TWI808542B - Electrochromic device with adjustable reflectivity and its forming method thereof - Google Patents

Abstract

An electrochromic device with adjustable reflectivity and its forming method thereof are provided, comprising a substrate and multiple stacked structures disposed on the substrate. Each stacked structure includes an electrochromic layer and a metal electrode layer. By adopting the metal electrode layer as an absorption film to absorb an incident light and the electrochromic effect provided by the electrochromic layer, the proposed electrochromic device is able to generate at least two various reflectivities and colors, and to switch there in between. The proposed device and forming method thereof can directly take the metal electrode layer as its electrode material to replace the existing ITO film, thereby optimizing the inventive effect of the present invention. In addition to reducing the fabrication process cost, the present invention also achieves in providing superior simplicity and conveniences than the prior arts.

Description

Electrochromic device with adjustable reflectivity and method of forming same

The present invention relates to an electrochromic device with adjustable reflectivity and its forming method, especially an electrochromic device which has advantages in manufacturing process and can save the use of conventional transparent conductive films and its forming method.

Press, the development of electrochromism (Electrochromism) technology can be traced back to the development since the 1960s, and it has been more than nearly 60 years. Generally speaking, electrochromism is a phenomenon in which the optical properties of a material (including: reflectivity, transmittance, absorptivity, etc.) undergo a stable and reversible color change under the action of an external electric field, and it is manifested as a reversible change in color and transparency in appearance.

For example, the principle of electrochromic coloring (colored) and bleaching (bleached) is that an applied voltage is applied to both ends of the transparent conductive layer of the electrochromic element, and ions move into (or move out of) the electrochromic layer under the influence of the applied voltage, so that the valence number of the electrochromic material matches the ion move in (or move out), the valence number will decrease (or increase), and the color will begin to change before the balance. After equilibration, the color change is also stabilized. In recent years, due to the advantages of electrochromic materials: low driving voltage, bistable state, and adjustability, the electrochromic technology has the possibility and prospect of vigorous development. In addition, the development trend of electrochromic technology is also advancing towards the technology of solid electrolytic layer or colloidal electrochromic material with high safety.

However, with its development, it is worthy of continuous attention in the industry that most of the existing electrochromic technology needs to use transparent conductive layers, such as Indium Tin Oxide (ITO) thin films as their electrode materials. Even though ITO transparent conductive films have good high conductivity and high transparency, they are the most commonly used transparent conductive materials. However, the ITO transparent conductive film still has the following disadvantages: (1) material shortage, because the content of indium (Indium, In) on the earth is quite scarce, and in recent years, its content is very small, so that its price has skyrocketed several times; (2) ITO transparent conductive film cannot directly obtain good photoelectric properties through a wet process, unless it is baked at a high temperature, so it usually needs to be produced by an expensive sputtering process, resulting in high production costs; (3) ITO is an inorganic material with brittleness and poor ductility. If it is used in soft electronics, its conductivity will be reduced. Therefore, in view of this, based on the consideration of the many problem points listed above, it is extremely necessary to adopt various considerations. For this reason, the inventor of the present invention feels that the above-mentioned deficiency can be improved, and based on the relevant experience in this field for many years, carefully observes and studies it, and cooperates with the application of theories, and proposes a novel design that effectively improves the above-mentioned deficiency.

In order to solve the problems existing in the conventional technology, one object of the present invention is to provide an electrochromic device with adjustable reflectance. Through the technical solution disclosed in the present invention, it combines electrochromic technology and optical film black film technology, so that the formed electrochromic device can switch between two or more reflectance spectra and colors.

On the other hand, another object of the present invention is to provide an electrochromic device and its forming method. The present invention increases the film thickness of the outermost electrochromic layer without using the traditional ITO transparent conductive film, and solves the problem of shortage of ITO materials. The electrode material used in the present invention is to select the metal element of the electrochromic layer. Therefore, compared with the existing technology, the manufacturing process is obviously more convenient and simple.

In yet another aspect, another object of the present invention is to adjust the reflectivity and color of the absorbing film by using electrochromic technology. The technical solution disclosed in the present invention is to coat more than one thin film layer combination on the absorbing film, wherein one film layer is combined into an electrochromic layer film and a metal layer film. Through the technical solution disclosed in the present invention, it can effectively regulate and realize the reflectance and color of the absorbing film that can present the design.

In order to achieve the goals of the above-mentioned inventions, the present invention provides an electrochromic device with adjustable reflectivity, including: a substrate, and a plurality of stacked composite structures formed on the substrate, wherein each of the stacked composite structures includes an electrochromic layer and a metal electrode layer, the metal electrode layer is used to absorb an incident light, and through the electrochromic effect of the electrochromic layer, the electrochromic device can produce more than two reflectances and colors, and can be used in these reflectances and colors to switch between.

According to an embodiment of the present invention, the electrochromic layer is preferably an electrochromic film, and the material of the electrochromic film is tungsten trioxide.

According to an embodiment of the present invention, wherein, the metal electrode layer is preferably a metal thin film, and the material of the metal thin film is tungsten.

According to an embodiment of the present invention, preferably, at least three of the stacked combination structures can be formed on the substrate. Furthermore, wherein, the electrochromic layer is located on the metal electrode layer, and is arranged on the substrate through direct contact with the bottommost metal electrode layer.

On the other hand, the present invention also discloses a method for forming the above-mentioned electrochromic device, which includes the following steps: providing a substrate; and forming a plurality of stacked composite structures on the substrate, wherein each of the stacked composite structures includes an electrochromic layer and a metal electrode layer, the metal electrode layer is used to absorb an incident light, and through the electrochromic effect of the electrochromic layer, the electrochromic device can produce two or more reflectances and colors, and can be used on the reflections Switch between rate and color.

According to an embodiment of the present invention, wherein the electrochromic layer is, for example, an electrochromic film made of tungsten trioxide. The metal electrode layer is, for example, a metal thin film made of tungsten. Therefore, the present invention can directly use tungsten metal film as its absorbing film, which acts to absorb incident light, and then uses electrochromic technology to change the optical constant of the electrochromic film, so that the reflectivity and color of the absorbing film of the electrochromic device can be changed.

According to a preferred embodiment of the present invention, the reflectances that can be changed and switched include, for example: the average reflectance in the spectral range of 450 to 750 nanometers (nm) is around 2%, and the electrochromic device is in a bleached state that is dark blue and close to black. After that, the optical constant of the electrochromic film is changed by electrochromic technology, thereby changing the reflectivity and color of the absorbing film. For example, the average reflectivity in the spectral range of 450 to 750 nanometers (nm) is around 9%, and the electrochromic device is in a khaki-colored state.

In view of the above, the electrochromic device with adjustable reflectance and its forming method disclosed in the present invention can switch between two or more reflectance spectra and colors according to different application requirements while the absorbing film still has the characteristics of low reflection and high absorption.

Below, the applicant further explains in detail with specific embodiments and attached drawings, so that it is easier to understand the purpose, technical content, characteristics and effects of the present invention.

The above description about the content of the present invention and the following embodiments are used to demonstrate and explain the spirit and principle of the present invention, and provide further explanation of the patent application scope of the present invention. Regarding the characteristics, implementation and effects of the present invention, preferred embodiments are described in detail below in conjunction with the drawings.

Wherein, reference is made to the preferred embodiments of the invention, examples of which are shown in the drawings, and throughout the drawings and description, the invention uses the same reference numerals as far as possible to refer to the same or like elements.

The existing electrochromic element structure mostly uses ITO transparent conductive film as its electrode material. Although it has good conductivity and transparency in theory, the material itself still has shortcomings such as shortage, difficulty in obtaining, and high cost. Therefore, in order to effectively improve the long-standing deficiencies in the prior art, the following invention discloses a novel electrochromic device and its forming method. The following disclosure of the embodiment of the invention is aimed at clarifying the main technical content and technical characteristics of the invention, and in order to enable those skilled in the art to understand, manufacture, and use the invention. However, it should be noted that the following embodiments are not intended to limit the scope of the present invention. Therefore, any equivalent modification or variation according to the spirit of the present invention should also be included in the scope of the present invention, which is described first.

Please refer to FIG. 1 , which is a structural diagram of an electrochromic device according to an embodiment of the present invention. The electrochromic device 1 disclosed in the present invention includes a substrate 100 and a plurality of stacked composite structures 200 formed on the substrate 100, wherein each of the stacked composite structures 200 includes an electrochromic layer 20A and a metal electrode layer 20B. As shown in FIG. 1 of the drawings of the present invention, three stacked composite structures 200 are provided on the substrate 100 as an illustrative example for illustration, but the present invention should not be limited thereto. In other words, those skilled in the art who have common knowledge can naturally make appropriate modifications or changes according to the technical solutions disclosed in the present invention without departing from the spirit of the present invention. For example, if three or more stacked and combined structures 200 are arranged on the substrate 100, they should still belong to the scope of the invention of the present invention. The present invention is not limited to the structural connections and the number of structures mentioned in the exemplary examples.

According to an embodiment of the present invention, the electrochromic layer 20A is preferably an electrochromic film, and the material of the electrochromic film can be tungsten trioxide (WO ₃ ), for example. The metal electrode layer 20B is preferably a metal film, and the material of the metal film is tungsten (W). As shown in the figure, the electrochromic layer 20A is located on the metal electrode layer 20B, and is disposed on the substrate 100 through direct contact with the bottommost metal electrode layer 20B in the stacked composite structure 200 .

Please refer to FIG. 2 , which is a forming method that can be used to manufacture the electrochromic device 1 disclosed in the present invention according to an embodiment of the present invention. The forming method includes steps S221-S223. As shown in step S221 , firstly, a substrate 100 is provided, and the substrate 100 can be, for example, a B270 substrate. Next, as shown in step S223 , the stacked assembly structures 200 are sequentially plated and formed on the substrate 100 . Specifically, in the present invention, a 100nm-thick tungsten metal thin film is first plated on the substrate 100 as the metal electrode layer 20B, and the tungsten metal thin film is used as an absorbing film to absorb incident light. Afterwards, a multi-layer thin film is made on the absorber film, and the order from top to bottom is: electrochromic layer 20A (WO ₃ , 55.9nm), metal electrode layer 20B (W, 10nm), electrochromic layer 20A (WO ₃ , 50.3nm), metal electrode layer 20B (W, 10.3nm), electrochromic layer 20A (WO ₃ , 126.4nm), metal electrode layer 20 B (W, 100 nm), stacked structure of B270 substrate 100 .

Therefore, the present invention can directly use the tungsten metal film as an absorbing film, which acts to absorb incident light, and then uses electrochromic technology to change the optical constants of the electrochromic film, so that the reflectivity and color of the absorbing film of the electrochromic device can be changed. Among them, in order to further highlight the color change effect of the electrochromic layer, in a preferred embodiment of the present invention, the outermost _WO3 film can be thickened, thereby increasing the color change effect of the electrochromic layer of the present invention.

In view of this structure, the present invention can make the formed electrochromic device produce more than two reflectances and colors through the electrochromic effect of the electrochromic layer, and can switch between these reflectances and colors.

Please refer to Fig. 3, which is a reflection spectrum data diagram of the electrochromic device 1 according to Fig. 1 of the present invention, wherein the solid line shows the reflection design spectrum of the electrochromic device 1, which is actually plated as a black film element and carried out actual spectrum measurement. The obtained reflection spectrum measurement data is shown by the dotted line in the figure. From these data, it can be clearly seen that when the spectral range of the incident light is between 450 and 750 nm, the average reflectance of the electrochromic device 1 is around 2%, which means it is in a bleached state and presents dark blue close to black, as shown by the solid line in FIG. 4 .

Afterwards, the electrolyte solution is 0.1M lithium perchlorate (LiClO ₄ ) mixed with anhydrous propylene carbonate (Propylene Carbonate), and then the black film element of the electrochromic device 1 is placed in the solution, and a voltage of negative 5 volts is applied, so that lithium ions inside the WO ₃ film of the electrochromic layer move in, resulting in a change in the optical constant of the WO ₃ film. The device 1 is in a colored state. When the incident light ranges from 450 to 750 nm, the average reflectance of the electrochromic device 1 is around 9%, and it appears earthy yellow.

Figure 5 is a comparison image of the electrochromic black film disclosed by the present invention before (left) and after (right) discoloration. It can be seen that the area L1 on the left side of the glass is the actual plated black film element, which is dark blue and close to black. In contrast, the area R1 on the right side of the glass is the coloring state of the black film element, which is earthy yellow. Therefore, in view of the data and image evidence provided in Figures 3, 4, and 5, it can effectively verify the electrochromic device and its formation method disclosed in the present invention. Not only can it successfully manufacture black-coated elements and adjust its reflectivity and color, but also can switch between two or more reflectance spectra and colors according to different application requirements while the absorbing film still has the characteristics of low reflection and high absorption. The present invention can not only be effectively applied to the existing solar energy technology field, but also can be widely used in any other related color display technology fields. It is obvious that the present invention has high industrial applicability and competitiveness.

On the other hand, the present invention also proposes a technical solution of increasing the film thickness of the outermost electrochromic layer, so as to further increase the color change effect of the electrochromic technology. In addition, considering the shortage of existing ITO transparent conductive film materials year by year, the present invention also improves this deficiency. It does not need to use traditional ITO transparent conductive film, and then directly uses the metal element of the electrochromic layer as its electrode material. The manufacturing process is also relatively simple, convenient, and low in cost.

From the above, it can be seen that the present invention mainly discloses an innovative electrochromic device and its forming method. Compared with the prior art, it is believed that the structure and technical solution disclosed in the present invention can effectively solve the existing deficiencies in the prior art. Moreover, based on the fact that the absorbing film can still have the characteristics of low reflection and high absorption, the present invention can realize more than two reflectance spectrums and colors and switch among them in response to different application requirements. It can not only be effectively used in solar energy, semiconductor industry, power electronics and other industries, but also widely used in various other color display technology fields. It is obvious that the technical solution requested by the applicant in this case does have excellent industrial applicability and competitiveness.

At the same time, the applicant has also verified through various experimental data and experience data, etc. that the technical features, methods, means and achieved effects disclosed in the present invention are significantly different from the current scheme, and it is not something that can be easily completed by those familiar with the technology, but should have the patent requirements.

The above-mentioned embodiments are only to illustrate the technical ideas and characteristics of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It should not be used to limit the patent scope of the present invention, that is, all equal changes or modifications made according to the spirit disclosed in the present invention should still be covered within the patent scope of the present invention.

It should be reminded that the present invention is not limited to the structures used in the above disclosed examples. Those skilled in the art with common knowledge can make equivalent modifications and changes based on the inventive concept and spirit of the present invention without departing from the spirit of the present invention, but within the scope of equality, they should still belong to the scope of the present invention.

1...Electrochromic device 100...Substrate 200...Stack combination structure 20A...Electrochromic layer 20B...Metal electrode layer S221, S223...Step L1...Area R1...Area

Fig. 1 is a schematic structural view of an electrochromic device according to an embodiment of the present invention. FIG. 2 is a flow chart of steps in a method of forming an electrochromic device according to an embodiment of the present invention. Fig. 3 is a reflection spectrum data diagram of the electrochromic device in Fig. 1 according to the present invention. Fig. 4 is a reflection spectrum data diagram of the electrochromic device in Fig. 1 according to the present invention in a colored state and a decolorized state. Fig. 5 is a schematic diagram of the comparison images of the electrochromic black film disclosed by the present invention before and after discoloration.

1…Electrochromic device 100...substrate 200…stacking combination structure 20A…Electrochromic layer 20B... Metal electrode layer

Claims (7)

An electrochromic device with adjustable reflectivity, comprising: a substrate; and a plurality of stacked composite structures formed on the substrate, wherein each of the stacked composite structures includes an electrochromic layer and a metal electrode layer, the electrochromic layer in each stacked composite structure is located on the metal electrode layer, and is arranged on the substrate through direct contact with the bottommost metal electrode layer, and the metal electrode layer absorbs an incident light and passes through the electrochromic effect of the electrochromic layer, The electrochromic device produces more than two reflectances and colors, and can switch between the reflectances and colors, wherein the metal electrode layer is a metal film, and the material of the metal film is tungsten. The electrochromic device according to claim 1, wherein the electrochromic layer is an electrochromic film, and the material of the electrochromic film is tungsten trioxide. The electrochromic device according to claim 1, wherein at least three of the stacked composite structures are formed on the substrate. The electrochromic device according to claim 1, wherein the reflectances are between 2% and 9%. A method for forming an electrochromic device as described in claim 1, which includes: providing a substrate; and forming a plurality of stacked composite structures on the substrate, wherein each of the stacked composite structures includes an electrochromic layer and a metal electrode layer, and the electrochromic layer in each of the stacked composite structures is located on the metal electrode layer and is directly contacted by the bottommost metal electrode layer Set on the substrate, the metal electrode layer absorbs an incident light, and through the electrochromic effect of the electrochromic layer, the electrochromic device produces more than two reflectivity and color, and can switch between the reflectivity and color, wherein the metal electrode layer is a metal film, and the material of the metal film is tungsten. The method as described in Claim 5, wherein the electrochromic layer is an electrochromic film, and the material of the electrochromic film is tungsten trioxide. The method according to claim 5, wherein the colors of the formed electrochromic device that can be switched include dark blue and khaki.