An electrochromic device containing a transparent CdO layer

Abstract

The present invention provides an electrochromic device containing a transparent CdO layer, comprising a first electrode, a gel electrolyte, and a second electrode. The first electrode comprises a first FTO conductive glass, a first cadmium oxide layer disposed on the first FTO conductive glass layer, and an electrochromic layer disposed on the first cadmium oxide layer. The second electrode comprises a second FTO conductive glass, a second cadmium oxide layer disposed on the FTO conductive glass, and a counter electrode material layer disposed on the second cadmium oxide layer. The gel electrolyte is positioned between the electrochromic layer of the first electrode and the counter electrode material layer of the second electrode. By using a cadmium oxide thin film to simultaneously adsorb electrochromic molecules and counter electrode molecules, the present invention effectively improves the performance of the electrochromic device, resulting in advantages such as good color change uniformity, a good memory effect, and a short response time.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochromic devices, and in particular relates to an electrochromic device containing a transparent CdO layer. Background Art

[0002] Electrochromism refers to the phenomenon in which the optical properties of a material (reflectivity, transmittance, absorptivity, etc.) undergo stable and reversible color changes under the action of an external electric field, which manifests itself in a reversible change in color and transparency. Devices made of electrochromic materials are called electrochromic devices. Currently, the electrochromic devices that have been industrialized mainly include: electrochromic smart dimming glass, electrochromic displays, and automatic anti-glare rearview mirrors for cars. Among them, electrochromic smart glass has the ability to adjust light absorption and transmission under the action of an electric field. It can selectively absorb or reflect external thermal radiation and internal heat diffusion, while also improving the level of natural light and preventing peeping, and is a development direction for energy-saving building materials.

[0003] Existing electrochromic devices have problems such as poor color uniformity, poor memory effect and slow response time. Summary of the Invention

[0004] Based on this, the object of the present invention is to provide an electrochromic device containing a transparent CdO layer, which has the advantages of good color change uniformity, good memory effect and short response time.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions.

[0006] An electrochromic device comprising a first electrode, a gel electrolyte, and a second electrode;

[0007] The first electrode comprises a first FTO conductive glass, a first cadmium oxide layer disposed on the first FTO conductive glass layer, and an electrochromic layer disposed on the first cadmium oxide layer;

[0008] The second electrode comprises: a second FTO conductive glass, a second cadmium oxide layer disposed on the FTO conductive glass, and a counter electrode material layer disposed on the second cadmium oxide layer;

[0009] The gel electrolyte is located between the electrochromic layer of the first electrode and the counter electrode material layer of the second electrode.

[0010] In some embodiments, the thickness of the first cadmium oxide layer and / or the second cadmium oxide layer is 5 nm to 20 nm.

[0011] In some embodiments, the electrochromic molecules in the electrochromic layer are selected from at least one of viologen, phenothiazines and triphenylamine; preferably, the electrochromic molecules are selected from viologen.

[0012] In some embodiments, the counter electrode molecules in the counter electrode material layer are selected from at least one of ferrocene and benzoquinone small molecule compounds.

[0013] In some embodiments, the gel electrolyte comprises lithium perchlorate, polyvinyl butyral and allyl carbonate; and the mass ratio of lithium perchlorate, polyvinyl butyral and allyl carbonate is (0.5-2):(1-2):(15-30); and / or the solid content of the gel electrolyte is 5%-25%.

[0014] The present invention also provides a method for preparing the electrochromic device as described above, comprising the following steps: (1) preparing a first electrode: applying a cadmium oxide solution with a concentration of 0.1 mmol / L to 5 mmol / L to the first FTO conductive glass, drying, and then immersing the solution containing electrochromic molecules, taking out and drying to obtain the first electrode; (2) preparing a second electrode: applying a cadmium oxide solution with a concentration of 0.1 mmol / L to 5 mmol / L to the second FTO conductive glass, drying, and then immersing the solution containing counter electrode molecules, taking out and drying to obtain the second electrode; (3) dripping the gel electrolyte on the electrochromic layer of the first electrode, smearing it evenly, and then staggering the second electrode on the gel electrolyte, leading out the electrode, and UV curing and packaging to obtain the electrochromic device.

[0015] In some embodiments, the solvent of the cadmium oxide solution comprises glycerol, isopropyl alcohol, and triethylamine, and the mass ratio of the glycerol, isopropyl alcohol, and triethylamine is (0.05-0.15): (2-3.5): (0.1-0.4).

[0016] In some embodiments, the concentration of the electrochromic molecules in the solution containing the electrochromic molecules is

[0017] 5mmol / L~50mmol / L; Preferably, the concentration of the electrochromic molecules in the solution containing the electrochromic molecules is 10mmol / L~45mmol / L.

[0018] In some embodiments, the concentration of the counter electrode molecules in the solution containing the counter electrode molecules is 5 mol / L to 100 mol / L; preferably, the concentration of the counter electrode molecules in the solution containing the counter electrode molecules is 10 mol / L to 80 mol / L.

[0019] In some embodiments, the electrochromic molecule is selected from at least one of viologen, phenothiazines, and triphenylamine; and / or, the counter electrode molecule is selected from at least one of ferrocene and benzoquinone small molecule compounds.

[0020] In some embodiments, the soaking time in step (1) and / or step (2) is 20 hours to 30 hours.

[0021] The present invention provides an electrochromic device, which has the following structure: FTO glass-cadmium oxide layer-electrochromic layer-electrolyte layer-counter electrode material layer-cadmium oxide layer-FTO glass. By using a cadmium oxide thin film to simultaneously adsorb electrochromic molecules and counter electrode molecules, the performance of the electrochromic device can be effectively improved, so that the device has the advantages of good color change uniformity, good memory effect and short reaction time. This is because the electrochromic molecules of the electrochromic device of the present invention can be very evenly adsorbed on the cadmium oxide layer, so that the color change and fading are very uniform; secondly, since the counter electrode molecules are adsorbed on the cadmium oxide particles, the migration of ions in and out is hindered, so the electrochromic device has a good memory effect and needs to apply a reverse voltage to achieve fading; finally, since the electrochromic molecules are adsorbed on the surface of the cadmium oxide layer, only the surface redox process occurs, and there is no diffusion process, so the reaction time is short. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram of fading and coloring of the electrochromic device in Example 1. DETAILED DESCRIPTION

[0023] The experimental methods in the following examples of the present invention, where specific conditions are not specified, are generally carried out under conventional conditions or conditions recommended by the manufacturers. The various commonly used chemical reagents used in the examples are all commercially available products.

[0024] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0025] The terms "comprise," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or device comprising a series of steps is not limited to the listed steps or modules but may optionally include steps not listed, or other steps inherent to the process, method, product, or device.

[0026] In this application, "at least one" refers to one or more than one. "And / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0027] The following describes the details in conjunction with specific embodiments.

[0028] Example 1

[0029] This embodiment provides an electrochromic device, comprising a first electrode, a gel electrolyte, and a second electrode; the first electrode comprises a first FTO conductive glass, a first cadmium oxide layer disposed on the first FTO conductive glass layer, and an electrochromic layer disposed on the first cadmium oxide layer; the second electrode comprises a second FTO conductive glass, a second cadmium oxide layer disposed on the FTO conductive glass, and a counter electrode material layer disposed on the second cadmium oxide layer;

[0030] The gel electrolyte is located between the electrochromic layer of the first electrode and the counter electrode material layer of the second electrode.

[0031] The gel electrolyte comprises lithium perchlorate, polyvinyl butyral and allyl carbonate; the mass ratio of the lithium perchlorate, polyvinyl butyral and allyl carbonate is 0.8:1:20; and the solid content is 15%.

[0032] The electrochromic device is prepared by the following method:

[0033] (1) preparing the first electrode: spin coating a 2.5 mmol / L cadmium oxide solution (the solvent contains glycerol, isopropyl alcohol and triethylamine, and the mass ratio of glycerol, isopropyl alcohol and triethylamine is 0.07:2.75:0.29) onto the first FTO conductive glass: the rotation speed is 3000 rpm / min, the annealing temperature is 100 ° C (60 mins), and then 200 ° C (60 mins) to obtain a first cadmium oxide layer with a dry film thickness of 15 nm, and then placed in a solution containing electrochromic molecules (the concentration of electrochromic molecules is 30 mmol / L) and immersed for 24 hours, taken out and dried to obtain the first electrode;

[0034] (2) Preparation of the second electrode: a cadmium oxide solution with a concentration of 2.5 mmol / L (the solvent contains glycerol, isopropanol and triethylamine, and the mass ratio of glycerol, isopropanol and triethylamine is 0.07:2.75:0.29) is spin-coated onto the second FTO conductive glass: the rotation speed is 3000 rpm / min, the annealing temperature is 100 ° C (60 mins), and then 200 ° C (60 mins) to obtain a second cadmium oxide layer with a dry film thickness of 15 nm, and then placed in a solution containing counter electrode molecules (the concentration of the counter electrode molecules is 50 mmol / L) and immersed for 24 h, taken out and dried to obtain the second electrode;

[0035] (3) The gel electrolyte (containing 100 μm spacer balls) is dripped onto the electrochromic layer of the first electrode and evenly coated with a scraper. The second electrode is then staggered and covered on the gel electrolyte. The electrode is drawn out and UV cured and packaged to obtain the electrochromic device. The fading and coloring of the device are shown in the figure. Figure 1 shown.

[0036] Example 2

[0037] This embodiment provides an electrochromic device, comprising a first electrode, a gel electrolyte, and a second electrode; the first electrode comprises a first FTO conductive glass, a first cadmium oxide layer disposed on the first FTO conductive glass layer, and an electrochromic layer disposed on the first cadmium oxide layer; the second electrode comprises a second FTO conductive glass, a second cadmium oxide layer disposed on the FTO conductive glass, and a counter electrode material layer disposed on the second cadmium oxide layer;

[0038] The gel electrolyte is located between the electrochromic layer of the first electrode and the counter electrode material layer of the second electrode.

[0039] The gel electrolyte comprises lithium perchlorate, polyvinyl butyral and allyl carbonate; the mass ratio of the lithium perchlorate, polyvinyl butyral and allyl carbonate is 1:1.5:25; and the solid content is 20%.

[0040] The electrochromic device is prepared by the following method:

[0041] (1) Preparation of the first electrode: spin coating a cadmium oxide solution with a concentration of 1.5 mmol / L (the solvent contains glycerol, isopropanol and triethylamine, and the mass ratio of glycerol, isopropanol and triethylamine is 0.1:3:0.32) onto the first FTO conductive glass: the rotation speed is 5000 rpm / min, the annealing temperature is 100°C (60 mins), and then 200°C (60 mins) to obtain a first cadmium oxide layer with a dry film thickness of 10 nm; then, the first electrode is immersed in a solution containing electrochromic molecules (the concentration of the electrochromic molecules is 15 mmol / L) for 26 hours, taken out and dried to obtain the first electrode;

[0042] (2) Preparation of the second electrode: a cadmium oxide solution with a concentration of 1.5 mmol / L (the solvent contains glycerol, isopropanol and triethylamine, and the mass ratio of glycerol, isopropanol and triethylamine is 0.1:3:0.32) is spin-coated onto the second FTO conductive glass: the rotation speed is 5000 rpm / min, the annealing temperature is 100 ° C (60 mins), and then 200 ° C (60 mins) to obtain a second cadmium oxide layer with a dry film thickness of 10 nm, and then placed in a solution containing counter electrode molecules (the concentration of the counter electrode molecules is 70 mmol / L) and immersed for 26 hours, taken out and dried to obtain the second electrode;

[0043] (3) The gel electrolyte (containing 100 μm spacer balls) is dripped onto the electrochromic layer of the first electrode and evenly coated with a scraper. The second electrode is then staggered and covered on the gel electrolyte. The electrode is drawn out, and UV curing and packaging are performed to obtain the electrochromic device.

[0044] Example 3

[0045] This embodiment provides an electrochromic device, comprising a first electrode, a gel electrolyte, and a second electrode; the first electrode comprises a first FTO conductive glass, a first cadmium oxide layer disposed on the first FTO conductive glass layer, and an electrochromic layer disposed on the first cadmium oxide layer; the second electrode comprises a second FTO conductive glass, a second cadmium oxide layer disposed on the FTO conductive glass, and a counter electrode material layer disposed on the second cadmium oxide layer;

[0046] The gel electrolyte is located between the electrochromic layer of the first electrode and the counter electrode material layer of the second electrode.

[0047] The gel electrolyte comprises lithium perchlorate, polyvinyl butyral and allyl carbonate; the mass ratio of the lithium perchlorate, polyvinyl butyral and allyl carbonate is 1.5:2:28; and the solid content is 10%.

[0048] The electrochromic device is prepared by the following method:

[0049] (1) preparing the first electrode: spin coating a cadmium oxide solution with a concentration of 4.5 mmol / L (the solvent contains glycerol, isopropyl alcohol and triethylamine, and the mass ratio of glycerol, isopropyl alcohol and triethylamine is 0.07:2.75:0.29) onto the first FTO conductive glass: the rotation speed is 2000 rpm / min, the annealing temperature is 100 ° C (60 mins), and then 200 ° C (60 mins) to obtain a first cadmium oxide layer with a dry film thickness of 8 nm, and then placed in a solution containing electrochromic molecules (the concentration of electrochromic molecules is 40 mmol / L) and immersed for 20 hours, taken out and dried to obtain the first electrode;

[0050] (2) Preparation of the second electrode: a cadmium oxide solution with a concentration of 4.5 mmol / L (the solvent contains glycerol, isopropanol and triethylamine, and the mass ratio of glycerol, isopropanol and triethylamine is 0.07:2.75:0.29) is spin-coated onto the second FTO conductive glass: the rotation speed is 2000 rpm / min, the annealing temperature is 100 ° C (60 mins), and then 200 ° C (60 mins) to obtain a second cadmium oxide layer with a dry film thickness of 8 nm, and then placed in a solution containing counter electrode molecules (the concentration of the counter electrode molecules is 30 mol / L) and immersed for 20 h, taken out and dried to obtain the second electrode;

[0051] (3) The gel electrolyte (containing 100 μm spacer balls) is dripped onto the electrochromic layer of the first electrode and evenly coated with a scraper. The second electrode is then staggered and covered on the gel electrolyte. The electrode is drawn out, and UV curing and packaging are performed to obtain the electrochromic device.

[0052] Example 4

[0053] This embodiment provides an electrochromic device. The electrochromic device is the same as that of Embodiment 1 except that the thickness of the first cadmium oxide layer and the second cadmium oxide layer are 3 nm.

[0054] Example 5

[0055] This embodiment provides an electrochromic device. The electrochromic device is the same as that of Embodiment 1 except that the thickness of the first cadmium oxide layer and the second cadmium oxide layer is 25 nm.

[0056] Comparative Example 1

[0057] This comparative example provides an electrochromic device. Except for not having the first cadmium oxide layer and the second cadmium oxide layer, the electrochromic molecules and the counter electrode molecules are dissolved in the gel electrolyte to form a uniform all-in-one gel electrochromic device. Other aspects are the same as those of Example 1.

[0058] Comparative Example 2

[0059] This comparative example provides an electrochromic device, which is the same as Example 1 except that the first cadmium oxide layer and the second cadmium oxide layer are replaced by the first silver nanowire conductive layer and the second silver nanowire conductive layer.

[0060] The coloring time and fading time of the electrochromic devices in the above examples and comparative examples were tested using an electrochemical workstation and a UV-visible spectrophotometer, using a chronopotentiometry method.

[0061] The results are shown in Table 1:

[0062] Table 1 Test results

[0063] Group Coloring Time Fading time Optical contrast (607nm) Example 1 2.1s 1.5s 76.3％ Example 2 1.9s 1.4s 72.3％ Example 3 1.7s 1.2s 60.1％ Example 4 1.3s 1.0s 41.9％ Example 5 2.5s 1.8s 54.9％ Comparative Example 1 4.5s 6.7s 75.8％ Comparative Example 2 - - -

[0064] The above results show that the electrochromic device of the present invention (Examples 1 to 3) has the advantages of good color change uniformity, good memory effect and short reaction time, and the coloring time and fading time are both short. Compared with Example 1, the thickness of the first cadmium oxide layer and the second cadmium oxide layer in Example 4 is smaller, and the thickness of the first cadmium oxide layer and the second cadmium oxide layer in Example 5 is larger. When the thickness of the cadmium oxide layer is too small (Example 4), the number of adsorbed electrochromic molecules is small, which will affect the optical contrast of the device; and when the thickness of the cadmium oxide layer is too large (Example 5), the migration and evacuation of ions may be greatly hindered, which will increase the reaction time, and the larger cadmium oxide thickness will make the cadmium oxide film itself have color, which will also affect the optical contrast of the device.

[0065] Compared to Example 1, Comparative Example 1 lacks the first and second cadmium oxide layers, resulting in significantly longer coloring and fading times for the electrochromic device because diffusion is involved in the color change and fading processes. Comparative Example 2 replaces the first and second cadmium oxide layers with first and second silver nanowire layers. However, since the nanowire layers cannot absorb sufficient electrochromic molecules, color change is not possible.

[0066] In summary, the present invention can effectively improve the performance of the electrochromic device by using a cadmium oxide film to simultaneously adsorb electrochromic molecules and counter electrode molecules, so that it has the advantages of good color change uniformity, good memory effect and short response time.

[0067] The technical features of the above-described embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An electrochromic device, characterized in that: The electrochromic device comprises a first electrode, a gel electrolyte, and a second electrode; The first electrode comprises a first FTO conductive glass, a first cadmium oxide layer disposed on the first FTO conductive glass layer, and an electrochromic layer disposed on the first cadmium oxide layer; The second electrode comprises: a second FTO conductive glass, a second cadmium oxide layer disposed on the FTO conductive glass, and a counter electrode material layer disposed on the second cadmium oxide layer; The gel electrolyte is located between the electrochromic layer of the first electrode and the counter electrode material layer of the second electrode.

2. The electrochromic device according to claim 1, wherein The thickness of the first cadmium oxide layer and / or the second cadmium oxide layer is 5 nm to 20 nm.

3. The electrochromic device according to claim 1, wherein The electrochromic molecules in the electrochromic layer are selected from at least one of viologen, phenothiazines and triphenylamine.

4. The electrochromic device according to claim 1, wherein The counter electrode molecules in the counter electrode material layer are selected from at least one of ferrocene and benzoquinone small molecule compounds.

5. The electrochromic device according to claim 1, wherein The gel electrolyte comprises lithium perchlorate, polyvinyl butyral and allyl carbonate; and the mass ratio of lithium perchlorate, polyvinyl butyral and allyl carbonate is (0.5-2):(1-2):(15-30); and / or the solid content of the gel electrolyte is 5%-25%.

6. The method for preparing an electrochromic device according to any one of claims 1 to 5, wherein: The method comprises the following steps: (1) preparing a first electrode: applying a cadmium oxide solution with a concentration of 0.1 mmol / L to 5 mmol / L to the first FTO conductive glass, drying the solution, and then immersing the solution in a solution containing electrochromic molecules, taking the solution out and drying the solution to obtain the first electrode; (2) preparing a second electrode: applying a cadmium oxide solution with a concentration of 0.1 mmol / L to 5 mmol / L to the second FTO conductive glass, drying the solution, and then immersing the solution in a solution containing counter electrode molecules, taking the solution out and drying the solution to obtain the second electrode; (3) dripping the gel electrolyte on the electrochromic layer of the first electrode, smearing the solution evenly, and then staggering the second electrode on the gel electrolyte, leading out the electrodes, and UV curing and packaging the solution to obtain the electrochromic device.

7. The preparation method according to claim 6, wherein The solvent of the cadmium oxide solution comprises glycerol, isopropyl alcohol and triethylamine, and the mass ratio of the glycerol, isopropyl alcohol and triethylamine is (0.05-0.15): (2-3.5): (0.1-0.4).

8. The preparation method according to claim 6, wherein The concentration of the electrochromic molecules in the solution containing the electrochromic molecules is 5 mmol / L to 50 mmol / L; and / or the concentration of the counter electrode molecules in the solution containing the counter electrode molecules is 5 mol / L to 100 mol / L.

9. The preparation method according to claim 6, wherein The electrochromic molecule is selected from at least one of viologen, phenothiazines and triphenylamine; and / or the counter electrode molecule is selected from at least one of ferrocene and benzoquinone small molecule compounds.

10. The preparation method according to claim 6, wherein The soaking time in step (1) and / or step (2) is 20 hours to 30 hours.

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