

[0152] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. A molybdenum-based multi-band controllable electrochromic device, characterized in that: From bottom to top, it includes: a first transparent conductive layer, a molybdenum oxide electrochromic layer, an electrolyte layer, and a second transparent conductive layer; The molybdenum oxide electrochromic layer is MoO with adjustable oxygen vacancies. 3-x film; The preparation method of the molybdenum oxide electrochromic layer comprises the following steps: (1) Molybdenum powder, hydrogen peroxide solution and water were mixed under the condition of ice water bath, and then allowed to stand to obtain MoO 3-x Sol precursor; (2) the MoO obtained in step (1) 3-x The sol precursor is coated and dried in sequence to obtain MoO 3-x Sol-gel precursor films; (3) the MoO obtained in step (2) 3-x The sol precursor film is annealed to obtain a molybdenum oxide electrochromic layer.

2. The molybdenum-based multi-band controllable electrochromic device according to claim 1, characterized in that: The first transparent conductive layer and the second transparent conductive layer are independently fluorine-doped tin oxide thin films or indium tin oxide thin films; the thickness of the first transparent conductive layer and the second transparent conductive layer are independently 100 to 500 nm.

3. The molybdenum-based multi-band controllable electrochromic device according to claim 1, characterized in that: The ratio of the mass of the molybdenum powder to the total volume of the hydrogen peroxide solution and water in the step (1) is 1 g: (3.75-7.5) mL.

4. The molybdenum-based multi-band controllable electrochromic device according to claim 1, characterized in that: The standing time in step (1) is 48 to 108 hours, the standing temperature is room temperature, and the standing pressure is normal pressure.

5. The molybdenum-based multi-band controllable electrochromic device according to claim 1, characterized in that: In the step (2), when coating, MoO 3-x The dosage of sol precursor is 5~10μL / cm 2 .

6. The molybdenum-based multi-band controllable electrochromic device according to claim 1, characterized in that: The annealing temperature in step (3) is 300-500° C., the annealing time is 0.5-5 h, and the annealing atmosphere is air.

7. The molybdenum-based multi-band controllable electrochromic device according to claim 1, characterized in that: The thickness of the molybdenum oxide electrochromic layer is 50 to 300 nm.

8. The molybdenum-based multi-band controllable electrochromic device according to claim 1, characterized in that: The electrolyte layer comprises a Nafion proton exchange membrane, and the thickness of the electrolyte layer is 50 to 200 μm.

9. The method for preparing a molybdenum-based multi-band controllable electrochromic device according to any one of claims 1 to 8, characterized in that: The following steps are involved: 1) Coating MoO on the surface of the first transparent conductive layer 3-x Sol precursor, and then dried to obtain MoO 3-x The sol precursor film is then annealed to obtain a molybdenum oxide electrochromic layer; 2) covering the surface of the molybdenum oxide electrochromic layer obtained in step 1) with an electrolyte layer; 3) Covering the surface of the electrolyte layer obtained in step 2) with a second transparent conductive layer to obtain a molybdenum-based multi-band controllable electrochromic device.

10. Application of the molybdenum-based multi-band controllable electrochromic device according to any one of claims 1 to 8 or the molybdenum-based multi-band controllable electrochromic device prepared by the preparation method according to claim 9 in smart window systems, adaptive display devices and military dynamic camouflage systems.

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