Electrochromic device and preparation method thereof

Abstract

The invention relates to the technical field of electrochromism, in particular to an electrochromism device which comprises a perovskite battery and an electrochromism device which are arranged in a stacked mode. The perovskite cell comprises a bottom electrode layer, an electron transport layer, a perovskite layer, a hole transport layer and a top electrode layer which are stacked in sequence. The electrochromic device comprises a top electrode layer, an electrochromic layer, an electrolyte layer and a counter electrode layer which are sequentially arranged in a stacked mode. The top electrode layer is a common transparent electrode of the perovskite cell and the electrochromic device, and the bottom electrode layer and the counter electrode layer are electrically connected through an on-off element; the open-circuit voltage of the perovskite cell is greater than the color-changing voltage of the electrochromic device. According to the electrochromic device, integration of the perovskite battery and the electrochromic device is achieved, color changing can be achieved under the condition that the electrochromic device is not connected with an external power source, self-power-supply and self-driving are achieved, and portable scene application is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochromic technology, in particular to an electrochromic device and a preparation method thereof. BACKGROUND

[0002] The color changing ability of the electrochromic device mainly depends on the electrochromic material. Under the action of an applied current or electric field, external ions are injected or extracted in the electrochromic material, so that the electrochromic material undergoes a reversible redox reaction, thereby causing the optical properties (including reflectivity, absorptivity and transmissivity) of the electrochromic material to change, and reversibly changing the appearance in color and transparency.

[0003] However, the coloring process of the electrochromic device needs to be driven by electric energy, so the electrochromic device needs to be connected to an external power source, which limits the application in portable scenarios. SUMMARY

[0004] Therefore, the present application provides an electrochromic device and a preparation method thereof to reduce the dependence of the electrochromic device on an external power source.

[0005] In a first aspect, the present application provides an electrochromic device, comprising a perovskite battery and an electrochromic device which are stacked; the perovskite battery comprises a bottom electrode layer, an electron transport layer, a perovskite layer, a hole transport layer and a top electrode layer which are sequentially stacked; the electrochromic device comprises the top electrode layer, an electrochromic layer, an electrolyte layer and a counter electrode layer which are sequentially stacked; the top electrode layer is a common transparent electrode of the perovskite battery and the electrochromic device, and the bottom electrode layer and the counter electrode layer are electrically connected through a on-off element; the open circuit voltage of the perovskite battery is greater than the color changing voltage of the electrochromic device.

[0006] In some optional embodiments, the difference between the open circuit voltage of the perovskite battery and the color changing voltage of the electrochromic device is 0.1V-0.6V.

[0007] In some optional embodiments, the open circuit voltage of the perovskite battery is 1.1V-1.3V.

[0008] In some optional embodiments, the color changing voltage of the electrochromic device is 0.5V-1.0V.

[0009] In some optional embodiments, the perovskite layer comprises a perovskite material, and the band gap of the perovskite material is 1.20ev-2.30ev.

[0010] In some optional embodiments, the perovskite material comprises FA 0.85 MA 0.15one or more of PbI3, CsPbBr3, FAPbI3.

[0011] In some alternative embodiments, the perovskite layer further comprises carbon quantum dots doped in the perovskite material.

[0012] In some alternative embodiments, the electrochromic layer comprises a metal oxide.

[0013] In some alternative embodiments, the material of the metal oxide comprises one or more of tungsten oxide, nickel oxide.

[0014] In some alternative embodiments, the electrochromic device further comprises a blocking layer between the top electrode layer and the electrochromic layer, the blocking layer comprising a crystalline solid electrolyte, the crystalline solid electrolyte having a minimum cross-sectional dimension of a lattice channel of 0.08 nm to 1.12 nm.

[0015] In some alternative embodiments, the crystalline solid electrolyte has a lithium ion conductivity greater than 10 -5 S / cm at room temperature.

[0016] In some alternative embodiments, the crystalline solid electrolyte has an electronic conductivity less than 10 - 10 S / cm at room temperature.

[0017] In some alternative embodiments, the crystalline solid electrolyte has a lithium ion transference number greater than or equal to 0.98 and less than 1.

[0018] In some alternative embodiments, the material of the crystalline solid electrolyte comprises LiAlO2.

[0019] In some alternative embodiments, the blocking layer further comprises metal oxide particles doped in the crystalline solid electrolyte, the mass fraction of the metal oxide particles in the blocking layer being 8 wt% to 12 wt%.

[0020] In some alternative embodiments, the metal oxide particles have a particle size of 1 nm to 5 nm.

[0021] In some alternative embodiments, the material of the metal oxide particles comprises one or more of aluminum oxide, zirconium oxide, silicon dioxide, titanium dioxide, magnesium oxide.

[0022] In some alternative embodiments, the blocking layer has a thickness of 3 nm to 100 nm.

[0023] In some alternative embodiments, the perovskite cell further comprises a substrate on a side of the bottom electrode layer facing away from the electron transport layer, and the substrate comprises a flexible substrate.

[0024] In some alternative embodiments, the electrochromic device further comprises an encapsulation layer covering the side of the counter electrode layer, the side of the perovskite cell, and the side of the electrochromic device.

[0025] In some alternative embodiments, the side of the bottom electrode layer facing away from the electron transport layer is a light-receiving side of the electrochromic device.

[0026] In some alternative embodiments, the side of the bottom electrode layer facing away from the electron transport layer is a light-receiving side of the electrochromic device.

[0027] In some alternative embodiments, the preparation method further comprises: depositing a barrier layer on a surface of a side of the top electrode layer facing away from the hole transport layer, the barrier layer comprising a crystalline solid electrolyte, a minimum cross-sectional dimension of a lattice channel of the crystalline solid electrolyte being 0.08 nm-1.12 nm, and the electrochromic layer being deposited on a surface of a side of the barrier layer facing away from the top electrode layer.

[0028] In some alternative embodiments, the process of depositing the barrier layer on the surface of the side of the top electrode layer facing away from the hole transport layer comprises an atomic layer deposition process.

[0029] In some alternative embodiments, the barrier layer further comprises metal oxide particles doped in the crystalline solid electrolyte. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the specific embodiments or the related art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the related art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0031] Figure 1 is a structural schematic diagram of an electrochromic device according to an embodiment of the present application; Figure 2 is a structural schematic diagram of an electrochromic device according to an embodiment of the present application.

[0032] Explanation of reference signs: 1 - perovskite cell; 11 - bottom electrode layer; 12 - electron transport layer; 13 - perovskite layer; 14 - hole transport layer; 15 - top electrode layer; 2 - electrochromic device; 21 - barrier layer; 22 - electrochromic layer; 23 - electrolyte layer; 24 - counter electrode layer; 3 - on-off element; 4 - encapsulation layer; 5 - substrate. DETAILED DESCRIPTION

[0033] The application will be further described below in conjunction with the drawings and embodiments. It can be understood that the embodiments described herein are only used to explain the application, but not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings, but not all the structures.

[0034] REFERENCE Figure 1 In a first aspect, the application provides an electrochromic device, comprising a perovskite cell 1 and an electrochromic device 2 which are stacked; the perovskite cell 1 comprises a bottom electrode layer 11, an electron transport layer 12, a perovskite layer 13, a hole transport layer 14 and a top electrode layer 15 which are stacked in sequence; the electrochromic device 2 comprises the top electrode layer 15, an electrochromic layer 22, an electrolyte layer 23 and a counter electrode layer 24 which are stacked in sequence; the top electrode layer 15 is a common transparent electrode of the perovskite cell 1 and the electrochromic device 2, the bottom electrode layer 11 and the counter electrode layer 24 are electrically connected through an on-off element 3; the open circuit voltage of the perovskite cell 1 is greater than the color voltage of the electrochromic device 2.

[0035] The perovskite cell 1 can convert the solar energy irradiated thereon into electrical energy, wherein the electrons generated by the perovskite layer 13 are transmitted to the bottom electrode layer 11 through the electron transport layer 12, and the holes generated by the perovskite layer 13 are transmitted to the top electrode layer 15 through the hole transport layer 14. The on-off element 3 is adapted to control the on-off of the current from the bottom electrode layer 11 to the counter electrode layer 24, thereby controlling the transmission of the electrons of the bottom electrode layer 11 to the counter electrode layer 24.

[0036] When the on-off element 3 is in the on state, the electrons of the bottom electrode layer 11 are transmitted to the counter electrode layer 24 through the on-off element 3, the potential of the counter electrode layer 24 is lower than that of the top electrode layer 15, and an electric field from the top electrode layer 15 to the counter electrode layer 24 is formed in the electrochromic device 2. Since the open-circuit voltage of the perovskite battery 1 is greater than the color-changing voltage of the electrochromic device 2, the electrochromic layer 22 can be colored and maintained in the colored state under the action of the electric field, that is, the unidirectional photovoltage of the perovskite battery 1 can drive the electrochromic layer 22 to be colored; when the on-off element 3 is in the off state, the electrochromic layer 22 is bleached and maintained in the bleached state. It can be seen that the electrochromic device realizes the integration of the perovskite battery 1 and the electrochromic device 2, and can realize color changing without connecting an external power supply, realizing self-power supply and self-driving, which is beneficial to portable scene application. Since the above-mentioned electrochromic device can realize bleaching without relying on the reverse of voltage or electric field, it is not necessary to set a bidirectional power supply, thereby reducing the complexity of the circuit in the electrochromic device, and having the advantages of simplified structure and low energy consumption. In addition, the above-mentioned electrochromic device can realize self-powered unidirectional driving, the lithium ions of the electrolyte layer 23 can migrate to the electrochromic layer 22 to color the electrochromic layer 22, and the electrochromic layer 22 has sufficient lithium ion capacity, so it is not necessary to additionally set an ion storage layer, thereby simplifying the structure of the electrochromic device.

[0037] It should be noted that the two film layers arranged in sequence can be adjacent or can be spaced apart by other functional layers.

[0038] In some optional embodiments, the difference between the open-circuit voltage of the perovskite battery 1 and the color-changing voltage of the electrochromic device 2 can be 0.1V-0.6V, such as 0.1V, 0.2V, 0.3V, 0.4V, 0.5V, 0.6V, or a range formed by any of the above values. By limiting the range of the difference between the above voltages, the perovskite battery 1 and the electrochromic device 2 have a higher point matching degree, which is beneficial to the full use of the electric energy generated by the perovskite battery 1.

[0039] In some optional embodiments, the open-circuit voltage of the perovskite battery 1 can be 1.1V-1.3V, such as 1.1V, 1.15V, 1.2V, 1.25V, 1.3V, or a range formed by any of the above values. The open-circuit voltage of the perovskite battery 1 is affected by the overall device structure of the perovskite battery 1, such as the material of the perovskite layer 13, the material of the electron transport layer 12, and the material of the hole transport layer 14, etc., wherein the material of the perovskite layer 13 is the main influencing factor.

[0040] Specifically, the perovskite layer 13 comprises a perovskite material, the band gap of the perovskite material is 1.20ev-2.30ev, such as 1.20ev, 1.30ev, 1.40ev, 1.50ev, 1.52ev, 1.54ev, 1.56ev, 1.58ev, 1.60ev, 1.70ev, 1.80ev, 1.90ev, 2.00ev, 2.10ev, 2.20ev, 2.30ev, or a range consisting of any of the above values. For example, the perovskite material is a three-dimensional perovskite material, the general structure of the three-dimensional perovskite material is ABX3, A is a monovalent cation, B is a divalent cation, and X is a halogen ion, wherein A includes but is not limited to one or more of a methylamino group (MA + ), a formamidinium group (FA + ) or a cesium ion (Cs + ), and B includes but is not limited to one or more of Pb 2+ , Sn 2+ . The three-dimensional perovskite material includes but is not limited to one or more of FA 0.85 MA 0.15 PbI3, CsPbBr3, FAPbI3; the thickness of the perovskite layer 13 can be 50nm-600nm. The greater the band gap of the perovskite material, the greater the thickness of the perovskite layer 13, so as to control the light transmittance of the perovskite solar cell 1.

[0041] Preferably, the perovskite layer 13 further comprises carbon quantum dots doped in the perovskite material, the carbon quantum dots can passivate perovskite grain boundary defects, which is conducive to improving the open-circuit voltage of the perovskite solar cell 1, and can also improve the absorption capacity of the perovskite layer 13 to external light by using the scattering effect, thereby improving the photoelectric conversion efficiency of the perovskite solar cell 1.

[0042] The material of the electron transport layer 12 includes but is not limited to one or more of titanium dioxide, tin oxide or zinc oxide, and the thickness can be 20nm-40nm; the material of the hole transport layer 14 includes but is not limited to Spiro-OMeTAD, and the thickness can be 100nm-150nm.

[0043] The material of the bottom electrode layer 11 can be a transparent conductive oxide (TCO), and the material of the top electrode layer 15 can be a transparent conductive oxide (TCO), the sheet resistance of the TCO layer is less than or equal to 20Ω / □, and the transparent conductive oxide includes but is not limited to fluorine-doped tin oxide (FTO), indium tin oxide (ITO) or aluminum-doped zinc oxide (AZO).

[0044] In some optional embodiments, the color-changing voltage of the electrochromic device 2 can be 0.5 V-1.0 V, such as 0.5 V, 0.6 V, 0.7 V, 0.8 V, 0.9 V, 1.0 V, or the like, or a range defined by any of the foregoing. The color-changing voltage of the electrochromic device 2 is the color-changing voltage of the electrochromic layer 22.

[0045] Specifically, the material of the electrochromic layer 22 includes but is not limited to metal oxides, which include one or more of tungsten oxide, nickel oxide. The thickness of the electrochromic layer 22 can be 40 nm-60 nm.

[0046] The material of the electrolyte layer 23 is a solid-state electrolyte, and the thickness can be 15 μm-25 μm.

[0047] The material of the counter electrode is a graphene / ITO hybrid material, and the sheet resistance is less than or equal to 15 Ω / □.

[0048] Reference Figure 2 In some optional embodiments, the electrochromic device 2 can further include a barrier layer 21 between the top electrode layer 15 and the electrochromic layer 22, and the barrier layer 21 includes a crystalline solid electrolyte, and the minimum cross-sectional dimension of the lattice channel of the crystalline solid electrolyte is 0.08 nm-1.12 nm, such as 0.08 nm, 0.1 nm, 0.2 nm, 0.3 nm, 0.4 nm, 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, 1.0 nm, 1.1 nm, 1.12 nm, or the like, or a range defined by any of the foregoing.

[0049] Metal cations and / or halogen ions in the perovskite layer 13 are prone to migrate out of the perovskite lattice and into other functional layers. If the metal cations and / or halogen ions migrate into the electrochromic device 2, the metal cations and / or halogen ions can cause interface side reactions with the electrolyte layer 23, and the disordered migration of ions can hinder the directional driving of the electric field in the electrochromic layer 22, thereby causing the color-changing response time of the electrochromic layer 22 to be prolonged, and further causing the light modulation response to be delayed (more than 100 ms). The minimum cross-sectional dimension of the lattice channel of the crystalline solid electrolyte in the barrier layer 21 is 0.08 nm-1.12 nm, which makes the barrier layer 21 have ion selectivity, while the size (I - 2 + ​The radius of Li+is about 0.119 nm, which is greater than the minimum cross-sectional dimension of the lattice channel of the crystalline solid electrolyte, so it cannot pass through the barrier layer 21, thereby avoiding its adverse effects on the color change response time of the electrochromic layer 22, and facilitating the shortening of the dimming response time. At the same time, the ion selectivity of the barrier layer 21 does not affect the voltage application of the electrochromic layer 22, so it will not affect the normal dimming of the electrochromic device 2. In addition, Li + located in the lattice site of the crystalline solid electrolyte, i.e. in a non-free state, will not diffuse into the functional layer of the perovskite battery 1, and will not affect the normal operation of the perovskite battery 1.

[0050] Li + The radius of Li+is about 0.076 nm, and the radius of Li+is about 0.076 nm. + The size of Li+is smaller than the minimum cross-sectional dimension of the lattice channel of the crystalline solid electrolyte in the barrier layer 21, so the Li+in the electrolyte layer 23 + can pass through the barrier layer 21, and the solid electrolyte generally has a high Li + mobility, which is conducive to eliminating competitive ion exchange and accelerating the transmission of Li + +. Specifically, the lithium ion mobility of the crystalline solid electrolyte can be greater than or equal to 0.98 and less than 1.

[0051] The crystalline solid electrolyte has a high lithium ion conductivity and a low electronic conductivity. Specifically, the lithium ion conductivity of the crystalline solid electrolyte at room temperature can be greater than 10 -5 S / cm, and the electronic conductivity at room temperature can be less than 10 -10 S / cm. The material of the crystalline solid electrolyte includes but is not limited to LiAlO2.

[0052] In some optional embodiments, the barrier layer 21 can also include metal oxide particles doped in the crystalline solid electrolyte, and the mass fraction of the metal oxide particles in the barrier layer 21 can be 8wt%-12wt%, such as 8wt%, 8.5wt%, 9wt%, 9.5wt%, 10wt%, 10.5wt%, 11wt%, 11.5wt%, 12wt%, etc., or a range consisting of any of the above values. The metal oxide particles can inhibit the growth of the grain boundary of the crystalline solid electrolyte, which is conducive to increasing the phase transition temperature of the barrier layer 21, slowing down the high-temperature crystallization of the barrier layer 21, and thereby improving the thermal stability of the electrochromic device.

[0053] The material of the metal oxide particles includes but is not limited to one or more of aluminum oxide, zirconium oxide, silicon dioxide, titanium dioxide, and magnesium oxide. The particle size of the metal oxide particles can be 1nm-5nm, such as 1nm, 2nm, 3nm, 4nm, 5nm, etc., or a range consisting of any of the above values.

[0054] The thickness of the barrier layer 21 can be 3 nm-100 nm, such as 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, etc., or a range consisting of any of the above values. The thickness of the barrier layer 21 can be less than or equal to 10 nm to be compatible with a flexible electrochromic device.

[0055] In some optional embodiments, the perovskite cell 1 further comprises a substrate 5 on the side of the bottom electrode layer 11 away from the electron transport layer 12, which can be a flexible substrate to make the electrochromic device have a certain bending ability. The flexible substrate includes but is not limited to a polyethylene terephthalate (PET) film, a polyethylene naphthalate (PEN) film, a polyimide (PI) film, and the thickness of the flexible substrate can be 10 μm-200 μm. The substrate 5 can also be a rigid substrate such as glass.

[0056] In some optional embodiments, the electrochromic device further comprises an encapsulation layer 4 covering the counter electrode layer 24, and the side of the perovskite cell 1 and the side of the electrochromic device 2, to protect the electrochromic device 2 and the perovskite cell 1, avoid the intrusion of external water and oxygen into the perovskite cell 1 to cause the perovskite cell 1 to fail, and improve the stability of the electrochromic device. The material of the encapsulation layer 4 includes but is not limited to a cured resin such as ultraviolet-cured fluororubber. The thickness of the encapsulation layer 4 above the counter electrode layer 24 can be 5 μm-100 μm.

[0057] The bottom electrode layer 11 is connected to the on-off element 3 through a lead wire, and the lead wire penetrates the encapsulation layer 4 on the side of the perovskite cell 1. The counter electrode layer 24 is connected to the on-off element 3 through a lead wire, and the lead wire penetrates the encapsulation layer 4 on the side of the electrochromic device 2.

[0058] The on-off element 3 can be a mechanical switch, a MOSFET, or a light-controlled switch, for controlling the on-off of the loop to realize manual or automatic dimming.

[0059] In some optional embodiments, the side of the bottom electrode layer 11 away from the electron transport layer 12 is the light-receiving side of the electrochromic device. That is, external light irradiates the perovskite layer 13 after passing through the bottom electrode and the electron transport layer 12.

[0060] In a second aspect, the present application provides a preparation method of the electrochromic device, for preparing the electrochromic device of the first aspect, the preparation method comprising: sequentially depositing an electrochromic layer 22, an electrolyte layer 23 and a counter electrode layer 24 on the surface of the top electrode layer 15 of the perovskite cell 1. It should be noted that the features (such as materials and thicknesses, etc.) and effects described for the electrochromic device also apply to the preparation method of the electrochromic device, which will not be repeated here.

[0061] The preparation method of the electrochromic device will be described in detail below.

[0062] Step S1, forming a bottom electrode layer 11 on the surface of the substrate 5. A transparent metal oxide can be deposited on the surface of the substrate 5 by a vapor deposition process to form the bottom electrode layer 11. The vapor deposition process includes a chemical vapor deposition process or a physical vapor deposition process (such as a vacuum evaporation process or a magnetron sputtering process).

[0063] Step S2, forming an electron transport layer 12 on one side of the bottom electrode layer 11. Specifically, the electron transport layer 12 can be formed on the side surface of the bottom electrode layer 11 away from the bottom electrode layer 11, and the process of forming the electron transport layer 12 includes but is not limited to a spin coating process, a doctor blade coating process, or a vapor deposition process. For example, SnO2 precursor solution can be spin-coated on the surface of the bottom electrode layer 11, and after annealing, an SnO2 layer is obtained. The concentration of SnO2 nanocrystals in the SnO2 precursor solution can be 15 mg / mL-50 mg / mL, the annealing temperature is 25℃-180℃, and the annealing time is 10 min-90 min.

[0064] Step S3, forming a perovskite layer 13 on the side surface of the electron transport layer 12 away from the substrate 5. The step of forming the perovskite layer 13 on the side surface of the electron transport layer 12 away from the substrate 5 can include: Step S31, preparing a perovskite precursor solution.

[0065] Specifically, BX2 and AX are dissolved in a solvent or a perovskite single crystal is dissolved in a solvent to obtain a perovskite precursor solution, A is a monovalent cation, B is a divalent cation, and X is a halogen ion; the concentration of perovskite in the perovskite precursor solution is 1 mol / L-1.5 mol / L, such as 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, etc., or a range consisting of any of the above values. The solvent of the perovskite precursor solution can be a DMF / DMSO mixed solvent, wherein the volume ratio of DMF (N,N-dimethylformamide) to DMSO (dimethyl sulfoxide) can be (3-5):1.

[0066] In some preferred embodiments, the perovskite precursor solution further contains carbon quantum dots, and the mass fraction of the carbon quantum dots in the perovskite precursor solution can be 1.5wt%-2.5wt%, such as 1.5wt%, 1.75wt%, 2.0wt%, 2.25wt%, 2.5wt%, or a range defined by any of the above values. By limiting the mass fraction of the carbon quantum dots to the above range, the photoelectric conversion capability of the perovskite layer 13 is not affected by the excessive content of the carbon quantum dots, and the open-circuit voltage of the perovskite battery 1 is effectively improved.

[0067] Step S32, coating the perovskite precursor solution on the side surface of the electron transport layer 12 away from the substrate 5 to obtain a perovskite liquid film.

[0068] The perovskite precursor solution can be coated by processes such as spin coating, blade coating, slot coating, etc. The concentration of the perovskite precursor solution can be adjusted according to the type of process.

[0069] For example, the coating step of the spin coating process includes: after the perovskite precursor solution is dropped on the electron transport layer 12, the substrate 5 is rotated at a speed of 3000rpm-6000rpm, and the anti-solvent is dropped on the surface of the rotating film layer at the 20th-25th second of rotation, and the total rotation time is 35s-40s. The anti-solvent includes but is not limited to ethyl acetate and chlorobenzene.

[0070] When the perovskite precursor solution is coated by the blade coating process, the blade coating speed can be 10mm / s-20mm / s, such as 10mm / s, 11mm / s, 12mm / s, 13mm / s, 14mm / s, 15mm / s, 16mm / s, 17mm / s, 18mm / s, 19mm / s, 20mm / s, etc. After the blade coating is completed, the perovskite liquid film is blown by a nitrogen gun until the film layer becomes brownish yellow, or a vacuum flash method is used to assist film formation to remove the solvent in the perovskite liquid film to a large extent.

[0071] Step S33, annealing the perovskite liquid film to obtain a solid perovskite layer 13. The annealing temperature can be 100℃-150℃, such as 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, and the time can be 10min-20min, such as 10min, 15min, 20min.

[0072] Step S4, a hole transport layer 14 is formed on the side of the perovskite layer 13 away from the substrate 5. Specifically, the hole transport layer 14 can be formed on the side surface of the perovskite layer 13 away from the substrate 5, and the process of forming the hole transport layer 14 includes but is not limited to a spin coating process, a doctor blade coating process, a vapor deposition process, the vapor deposition process including a chemical vapor deposition process or a physical vapor deposition process (such as a vacuum evaporation process, a magnetron sputtering process). For example, a Spiro-OMeTAD solution can be spin-coated on the surface of the perovskite layer 13, and the hole transport layer 14 can be obtained after annealing.

[0073] Step S5, a top electrode layer 15 is formed on the side surface of the hole transport layer 14 away from the substrate 5. Specifically, the method of forming the top electrode layer 15 includes but is not limited to a vacuum evaporation method.

[0074] Step S6, an electrochromic layer 22 is formed on the side of the top electrode layer 15 away from the substrate 5. The process of forming the electrochromic layer 22 includes but is not limited to a spin coating process, a doctor blade coating process, a vapor deposition process, the vapor deposition process including a chemical vapor deposition process or a physical vapor deposition process (such as a vacuum evaporation process, a magnetron sputtering process).

[0075] Step S7, an electrolyte layer 23 is formed on the side surface of the electrochromic layer 22 away from the substrate 5. The electrolyte layer 23 can be formed by using an electrolyte solution containing a LiClO4-PC system, and the concentration of the electrolyte salt in the electrolyte solution is 0.5 mol / L-1.5 mol / L.

[0076] Step S8, a counter electrode layer 24 is formed on the side surface of the electrolyte layer 23 away from the substrate 5. Specifically, the method of forming the counter electrode layer 24 includes but is not limited to a magnetron sputtering process.

[0077] Step S9, a packaging layer 4 covering the counter electrode layer 24, the side of the perovskite battery 1 and the side of the electrochromic device 2 is formed. For example, a solidified resin can be coated on the surface of the counter electrode layer 24, the side of the perovskite battery 1 and the side of the electrochromic device 2, and the packaging layer 4 can be obtained by solidifying the above-mentioned solidified resin. The solidification mode of the ultraviolet solidified resin is ultraviolet light irradiation.

[0078] In some optional embodiments, the preparation method further includes: Step S55, a barrier layer 21 is deposited on the side surface of the top electrode layer 15 away from the hole transport layer 14, the barrier layer 21 includes a crystalline solid electrolyte, the minimum cross-sectional dimension of the lattice channel of the crystalline solid electrolyte is 0.08 nm-1.12 nm, and the electrochromic layer 22 is deposited on the side surface of the barrier layer 21 away from the top electrode layer 15.

[0079] Preferably, the barrier layer 21 further comprises metal oxide particles doped in the crystalline solid electrolyte.

[0080] The process of depositing the barrier layer 21 includes but is not limited to an atomic layer deposition process, which results in a dense and pore-free barrier layer 21 capable of physically blocking ion diffusion.

[0081] The embodiments of the technical solutions of the present application are described in detail below. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, but cannot limit the protection scope of the present application.

[0082] Embodiment 1 The present embodiment provides an electrochromic device, and a preparation method thereof includes the following steps: 1. Preparation of perovskite battery: An ITO layer with a sheet resistance of 7.5 Ω / □ is deposited on one side of the PI film by a magnetron sputtering process; A SnO2 precursor solution is spin-coated on the surface of the bottom electrode layer, the concentration of SnO2 nanocrystals in the SnO2 precursor solution is 25 mg / mL, and the thickness of the SnO2 layer is 30 nm after annealing at 80°C for 30 min; MAI, FAI, PbI2 and carbon quantum dots are added to a DMF / DMSO mixed solvent (DMF / DMSO = 3:1), and a perovskite precursor solution is obtained after shaking and mixing uniformly, the concentration of FA 0.85 MA 0.15 The concentration of PbI3 is 1.1 mol / L, and the concentration of carbon quantum dots is 2 wt%; After adding the perovskite precursor solution to the surface of the electron transport layer, the substrate is rotated at a speed of 4500 rpm, and chlorobenzene is added to the surface of the rotating film layer at the 20th-25th second of rotation, the total rotation time is 35s-40s, and then annealing at 100°C for 15 min, a perovskite layer with a thickness of 200 nm is obtained; A Spiro-OMeTAD solution containing an additive lithium salt is spin-coated on the surface of the perovskite layer, and then annealed at 80°C for 10 min to obtain a hole transport layer with a thickness of 120 nm; An ITO layer with a thickness of 20 nm is deposited on the surface of the hole transport layer by a vacuum evaporation process; 2. Preparation of electrochromic device: A LiAlO2 layer with a thickness of 5 nm is deposited on the surface of the top electrode layer by an atomic layer deposition process at a deposition temperature of 100°C and a pulse time of 1 s; The tungsten oxide is deposited on the surface of the barrier layer by a magnetron sputtering process, and annealed at 200℃ for 1h after the deposition is completed, to obtain an electrochromic layer with a thickness of 50nm; An electrolyte layer is formed on the surface of the electrochromic layer by using an electrolyte solution containing a LiClO4-PC system, the concentration of the electrolyte salt LiClO4 in the electrolyte solution is 1mol / L, and the thickness of the electrolyte layer is 20μm; The indium tin oxide ITO is deposited on the surface of the electrolyte layer by a magnetron sputtering process, to obtain a counter electrode layer with a sheet resistance of 12Ω / □; 3. Packaging: The ultraviolet-curable fluororubber is coated on the surface of the counter electrode layer, the side surface of the perovskite cell and the side surface of the electrochromic device, and the ultraviolet-curable fluororubber is cured by irradiating the ultraviolet light with a wavelength of 365nm for 30s, to obtain a packaging layer, wherein the thickness of the packaging layer on the surface of the counter electrode layer is 20μm; the bottom electrode layer and the on-off element are connected by a lead wire, the lead wire penetrates through the packaging layer on the side surface of the perovskite cell; the counter electrode layer and the on-off element are connected by a lead wire, and the lead wire penetrates through the packaging layer on the side surface of the electrochromic device.

[0083] Example 2 The difference between this example and Example 1 is that the LiAlO2 is not deposited on the surface of the top electrode layer to obtain a barrier layer, but the tungsten oxide is directly deposited on the surface of the barrier layer by a magnetron sputtering process, and annealed at 200℃ for 1h after the deposition is completed, to obtain an electrochromic layer with a thickness of 50nm.

[0084] Example 3 The difference between this example and Example 2 is that the carbon quantum dots are not contained in the perovskite precursor solution.

[0085] Performance test (1) Electrochromic test The AM 1.5G solar simulator is used to provide 100 mW / cm 2 of light irradiation to the electrochromic device, the light irradiation is from the PI film to the electrochromic device, and the electrochemical workstation and the photometer / spectrometer are used to obtain the response time of the electrochromic device.

[0086] (2) Perovskite cell photoelectric conversion efficiency test: The AM 1.5G solar simulator is used to provide 100 mW / cm 2 of light irradiation to the perovskite cell, the digital source meter is used to measure the volt-ampere characteristic curve of the perovskite cell under light irradiation, to obtain the open circuit voltage Voc, the short circuit current density Jsc, the fill factor FF and the photoelectric conversion efficiency PCE of the perovskite cell, and the effective area of the perovskite cell is 1cm 2 .

[0087] (3) Bending performance test: The electrochromic device was bent 10,000 times at room temperature with a bending radius of 3 mm, and then the photovoltaic conversion efficiency PCE of the perovskite cell after bending was tested. w PCE w The ratio of the photovoltaic conversion efficiency PCE of the perovskite cell after bending to the photovoltaic conversion efficiency PCE0 of the perovskite cell before bending is the PCE retention rate of the perovskite cell.

[0088] The electrochromic devices of Examples 1-3 were subjected to the above test, and the test results are shown in Table 1.

[0089] Table 1: Test results of the electrochromic devices of Examples 1-3

[0090] During the electrochromic test, the electrochromic devices of Examples 1-3 all colored after being subjected to light, and all faded after the light was removed. As can be seen from Table 1, since the open-circuit voltage of the perovskite cell in the electrochromic device is higher than the color-changing voltage (0.5-1.0 V) of the electrochromic device, the electrochromic device can be driven to color; after the light is removed, the voltage generated by the perovskite cell is zero, and the electrochromic device fades immediately.

[0091] As can be seen from Table 1, the attenuation degree of the photovoltaic conversion efficiency of the perovskite cell after being bent 10,000 times with a smaller bending radius of 3 mm is lower, indicating that the electrochromic device has excellent bending performance; as can be seen from the comparison of Examples 1-3, the setting of the barrier layer can effectively shorten the response time of the electrochromic device.

[0092] The above are only preferred embodiments of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the above specific embodiments, and those skilled in the art can make various obvious changes, re-adjustments, mutual combinations and replacements without departing from the protection scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the protection scope of the present application is determined by the scope of the appended claims.

[0093] Reference to“an embodiment” or“the embodiment” herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment or implementation of the application. The appearances of the phrase“in one embodiment” or“in an embodiment” in various places in the specification are not necessarily referring to the same embodiment or implementation, nor are they necessarily mutually exclusive of one another. It is expressly understood that any of the embodiments described herein can be combined with any of the other embodiments unless specifically noted otherwise. Reference to“an implementation” herein has a similar meaning to“an embodiment.” All implementations of the application, and optional implementations, can be combined with each other unless specifically noted otherwise, to form new technical solutions.

[0094] As used herein, the terms“plurality,”“various,”“a plurality of,”“several,” and the like, mean two or more, unless otherwise indicated.

[0095] As used herein, the term“room temperature” generally refers to 4°C to 35°C, and can refer to 20°C ± 5°C. In some embodiments of the application, room temperature refers to 20°C to 30°C.

[0096] Furthermore, in the present application, the terms“first,”“second,”“third,”“fourth,” and the like in the“first aspect,”“second aspect,”“third aspect,” and the like, are used only to describe different instances and do not constitute an important or quantitative indication. Moreover, the terms“first,”“second,” and the like only serve the purpose of non-exhaustive enumeration and should be understood as not constituting a closed quantitative limitation.

Claims

1. An electrochromic device, characterized in that, The device comprises a perovskite cell and an electrochromic device stacked together; the perovskite cell comprises a bottom electrode layer, an electron transport layer, a perovskite layer, a hole transport layer and a top electrode layer stacked in sequence; the electrochromic device comprises the top electrode layer, an electrochromic layer, an electrolyte layer and a counter electrode layer stacked in sequence; the top electrode layer is a common transparent electrode of the perovskite cell and the electrochromic device; the bottom electrode layer and the counter electrode layer are electrically connected through a switching element; the open circuit voltage of the perovskite cell is greater than the color voltage of the electrochromic device.

2. The electrochromic device of claim 1, wherein, The difference between the open circuit voltage of the perovskite cell and the color voltage of the electrochromic device is 0.1V-0.6V; And / or, the open circuit voltage of the perovskite cell is 1.1V-1.3V; And / or, the color voltage of the electrochromic device is 0.5V-1.0V.

3. The electrochromic device of claim 2, wherein, The perovskite layer comprises a perovskite material, and the band gap of the perovskite material is 1.20ev-2.30ev; Preferably, the perovskite material comprises FA 0.85 MA 0.15 one or more of PbI3, CsPbBr3, FAPbI3; Preferably, the perovskite layer further comprises carbon quantum dots doped in the perovskite material.

4. The electrochromic device of claim 2, wherein, The material of the electrochromic layer comprises a metal oxide; Preferably, the metal oxide comprises one or more of tungsten oxide and nickel oxide.

5. The electrochromic device according to any one of claims 1 to 4, characterized in that, The electrochromic device further comprises a barrier layer between the top electrode layer and the electrochromic layer, and the barrier layer comprises a crystalline solid electrolyte, and the minimum cross-sectional dimension of the crystal lattice channel of the crystalline solid electrolyte is 0.08nm-1.12nm.

6. The electrochromic device of claim 5, wherein, One or more of the following conditions are met: The crystalline solid electrolyte has a lithium ion conductivity greater than 10 -5 S / cm at room temperature. The crystalline solid electrolyte has an electronic conductivity of less than 10 -10 S / cm at room temperature. The number of lithium ion migrations of the crystalline solid electrolyte is greater than or equal to 0.98 and less than 1; The material of the crystalline solid electrolyte comprises LiAlO2; The thickness of the barrier layer is 3nm-100nm.

7. The electrochromic device of claim 5, wherein, The barrier layer further comprises metal oxide particles doped in the crystalline solid electrolyte, and the mass fraction of the metal oxide particles in the barrier layer is 8wt%-12wt%; Preferably, the particle size of the metal oxide particles is 1nm-5nm; and / or, the material of the metal oxide particles comprises one or more of aluminum oxide, zirconium oxide, silicon dioxide, titanium dioxide and magnesium oxide.

8. The electrochromic device according to any one of claims 1 to 4, wherein: The perovskite cell further comprises a substrate on the side of the bottom electrode layer away from the electron transport layer, and the substrate comprises a flexible substrate; And / or, the electrochromic device further comprises an encapsulation layer covering the counter electrode layer, and the side of the perovskite cell and the side of the electrochromic device; And / or, the side of the bottom electrode layer away from the electron transport layer is the light receiving side of the electrochromic device.

9. The method of producing an electrochromic device according to any one of claims 1 to 8, wherein Comprise: Depositing an electrochromic layer, an electrolyte layer and a counter electrode layer on the surface of the top electrode layer of the perovskite cell in sequence.

10. The production method according to claim 9, characterized by, Further comprise: A barrier layer is deposited on the side surface of the top electrode layer away from the hole transport layer, the barrier layer comprising a crystalline solid electrolyte, the minimum cross-sectional dimension of the lattice channel of the crystalline solid electrolyte being 0.08 nm-1.12 nm, and the electrochromic layer is deposited on the side surface of the barrier layer away from the top electrode layer; Preferably, the process of depositing the barrier layer on the side surface of the top electrode layer away from the hole transport layer comprises an atomic layer deposition process. Preferably, the barrier layer further comprises metal oxide particles doped in the crystalline solid electrolyte.

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