KR102335565B1 - Electrochromic device - Google Patents

Abstract

The electrochromic device according to embodiments of the present invention includes a first electrode, a second electrode opposite to the first electrode, and an electrolyte layer interposed between the first electrode and the second electrode and including an electrochromic material , and a porous layer interposed between at least one of the first and second electrodes and the electrolyte layer.

Description

Electrochromic device

The present invention relates to an electrochromic device, and more particularly, to an electrochromic device using an oxidation/reduction reaction.

An electrochromic device is a device having characteristics of changing color and transmittance by an electrochemical reaction. When a potential difference is generated by an external electrical stimulus in the electrochromic device, ions or electrons included in the electrolyte layer move into the electrochromic layer to cause oxidation/reduction reactions. The color of the electrochromic element is changed by the oxidation/reduction reaction of the electrochromic layer, and the degree of being able to transmit visible light or infrared rays is changed by the change in color of the electrochromic material. Accordingly, the electrochromic device is applied to a light shutter, a reflective display, a color-changing mirror for automobiles, a smart window, and the like.

An object of the present invention is to provide an electrochromic device having improved discoloration transmittance.

The problem to be solved by the present invention is not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, an electrochromic device according to embodiments of the present invention includes a first electrode, a second electrode facing the first electrode, and interposed between the first electrode and the second electrode, , an electrolyte layer comprising an electrochromic material, and a porous layer interposed between at least one of the first and second electrodes and the electrolyte layer.

According to one embodiment, the porous layer may include a porous metal oxide.

According to an embodiment, the electrochromic material of the electrolyte layer may include phenothiazine.

According to an embodiment, the porous layer may include at least one of titanium dioxide (TiO2) and indium tin oxide (ITO).

According to an embodiment, the porous layer may include at least one of fluorinated tin oxide (FTO), ZnO, SnO2, and antimony-doped tin oxide.

According to an embodiment, it further comprises an electrochromic layer, wherein the porous layer is interposed between any one of the first and second electrodes and the electrolyte layer, and the electrochromic layer is the first and second electrodes. It may be interposed between the other one of them and the electrolyte layer.

In an embodiment, the electrochromic layer may include tungsten oxide (Wox).

In order to achieve the above object, an electrochromic device according to embodiments of the present invention includes a first electrode, a first electrochromic layer on the first electrode, a second electrode facing the first electrode, and the second electrode a coating layer on two electrodes and an electrolyte layer interposed between the first electrochromic layer and the coating layer, wherein the electrolyte layer comprises a first electrochromic material and the electrolyte layer comprises a second electrochromic material; The coating layer includes a porous metal oxide.

According to an embodiment, the first electrochromic material may include an organic color change material, and the second electrochromic material may include an inorganic color change material.

The details of other embodiments are included in the detailed description and drawings.

According to the embodiments of the present invention, it is possible to provide an electrochromic device having improved discoloration transmittance.

1A is a cross-sectional view of an electrochromic device according to an embodiment of the present invention.
FIG. 1B is an enlarged view of FIG. 1A .
2A is a view illustrating a case in which the electrochromic materials of the electrochromic device are discolored.
2B is a diagram illustrating a case in which the electrochromic materials of the electrochromic device are colored.
3 is a cross-sectional view of an electrochromic device according to an exemplary embodiment.
4 is a graph showing a reflection spectrum according to a comparative example.
5 is a graph illustrating a reflection spectrum using the electrochromic device of FIG. 3 .
6 is a graph showing a transmission spectrum using the electrochromic device of FIG. 1 .

Advantages and features of the present invention, and methods for achieving them, will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only this embodiment serves to complete the disclosure of the present invention, and to obtain common knowledge in the technical field to which the present invention pertains. It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, 'comprises' and/or 'comprising' means that a referenced component, step, operation and/or element is the presence of one or more other components, steps, operations and/or elements. or addition is not excluded.

Further, the embodiments described herein will be described with reference to cross-sectional and/or plan views, which are ideal illustrative views of the present invention. In the drawings, thicknesses of films and regions are exaggerated for effective description of technical content. Accordingly, the shape of the illustrative drawing may be modified due to manufacturing technology and/or tolerance. Accordingly, the embodiments of the present invention are not limited to the specific form shown, but also include changes in the form generated according to the manufacturing process. Accordingly, the regions illustrated in the drawings have a schematic nature, and the shapes of the illustrated regions in the drawings are intended to illustrate specific shapes of regions of the device and not to limit the scope of the invention.

1A is a cross-sectional view of an electrochromic device 1 according to an embodiment of the present invention. FIG. 1B is an enlarged view of FIG. 1A . 1A and 1B, the electrochromic device 1 includes a lower substrate 10, a lower electrode 20, a porous layer 30, an electrolyte layer 40, an electrochromic layer 50, and an upper electrode ( 60 ), an upper substrate 70 , and a sealant 80 . The electrochromic element 1 may be transparent.

The lower substrate 10 may be spaced apart from the upper substrate 70 to face each other. The lower substrate 10 and the upper substrate 70 may be transparent substrates. For example, the lower substrate 10 and the upper substrate 70 may include a glass substrate, but is not limited thereto.

The lower electrode 20 may be disposed on the lower substrate 10 . The upper electrode 60 may be disposed under the upper substrate 70 . The upper electrode 60 and the lower electrode 20 may face each other. The upper electrode 60 and the lower electrode 20 may be provided as transparent electrodes. For example, the upper electrode 60 and the lower electrode 20 may include ITO or FTO. The lower electrode 20 may be patterned and include a plurality of sub lower electrodes. The upper electrode 60 may be patterned to include a plurality of sub-upper electrodes.

The porous layer 30 may be disposed on the lower electrode 20 . The porous layer 30 may be interposed between the lower electrode 20 and the electrolyte layer 40 . The porous layer 30 may include a porous metal oxide. For example, referring to FIG. 1B , the porous layer 30 may include titanium dioxide (TiO2, 32). Alternatively, the porous layer 30 may include ZnO, indium tin oxide (ITO), fluorinated tin oxide (FTO), SnO2, antimony-doped SnO2, or the like. The porous layer 30 may be a coating layer coated on the lower electrode 20 . The thickness of the porous layer 30 may be within about 100 nm to about 50 um. As an example, the thickness of the porous layer 30 may be within a range of about 500 nm to about 10 μm. The porous layer 30 may be composed of particles having a size within about 1 nm to about 1000 nm. For example, the porous layer 30 may be composed of particles having a size within a range of about 1 nm to about 100 nm. The porous layer 30 may be manufactured by various methods such as spin coating, slot die coating, or bar coating. The porous layer 30 may be manufactured through a heat treatment process after coating, and the heat treatment process may be performed at room temperature to about 1000° C., but is not limited thereto. 1A shows that the porous layer 30 is disposed on the lower electrode 20 as an example, but unlike this, the porous layer 30 is disposed on the upper electrode 60 or on the upper and lower electrodes 60 and 20 ) can all be placed on the

The electrolyte layer 40 may be interposed between the porous layer 30 and the electrochromic layer 50 . The electrolyte layer 40 may be in a liquid, gel, or solid state. The electrolyte layer 40 may include a first electrochromic material and a compound electrolyte layer. The first electrochromic material may include organic molecules, and the compound electrolyte layer may include hydrogen ions (H+) or lithium ions (Li+). For example, the electrolyte layer 40 may include phenothiazine as the first electrochromic material and LiCO ₄ as the compound electrolyte layer. In contrast, the first electrochromic material is triarylamine, triphenylamine, triarylamine derivative, triphenylamine derivative, phenazine, phenothiazine ) derivatives and phenazine derivatives. The electrolyte layer 40 may transport ions between the porous layer 30 and the electrochromic layer 50 . In addition, the electrolyte layer 40 may participate in a color change reaction by including the first electrochromic material. This will be described later together with the electrochromic layer 50 . The concentration of the first electrochromic material may range from about 0.1 to 50% (w/w). For example, the concentration of the first electrochromic material may range from about 1 to 10% (w/w). The solvent of the electrolyte may be an organic molecule including propylene carbonate.

The electrochromic layer 50 may be disposed under the upper electrode 60 . The electrochromic layer 50 may be interposed between the upper electrode 60 and the electrolyte layer 40 . The electrochromic layer 50 may face the porous layer 30 . In other words, the porous layer 30 is disposed between the electrolyte layer 40 and any one of the upper and lower electrodes 60 and 20, and the electrolyte layer 40 and the upper and lower electrodes 60 and 20 ), an electrochromic layer 50 may be disposed between the other electrodes. The electrochromic layer 50 may include a second electrochromic material. The second electrochromic material may include inorganic molecules. For example, the second electrochromic material may include tungsten oxide (WOx). The thickness of the tungsten oxide may be between about 10 nm and 20,000 nm. For example, the thickness of tungsten oxide may range from about 50 nm to 500 nm. Tungsten oxide may be prepared by a dry method (eg, vacuum deposition method) or may be prepared by a wet method (eg, sol-gel method).

As described above, the porous layer 30 may include a first electrochromic material, and the electrochromic layer 50 may include second electrochromic materials. The first and second electrochromic materials cause electrochromism by oxidation/reduction processes according to injection and desorption of electrons and ions. At this time, the porous layer 30 and the electrochromic layer 50 may perform a mutual reaction corresponding to each other. As an example, the porous layer 30 may be an ion storage layer, the electrolyte layer 40 may be an ion migration path and an oxidative color change electrode layer, and the electrochromic layer 50 may be a reduction color change electrode layer. However, the present invention is not limited thereto, and the porous layer 30 may be a reductive color change electrode layer and the electrochromic layer 50 may be an oxidation color change electrode layer. Depending on the voltage applied to the upper and lower electrodes 20 and 60 , hydrogen ions (H+) or lithium ions (Li+) contained in the electrolyte layer 40 are transferred to the porous layer 30 and the electrochromic layer 50 . inserted or detached. At this time, in order to satisfy the charge neutral condition in the compound, the oxidation numbers of the porous layer 30 and the electrochromic layer 50 are changed, and the optical properties of the porous layer 30 and the electrochromic layer 50 themselves (for example, For example, color, transmittance) will change.

The barrier rib 80 may be coupled to the upper and lower electrodes 20 and 60 to couple the separated upper and lower electrodes 20 and 60 to the electrolyte layer 40 . For example, as shown in FIG. 1A , the partition wall 80 may be provided to surround the side surface of the electrolyte layer 40 .

2A and 2B are diagrams illustrating electrochromic characteristics of the electrochromic device 1 of FIG. 1A . More specifically, FIG. 2A is a view showing when the electrochromic materials of the electrochromic device 1 are discolored, and FIG. 2B is a view showing when the electrochromic materials of the electrochromic device 1 are colored.

Referring to FIG. 2A , when a first driving voltage is applied to the electrochromic device 1 , both the electrolyte layer 40 and the electrochromic layer 50 including the electrochromic materials are discolored to transmit light applied from the outside. It can indicate a transparent state. For example, the first driving voltage may be about -3V to 3V. At this time, phenothiazine of the electrolyte layer 40 may be reduced, and tungsten oxide (WOx) of the electrochromic layer 50 may be oxidized. Both the electrolyte layer 40 including reduced phenothiazine and the electrochromic layer 50 including oxidized tungsten oxide (WOx) may be transparent. On the other hand, referring to FIG. 2B , when a second driving voltage is applied to the electrochromic device 1, both the electrolyte layer 40 and the electrochromic layer 50 including the electrochromic materials are colored and applied from the outside. It may indicate a blocking state that blocks light. For example, the second driving voltage may be a voltage of about -3V to 3V. In this case, phenothiazine of the electrolyte layer 40 may be oxidized, and tungsten oxide WOx of the electrochromic layer 50 may be reduced. The electrolyte layer 40 including oxidized phenothiazine may have a red color, and the electrochromic layer 50 including reduced tungsten oxide (WOx) may exhibit a blue color. In this way, by adjusting the applied voltage, it is possible to adjust the coloring, discoloration, and transparency.

3 is a cross-sectional view of an electrochromic device 2 according to an embodiment. The electrochromic element 2 includes a lower substrate 10 , a lower electrode 20 , a porous layer 30 , an electrolyte layer 40 , an electrochromic layer 50 , an upper electrode 62 , an upper substrate 70 , and a partition wall (sealant, 80). For the electrochromic element 2, the same reference numerals are provided to the components substantially the same as those of the electrochromic element 1 described with reference to FIGS. 1A and 1B, and repeated descriptions may be omitted for the sake of simplification of the description. have. The upper electrode 62 may include a first electrode layer 62a and a second electrode layer 62b stacked on each other. The first electrode layer 62a may be a mirror electrode, and the second electrode layer 62b may be a transparent electrode. For example, the first electrode layer 62a may include Ag, and the second electrode layer 62b may include ITO. Alternatively, the upper electrode 62 may be provided as a single mirror electrode. The lower electrode 20 may include ITO or FTO.

A typical electrochromic device includes an electrolyte layer including a first electrochromic material, an electrochromic layer adjacent to the electrolyte layer and including a second electrochromic material, and an opposite electrode of a thin film adjacent to the electrolyte layer and facing the electrochromic layer An electrochromic device having a structure including the following, and having such a structure, is hereinafter referred to as a comparative example. In the electrochromic device according to the comparative example, incomplete discoloration may occur during color changeover, and thus discoloration transmittance may be reduced. As an example, when the electrolyte layer includes phenothiazine and the electrochromic layer includes tungsten oxide (WOx), the color may be incompletely decolorized during decolorization conversion after coloring, thereby exhibiting a red color instead of a transparent color. . However, in the electrochromic devices 1 and 2 according to an embodiment of the present invention, the surface area to volume ratio of the porous layer in contact with the electrolyte layer by including a porous layer on the opposite electrode opposite to the electrochromic layer volume ratio) can be increased. Through this, it is possible to promote the redox reaction of the first electrochromic material of the electrolyte layer, and to increase the decolorization transmittance. Hereinafter, with reference to FIGS. 4 and 5, this will be described supplementarily.

4 is a graph illustrating a reflection spectrum according to a comparative example, and FIG. 5 is a graph illustrating a reflection spectrum using the electrochromic device 2 of FIG. 3 . In FIG. 4, ① is the reflectance at the time of decolorization according to the comparative example, and ② is the reflectance at the time of coloring according to the comparative example. In FIG. 5, ①' is a reflectance at the time of discoloration according to an embodiment of the present invention, and ②' is a reflectance at the time of coloring according to an embodiment of the present invention. The first driving voltage of FIGS. 4 and 5 , that is, the driving voltage during decolorization, may be 0V, and the second driving voltage, ie, the driving voltage during coloring, may be about -1.0V. 4 and 5, the reflectances at the time of coloring according to the comparative example and the embodiment of the present invention are generally similar to each other (see ① and ① '), but the reflectances at the time of decolorization are in one section, that is, in section B. It can be seen that there is a difference (refer to ② and ②'). Compared to FIG. 5 , a phenomenon in which reflectivity is lowered occurs in section B of FIG. 4 . Section B may be about 480 nm to 530 nm. That is, according to the comparative example, it can be confirmed that the electrochromic element has a red color by absorbing green-based visible light when discolored. On the other hand, according to an embodiment of the present invention, it can be understood that the absorption of green-based visible light is prevented during color decolorization conversion, and thus decolorization transmittance is improved.

FIG. 6 is a graph showing a transmission spectrum using the electrochromic device 1 of FIG. 1 . As described above, the upper electrode 60 and the lower electrode 20 of the electrochromic device 1 of FIG. 1 may be provided as transparent electrodes. 3 in FIG. 6 is the transmittance of the electrochromic element 1 at the time of discoloration, and 4 is the transmittance of the electrochromic element 1 at the time of coloring. The first driving voltage, ie, the driving voltage during decolorization, may be 0 V, and the second driving voltage, ie, the driving voltage during coloring, may be about -1.2 V. Referring to FIG. 6 , the spectral dimple phenomenon does not occur in the B section in the transmittance at the time of decolorization. In other words, it can be seen that there is no red afterimage on the electrochromic device during discoloration.

An electrochromic device according to embodiments of the present invention includes an electrolyte layer including a first electrochromic material, an electrochromic layer including a second electrochromic material between the electrolyte layer and the first electrode, and between the electrolyte layer and the second electrode Including a porous layer containing a porous metal oxide to prevent loss of discoloration transmittance and remove discoloration afterimages. On the other hand, when phenothiazine included in the electrolyte layer is incompletely reduced, the electrochromic device may exhibit a discoloration afterimage, for example, the electrochromic device has a red color. In addition, when the electrochromic device according to embodiments of the present invention includes a mirror, light reflectivity may be improved. Also, referring to FIGS. 4 to 6 , it can be seen that the present invention can be applied to both a transmissive electrochromic device and a reflective electrochromic device.

In the above embodiments, the electrochromic devices have been described as including upper/lower substrates and upper/lower electrodes. However, the present invention is not limited thereto.

As mentioned above, although embodiments of the present invention have been described with reference to the accompanying drawings, those of ordinary skill in the art to which the present invention pertains can implement the present invention in other specific forms without changing its technical spirit or essential features. You can understand that there is Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (9)

a first electrode and an electrochromic layer on the first electrode;
a second electrode facing the first electrode and a coating layer on the second electrode; and
An electrolyte layer interposed between the electrochromic layer and the coating layer,
the electrolyte layer comprises a first electrochromic material, the electrochromic layer comprises a second electrochromic material, and the coating layer comprises a porous metal oxide;
The electrochromic layer and the coating layer are spaced apart from each other with the electrolyte layer therebetween,
wherein the first electrochromic material comprises phenothiazine;
the second electrochromic material comprises tungsten oxide;
The porous metal oxide includes _{at least one of TiO 2} (Titanium dioxide), ITO (indium tin oxide), FTO (fluorinated tin oxide), ZnO, SnO ₂ and Antimony-doped tin oxide, electrochromic device.
delete delete delete delete delete delete delete delete

Images