CN114415435A - Multicolor electrochromic device and method of making the same, display panel, and display device - Google Patents

Abstract

The invention provides a multicolor electrochromic device, a manufacturing method thereof, a display panel and a display device. The resonant cavity structure provided by the invention improves the reflectivity and the color display range of the electrochromic device, and the resonant cavity structure and the electrochromic layer of the counter electrode form a complementary electrochromic device to further expand the color change range. The display panel based on the multicolor electrochromic device can realize color display by adopting 1 or 2 sub-pixels, and the reflection display brightness of the display panel is greatly improved.

Description

Multicolor electrochromic device and method of making the same, display panel, and display device

technical field

The present invention relates to the field of display technology, and in particular, to a multi-color electrochromic device and a manufacturing method thereof, a display panel and a display device.

Background technique

Traditional displays (such as liquid crystal displays, organic light-emitting diode displays) use backlighting or self-illumination to display text or images on the screen. Such displays work well in low ambient light indoors, but when used outdoors in strong ambient light , because the reflected light intensity of ambient light on the screen surface is greatly increased, the contrast of the display screen is reduced, and the viewing effect is seriously affected.

Reflective displays have always been favored by display technology researchers due to their low power consumption, excellent outdoor readability, light weight, and eye protection. However, reflective displays have been unable to achieve the same display effect as traditional displays used for indoor displays due to many challenges in optical design. In transmissive display or self-luminous display, the problem of low light efficiency can be solved simply by increasing the power consumption. However, for reflective display technology, because it does not require an internal light source, the low light efficiency of the pixel will directly lead to the degradation of image quality.

Common reflective display technologies include reflective liquid crystal display technology and electronic ink (E-ink) display. Reflective liquid crystal displays have the advantages of high refresh rate and color display, and have been used in educational flat panel, outdoor industrial control display and other fields, but due to the loss of light efficiency on polarizers and color filters, and the addition of directional scattering films or diffuse reflections After the structure, the balance of light effect and viewing angle leads to poor display effect. E-ink display has the advantages of high contrast ratio and large viewing angle of black and white display, and has been used in the fields of e-book display, electronic price tag and smart conference display, but it also faces the problem of low light efficiency when developing color display, and The problem of low refresh rate limited by its own working principle greatly limits the wide application of electronic ink display in other fields.

The electrochromic device is to adjust the structure and optical constants (refractive index and extinction coefficient) of the electrochromic layer material by controlling the external electric field, so that the optical properties (reflectivity, transmittance or absorptivity) of the electrochromic device are changed. Appears as a stable, reversible color change. Therefore, electrochromic devices can in principle be used for transmissive or reflective displays. However, for specific electrochromic materials or electrochromic devices prepared with them, the color change is limited, especially for inorganic electrochromic materials with relatively stable properties, which generally only have two color changes, which greatly limits the application of electrochromic Applications in display, camouflage, and imaging devices.

Patent CN104423114A discloses an all-solid-state electrochromic composite device, which forms a variety of colors through the combination of a PVD decorative plating color layer and an electrochromic layer, but the modulation color range is limited, such as changing from light green to blue, black to ink. Change between blue and so on. Patent CN111624829A discloses a colorful electrochromic structure, which consists of a metal reflective layer and an electrochromic material layer to form an optical cavity. The color modulation range of the scheme is still limited, and its reflectivity is less than 50%, making it impossible to form a practical reflection display.

How to develop a multi-color electrochromic device with modulation characteristics of multiple primary colors (such as three primary colors, five primary colors, or six primary colors, etc.) has become a difficult problem to be solved in the art.

SUMMARY OF THE INVENTION

In a first aspect, an embodiment of the present invention provides a multi-color electrochromic device, comprising: a first substrate, a second substrate, and an electrolyte layer disposed between the first substrate and the second substrate, the first substrate comprising: a first substrate, a working electrode disposed on the side of the first substrate facing the electrolyte layer; the second substrate includes a second substrate, a pair of electrodes disposed on the side of the second substrate facing the electrolyte layer electrode; wherein, the working electrode is a resonant cavity structure, and the resonant cavity structure includes a metal reflection layer, a dielectric layer and a broadband absorption layer that are stacked in sequence, and the resonant cavity structure can be realized by adjusting the thickness of the dielectric layer. Different reflective structural color adjustment, through the modulation of the external electric field, can realize a variety of color changes.

Preferably, the material of the metal reflective layer is an inactive metal; preferably, the inactive metal includes gold (Au), silver (Ag), copper (Cu), platinum (Pt), aluminum (Al) or titanium (Ti), and a composite metal formed by a variety of metals; the thickness of the metal reflective layer is above 20 nm, preferably 50-500 nm;

The material of the dielectric layer is an inorganic electrochromic material and/or an organic electrochromic material; the thickness of the dielectric layer is 10-3000 nm, preferably 50-800 nm;

The material of the broadband absorption layer includes transition metal, FeSi ₂ , amorphous silicon, or noble metal; the transition metal is preferably Cr, Ni, Ti, and the noble metal is preferably Au, Pt; the thickness of the broadband absorption layer is 5～ 50nm, preferably 5-15nm;

The material of the electrolyte layer includes liquid electrolyte, gel electrolyte and solid electrolyte; the thickness of the liquid electrolyte layer is 0.01-3 mm; the thickness of the gel electrolyte layer is 0.1-500 μm; the thickness of the solid electrolyte layer is 10-500 nm ;

The counter electrode includes a transparent conductive electrode and an electrochromic layer that are stacked in sequence; the electrochromic layer in the counter electrode has both an ion storage function; the material of the electrochromic layer includes inorganic electrochromic materials and/or Or an organic electrochromic material; the thickness of the electrochromic layer is 10-1000 nm, preferably 50-800 nm.

Preferably, the metal reflective layer is a reticulated hollow structure; the material of the metal reflective layer is an inactive metal; preferably, the inactive metal includes Au, Ag, Cu, Pt, Al or Ti, and various Composite metals formed from metals;

And/or, the thickness of the metal reflective layer is 20 nm or more, preferably 50-500 nm; the line width of the mesh-shaped hollow is 0.1-20 μm, preferably 1-10 μm.

As a first preference, the broadband absorption layer is a metal nanoporous structure layer; the metal is a noble metal, preferably Au and Pt;

And/or, the thickness of the metal nanopore structure layer is 5-50 nm, preferably 10-20 nm; the diameter of the nanopore is 10-500 nm, preferably 100-300 nm.

As a second preference, the broadband absorption layer is a network hollow structure; the broadband absorption layer is made of transition metal, FeSi ₂ , amorphous silicon, or noble metal; the transition metal is preferably Cr, Ni, Ti, and the Preferable precious metals are Au and Pt;

And/or, the thickness of the broadband absorption layer is 5-50 nm, preferably 5-15 nm; the width of the mesh-shaped hollow line is 0.1-20 μm, preferably 1-10 μm.

Preferably, the materials of the first substrate and the second substrate include glass, polymer plastic materials, and metal foils (eg, stainless steel foils).

In a second aspect, an embodiment of the present invention provides the above-mentioned method for preparing a multicolor electrochromic device, comprising the following steps:

forming a metal reflective layer, a dielectric layer and a broadband absorbing layer in sequence on the first substrate to obtain a first substrate;

forming a transparent conductive electrode and an electrochromic layer in sequence on the second substrate to obtain a second substrate;

sealing the first and second substrates along their peripheral regions and defining a cavity; and

An electrolyte is disposed in the cavity.

In a third aspect, an embodiment of the present invention further provides a display panel, comprising: the above-mentioned multi-color electrochromic device.

Preferably, the display panel includes: a plurality of sub-pixels, and each of the sub-pixels includes at least one of the multi-color electrochromic devices stacked in sequence.

In a fourth aspect, an embodiment of the present invention further provides a display device, including: the above-mentioned display panel.

The beneficial effects of the present invention are as follows:

The resonant cavity structure provided by the invention improves the reflectivity and color display range of the electrochromic device, and the resonant cavity structure and the electrochromic layer of the counter electrode form a complementary electrochromic device to further expand the color variation range. The display panel based on the multi-color electrochromic device of the present invention can realize color display by using one or two sub-pixels, and greatly improves the reflective display brightness of the display panel.

Description of drawings

1 is a schematic structural diagram of a multicolor electrochromic device provided by an embodiment of the present invention;

2 is a schematic structural diagram of a first substrate (metal reflection layer/dielectric layer/broadband absorption layer) provided by an embodiment of the present invention;

3 is a schematic diagram of a mesh hollow structure of a reflective metal layer or a broadband absorption layer provided by an embodiment of the present invention;

4 is a schematic structural diagram of another first substrate (metal reflective layer/dielectric layer/metal nanoporous structure layer) provided by an embodiment of the present invention;

5 is a schematic structural diagram of another first substrate (broadband absorption layer/dielectric layer/metal nanoporous structure layer) provided by an embodiment of the present invention;

6 is a schematic structural diagram of a second substrate provided by an embodiment of the present invention;

7 is a schematic structural diagram of a display panel based on two multi-color electrochromic devices according to an embodiment of the present invention;

8 is a schematic structural diagram of a display panel based on three multi-color electrochromic devices according to an embodiment of the present invention;

9 is a schematic structural diagram of another display panel based on three multicolor electrochromic devices according to an embodiment of the present invention;

10 is a schematic structural diagram of a resonant cavity (Ag/WO ₃ /Au nanoporous film) and a Prussian blue-like complementary electrochromic device provided in an embodiment of the present invention;

11 is a schematic diagram of a non-uniform Au nanopore array prepared by a colloidal etching process according to an embodiment of the present invention;

12 is a schematic structural diagram of a resonant cavity (Al/WO ₃ /Cr) and a Prussian blue-like thin film complementary multicolor flexible electrochromic device provided in an embodiment of the present invention;

FIG. 13 provides reflection spectra of Glass/ITO/Al/WO ₃ /Cr under different thicknesses of tungsten trioxide according to an embodiment of the present invention;

14 is a schematic structural diagram of a reflective type (Glass/Cr/WO ₃ /Al nanoporous film) bottom color multicolor electrochromic device provided by an embodiment of the present invention;

FIG. 15 is a schematic diagram of a non-uniform Au nanohole array prepared by a nanoimprint process provided in an embodiment of the present invention;

Reference numerals: 1 first substrate; 11 first substrate; 12 working electrode; 121 metal reflection layer; 122 dielectric layer; 123 broadband absorption layer; 124 metal nanoporous structure layer; 2 second substrate; 21 second substrate 22 pairs of electrodes; 221 transparent conductive electrodes; 222 electrochromic layers; 3 electrolyte layers; 4 sealants.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the specific implementations of the multi-color electrochromic device and its manufacturing method, display panel, and display device provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

The first aspect of the embodiments of the present invention provides a multi-color electrochromic device, which is used to solve the problem that the electrochromic device in the prior art has few types of variable colors, and the low reflectivity leads to low light efficiency utilization, which cannot be used for mature problems for industrial applications.

In view of the above technical problems, the embodiments of the present invention provide the following technical solutions:

FIG. 1 is a schematic structural diagram of a multicolor electrochromic device provided by an embodiment of the present invention, and FIG. 2 is a schematic structural schematic diagram of a first substrate provided by an embodiment of the present invention. 1 and 2, the multi-color electrochromic device includes: a first substrate 1 (including a first substrate 11, a working electrode 12), a second substrate 2 (including a second substrate 21, a counter electrode 22), The electrolyte layer 3 between the working electrode 12 and the counter electrode 22 , and the sealant 4 for sealing the working electrode 12 and the counter electrode 22 .

The working electrode 12 is a resonant cavity structure, including a metal reflective layer 121, a dielectric layer 122 and a broadband absorption layer 123 that are stacked in sequence. By adjusting the thickness of the dielectric layer, the resonant cavity structure can achieve different reflective structural color adjustment. Electric field modulation enables a variety of color changes.

It is found in the present invention that the wavelength selection function can be realized by using the above-mentioned resonant cavity structure, and then full color can be obtained.

Specifically, referring to FIG. 2 , the first substrate 1 includes a first substrate 11 , a metal reflection layer 121 , a dielectric layer 122 and a broadband absorption layer 123 which are stacked in sequence. in,

The first substrate is glass, polymer plastic material, metal foil (eg stainless steel foil).

The material of the metal reflective layer is an inactive metal; preferably, the inactive metal includes Au, Ag, Cu, Pt, Al or Ti, and a composite metal formed by a variety of metals; the thickness of the metal reflective layer is above 20 nm, preferably 50-500 nm. The present invention further finds that by using the above inactive metal, the formed resonant cavity structure can not only realize the wavelength selection function, but also have higher reflectivity.

The dielectric layer is mainly composed of electrochromic materials, including inorganic electrochromic materials and/or organic electrochromic materials. Wherein, the inorganic electrochromic material includes any one or a combination of transition metal oxides, Prussian blue or its derivatives, and heteropolyacids; preferably transition metal oxides, transition metal oxides include W, Ni, Ti , Nb, Fe, Co or Mo elements in combination with any one or more of the compounds formed with oxygen. Organic electrochromic materials include any one or a combination of organic small molecules, conductive polymers, and metal-organic compounds. As an example, the organic small molecule includes viologen and methyl viologen; the conductive polymer includes any one or a combination of polyaniline, polythiophene, and polypyrrole; and the metal-organic compound is a metal-organic chelate. The thickness of the dielectric layer is 10-3000 nm, preferably 50-800 nm.

The materials of the broadband absorption layer include transition metals such as Cr, Ni, Ti, FeSi ₂ , amorphous silicon or noble metals such as Au and Pt. The thickness of the broadband absorption layer is 5 to 50 nm, preferably 5 to 15 nm.

In some preferred embodiments, the broadband absorbing layer is a reticulated hollow structure, and FIG. 3 shows a schematic diagram of the reticulated hollow structure of the broadband absorbing layer; the materials of the broadband absorbing layer are transition metals such as Cr, Ni, Ti, FeSi ₂ , non-metallic Crystalline silicon, or noble metals such as Au and Pt; the thickness of the broadband absorption layer is 5-50 nm, preferably 5-15 nm; the width of the mesh hollow line is 0.1-20 μm, preferably 1-10 μm. The present invention further finds that the hollow area of the broadband absorption layer of the network hollow structure is connected with the electrochromic material and the electrolyte, thereby reducing the response time of the multicolor electrochromic device.

In some preferred embodiments, in order to increase the adhesion between the metal reflective layer and the first substrate, a transition layer can be added between the first substrate and the metal reflective layer. Preferably, the materials of the transition layer are Cr and Ti, and the thickness of the transition layer is 1-20 nm.

FIG. 4 is a schematic structural diagram of another first substrate (metal reflective layer/dielectric layer/metal nanoporous structure layer) according to an embodiment of the present invention. Referring to FIG. 4 , the first substrate includes a first substrate 11 , a metal reflective layer 121 , a dielectric layer 122 and a metal nanoporous structure layer 124 which are stacked in sequence. in,

The first substrate is glass, polymer plastic material, metal foil (eg stainless steel foil).

The metal reflective layer is an inactive metal; preferably, the inactive metal includes gold, silver, copper or titanium; the thickness of the metal layer is above 20 nm, preferably 50-500 nm.

The dielectric layer is mainly composed of electrochromic materials, including inorganic electrochromic materials and organic electrochromic materials. Wherein, the inorganic electrochromic material includes any one or a combination of transition metal oxides, Prussian blue or its derivatives, and heteropolyacids; preferably transition metal oxides, transition metal oxides include W, Ni, Ti , Nb, Fe, Co or Mo elements in combination with any one or more compounds formed by oxygen. The organic electrochromic material includes any one or a combination of small organic molecules, conductive polymers, and metal-organic compounds; as an example, the small organic molecules include viologen and methyl viologen; the conductive polymer includes polyaniline A combination of any one or more of , polythiophene and polypyrrole; the metal organic compound is a metal organic chelate compound. The thickness of the dielectric layer is 1-3000 nm, preferably 50-500 nm.

The material of the metal nanoporous structure layer is noble metal, preferably gold and platinum. The thickness of the metal nanoporous structure layer is 5-50 nm, preferably 10-20 nm. The nanopore diameter of the metal nanopore structure layer is 50-500 nm, preferably 100-300 nm.

The present invention further finds that the metal nanoporous structure layer has the following functions: forming a resonant cavity structure, realizing the wavelength selection function, and high reflectivity; having a plasma enhancement effect, which can increase the reflectivity of the resonant cavity; It can increase the viewing angle of the resonant cavity; it can have the effect of decolorization; the nanopores in the metal nanopore structure connect the electrochromic layer and the electrolyte layer, so that ions can be quickly injected into or out of the electrochromic layer, increasing the electrochromic layer. Color change response time.

Likewise, in order to increase the adhesion between the metal reflective layer and the first substrate, a transition layer may be provided between the first substrate and the metal reflective layer. Preferably, the materials of the transition layer are Cr and Ti, and the thickness of the transition layer is 1-20 nm.

FIG. 5 is a schematic structural diagram of another first substrate (broadband absorption layer/dielectric layer/metal nanoporous structure layer) according to an embodiment of the present invention. The present invention further finds that the metal reflective layer and the broadband absorbing layer can be reversed in position, referring to FIG. By adjusting the thickness of the dielectric layer, different reflective structural colors can be adjusted. The reflection structure color of the broadband absorption layer/dielectric layer/metal nanoporous film structure in this embodiment belongs to the bottom reflection type structure, that is, both incoming light and outgoing light pass through the first substrate. in,

The materials of the broadband absorption layer include Cr, Ni, Ti, FeSi ₂ , and amorphous silicon. The thickness of the broadband absorption layer is 5 to 50 nm, preferably 5 to 15 nm.

The dielectric layer is mainly composed of electrochromic materials, including inorganic electrochromic materials and organic electrochromic materials. Inorganic electrochromic materials include transition metal oxides, Prussian blue or its derivatives, and a combination of any one or more of heteropolyacids; preferably transition metal oxides, including W, Ni, Ti, Nb, Fe, Co Or a compound formed by any one or more combination of Mo elements and oxygen. The organic electrochromic material includes any one or a combination of small organic molecules, conductive polymers, and metal-organic compounds; preferably, the small organic molecules include viologen and methyl viologen; the conductive polymer includes polyaniline A combination of any one or more of , polythiophene and polypyrrole; the metal organic compound is a metal organic chelate compound. The thickness of the dielectric layer is 0 to 3000 nm, preferably 50 to 500 nm.

The material of the metal nanopore structure layer includes gold, platinum, silver, aluminum and copper; the thickness of the metal nanopore film is 20-200 nm, preferably 50-100 nm; the diameter of the nano-pore is 50-500 nm, preferably 100-300 nm; the nano-pore period is 50 ~1000 nm, preferably 100 to 500 nm.

In some preferred embodiments, the metal reflective layer is a reticulated hollow structure, and FIG. 3 shows a schematic diagram of the reticulated hollow structure of the metal reflective layer; the material of the reflective layer is an inactive metal; the inactive metal material includes Au, Ag, A composite metal formed of Cu, Pt, Al or Ti, and various metals; the thickness of the metal reflective layer is more than 20 nm, preferably 50-500 nm; the width of the mesh hollow line is 0.1-20 μm, preferably 1-10 μm. The present invention further finds that the hollow area of the reflective layer of the mesh hollow structure is connected with the electrochromic material and the electrolyte, thereby reducing the response time of the multi-color electrochromic device.

FIG. 6 is a schematic structural diagram of a second substrate according to an embodiment of the present invention. Referring to FIG. 6 , the second substrate includes a second substrate 21 , a transparent conductive electrode 221 and an electrochromic layer 222 that are stacked in sequence. in:

The second substrate is a visible light transparent material, including glass, and a polymer plastic material, such as any one of polyethylene terephthalate (PET), polyimide (PI), and polycarbonate (PC).

The transparent conductive electrode includes any one of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), silver nanowire film, and carbon nanotube film.

Materials of the electrochromic layer include inorganic electrochromic materials and/or organic electrochromic materials. Preferably, the material of the electrochromic layer is an anode electrochromic material, including Prussian blue and nickel oxide. More preferably, the anodic electrochromic material is a Prussian blue-like material; further, the Prussian blue-like material includes at least one of Prussian blue, Prussian blue analogs and derivatives thereof. The thickness of the Prussian blue-like thin film is preferably 50 to 800 nm.

Among them, the chemical formula of Prussian blue is Fe ₄ [Fe(CN) ₆ ] ₃ ·mH ₂ O (m=14-16); the general formula of Prussian blue analogs is A _x M _A [M _B (CN) ₆ ] _y nH ₂ O (x, y, n are stoichiometric ratios), _A is K ⁺ , Na ⁺ conducting ions, MA and _MB are transition metal elements such as Mn, Fe, Co, Ni or Cu; or Na _x M[Fe(CN) ₆ ]·nH ₂ O (n is the stoichiometric ratio), where M is one of Mn, Fe, Co, Ni or Cu; the derivatives of Prussian blue and its analogs are Using Prussian blue and its analogs as sacrificial templates, various core-shell, hollow-shell and other nanostructured materials with different morphologies, compositions, sizes, shapes and chemical properties were designed.

The function of the electrolyte layer provided in the present invention in the multi-color electrochromic device is to provide active ion channels connected to each other for the color-changing electrodes, and to isolate electron conduction. The material of the electrolyte layer includes liquid electrolyte, gel electrolyte, and solid electrolyte; preferably, the liquid electrolyte uses propylene carbonate as solvent, lithium perchlorate and organic weak acid as solutes, and further preferably, in molar concentration, lithium perchlorate is used as the solute. It is 0.08 to 0.12 mol/L, and the organic weak acid is 0.008 to 0.012 mol/L.

The present invention further finds that the electrochromic performance stability of the Prussian blue film is improved by introducing an organic weak acid into the Li ⁺ electrolyte system to optimize the pH value of the electrolyte and inhibit the combination of OH ⁱⁿ the electrolyte and the iron ions in Prussian blue. . Preferably, the weak organic acid is at least one of citric acid, oxalic acid and acetic acid. The above organic weak acid can not only effectively inhibit the combination of OH ⁱⁿ the electrolyte and the iron ion in Prussian blue, but also will not destroy other chemical reactions and avoid the failure of the electrolyte system.

A second aspect of the embodiment of the present invention provides the above-mentioned preparation method of a multicolor electrochromic device, comprising the following steps:

forming a metal reflective layer, a dielectric layer and a broadband absorbing layer in sequence on the first substrate to obtain a first substrate;

forming a transparent conductive electrode and an electrochromic layer in sequence on the second substrate to obtain a second substrate;

sealing the first and second substrates along their peripheral regions and defining a cavity; and

An electrolyte is disposed in the cavity.

Wherein, the preparation method of the metal reflective layer includes but is not limited to any one of magnetron sputtering, thermal evaporation, electron beam evaporation, ion plating, and electrochemical deposition;

The preparation method of the dielectric layer includes, but is not limited to, any one of magnetron sputtering, thermal evaporation, electron beam evaporation, ion plating, electrochemical deposition, and chemical vapor deposition.

When the material of the broadband absorption layer includes Cr, Ni, Ti, _FeSi2 or amorphous silicon, the preparation method of the broadband absorption layer includes but is not limited to magnetron sputtering, thermal evaporation, electron beam evaporation, ion plating, chemical vapor deposition , any method in electrochemical deposition.

When the broadband absorption layer is a metal nanoporous structure layer, its preparation method includes but is not limited to colloidal etching and nanoimprinting.

When the broadband absorption layer is a network hollow structure, its preparation method includes but is not limited to mask evaporation, and exposure, development, and etching processes commonly used in semiconductor technology.

A third aspect of the embodiments of the present invention provides a display panel based on the above-mentioned multi-color electrochromic device.

Traditional color display generally introduces sub-pixels to form display pixels, and the number of sub-pixels is generally three, that is, a display mode of three primary colors is used, and the three primary colors are red, green, blue or cyan, magenta, and yellow. Taking the most widely used electronic ink display in reflective display as an example, its grayscale is adjusted by the area ratio of black particles, and the color is realized by adding a color filter. The reflectivity of each sub-pixel displayed by the electronic ink is less than 50%. In order to form a color, the reflectivity of the pixel needs to be reduced by more than 3 times. Therefore, the color display effect is poor.

Since a single multi-color electrochromic device of the present invention can display multiple colors. Therefore, the display mode of the display panel composed of multi-color electrochromic devices is different from that of the conventional display. A display panel based on a multi-color electrochromic device can realize color display by using one or two sub-pixels, which can greatly improve the reflective display brightness of the display panel. The present invention designs a display panel based on a multicolor electrochromic device.

The first display panels based on multicolor electrochromic devices employed two sub-pixels. FIG. 7 is a schematic structural diagram of a display panel composed of two multicolor electrochromic devices according to an embodiment of the present invention. Referring to Figure 7, each sub-pixel can display other colors such as red, yellow, green and blue. When both sub-pixels display red, the pixel displays red; when both sub-pixels display green, the pixel displays green; when both sub-pixels display green, the pixel displays green; When all the pixels display blue, the pixel displays blue; when the two sub-pixels display blue and yellow respectively, the pixel displays white; since the multicolor electrochromic device of the present invention displays red, yellow, green and blue, Colors such as orange, yellow-green, and cyan can also be displayed, so with the combination of two sub-pixels, the pixel can display rich colors.

FIG. 8 is a schematic structural diagram of a display panel based on three multicolor electrochromic devices according to an embodiment of the present invention. Referring to Fig. 8, the pixel of the display panel is composed of three sub-pixels, each sub-pixel can display other colors such as red, green and blue, when all three sub-pixels display red, the pixel displays red; when all three sub-pixels display green When the three sub-pixels display blue, the pixel displays blue; when the three sub-pixels display red, green, and blue, respectively, the pixel displays white; when the three sub-pixels display red, red, and green, respectively When , the pixel displays yellow; since the multi-color electrochromic device can display orange, yellow-green, and blue-green colors in addition to red, green, and blue, the pixel can display rich colors through the combination of three sub-pixels.

FIG. 9 is a schematic structural diagram of another display panel based on three multi-color electrochromic devices according to an embodiment of the present invention. Referring to FIG. 9 , the pixels of the display panel are composed of three sub-pixels, the three sub-pixels include red, green and blue pixels, and the three sub-pixels can be switched between red/black, green/black and blue/black respectively. When the red sub-pixel is turned on and the green and blue sub-pixels are turned off, the pixel displays red; when the green sub-pixel is turned on and the red and blue sub-pixels are turned off, the pixel displays green; when the blue sub-pixel is turned on and the green and red sub-pixels are turned off , the pixel displays blue; when the red, green and blue sub-pixels are all turned on, the pixel displays white; when the red, green and blue sub-pixels are all turned off, the pixel displays black; since the multi-color electrochromic device can be adjusted by adjusting The reflectivity can be adjusted by voltage or time, so through the combination of three sub-pixels, the pixels can be freely switched between color and black to display rich colors.

A fourth aspect of the embodiments of the present invention provides a display device based on the above-mentioned display panel. The display device can be any product or component with a display function, such as an electronic book, a mobile phone, a tablet computer, a TV, a monitor, a notebook computer, a digital photo frame or a navigator.

Example 1

As shown in FIG. 10 , this embodiment provides a complementary multi-color electrochromic device composed of a resonant cavity (Ag/WO ₃ /Au nanoporous film) and a Prussian blue-like film, which belongs to a reflective top color rendering structure, including :

The first substrate includes a first substrate 11, a metal reflection layer 121, a dielectric layer 122, and a metal nanoporous structure layer 124 in a stacking sequence, wherein the first substrate is glass, the metal reflection layer is a metal Ag film, and the dielectric layer is Tungsten trioxide film, the metal nanoporous structure layer is gold nanoporous film;

The second substrate includes a second substrate 21, a transparent conductive electrode 221, and an electrochromic layer 222 in a stacking sequence, wherein the second substrate is glass, the transparent conductive electrode is an ITO transparent conductive layer, and the electrochromic layer is a Prussian-like layer blue film;

The frame sealant 4 is substantially disposed between the peripheral regions of the first substrate and the second substrate in the circumferential direction, so as to seal the upper surface of the metal nanoporous structure layer 124 and the lower surface of the electrochromic layer 222 to each other and define a cavity; and

Electrolyte 3 is provided in the cavity. The electrolyte uses propylene carbonate as solvent, lithium perchlorate and acetic acid as solutes, and in molar concentration, lithium perchlorate is 0.1 mol/L and acetic acid is 0.01 mol/L; the pH value of the electrolyte is 3.

The working mechanism of the resonant cavity and the Prussian blue complementary electrochromic device in this embodiment is as follows: the tungsten trioxide in the resonant cavity is a cathodic color changing material. When the power is turned on, the tungsten trioxide obtains electrons, and the optical constant of the material changes, which in turn causes The resonant cavity has a structural color that does not pass through; while Prussian blue is an anodic electrochromic material, which is a coordination compound that can coordinately combine with Li ^{+ and H + in the electrolyte. When electrified, the coordination combines Li + and} H ⁺ The Prussian blue film of H ⁺ loses electrons and changes from a transparent state to a blue colored state; Li ⁺ and H ⁺ in the electrolyte play a synergistic role in ion transport; the structural color of the resonant cavity is controlled by the electric field and the electrochromic state of Prussian blue Composite, to achieve the effect of multiple color regulation of a single device.

The preparation method of the resonant cavity and the Prussian blue complementary multicolor electrochromic device of the present embodiment includes the following steps:

Preparation of the first substrate:

The glass substrate is placed in a vacuum chamber, the back is vacuumed to below 3×10 ^-4 Pa, the argon flow rate is 50sccm, the deposition pressure is 1.5Pa, the sputtering power is 50W, the target is a metal Ag target, and the glass substrate is sputtered on the glass substrate by DC sputtering. Ag film layer is deposited on the top, and the thickness of the Ag film layer is controlled to 150nm;

The backside was evacuated to less than 3×10 ^-4 Pa, the flow rate of argon gas was 80 sccm, the flow rate of oxygen gas was 10 sccm, the deposition pressure was 3.0 Pa, the sputtering power was 50 W, and the target was tungsten trioxide, which was sputtered on the Ag film by radio frequency. A tungsten trioxide film is deposited, and the thickness of the tungsten trioxide film is controlled to be 120nm;

The tungsten trioxide film was treated in a weak oxygen plasma (50W) for 60 s to increase the surface wettability; then the glass/ _Ag /WO3 was immersed in 2.5 wt.% polydiallyldimethylammonium chloride ( PDDA) solution for 2 minutes to form a single polyelectrolyte layer on the surface of the tungsten trioxide film, and the substrate was carefully rinsed in deionized water to remove excess PDDA, and dried with nitrogen; secondly, a layer of PDDA-modified substrate was covered ²⁰ μL/cm of polystyrene nanoparticle solution (0.5 wt.%), after 30 min, tilt the substrate to nearly 90° and hold for 5 s to let the excess solution flow out, then, immerse the substrate in boiling water 5s, blow dry with nitrogen; then, DC sputtering is used, the target is Au target, the back is vacuumed to below 3 × 10 ^-4 Pa, the flow rate of argon is 50sccm, the deposition pressure is 1.5Pa, the sputtering power is 50W, and the sputtering power is 50W. An Au film was deposited on the surface of the styrene nanopore array, and the thickness of the Au film layer was controlled to be 20 nm; finally, the sample was soaked in toluene and sonicated for 30 minutes to remove all polystyrene nanospheres, thereby forming a non-uniform Au nanopore array. Among them, the preparation steps of the polystyrene nanoparticle solution are: add 90mL of deionized water to a 250mL three-necked round bottom flask, heat the oil bath to 80°C; then add 8.5mL of clean styrene to form 200nm nanospheres, The mixed solution was kept at 80 °C for 5 minutes under constant nitrogen purge and reflux; 350 mg of potassium persulfate and 50 mg of sodium dodecyl sulfate were dissolved in 10 mL of deionized water, kept at 65 °C, and the solution was added to a three-necked flask The synthesis was started in 2000, and the synthesis was completed after 4 hours; the synthesized polystyrene nanosphere solution was centrifuged at 6000 rpm, washed 4 times with deionized water before use, and the obtained polystyrene solution was mixed with ethanol 1:1, adjusted to About 1 wt.% (see Figure 11 for the specific process).

The resonant cavity film layer formed by the fabrication is displayed in red under natural light.

Preparation of the second substrate:

Prussian blue-like electrochromic thin films were prepared by magnetron sputtering on glass substrate by magnetron sputtering deposition of ITO transparent conductive electrode and electrochemical deposition method;

Prepare a precursor solution consisting of 10 mmol/L FeCl ₃ ·6H ₂ O, 10 mmol/L K ₃ Fe(CN) ₆ , 0.1 mol/L KCl and 0.1 mol/L HCl; The substrate is the working electrode, and the Pt sheet is used as the counter electrode to form an electrochemical deposition working cell, and the prepared precursor solution is added. ₄ [Fe(CN) ₆ ] type ₃ Prussian blue film, the thickness of this type of Prussian blue film is 500 nm;

The Prussian blue-like film formed by the fabrication is dark blue;

Box assembling process: the above-mentioned first substrate and second substrate are bonded along their peripheral regions by a frame sealant, and a cavity is defined;

Electrolyte perfusion: add 0.1 mol/L lithium perchlorate and 0.01 mol/L acetic acid to propylene carbonate to configure an electrolyte with a pH value of 3; then vacuum it into the cavity of the box; After packaging, the resonant cavity and Prussian blue complementary multicolor electrochromic device is obtained.

The resonant cavity of this embodiment and the Prussian blue complementary multi-color electrochromic device can obtain full colors, such as red, orange, yellow, green, blue-green and blue, by adjusting the voltage. Specifically: when a positive voltage is applied by a DC regulated power supply, the Prussian blue fades, and the device changes from blue to red; when a negative voltage is applied, by adjusting the voltage or time, the device can display red, orange, yellow, green, blue-green and blue.

Example 2

As shown in FIG. 12 , this embodiment provides a complementary multi-color flexible electrochromic device composed of a resonant cavity (Al/WO ₃ /Cr) and a Prussian blue-like film, which belongs to a reflective top color rendering structure, including:

The first substrate includes a first substrate 11, a metal reflection layer 121, a dielectric layer 122, and a broadband absorption layer 123 in a stacking sequence, wherein the first substrate is a polyimide film, the metal reflection layer is a metal Al film, and the dielectric The layer is a tungsten trioxide film, and the broadband absorption layer is a metal Cr film;

The second substrate includes a second substrate 21, a transparent conductive electrode 221, and an electrochromic layer 222 in a stacking sequence, wherein the second substrate is a transparent polyimide film; the transparent conductive electrode is an ITO transparent conductive layer; The color-changing layer is a Prussian blue-like film;

a frame sealant, arranged between the peripheral regions of the first substrate and the second substrate substantially along the circumferential direction, so as to seal the upper surface of the broadband absorption layer 123 and the lower surface of the electrochromic layer 222 to each other and define a cavity; as well as

The electrolyte is provided in the cavity. The electrolyte uses propylene carbonate as a solvent, lithium perchlorate and acetic acid as solutes, and in terms of molar concentration, lithium perchlorate is 0.1 mol/L and acetic acid is 0.01 mol/L; the pH of the electrolyte is 3.

As shown in FIG. 13 , by changing the thickness of the tungsten trioxide film in the working electrode, the reflection spectrum of the first substrate is different, and different colors can be reflected and displayed.

The preparation method of the resonant cavity and the Prussian blue complementary multicolor electrochromic device of the present embodiment includes the following steps:

Preparation of the first substrate:

The manufacturing steps of preparing the metal Cr/Al/WO ₃ /Cr film layer by the electron beam evaporation method are as follows: placing the crucible containing the metal Cr, Al and WO ₃ evaporation materials and the first polyimide substrate in a vacuum chamber , the back of the vacuum chamber was evacuated to below 3×10 ^-4 Pa, the substrate temperature was kept at 250 °C, and the accelerated working voltage of the electron gun was controlled at 6kV to sequentially deposit Cr, Al, WO ₃ and Cr by electron beam evaporation; the obtained Cr film, The thicknesses of Al film, WO ₃ film and Cr film are controlled to be 20 nm, 150 nm, 250 nm and 10 nm, respectively;

The resonant cavity film layer formed by the fabrication is displayed in red under natural light.

Preparation of the second substrate: a Prussian blue-like film is deposited on a polyimide/FTO substrate by a hydrothermal method; the Prussian blue-like film is specifically Na _1.92 Fe[Fe(CN) ₆ ]·nH ₂ O(n is the stoichiometric ratio of chemical elements);

The preparation steps of the Prussian blue-like film Na _1.92 Fe[Fe(CN) ₆ ]·nH ₂ O are: dissolving 3 mmol of Na ₄ Fe(CN) ₆ in 100 mL of deionized water, and adjusting the pH of the solution with ascorbic acid. 6.5; then transfer the solution to the autoclave and put it into the polyimide/FTO flexible conductive substrate; seal the reaction kettle and maintain it at 140°C for 20 hours; after the reaction kettle is naturally cooled, take out the second conductive substrate and use Rinse twice with deionized water and once with acetone; then, put it in a vacuum drying oven and vacuum dry at 120°C for 12 hours to obtain a Prussian blue-like film Na _1.92 Fe[Fe(CN) ₆ ]·nH ₂ O; The thickness of the Prussian blue-like film is 120 nm;

The process steps of box matching are the same as those of the box matching process described in Example 1;

Lithium perchlorate of 0.08mol/L and citric acid of 0.008mol/L were added to the propylene carbonate solvent, and configured into an electrolyte with a pH value of 2; then the electrolyte was vacuum-perfused into the empty space of the pair of boxes. After encapsulation, the resonant cavity and the Prussian blue-like complementary multicolor electrochromic device are obtained.

The resonant cavity (Al/WO ₃ /Cr) of this embodiment and the Prussian blue complementary multi-color electrochromic device can obtain full color by adjusting the voltage.

Example 3

As shown in FIG. 14 , this embodiment provides a multi-color electrochromic device composed of a resonant cavity (Cr/WO ₃ /Al nanoporous film) and a NiO film, which belongs to a reflective bottom color rendering structure, including:

The first substrate includes a first substrate 11, a broadband absorption layer 123, a dielectric layer 122, and a metal nanoporous structure layer 124 in a stacking sequence, wherein the first substrate is glass; the broadband absorption layer is a metal Cr film with a thickness of 10 nm; The dielectric layer is a tungsten trioxide film with a thickness of 250 nm; the metal nanoporous structure layer is a metal Al nanoporous film with a thickness of 100 nm;

The second substrate includes a second substrate 21, a transparent conductive electrode 221, and an electrochromic layer 222 in a stacking sequence, wherein the second substrate is glass; the transparent conductive electrode is an ITO transparent conductive layer; and the electrochromic layer is NiO ions storage layer;

The frame sealant is arranged between the peripheral regions of the first substrate and the second substrate in the circumferential direction, so as to seal the upper surface of the metal nanoporous structure layer 124 and the lower surface of the electrochromic layer 222 to each other and define a cavity; as well as

Electrolyte is provided in the cavity. The electrolyte uses propylene carbonate as a solvent, lithium perchlorate as a solute, and in molar concentration, lithium perchlorate is 0.1 mol/L.

The reflective bottom-color multicolor electrochromic device of this embodiment can display red, orange, yellow and green by controlling the voltage value and time.

Example 4

This embodiment provides a multi-color electrochromic device composed of a resonant cavity (Al/SiO ₂ /Au nanoporous film) and a polypyrrole film, which belongs to a reflective top color rendering structure, and its structure is the same as that of Embodiment 1, including:

The first substrate includes a first substrate 11, a metal reflective layer 121, a dielectric layer 122 and a metal nanoporous structure layer 124 in a stacking sequence, wherein the first substrate is glass; the metal reflective layer is a metal Al film with a thickness of 150 nm, The dielectric layer is a SiO ₂ film with a thickness of 50 nm, and the metal nanoporous structure layer is an Au nanoporous film with a thickness of 20 nm;

The second substrate includes a second substrate 21, a transparent conductive electrode 221 and a polypyrrole film 222 with a thickness of 500 nm in a stacking sequence, wherein the second substrate is glass; the transparent conductive electrode is a FTO transparent conductive layer; the electrochromic layer is Polypyrrole film;

the frame sealant is arranged between the peripheral regions of the first substrate and the second substrate in the circumferential direction, so as to seal the upper surface of the metal nanoporous structure layer 124 and the lower surface of the electrochromic layer 222 to each other and define a cavity; as well as

The electrolyte is arranged in the cavity; the electrolyte is a 1 mol/L potassium chloride aqueous solution.

The Au nanoporous film can adopt a nanoimprinting process, and the nanoimprinting process can be used for the fabrication of a large-area metal nanopore array.

As shown in FIG. 15 , the fabrication steps for preparing the Au nanopore array film by the nanoimprinting process are: 1. hard template fabrication and surface treatment; 2. soft template replication; 3. pattern imprinting process; 4. pattern dry engraving.

The specific steps of making and surface treatment of the hard template are: first, use an electron beam exposure and etching process to make a master template pattern on the silicon wafer; The master template of the adhesive was baked on a heating table at 120°C for 10 minutes.

The specific steps of duplicating the soft template are as follows: coating template glue on the main template treated with the anti-adhesive agent, pre-baking at 120° C. for 5-10 s; placing a substrate on the main template coated with template glue, using a roller Imprinting is performed; after imprinting, a soft template is obtained after UV irradiation and demoulding.

The specific steps of the pattern imprinting are as follows: the substrate on which the 20nm Au film is deposited is cleaned and then coated with imprinting glue; after pre-baking, placing a soft template for imprinting; 40mm/s; transfer the soft film pattern to the substrate after demolding;

The specific steps of the pattern dry etching are as follows: the pattern-transferred substrate is etched by inductively coupled plasma (ICP) etching to obtain the required height of the pattern; A non-uniform Au nanopore array was obtained.

The preparation steps of the electrodeposited polypyrrole film are as follows: using a galvanostatic method in electrochemical oxidation, the Au nanoporous conductive substrate is used as a working electrode, a Pt sheet electrode is used as a counter electrode, a saturated calomel electrode is used as a reference electrode, and the deposition current density is is 0.05mA/cm ² , and the deposition time is 15s;

The preparation steps of the deposition solution of the electrodeposited polypyrrole film are as follows: adding 1.05 mL of pyrrole to 150 mL of deionized water; after the pyrrole is dissolved, adding 1.92 g of sodium p-benzenesulfonate; A deposition solution for the deposition of polypyrrole films.

The reflective top-color multicolor electrochromic device composed of the resonant cavity (Al/SiO ₂ /Au nanoporous film) and the polypyrrole film of this embodiment can be switched between red and black by controlling the voltage value and time.

The polypyrrole film can also be located on the top of the Au nanoporous film, facing the electrolyte side, which can achieve the same effect as this embodiment.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. a multicolor electrochromic device, is characterized in that, comprises: a first substrate, a second substrate, an electrolyte layer disposed between the first substrate and the second substrate, the first substrate including a first substrate, a work disposed on the side of the first substrate facing the electrolyte layer an electrode; the second substrate includes a second substrate, a counter electrode disposed on the side of the second substrate facing the electrolyte layer; Wherein, the working electrode is a resonant cavity structure, and the resonant cavity structure includes a metal reflective layer, a dielectric layer and a broadband absorption layer that are stacked in sequence. By adjusting the thickness of the dielectric layer, the resonant cavity structure can achieve different reflections A variety of color changes can be achieved through external electric field modulation. 2. The multicolor electrochromic device according to claim 1, characterized in that, The material of the metal reflection layer is an inactive metal; preferably, the inactive metal includes Au, Ag, Cu, Pt, Al or Ti, and a composite metal formed by a variety of metals; the thickness of the metal reflection layer is 20nm or more, preferably 50-500nm; The material of the dielectric layer is an inorganic electrochromic material and/or an organic electrochromic material; the thickness of the dielectric layer is 10-3000 nm, preferably 50-800 nm; The material of the broadband absorption layer includes transition metal, FeSi ₂ , amorphous silicon, or noble metal; the transition metal is preferably Cr, Ni, Ti, and the noble metal is preferably Au, Pt; the thickness of the broadband absorption layer is 5～ 50nm, preferably 5-15nm; The material of the electrolyte layer includes liquid electrolyte, gel electrolyte and solid electrolyte; the thickness of the liquid electrolyte layer is 0.01-3 mm; the thickness of the gel electrolyte layer is 0.1-500 μm; the thickness of the solid electrolyte layer is 10-500 nm ; The counter electrode includes a transparent conductive electrode and an electrochromic layer that are stacked in sequence; the electrochromic layer in the counter electrode has both an ion storage function; the material of the electrochromic layer includes inorganic electrochromic materials and/or Or an organic electrochromic material; the thickness of the electrochromic layer is 10-1000 nm, preferably 50-800 nm. 3 . The multicolor electrochromic device according to claim 2 , wherein the metal reflective layer is a reticulated hollow structure; the material of the metal reflective layer is an inactive metal; preferably, the inactive metal Metals include Au, Ag, Cu, Pt, Al or Ti, and composite metals formed by various metals; And/or, the thickness of the metal reflective layer is 20 nm or more, preferably 50-500 nm; the line width of the mesh-shaped hollow is 0.1-20 μm, preferably 1-10 μm. 4. The multicolor electrochromic device according to claim 2, wherein the broadband absorption layer is a metal nanoporous structure layer; the metal is a noble metal, preferably Au or Pt; And/or, the thickness of the metal nanopore structure layer is 5-50 nm, preferably 10-20 nm; the diameter of the nanopore is 10-500 nm, preferably 100-300 nm. 5 . The multicolor electrochromic device according to claim 2 , wherein the broadband absorbing layer is a reticulated hollow structure; the broadband absorbing layer material is transition metal, FeSi ₂ , amorphous silicon, or noble metal. 6 . ; The transition metal is preferably Cr, Ni, Ti, and the noble metal is preferably Au, Pt; And/or, the thickness of the broadband absorption layer is 5-50 nm, preferably 5-15 nm; the width of the mesh-shaped hollow line is 0.1-20 μm, preferably 1-10 μm. 6 . The multicolor electrochromic device according to claim 1 , wherein the materials of the first substrate and the second substrate comprise glass, polymer plastic materials, and metal foils. 7 . 7. the preparation method of the multicolor electrochromic device described in any one of claim 1-6, is characterized in that, comprises the steps: forming a metal reflective layer, a dielectric layer and a broadband absorbing layer in sequence on the first substrate to obtain a first substrate; forming a transparent conductive electrode and an electrochromic layer in sequence on the second substrate to obtain a second substrate; sealing the first and second substrates along their peripheral regions and defining a cavity; and An electrolyte is provided in the cavity. 8. A display panel, comprising: the multicolor electrochromic device according to any one of claims 1-7. 9 . The display panel according to claim 8 , wherein the display panel comprises: a plurality of sub-pixels, and each of the sub-pixels comprises at least one of the multi-color electrochromic devices stacked in sequence. 10 . 10. A display device, comprising: the display panel according to claim 8 or 9.

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