An electrochromic device containing a loose medium layer and a method of making the same

Abstract

The application discloses an electrochromic device containing a loose medium layer and a preparation method thereof. x The preparation method comprises the following steps: forming a polyorganosilazane curing layer on the surface of an ITO / electrochromic layer substrate in advance, then preparing a loose SiOx / SiN medium layer by laser pyrolysis or vacuum ultraviolet photolysis condensation, and then sputtering an ion storage layer and a transparent conductive layer, so that an electrochromic device preparation process with high color change rate is provided. The application overcomes the defects of the prior art, such as dense medium layer of the electrochromic device, low ion transmission efficiency, and complex preparation process and high cost, and first proposes that the organic silicon material is changed into a loose inorganic medium layer with high stability and high lithium ion migration rate, so that a new technical path is provided for electrolyte layer design and preparation of the high-performance electrochromic device.

Description

Technical Field

[0001] This invention relates to the field of electrochromic materials and devices, specifically to an electrochromic device containing a porous dielectric layer and its preparation method, particularly a method for preparing porous SiO2 / SiN based on the photolysis condensation or pyrolysis of polysilazane. x Methods for using a dielectric layer, and fabrication processes for electrochromic devices with high color-changing rates incorporating the dielectric layer. Background Technology

[0002] Electrochromism refers to the phenomenon where the optical properties of a material, such as reflectivity, transmittance, and absorptivity, undergo reversible color changes under the influence of an applied electric field. This manifests as reversible changes in color and transparency. The principle of electrochromism is that electrochromic materials undergo electrochemical oxidation-reduction reactions under an applied electric field, changing their color through the gain or loss of electrons. Taking tungsten oxide (WO3) as an example, when a voltage is applied, cations and electrons are injected into the interstitial spaces of the WO3 crystal lattice, resulting in a color change. Due to their reversible controllability of optical properties under an applied electric field, electrochromic devices have broad application prospects in fields such as smart windows, anti-glare rearview mirrors, and display devices.

[0003] The typical structure of existing inorganic all-solid-state electrochromic devices is "ITO conductive layer / electrochromic layer (such as WO3) / electrolyte layer / ion storage layer (such as NiO) / ITO conductive layer". Among them, the electrolyte layer serves as a lithium-ion transport channel, and its structural density directly affects the ion migration rate. Traditional electrolyte layers (such as LiTaO3 and LiAlO2) are mostly prepared by magnetron sputtering and sol-gel methods, which easily form dense columnar structures. The ion migration channels are narrow and tortuous, resulting in low lithium-ion insertion / extraction efficiency. The device coloring time often exceeds 10 seconds and the fading time exceeds 5 seconds, which is difficult to meet the requirements for fast response.

[0004] In addition, silicon-based dielectric materials (such as SiO2, SiN) x Silicon-based dielectric layers are considered good candidate materials for electrolyte layers (dielectric layers) due to their good chemical stability and strong adhesion to inorganic substrates. However, silicon-based dielectric layers formed by sputtering and vapor deposition are mostly dense structures, which cannot meet the requirements of rapid ion transport, and there is a lack of effective means to prepare porous silicon-based dielectric layers on a large scale. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing electrochromic devices, such as dense dielectric layers, low ion transport efficiency, and complex and costly fabrication processes. This invention provides an electrochromic device containing a porous dielectric layer and its fabrication method, specifically based on the preparation of porous SiO2 / SiN by pyrolysis or photopyrolysis condensation of polysilazane. xThis invention provides a method for creating a dielectric layer, and also offers a fabrication process for electrochromic devices with high color-changing rates incorporating this dielectric layer. This invention is the first to propose transforming organosilicon materials into a porous inorganic dielectric layer with high stability and high lithium-ion mobility, providing a new technical pathway for the design and fabrication of dielectric layers in high-performance electrochromic devices.

[0006] The objective of this invention can be achieved through the following methods: This invention provides an electrochromic device containing a porous dielectric layer, comprising a first conductive layer, an electrochromic layer, a dielectric layer, an ion storage layer, a lithiation layer, and a second conductive layer arranged in sequence. The dielectric layer is obtained by coating an organosilicon solution onto an electrochromic layer, drying the resulting organosilicon film, and then subjecting it to laser pyrolysis or vacuum ultraviolet irradiation for photolysis and condensation; the organosilicon is polysilazane.

[0007] Compared to conventional methods, such as vapor deposition, the SiO2 dielectric layer prepared by this invention has a very low structural porosity, making it difficult to obtain an amorphous structure with a mesoporous network morphology, thus hindering the rapid migration of lithium ions. x / SiN x The microstructure is more porous because the original organic components, through pyrolysis and volatilization during preparation, act as pore-forming agents. The Si-N molecular chains condense to form a loose inorganic mesoporous three-dimensional network framework. Furthermore, the condensation and rearrangement temperature of Si-O / Si-N bonds is lower, and in an inert atmosphere, it tends to form a short-range ordered, long-range disordered amorphous structure. Therefore, the amorphous structure with its inorganic mesoporous network is much more porous than crystalline silicon dioxide and significantly increases the migration channels for lithium ions.

[0008] The polysilazane used in this invention, as a ceramizable polymer precursor, can be transformed into silicon-based inorganic ceramics (SiO2, SiN) after pyrolysis or photodegradation condensation under a specific atmosphere. x or SiO2 / SiN x The composite phase, and the volatilization of small molecule groups during pyrolysis can form a porous structure of about tens of nanometers. This loose and stable inorganic structure with a thickness of tens of nanometers is an excellent dielectric layer material for inorganic all-solid-state electrochromic devices.

[0009] In one embodiment of the present invention, the organosilicon solution has a mass fraction of 5%-10%. The solvent of the organosilicon solution includes one or more of toluene, xylene, n-hexane, and tetrahydrofuran.

[0010] As one embodiment of the present invention, the coating method is one of spin coating, scraping coating, or dip coating / lift coating.

[0011] In one embodiment of the present invention, the thickness of the obtained organosilicon film is 150-300 nm.

[0012] In one embodiment of the present invention, the drying temperature is 70-100°C and the time is 3-10 minutes. Heating and drying removes solvents and increases the adhesion of the substrate layer.

[0013] In one embodiment of the present invention, the laser pyrolysis involves irradiating the thin film with a laser, specifically a CO2 laser (10.6 μm) or a UV laser (193 / 248 nm), with a power density of 15-40 mJ / pulse, a repetition rate of 10-100 Hz, and an irradiation time of 5-20 min. The laser irradiation is performed under a mixed gas containing Ar and N2, or Ar and O2. Laser irradiation can convert organosilicon into silicon-based inorganic ceramics (SiO2, SiN). x or SiN x O y (Composite phase).

[0014] As one embodiment of the present invention, the vacuum ultraviolet irradiation for photolysis and condensation refers to placing the thin film in a vacuum ultraviolet irradiation lamp box for irradiation; vacuum degree 10 -4 ~10 -6 mbar, the light source is an Xe2 lamp with a wavelength of 172nm±12nm; the irradiation power density is 20-40mW / cm². 2 The distance between the light source and the sample is 20-30 mm, and the irradiation time is 5-20 min. Photolysis and condensation reactions are carried out in a low-oxygen atmosphere to form Si-Ni-Si or -O-Si-N-Si molecular chains, transforming them into amorphous SiNi. x Or SiN x O y Dielectric layer.

[0015] Vacuum ultraviolet irradiation has better technical effects, possibly because its reaction process occurs uniformly in the bulk phase, resulting in more uniform bond breaking and cross-linking capabilities, making it easier to form uniform nanopores and network structures with better mesoporous continuity and stability.

[0016] In one embodiment of the present invention, the thickness of the dielectric layer is 50-150 nm.

[0017] In one embodiment of the present invention, the substrate material of the first conductive layer is one of fluorine-doped tin oxide (FTO), indium tin oxide (ITO), or aluminum-doped zinc oxide (AZO) glass. The thickness of the first conductive layer is 1-5 mm.

[0018] In one embodiment of the present invention, the electrochromic layer is made of tungsten; the tungsten layer material is one or more of tungsten oxide (WO3) and tungsten oxide derivatives, wherein the tungsten oxide derivatives are element-doped tungsten oxides, and the doping elements include one or more of Ti, Al, and Ni. The thickness of the electrochromic layer is 200-450 nm.

[0019] In one embodiment of the present invention, the thickness of the dielectric layer is 5-200 nm.

[0020] In one embodiment of the present invention, the thickness of the ion storage layer is 100-250 nm.

[0021] In one embodiment of the present invention, the thickness of the second conductive layer is 150-400 nm.

[0022] This invention provides a method for fabricating the electrochromic device containing a porous dielectric layer, comprising the following steps: S1. Prepare an electrochromic layer on the first conductive layer; S2. The organosilicon solution is coated onto the electrochromic layer. After the organosilicon film is dried, it is subjected to laser pyrolysis or vacuum ultraviolet irradiation for photolysis and condensation to obtain a sample substrate containing a dielectric layer. S3. An ion storage layer, a lithium layer, and a second conductive layer are sequentially sputtered onto a sample containing a dielectric layer. Laser scribing and fixing of metal electrodes are then performed to obtain the electrochromic device containing a porous dielectric layer.

[0023] In one embodiment of the present invention, in step S1, the electrochromic layer is prepared by magnetron sputtering deposition.

[0024] In one embodiment of the present invention, in step S2, the obtained sample substrate containing the dielectric layer is purged to remove floating dust. Removing floating dust involves cooling the sample substrate to room temperature and then purging the surface dust with compressed N2 airflow (pressure 0.1-0.2 MPa) to ensure the surface of the dielectric layer is clean.

[0025] In one embodiment of the present invention, in step S3, the sputtered ion storage layer refers to a sputtered NiO thin film, with metallic Ni as the target material, Ar / O2 mixed gas as the working gas, sputtering pressure of 1-1.5 Pa, sputtering power of 150-200 W, substrate temperature of 25-150 °C, deposition thickness of 100-250 nm, and time of 25-40 min.

[0026] In one embodiment of the present invention, in step S3, the ion storage layer is further annealed at a temperature of 150-450°C for 5 minutes to 2 hours. Within the same vacuum chamber, lithium doping can be performed using radio frequency sputtering to ensure that the pre-stored lithium ion quantity meets the color change requirements, followed by an annealing process.

[0027] In one embodiment of the present invention, in step S3, the lithiation layer is obtained by sputtering with a Li metal target in an Ar atmosphere; the sputtering pressure is 0.3-0.5 Pa, the sputtering power is 50-100 W, and the time is 3-20 min.

[0028] In one embodiment of the present invention, in step S3, sputtering the second conductive layer (transparent conductive layer) involves switching the substrate to an ITO target, introducing an Ar / O2 mixed gas with an oxygen content of 0.5-4%, controlling the sputtering power to be 60-200W, and the sputtering time to be 10-15 min, depositing an ITO top layer with a thickness of 150-200nm on the surface of the ion storage layer, and the substrate temperature to be 200-300℃.

[0029] As one embodiment of the present invention, in step S3, the laser scribing refers to electrochromic or leakage current control technology typical of the photovoltaic industry.

[0030] In one embodiment of the present invention, in step S3, the fixed metal electrode refers to the metal main electrode fixed on the upper and lower transparent electrode layers at the edge of the electrochromic device for connecting to the power controller, and the method includes, but is not limited to, pasting or screen printing silver paste and curing.

[0031] Compared with the prior art, the present invention has the following beneficial effects: (1) Innovation in dielectric layer preparation process: This invention is the first to convert polysilazane into loose SiO2 / SiN through atmosphere-controlled combustion. x The dielectric layer utilizes the natural formation of mesoporous structures by the volatilization of organic groups during the ceramicization process of polysilazane, eliminating the need for additional etching templates or pore-forming agents, resulting in a simple and low-cost process.

[0032] (2) The device response speed is significantly improved: loose SiO2 / SiN x The porous structure of the dielectric layer provides abundant transport channels for lithium ions. Combined with the high ion capacity of the lithium-ion storage layer, the device coloring and fading time is significantly shortened, and the response speed is improved.

[0033] (3) Stable device performance: Combined with the annealing process of the ion storage layer, the bonding force between the layers is further improved, and the cycle life is better than that of traditional devices. Attached Figure Description

[0034] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the electrochromic device of the present invention; Figure 2 This is a microscopic morphology diagram of the dielectric layer prepared in Example 1 of the present invention. Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0036] This invention provides a method for preparing a porous electrochromic dielectric layer formed by the pyrolysis of organosilicon, comprising the following steps: (1) A 300-450 nm tungsten oxide layer was deposited by magnetron sputtering on a cleaned ITO glass substrate; (2) Spin-coating a uniform polysilazane film with a thickness of 150-300 nm onto tungsten oxide; spin-coating refers to dissolving polysilazane in a solvent to form a solution with a mass concentration of 5%-10%, stirring for 30 min, preferably to form a uniform film on the substrate material; by controlling the rotation speed and solution concentration, a uniform film with a thickness of 150-300 nm is formed; it also includes other methods such as blade coating or dip coating and pull coating that can form a uniform film; (3) Place on a heating plate for soft baking to remove solvent and increase the adhesion of the substrate layer; soft baking refers to holding the heating plate at 70-100℃ for 3-10 min. (4) The polysilazane film is subjected to laser pyrolysis or vacuum ultraviolet irradiation for photolysis and condensation to form 50-150nm amorphous SiO2. x Or SiN x O y Dielectric layer; The laser pyrolysis described herein specifically refers to laser irradiation (CO2 laser 10.6 μm, 193 / 248 nm UV laser) under a mixture of Ar and N2 or Ar and O2 gas, with a power density of 15-40 mJ / pulse and a repetition frequency of 10-100 Hz, transforming the material into amorphous SiN. x Or SiN x O y Dielectric layer.

[0037] The aforementioned vacuum ultraviolet irradiation for photolysis and condensation refers to placing a substrate coated with a polysilazane film in a vacuum ultraviolet irradiation lamp box with a vacuum degree of 10. -4 mbar, the light source is an Xe2 lamp with a wavelength of 172nm±12nm; the irradiation power density is 20-40mW / cm². 2 The distance between the light source and the sample is 20-30 mm, and the irradiation time is 5-20 min. Photolysis and condensation reactions are carried out in an oxygen or nitrogen-oxygen mixed atmosphere to form Si-O-Si or -O-Si-N-Si molecular chains, transforming them into amorphous SiO₂. x Or SiN x O y Dielectric layer.

[0038] (5) Remove floating dust; (6) Continue sputtering a 150-250 nm ion storage layer, a 20-100 nm lithiation layer, and a 150-200 nm transparent conductive layer; (7) Electrochromic devices with high color change rate obtained by laser scribing and fixing metal electrodes.

[0039] Example 1 This embodiment provides an electrochromic device containing a porous dielectric layer, such as Figure 1 As shown, it includes a first conductive layer, an electrochromic layer, a dielectric layer, an ion storage layer, and a second conductive layer arranged sequentially; its preparation method includes the following steps: 1. Substrate pretreatment: Select 100mm×100mm ITO conductive glass (ITO thickness 2mm), and deposit a WO3 layer using magnetron sputtering: vacuum degree 5×10 -6 Pa, WO3 target, Ar / O2 (volume ratio 6:1), sputtering power 150 W, gas pressure 1 Pa; time 40 min, to form WO3 layer (400 nm), to obtain ITO / WO3 substrate. 2. Clean the substrate sequentially with acetone, ethanol, and deionized water using ultrasonic cleaning for 5 minutes each, and then dry it in a 100°C oven for 30 minutes. 3. Polysilazane spin coating: Polysilazane is mixed with a solvent containing toluene and n-hexane (mass ratio of 1:1) to form a 5% mass concentration solution. The solution is stirred for 30 min to obtain a spin coating liquid. Then, the spin coater is used at a speed of 4000 r / min for 45 s to form a uniform film with a thickness of 200 nm. 4. Soft baking: Place the sample on a heating plate at 85℃ for 5 minutes to remove solvent and cure the substrate; 5. Laser pyrolysis: The sample was placed in an Ar / O2 (volume ratio 4:1) mixed gas and irradiated with a UV laser for 25 min. The UV laser wavelength was 193 nm, the power density was 40 mJ / pulse, and the repetition frequency was 50 Hz. This process transformed the sample into amorphous SiN. x O y The dielectric layer (85 nm thick) has the following microstructure: Figure 2 As shown; 6. After pyrolysis, allow the mixture to cool to room temperature, then purge with nitrogen (0.1 MPa pressure) to remove any floating dust. 7. Place the substrate in a vacuum chamber and continue sputtering the ion storage layer: Place the substrate in a Ni metal target reactive sputtering chamber and perform reactive sputtering using a medium-frequency power supply. The Ar / O2 volume ratio is 1:1; the sputtering pressure is 1.2 Pa; the sputtering power is 150 W; the substrate temperature is 25 °C; the time is 30 min; and the deposition thickness is 155 nm. Then perform annealing treatment (270 °C, 2 h) to obtain the ion storage layer. 8. After the substrate is cooled to 100°C, lithium metal lithiation is performed by Li metal target sputtering in an Ar atmosphere; sputtering pressure is 0.3 Pa, sputtering power is 50 W, and time is 5 min. 9. Sputtering a transparent conductive layer: The substrate is placed in the ITO chamber and sputtered using a DC pulse power supply. The substrate is heated to 300°C and an Ar / O2 mixed gas (O2 volume content 1.83%) is introduced. The sputtering pressure is 0.3 Pa, the power is 100 W, and the time is 15 min to obtain a transparent conductive layer (thickness of 196 nm). 10. Laser scribing and edge clearing: Using laser scribing P1, P2, P3, P4 and edge clearing process, a lower transparent conductive electrode is prepared; an electrochromic device with exposed edges and electrodes separated at the upper and lower edge positions. 11. Fix the main electrode: Apply conductive copper tape to the position where the lower transparent electrode is exposed and the corresponding upper electrode position on the other side.

[0040] 12. Performance testing: The test methods shall be in accordance with the test methods of ASTM E2141-21 and ISO18510:2017 standards.

[0041] Response time: At 3V, coloring time is 14.1s, fading time is 6s; Cycle life: After 5000 cycles of color change, the rate of change in optical transmittance remains at 80%; Transmittance adjustment range: transmittance variation in the visible light region (550nm) is 3%-65%, meeting the needs of smart window use.

[0042] Example 2 This embodiment provides a method for fabricating an electrochromic device containing a porous dielectric layer, comprising the following steps: 1. Substrate pretreatment: Select 150mm×200mm ITO conductive glass (ITO thickness 2mm), and deposit a WO3 layer using magnetron sputtering: vacuum degree 5×10 -6 Pa, WO3 target, Ar / O2 (volume ratio 6:1), sputtering power 150 W, gas pressure 1 Pa; time 40 min, to form WO3 layer (400 nm), to obtain ITO / WO3 substrate. 2. Clean the substrate sequentially with acetone, ethanol, and deionized water using ultrasonic cleaning for 5 minutes each, and then dry it in a 100°C oven for 30 minutes. 3. Polysilazane spin coating: Polysilazane and tetrahydrofuran are mixed to form a 5% (w / w) solution. The mixture is stirred for 30 min to obtain a spin coating solution. Then, a spin coater is used at a speed of 3500 r / min for 45 s to form a uniform film with a thickness of 150 nm. 4. Soft baking: Place the sample on a heating plate at 85℃ for 8 minutes to remove solvent and cure the substrate; 5. Vacuum UV photolysis: The substrate coated with a polysilazane film is placed in a vacuum UV irradiation chamber with a vacuum degree of 10. -4 mbar, the light source is an Xe2 lamp with a wavelength of 172nm±12nm; the irradiation power density is 40mW / cm³. 2 The distance between the light source and the sample was 20 mm, and the irradiation time was 20 min. The sample was placed in an Ar / O2 (volume ratio 3:1) mixed gas environment for photolysis and condensation reactions, forming Si-O-Si-N-Si molecular chains, which were then transformed into SiO2 molecules with a thickness of 68 nm. x N y film; 6. After photolysis, nitrogen gas (pressure 0.1 MPa) is used to purge and remove floating dust; 7. Place the substrate in the vacuum chamber and continue sputtering the ion storage layer: Place the substrate in the Ni metal target reactive sputtering chamber and perform reactive sputtering using a medium frequency power supply. The Ar / O2 volume ratio is 1:1; the sputtering pressure is 1.2 Pa; the sputtering power is 180 W; the substrate temperature is 25 °C; and the time is 25 min. 8. Perform lithium metal lithiation by Li metal target sputtering in an Ar atmosphere; sputtering pressure 0.3 Pa, sputtering power 50 W, time 5 min; 9. Sputtering a transparent conductive layer: The substrate is placed in the ITO chamber and sputtered using a DC pulse power supply. The substrate is heated to 300°C and an Ar / O2 mixed gas (O2 volume content 1.83%) is introduced. The sputtering pressure is 0.3 Pa, the power is 100 W, and the time is 10 min to obtain a transparent conductive layer. 10. Laser scribing and edge clearing: Using laser scribing P1, P2, P3, P4 and edge clearing process, a lower transparent conductive electrode is prepared; an electrochromic device with exposed edges and electrodes separated at the upper and lower edge positions. 11. Fix the main electrode; apply conductive copper tape to the position where the lower transparent electrode is exposed and the corresponding upper electrode position on the other side; 12. Performance testing; the test methods shall be in accordance with the test methods of ASTM E2141-21 and ISO18510:2017 standards.

[0043] Response time: At 3V, coloring time is 4.1s, fading time is 3.2s; Cycle life: After 5000 cycles of color change, the rate of change in optical transmittance retains 85%; Transmittance adjustment range: transmittance variation of 7%-55% in the visible light region (550nm), meeting the needs of smart window use.

[0044] Example 3 This embodiment provides a method for preparing an electrochromic device containing a porous dielectric layer, which is basically the same as that in Embodiment 1, except that the method for preparing the dielectric layer is different.

[0045] A method for preparing a porous electrochromic dielectric layer by pyrolysis of organosilicon includes the following steps: 1. Substrate pretreatment: Select 100mm×100mm ITO conductive glass (ITO thickness 2mm), and deposit a WO3 layer using magnetron sputtering: vacuum degree 5×10 -6 Pa, WO3 target, Ar / O2 (volume ratio 6:1), sputtering power 150 W, gas pressure 1 Pa; time 40 min, to form WO3 layer (400 nm), to obtain ITO / WO3 substrate. 2. Clean the substrate sequentially with acetone, ethanol, and deionized water using ultrasonic cleaning for 5 minutes each, and then dry it in a 100°C oven for 30 minutes.

[0046] 3. Polysilazane spin coating: Polysilazane is mixed with a solvent containing toluene and n-hexane (mass ratio of 1:1) to form a 5% mass concentration solution. The mixture is stirred for 30 min to obtain a spin coating solution. Then, the spin coater is used at a speed of 4000 r / min for 45 s to form a uniform film with a thickness of 200 nm.

[0047] 4. Soft baking: Place the sample on a heating plate at 85℃ for 5 minutes to remove solvent and cure the substrate.

[0048] 5. Vacuum UV photolysis: The substrate coated with a polysilazane film is placed in a vacuum UV irradiation chamber with a vacuum degree of 10.-4 mbar, the light source is an Xe2 lamp with a wavelength of 172nm±12nm; the irradiation power density is 45mW / cm³. 2 The distance between the light source and the sample was 15 mm, and the irradiation time was 25 min. The sample was placed in a mixed gas of Ar / O2 (volume ratio of 3:1) to carry out photolysis and condensation reactions, forming Si-O-Si-N-Si molecular chains, which were then converted into a 90 nm thick dielectric layer.

[0049] 6. After pyrolysis, allow the mixture to cool to room temperature and purge with nitrogen (0.1 MPa pressure) to remove any floating dust.

[0050] 7. Place the substrate in a vacuum chamber and continue sputtering the ion storage layer: Place the substrate in a Ni metal target reactive sputtering chamber and perform reactive sputtering using a medium-frequency power supply. The Ar / O2 volume ratio is 1:1; the sputtering pressure is 1.2 Pa; the sputtering power is 150 W; the substrate temperature is 25 °C; the time is 30 min; and the deposition thickness is 155 nm. Then perform annealing treatment (270 °C, 2 h) to obtain the ion storage layer. 8. After the substrate cools to 80°C, lithium metal lithiation is performed using a Li metal target sputtering atmosphere of Ar; sputtering pressure is 0.3 Pa, sputtering power is 50 W, and time is 5 min. 9. Sputtering a transparent conductive layer: The substrate is placed in the ITO chamber and sputtered using a DC pulse power supply. The substrate is heated to 300°C and an Ar / O2 mixed gas (O2 volume content 1.83%) is introduced. The sputtering pressure is 0.3 Pa, the power is 100 W, and the time is 15 min to obtain a transparent conductive layer (thickness of 196 nm). 10. Laser scribing and edge clearing: Using laser scribing P1, P2, P3, P4 and edge clearing process, a lower transparent conductive electrode is prepared; an electrochromic device with exposed edges and electrodes separated at the upper and lower edge positions. 11. Fix the main electrode: Apply conductive copper tape to the position where the lower transparent electrode is exposed and the corresponding upper electrode position on the other side.

[0051] 12. Performance testing: The test methods shall be in accordance with the test methods of ASTM E2141-21 and ISO18510:2017 standards.

[0052] Response time: At 3V, coloring time is 4.6s, fading time is 3.5s; Cycle life: After 5000 cycles of color change, the rate of change in optical transmittance remains at 87%; Transmittance adjustment range: transmittance variation in the visible light region (550nm) is 4%-58%, meeting the needs of smart window use.

[0053] Comparative Example 1 This comparative example provides a method for fabricating an electrochromic device containing a dielectric layer, which is basically the same as that in Example 1, except that the dielectric layer is prepared by a different method, using conventional vapor deposition: magnetron sputtering, to prepare a dielectric layer of the same thickness.

[0054] step: 1. Substrate pretreatment: Select 100mm×100mm ITO conductive glass (ITO thickness 2mm), and deposit a WO3 layer using magnetron sputtering: vacuum degree 5×10 - 6 Pa, WO3 target, Ar / O2 (volume ratio 6:1), sputtering power 150 W, gas pressure 1 Pa; time 40 min, to form WO3 layer (400 nm), to obtain ITO / WO3 substrate; 2. Clean the substrate sequentially with acetone, ethanol, and deionized water using ultrasonic cleaning for 5 minutes each, and then dry it in a 100°C oven for 30 minutes.

[0055] 3. Preparation of SiO by magnetron sputtering X N y The dielectric layer uses SiAl (atomic ratio 9:1) as the target material and Ar / O. 2 / N2 (volume ratio 30:1:10) sputtering power 100 W, gas pressure 1.3 Pa; time 10 min, forming 85 nm thick SiO2. x N y Thin film (with a composition substantially the same as that of the dielectric layer in Example 1).

[0056] 4. Place the substrate in a vacuum chamber and continue sputtering the ion storage layer: Place the substrate in a Ni metal target reactive sputtering chamber and perform reactive sputtering using a medium-frequency power supply. The Ar / O2 volume ratio is 1:1; the sputtering pressure is 1.2 Pa; the sputtering power is 150 W; the substrate temperature is 25 °C; the time is 30 min; and the deposition thickness is 155 nm. Then perform annealing treatment (270 °C, 2 h) to obtain the ion storage layer. 5. After the substrate is cooled to 120°C, lithium metal lithiation is performed by Li metal target sputtering in an Ar atmosphere; sputtering pressure is 0.3 Pa, sputtering power is 50 W, and time is 5 min. 6. Sputtering a transparent conductive layer: The substrate is placed in the ITO chamber and sputtered using a DC pulse power supply. The substrate is heated to 300°C and an Ar / O2 mixed gas (O2 volume content 1.83%) is introduced. The sputtering pressure is 0.3 Pa, the power is 100 W, and the time is 15 min to obtain a transparent conductive layer (thickness of 196 nm). 7. Laser scribing and edge clearing: Using laser scribing P1, P2, P3, P4 and edge clearing process, a lower transparent conductive electrode is prepared; an electrochromic device with exposed edges and electrodes separated at the upper and lower edge positions; 8. Fix the main electrode: Apply conductive copper tape to the position where the lower transparent electrode is exposed and the corresponding upper electrode position on the other side.

[0057] 9. Performance testing: The test methods shall be in accordance with the test methods of ASTM E2141-21 and ISO18510:2017 standards.

[0058] Response time: At 3V voltage, coloring time is 40s, fading time is 25s; Cycle life: After 5000 cycles of color change, the rate of change in optical transmittance is maintained at 75%.

[0059] Comparative Example 2 This comparative example provides a method for preparing an electrochromic device containing a dielectric layer, which is basically the same as that in Example 1, except that polysilazane is replaced with polyaluminosilicate to prepare a dielectric layer of the same thickness.

[0060] Response time: At 3V, coloring time is 16 s, fading time is 9 s; Cycle life: After 5000 cycles of color change, the optical transmittance change rate is maintained at 82%.

[0061] Comparative Example 3 This comparative example provides a method for preparing an electrochromic device containing a dielectric layer, which is basically the same as that in Example 1, except that polysilazane is replaced with polyborosilazane to prepare a dielectric layer of the same thickness.

[0062] Response time: At 3V, coloring time is 18 s, fading time is 12 s; Cycle life: After 5000 cycles of color change, the rate of change in optical transmittance remains at 80%.

[0063] Comparative Example 4 This comparative example provides a method for preparing an electrochromic device containing a dielectric layer, which is basically the same as that in Example 1, except that polysilazane is replaced with polydimethylsiloxane to prepare a SiO2 dielectric layer of the same thickness.

[0064] Response time: At 3V, coloring time is 20 s, fading time is 15 s; Cycle life: After 5000 cycles of color change, the rate of change in optical transmittance is maintained at 85%.

[0065] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. An electrochromic device containing a porous dielectric layer, characterized in that, It includes a first conductive layer, an electrochromic layer, a dielectric layer, an ion storage layer, a lithiation layer, and a second conductive layer; The dielectric layer is obtained by coating an organosilicon solution onto an electrochromic layer, drying the resulting organosilicon film, and then performing laser pyrolysis or vacuum ultraviolet irradiation for photolysis and condensation. The organosilicon is a polysilazane; Laser pyrolysis or vacuum ultraviolet irradiation for photolysis and condensation converts organosilicon thin films into silicon-based inorganic ceramics, yielding SiO₂. x or SiN x O y The dielectric layer has an inorganic mesoporous network amorphous structure.

2. The electrochromic device containing a porous dielectric layer according to claim 1, characterized in that, The mass fraction of the organosilicon solution is 5%-10%; And / or, the solvent for the organosilicon solution includes one or more of toluene, xylene, n-hexane, and tetrahydrofuran.

3. The electrochromic device containing a porous dielectric layer according to claim 1, characterized in that, The thickness of the obtained organosilicon film is 150-300 nm.

4. The electrochromic device containing a porous dielectric layer according to claim 1, characterized in that, The laser pyrolysis involves irradiating the thin film with a laser, either a CO2 laser or a UV laser. The power density is 15-40 mJ / pulse, the repetition frequency is 10-100 Hz, and the irradiation time is 5-20 min.

5. The electrochromic device containing a porous dielectric layer according to claim 1, characterized in that, The aforementioned vacuum ultraviolet irradiation for photolysis and condensation refers to placing the thin film in a vacuum ultraviolet irradiation lamp box for irradiation; Irradiation power density 20-40 mW / cm 2 Irradiation time: 5-20 min.

6. The electrochromic device containing a porous dielectric layer according to claim 1, characterized in that, The thickness of the dielectric layer is 50-150 nm.

7. The electrochromic device containing a porous dielectric layer according to claim 1, characterized in that, The substrate material of the first conductive layer is one of fluorine-doped tin oxide, indium tin oxide, or aluminum-doped zinc oxide glass. And / or, the electrochromic layer is made of tungsten material; the tungsten material is one or more of tungsten oxide and tungsten oxide derivatives, and the tungsten oxide derivatives are element-doped tungsten oxides, with the doping elements including one or more of Ti, Al, and Ni.

8. The electrochromic device containing a porous dielectric layer according to claim 1, characterized in that, The thickness of the first conductive layer is 120-500 nm; And / or, the thickness of the electrochromic layer is 200-450 nm; And / or, the thickness of the dielectric layer is 5-200 nm; And / or, the thickness of the ion storage layer is 100-250 nm; And / or, the thickness of the second conductive layer is 150-400 nm.

9. A method for preparing an electrochromic device as described in claim 1, characterized in that, Includes the following steps: S1. Prepare an electrochromic layer on the first conductive layer; S2. The organosilicon solution is coated on the electrochromic layer. After the film is dried, it is subjected to laser pyrolysis or vacuum ultraviolet irradiation for photolysis and condensation to obtain a sample substrate containing a dielectric layer. S3. The sample containing the dielectric layer is further sputtered with an ion storage layer, a lithiation layer, and a second conductive layer, laser scribing is performed, and a metal electrode is fixed to obtain the electrochromic device containing the porous dielectric layer.

10. The preparation method according to claim 9, characterized in that, In step S1, the electrochromic layer is prepared by magnetron sputtering deposition. And / or, in step S3, the sputtered ion storage layer refers to a sputtered NiO thin film, with metallic Ni as the target material, Ar / O2 mixed gas as the working gas, sputtering pressure of 1-1.5 Pa, sputtering power of 150-200 W, substrate temperature of 25-150 °C, deposition thickness of 100-250 nm, and time of 25-40 min; And / or, in step S3, the lithiation layer is obtained by sputtering with a Li metal target in an Ar atmosphere; the sputtering pressure is 0.3-0.5 Pa, the sputtering power is 50-100 W, and the time is 3-20 min. And / or, in step S3, sputtering the second conductive layer involves switching to an ITO target, introducing an Ar / O2 mixed gas with an oxygen content of 0.5-4%, controlling the sputtering power to be 60-200W, and the sputtering time to be 10-15 min, depositing an ITO top layer with a thickness of 150-200nm on the surface of the ion storage layer, and the substrate temperature to be 200-300℃.

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