CN116445872A - An amorphous molybdenum-doped tungsten oxide electrochromic material and its preparation method - Google Patents

Abstract

The invention discloses an amorphous molybdenum-doped tungsten oxide electrochromic material and a preparation method thereof. The method comprises the following steps, making the pre-vacuum degree of a magnetron sputtering coating instrument reach below 2* ^10-4 Pa, and In an argon-oxygen mixed atmosphere, the amorphous molybdenum-doped WO ₃ target is subjected to radio frequency reactive deposition sputtering on the surface of a conductive glass substrate to obtain a Mo-doped WO ₃ film, and the Mo-doped WO ₃ film is annealed , to obtain an amorphous molybdenum-doped tungsten oxide electrochromic material. The invention has higher transmittance in the faded state and lower transmittance in the colored state, and the contrast can reach 56.6% to 72.8%. It can realize the reversible conversion between transparent and gray-black under different voltages, and realizes the process of discoloration of the tungsten oxide film. Chroma changes. It can be applied to various occasions such as electrochromic smart windows, anti-glare rearview mirrors, and new energy vehicle sunroofs.

Description

An amorphous molybdenum-doped tungsten oxide electrochromic material and its preparation method

technical field

The invention relates to the field of electrochromism, in particular to an amorphous molybdenum-doped tungsten oxide electrochromic material and a preparation method thereof.

Background technique

Electrochromism refers to changes in optical properties such as transmittance, reflectivity, and absorptivity of materials when driven by an external potential, and the macroscopic manifestations are changes in color, transparency, etc. Electrochromic materials typically change between a colored state and a faded state, or directly between two different colored states. Electrochromic materials need to prepare electrochromic thin films on substrates, which are mainly divided into chemical methods and physical methods. Chemical methods include chemical vapor deposition, hydrothermal method, spin coating method, chemical solution deposition method, electrodeposition method, etc.; physical methods include sputtering method, thermal evaporation method, etc. Tungsten oxide is the earliest studied cathodic electrochromic material, which can be divided into crystalline tungsten oxide and amorphous tungsten oxide. Tungsten oxide electrochromic film has many advantages such as large optical modulation range in the visible and infrared bands, high coloring efficiency, and good reversibility. Compared with organic electrochromic materials, tungsten oxide film can also be used in multiple cycles. Maintain stable, reversible color changes in the environment, and continue to work in harsh environments.

In the process of realizing the industrialization of the existing tungsten oxide electrochromic materials, because of its coloring state showing blue or dark blue characteristics, in the actual use process, blue will make people melancholy in color psychology and produce some negative effects. mood.

Contents of the invention

The object of the present invention is to provide an amorphous molybdenum-doped tungsten oxide electrochromic material and its preparation method, which is realized under the doping effect of molybdenum element by magnetron sputtering, a physical vapor deposition (PVD) method. The coloring state of amorphous tungsten oxide changes from dark blue to gray-black in PC/LiClO ₄ solution, which is suitable for electrochromic smart windows, anti-glare rearview mirrors, new energy vehicle sunroofs and other occasions.

In one aspect of the present invention, the present invention provides a method for preparing a molybdenum-doped tungsten oxide electrochromic material. According to an embodiment of the present invention, the method includes the following steps:

Make the pre-vacuum degree of the magnetron sputtering coater reach below 2*10 ^-4 Pa, and in the argon-oxygen mixed atmosphere, carry out radio frequency reactive deposition sputtering on the amorphous molybdenum-doped WO ₃ target on the surface of the conductive glass substrate The Mo-doped WO ₃ film was obtained by irradiation, and the Mo-doped WO ₃ film was annealed to obtain an amorphous molybdenum-doped tungsten oxide electrochromic material.

In addition, the method for preparing an amorphous molybdenum-doped tungsten oxide electrochromic material according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

In some embodiments of the present invention, the conductive glass substrate is ultrasonically cleaned in acetone, absolute ethanol, and deionized water for 10-20 minutes before magnetron sputtering, and dried. The conductive glass substrate is ITO conductive Glass or FTO conductive glass.

In some embodiments of the present invention, the Mo doping amount of the amorphous molybdenum-doped WO ₃ target is 1wt%˜10wt%.

In some embodiments of the present invention, the volume fraction of oxygen sputtered by the radio frequency reactive deposition is 5%-30%, the sputtering power is 50-100W, the sputtering pressure is 0.8-3.0Pa, and the sputtering time is 100 ～150min, the working distance is 5～10cm, the temperature of the conductive glass substrate is 20-110℃.

In some embodiments of the present invention, the volume fraction of oxygen in the mixed atmosphere varies with sputtering time from 5% to 20% with a uniform gradient of 1% over time.

In some embodiments of the present invention, the annealing temperature of the annealing treatment is 300-400° C., and the annealing time is 0.5-2 hours.

In some embodiments of the present invention, the thickness of the amorphous molybdenum-doped tungsten oxide electrochromic material is 300-350 nm, the thin film is dense and uniform, and the sputtering morphology is columnar crystal granular.

In another aspect of the present invention, the present invention proposes an amorphous molybdenum-doped tungsten oxide electrochromic material prepared by the method for preparing the amorphous molybdenum-doped tungsten oxide electrochromic material.

In addition, the amorphous molybdenum-doped tungsten oxide electrochromic material according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

In some embodiments of the present invention, the initial state of the amorphous molybdenum-doped tungsten oxide electrochromic material is colorless and transparent, and in a lithium ion liquid electrolyte (such as PC/LiClO ₄ solution), the colored state is gray-black and black. Color transition from colorless to transparent in the faded state.

In another aspect of the present invention, the present invention provides an electrochromic device, comprising a base layer, a conductive layer, and an electrochromic material layer. According to an embodiment of the present invention, the electrochromic material layer is the amorphous molybdenum-doped tungsten oxide electrochromic material.

Compared with prior art, the beneficial effect of the present invention is:

1. The present invention utilizes the method of magnetron sputtering to reduce the randomness caused by wet chemistry in the experimental process, and at the same time adopts the method of doping the doping element Mo into the WO ₃ target, by using single target sputtering Instead of double-target sputtering, the cost of equipment and targets can be reduced, and amorphous tungsten oxide with a more uniform composition can be obtained through reactive sputtering of doped targets.

2. The present invention will adjust the stoichiometric ratio of tungsten oxide by introducing argon-oxygen mixed gas to participate in reactive sputtering. Argon gas is used as a protective atmosphere to ionize to form plasma (argon ions) under the action of magnetron sputtering electric field, and to form plasma (argon ions) under the action of magnetic field. Under the bombardment of the target, the atoms on the surface of the target are bombarded by argon ions and sputtered out, and deposited on the substrate to form a thin film. Oxygen therein reacts the target atoms to form oxides or regulates oxygen vacancies. Adjusting the ratio of argon to oxygen can adjust the sputtering yield, that is, the ratio of sputtering speed to molybdenum. By adjusting the ratio of argon and oxygen to control the doping content of molybdenum element, the sputtering yield and the change of doping content are realized, thus forming the doping content of molybdenum element in the tungsten oxide electrochromic material from the inside to the outside. Multi-gradient distribution, while preventing the enrichment of molybdenum elements, the inner layer retains the substrate bonding force, and the surface layer achieves the effect of chromaticity transformation. On the whole, the stability of the structure of the amorphous tungsten oxide film and the improvement of the electrochromic performance are realized.

3. The coloring state of the tungsten oxide electrochromic material not doped with molybdenum is blue or dark blue. The present invention introduces molybdenum element by means of doping, and adds an impurity energy level to the wide bandgap semiconductor tungsten oxide, so that light absorption occurs Change, improve the absorption of amorphous tungsten oxide, and then change the color of the tungsten oxide electrochromic film in the colored state, so that the color in the colored state becomes more neutral gray-black in the macroscopic view, and the color in the faded state becomes more transparent. The change process of coloring-fading rarely involves the change of chromaticity, and it is mainly reflected in the reversible change from gray-black to colorless and transparent, which realizes the change of chromaticity of tungsten oxide film.

4. The transmittance in the faded state of the present invention is relatively high (up to 79.0% to 85.1%), the transmittance in the colored state is low (up to 9.1% to 26.4%), and the contrast can reach 56.6% to 72.8%. Under voltage, the reversible conversion between transparent and gray-black is realized, and the chromaticity change during the discoloration process of the tungsten oxide film is realized (the absolute values of a ^* and b ^* coordinates are less than 0.5). It can be applied to various occasions such as electrochromic smart windows, anti-glare rearview mirrors, and new energy vehicle sunroofs.

5. The preparation method of the present invention is a magnetron sputtering method, the preparation process is simple and stable, and the size and thickness of the sample are controllable, which is beneficial to large-scale industrial production.

Description of drawings

Fig. 1 is the X-ray diffraction figure of the amorphous non-doped tungsten oxide electrochromic thin film prepared by the comparative example of the present invention;

Fig. 2 is the X-ray diffraction diagram of the molybdenum-doped tungsten oxide electrochromic film prepared in Example 1 of the present invention;

Fig. 3 is the X-ray diffraction diagram of the molybdenum-doped tungsten oxide electrochromic film prepared in Example 2 of the present invention;

Fig. 4 is the X-ray diffraction diagram of the molybdenum-doped tungsten oxide electrochromic film prepared in Example 3 of the present invention;

Fig. 5 is the Raman spectrogram of the molybdenum-doped tungsten oxide electrochromic film prepared in Example 2 of the present invention;

Fig. 6 is the Raman spectrogram of the molybdenum-doped tungsten oxide electrochromic film prepared in Example 3 of the present invention;

7 is a scanning electron microscope image of the molybdenum-doped tungsten oxide electrochromic film prepared in Example 2 of the present invention;

Figure 8 is a transmission spectrum performance diagram of the molybdenum-doped tungsten oxide electrochromic film prepared in Example 1 of the present invention;

9 is a transmission spectrum performance diagram of the molybdenum-doped tungsten oxide electrochromic film prepared in Example 2 of the present invention;

Fig. 10 is a transmission spectrum performance diagram of the molybdenum-doped tungsten oxide electrochromic film prepared in Example 3 of the present invention;

Figure 11 is a transmission spectrum performance diagram of the molybdenum-doped tungsten oxide electrochromic film prepared in Example 4 of the present invention;

Fig. 12 is a diagram of the electrochromic kinetic performance (633nm, -1v ~ 1v) of the molybdenum-doped tungsten oxide thin film prepared in Example 2 of the present invention;

Fig. 13 is a diagram of the electrochromic kinetic performance (633nm, -1v ~ 1v) of the molybdenum-doped tungsten oxide thin film prepared in Example 3 of the present invention;

Figure 14 is the electrochromic dynamics CA cycle current density diagram (-1v～1v) of the molybdenum-doped tungsten oxide film prepared in Example 3;

FIG. 15 is a diagram of the electrochromic dynamics CA cycle current density (-1v to 1v) of the molybdenum-doped tungsten oxide thin film prepared in Example 4. FIG.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

A method for preparing an amorphous molybdenum-doped tungsten oxide electrochromic material, the specific steps are as follows:

(1) The ITO glass substrate was ultrasonically cleaned in acetone, absolute ethanol, and deionized water for 15 minutes, and dried;

(2) Install the Mo-doped WO ₃ target and the dried ITO glass substrate in the magnetron sputtering coater, and vacuumize;

(3) When the pre-vacuum degree reaches below 2*10 ^-4 Pa, use molybdenum-doped WO ₃ with a purity of 99.99% and a mass fraction of 5% as the target, and perform radio frequency reactive deposition sputtering at a substrate temperature of 110°C. Carried out in an argon-oxygen mixed atmosphere, the oxygen volume fraction in the mixed atmosphere is 15%, the sputtering power is 100W, the sputtering pressure is 2Pa, the sputtering time is 150 minutes, and the working distance is 10cm, and the doped Mo's WO ₃ thin film;

(4) Place the Mo-doped _WO3 thin film obtained in step (3) in a tube furnace for annealing treatment at an annealing temperature of 300° C. and an annealing time of 0.5 hour to obtain an amorphous molybdenum-doped tungsten oxide electrode. Chromogenic film.

Example 2

A method for preparing an amorphous molybdenum-doped tungsten oxide electrochromic material, the specific steps are as follows:

(1) The ITO glass substrate was ultrasonically cleaned in acetone, absolute ethanol, and deionized water for 15 minutes, and dried;

(2) Install the Mo-doped WO ₃ target and the dried ITO glass substrate in the magnetron sputtering coater, and vacuumize;

(3) When the pre-vacuum degree reaches below 2*10 ^-4 Pa, use 8% molybdenum-doped WO ₃ with a purity of 99.99% as the target material, and perform radio frequency reactive deposition sputtering at a substrate temperature of 25°C. - carry out in an oxygen mixed atmosphere, the volume fraction of oxygen in the mixed atmosphere is 5%, the sputtering power is 50W, the sputtering pressure is 1Pa, the sputtering time is 120 minutes, and the working distance is 5cm, to obtain Mo-doped WO ₃ film;

(4) Place the Mo-doped _WO3 thin film obtained in step (3) in a tube furnace for annealing treatment at an annealing temperature of 350° C. and an annealing time of 1.5 hours to obtain an amorphous molybdenum-doped tungsten oxide electrode. Chromogenic film.

Example 3

A method for preparing an amorphous molybdenum-doped tungsten oxide electrochromic material, the specific steps are as follows:

(1) The ITO glass substrate was ultrasonically cleaned in acetone, absolute ethanol, and deionized water for 15 minutes, and dried;

(2) Install the Mo-doped WO ₃ target and the dried ITO glass substrate in the magnetron sputtering coater, and vacuumize;

(3) When the pre-vacuum degree reaches below 2*10 ^-4 Pa, use 2% molybdenum-doped WO ₃ with a purity of 99.99% as the target, and perform radio frequency reactive deposition sputtering at a substrate temperature of 25°C. - Carried out in an oxygen mixed atmosphere, the oxygen volume fraction in the mixed atmosphere changes from 5% to 20% with the sputtering time at a rate of 1% every 8 minutes, and the sputtering power is 50W, and the sputtering power is 50W. The sputtering pressure is 1Pa, the sputtering time is 120 minutes, and the working distance is 5cm to obtain a Mo-doped WO ₃ film;

(4) Place the Mo-doped _WO3 thin film obtained in step (3) in a tube furnace for annealing treatment at an annealing temperature of 350° C. and an annealing time of 1.5 hours to obtain an amorphous molybdenum-doped tungsten oxide electrode. Chromogenic film.

Example 4

A method for preparing an amorphous molybdenum-doped tungsten oxide electrochromic material, the specific steps are as follows:

(1) The ITO glass substrate was ultrasonically cleaned in acetone, absolute ethanol, and deionized water for 15 minutes, and dried;

(2) Install the Mo-doped WO ₃ target and the dried ITO glass substrate in the magnetron sputtering coater, and vacuumize;

(3) When the pre-vacuum degree reaches below 2*10 ^-4 Pa, use 2% molybdenum-doped WO ₃ with a purity of 99.99% as the target, and perform radio frequency reactive deposition sputtering at a substrate temperature of 25°C. - carry out in an oxygen mixed atmosphere, the oxygen volume fraction in the mixed atmosphere is fixed at 15%, the sputtering power is 50W, the sputtering pressure is 1Pa, the sputtering time is 120 minutes, and the working distance is 5cm, to obtain doped Mo WO ₃ film;

(4) Place the Mo-doped _WO3 thin film obtained in step (3) in a tube furnace for annealing treatment at an annealing temperature of 350° C. and an annealing time of 1.5 hours to obtain an amorphous molybdenum-doped tungsten oxide electrode. Chromogenic film.

comparative example

A method for preparing an amorphous non-doped tungsten oxide electrochromic material, the specific steps are as follows:

(1) The ITO glass substrate was ultrasonically cleaned in acetone, absolute ethanol, and deionized water for 15 minutes, and dried;

(2) Install the WO ₃ target and the dried ITO glass substrate in the magnetron sputtering coater, and vacuumize;

(3) When the pre-vacuum degree reaches below 2*10 ^-4 Pa, using WO ₃ with a purity of 99.99% as the target material, conduct radio frequency reactive deposition sputtering at a substrate temperature of 110°C in an argon-oxygen mixed atmosphere, The volume fraction of oxygen in the mixed atmosphere is 15%, the sputtering power is 100W, the sputtering pressure is 2Pa, the sputtering time is 150 minutes, and the working distance is 10cm;

(4) Place the amorphous non-doped tungsten oxide film obtained in step (3) in a tube furnace for annealing treatment at an annealing temperature of 300°C and an annealing time of 0.5 hours to obtain an amorphous non-doped tungsten oxide film. Tungsten electrochromic film.

It can be seen from the X-ray diffraction patterns in Figures 1-4 that the diffraction peaks of the tungsten oxide electrochromic material prepared in the comparative example as a control group are consistent with those of the ITO substrate, and there is no new phase diffraction peak, which can be inferred to be amorphous. The molybdenum-doped tungsten oxide electrochromic materials prepared in Example 1, Example 2, and Example 3 are also consistent with the diffraction peaks of the ITO substrate, and it can be confirmed that the prepared electrochromic films are all amorphous.

The broad peak at approximately 650-850 cm ^-1 in the Raman spectra of Figures 5-6 can be attributed to W ⁶⁺ -O, and the presence of this broad peak indicates that the amorphous nature of Examples 2 and 3 does not Consistent with the conclusion obtained from the XRD test results, the peak at about 950cm ^-1 in the spectrum can be attributed to the stretching of the W6 ⁺ =O terminal caused by water molecules.

It can be seen from FIG. 7 that the surface of the amorphous molybdenum-doped tungsten oxide electrochromic material prepared in Example 2 is dense and flat, and the thickness is about 300-350 nm.

The performance graphs of the transmitted light spectrum and electrochromic kinetics graphs in Figure 8-13 show that: in a three-electrode system, with platinum wire as the counter electrode and Ag/AgCl as the reference electrode, the prepared amorphous molybdenum doped The tungsten oxide electrochromic material is used as the working electrode, and a voltage of -1 to 1V is applied for performance testing. The molybdenum-doped tungsten oxide electrochromic thin film sample in Example 1 has the highest transmittance of 79.0% in the faded state at 633nm, and the transparent state in the colored state. The lowest pass rate is 26.4%, and the electrochromic contrast ratio is 52.6%. The highest transmittance of the electrochromic film prepared in Example 2 reaches 84.0% at 633nm, the lowest transmittance reaches 13.9%, the electrochromic contrast reaches 70.1%, the coloring time is 48.6 seconds, and the fading time is 63.0 seconds. The highest transmittance of the electrochromic film prepared in Example 3 reaches 85.1% at 633nm, the lowest transmittance reaches 12.3%, the electrochromic contrast reaches 72.8%, and the response time of coloring and fading is significantly greater than that of Example 2. promote. The electrochromic thin film prepared in Example 4 has a maximum transmittance of 81.2% at 633 nm, a minimum transmittance of 9.1%, and an electrochromic contrast of 72.1%.

It can be seen from the electrochromic dynamics CA cycle current density diagrams of Figures 14-15 that after 400 cycles, compared with Example 4, the peak current of the electrochromic film prepared in Example 3 is very stable, which shows that the implementation The electrochromic thin film prepared in Example 3 realizes the change of the doping content by dynamically adjusting the ratio of argon and oxygen under the condition of reducing the doping amount, and forms the molybdenum element in the tungsten oxide electrochromic material from inside to The external doping content is distributed in a gradient from less to more. While preventing the enrichment of molybdenum elements, the inner layer retains the substrate bonding force, and the surface layer achieves the effect of chromaticity transformation. On the whole, the stability of the structure of the amorphous tungsten oxide film and the improvement of the electrochromic performance are realized.

Table 1 is the CIE L ^* a ^* b ^* chromaticity coordinate comparison list of the chromaticity of the molybdenum-doped tungsten oxide electrochromic thin film control group prepared in Examples 1, 2, and 3. L ^* indicates the degree of brightness and darkness, and a ^* indicates The degree of red-green tendency of the color, b ^* indicates the degree of yellow-blue tendency of the color. The amorphous molybdenum-doped tungsten oxide electrochromic material prepared in Examples 1-3 is compared with the comparative example, and we find that when Example 2 and Example 3 are in the faded state, the b ^* value increases and the absolute value tends to be more It is close to 0, which indicates that in the change of the faded state, the color of the film changes from blue to light, that is, the faded state will be closer to the colorless and transparent state. At the same time, the b ^* of the colored state of Example 1 and Example 2 has also increased compared with the undoped comparison ratio, and the absolute value is closer to 0, which shows that in the change of the colored state, the color of the film changes from dark blue to blue. Gray and black. As can be seen from the chromaticity coordinates of Example 2, this embodiment is less involved in the color change in the process of coloring-fading change, and is more reflected in the change of film L ^* , that is, the change of brightness and darkness, that is, the film changes from The reversible transformation from gray-black to colorless and transparent realizes the color change of tungsten oxide film.

Table 1

Example 5

An electrochromic device, comprising a base layer, a conductive layer, and an electrochromic material layer. The electrochromic material layer is the amorphous molybdenum-doped tungsten oxide electrochromic material prepared in Examples 1-4.

The above content is only an example and description of the structure of the present invention. Those skilled in the art make various modifications or supplements to the described specific embodiments or replace them in similar ways, as long as they do not deviate from the structure of the present invention. Or beyond the scope defined in the claims, all should belong to the protection scope of the present invention.

Claims (10)

1. The preparation method of the molybdenum-doped tungsten oxide electrochromic material is characterized by comprising the following steps of:

the pre-vacuum degree of the magnetron sputtering coating instrument reaches 2 x 10 ^-4 Under Pa, doping amorphous molybdenum into WO in an argon-oxygen mixed atmosphere ₃ Performing radio frequency reaction deposition sputtering on the surface of the conductive glass substrate by the target material to obtain Mo-doped WO ₃ Thin film of Mo doped with WO ₃ And annealing the film to obtain the amorphous molybdenum doped tungsten oxide electrochromic material.

2. The method for preparing the amorphous molybdenum-doped tungsten oxide electrochromic material according to claim 1, wherein the method comprises the following steps: the conductive glass substrate is sequentially ultrasonically cleaned in acetone, absolute ethyl alcohol and deionized water for 10-20 minutes before magnetron sputtering, and is dried, and the conductive glass substrate is ITO conductive glass or FTO conductive glass.

3. The method for preparing the amorphous molybdenum-doped tungsten oxide electrochromic material according to claim 1, wherein the method comprises the following steps: the amorphous molybdenum is doped with WO ₃ The Mo doping amount of the target material is 1-10wt%.

4. The method for preparing the amorphous molybdenum-doped tungsten oxide electrochromic material according to claim 1, wherein the method comprises the following steps: the volume fraction of oxygen for the radio frequency reactive deposition sputtering is 5% -30%, the sputtering power is 50-100W, the sputtering air pressure is 0.8-3.0 Pa, the sputtering time is 100-150 min, the working distance is 5-10 cm, and the temperature of the conductive glass substrate is 20-110 ℃.

5. The method for preparing the amorphous molybdenum-doped tungsten oxide electrochromic material according to claim 4, wherein the method comprises the following steps: the oxygen volume fraction in the mixed atmosphere is uniformly graded from 5% to 20% along with the sputtering time at every 1% along with the time.

6. The method for preparing the amorphous molybdenum-doped tungsten oxide electrochromic material according to claim 1, wherein the method comprises the following steps: the annealing temperature of the annealing treatment is 300-400 ℃ and the annealing time is 0.5-2 h.

7. The method for preparing the amorphous molybdenum-doped tungsten oxide electrochromic material according to claim 1, wherein the method comprises the following steps: the thickness of the amorphous molybdenum doped tungsten oxide electrochromic material is 300-350nm, the film is compact and uniform, and the sputtering appearance is in the form of columnar crystal grains.

8. An amorphous molybdenum-doped tungsten oxide electrochromic material prepared by the method of preparing an amorphous molybdenum-doped tungsten oxide electrochromic material according to any one of claims 1-7.

9. An amorphous molybdenum doped tungsten oxide electrochromic material according to claim 8, characterized in that: the amorphous molybdenum doped tungsten oxide electrochromic material is transparent in initial state, and the grey black in coloring state and transparent color conversion in fading state are realized in the lithium ion liquid electrolyte.

10. An electrochromic device comprising a substrate layer, a conductive layer, and an electrochromic material layer, characterized in that: the electrochromic material layer is the amorphous molybdenum doped tungsten oxide electrochromic material of claim 8.