CN114415435A

CN114415435A - Multicolor electrochromic device, manufacturing method thereof, display panel and display device

Info

Publication number: CN114415435A
Application number: CN202111520807.4A
Authority: CN
Inventors: 张世玉; 郑陆一; 吝凯; 吕勇; 牛春晖; 刘洋
Original assignee: Beijing Information Science and Technology University
Current assignee: Beijing Information Science and Technology University
Priority date: 2021-12-13
Filing date: 2021-12-13
Publication date: 2022-04-29

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, manufacturing method thereof, display panel and display device

Technical Field

The invention relates to the technical field of display, in particular to a multicolor electrochromic device, a manufacturing method of the multicolor electrochromic device, a display panel and a display device.

Background

The traditional display screen (such as a liquid crystal display and an organic light emitting diode display) displays texts or images on the screen by using backlight or self-luminescence, the display has good use effect under indoor weak ambient light, but when the display screen is used under outdoor strong ambient light, the contrast of the display screen is reduced because the reflected light intensity of the ambient light on the surface of the screen is greatly increased, and the viewing effect is seriously influenced.

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

Common reflective display technologies are reflective liquid crystal display technology and electronic ink (E-ink) display. The reflective liquid crystal display has the advantages of high refresh rate, color display and the like, and is used in the fields of education flat panels, outdoor industrial control display and the like, but the display effect is poor due to the light effect loss of the reflective liquid crystal display on a polaroid and a color film and the balance problem of light effect and visual angle after an oriented scattering film or a diffuse reflection structure is added. The electronic ink display has the advantages of high contrast and large viewing angle of black-white display, and has been used in the fields of electronic book display screens, electronic price tags, intelligent conference display screens and the like, but also has the problem of low light efficiency when developing color display screens and the problem of low refresh rate limited by the working principle of the electronic ink display, thereby greatly limiting the wide application of the electronic ink display in other fields.

The electrochromic device is characterized in that the structure and optical constants (refractive index and extinction coefficient) of an electrochromic layer material are adjusted by controlling an external electric field, so that the optical properties (reflectivity, transmissivity or absorptivity) of the electrochromic device are changed, and the electrochromic device is stable and reversible in appearance. Therefore, the electrochromic device can be used for a transmissive display or a reflective display in principle. However, for a specific electrochromic material or an electrochromic device prepared by using the same, the color change is limited, and especially, the inorganic electrochromic material with stable performance generally has only two color changes, which greatly limits the application of the electrochromic in the fields of display, camouflage, imaging equipment and the like.

Patent CN104423114A discloses an all-solid-state electrochromic composite device, which forms multiple colors by compositing a PVD decoration plating color layer and an electrochromic layer, but has a limited modulation color range, such as a light green to blue conversion, a black to dark blue conversion, and the like. Patent CN111624829A discloses a multi-color electrochromic structure, which comprises an optical cavity composed of a metal reflective layer and an electrochromic material layer, and the optical constants of the electrochromic material layer are changed by regulating and controlling the applied voltage, so as to realize multiple structural colors, but the color modulation range of this scheme is still limited, and the reflectivity is less than 50%, so that a practical reflective display cannot be formed.

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

Disclosure of Invention

In a first aspect, embodiments of the present invention provide a multicolor electrochromic device, including: the electrolyte layer is arranged between the first base plate and the second base plate, and the first base plate comprises a first substrate and a working electrode arranged on the side, facing the electrolyte layer, of the first substrate; the second base plate comprises a second substrate and a counter electrode arranged on the side, facing the electrolyte layer, of the second substrate; the working electrode is of a resonant cavity structure, the resonant cavity structure comprises a metal reflecting layer, a dielectric layer and a broadband absorbing layer which are sequentially stacked, color adjustment of different reflection-type structures can be achieved through adjustment of the thickness of the dielectric layer, and multiple color changes can be achieved through modulation of an external electric field.

Preferably, the material of the metal reflecting layer is an inactive metal; preferably, the non-active metal includes gold (Au), silver (Ag), copper (Cu), platinum (Pt), aluminum (Al) or titanium (Ti), and a composite metal formed of a plurality of metals; the thickness of the metal reflecting layer is more than 20nm, preferably 50-500 nm;

the dielectric layer is made of 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 comprises transition metal, FeSi₂Amorphous silicon, or noble metals; the transition metal is preferably Cr, Ni and Ti, and the noble metal is preferably Au and Pt; the thickness of the broadband absorption layer is 5-50 nm, preferably 5-15 nm;

the material of the electrolyte layer comprises a liquid electrolyte, a gel electrolyte and a 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 mu m; the thickness of the solid electrolyte layer is 10-500 nm;

the counter electrode comprises a transparent conductive electrode and an electrochromic layer which are sequentially stacked; the electrochromic layer in the counter electrode has an ion storage function; the material of the electrochromic layer comprises an inorganic electrochromic material and/or an organic electrochromic material; the thickness of the electrochromic layer is 10-1000 nm, preferably 50-800 nm.

Preferably, the metal reflecting layer is of a net-shaped hollow structure; the metal reflecting layer is made of non-active metal; preferably, the non-active metal comprises Au, Ag, Cu, Pt, Al or Ti, and a composite metal formed by a plurality of metals;

and/or the thickness of the metal reflecting layer is more than 20nm, preferably 50-500 nm; the line width of the mesh hollow-out part is 0.1-20 mu m, and preferably 1-10 mu m.

As a first preference, the broadband absorbing layer is a metal nanopore 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 pore diameter of the nano-pores is 10-500 nm, preferably 100-300 nm.

As a second preferred mode, the broadband absorbing layer is of a net-shaped hollow structure; the broadband absorbing layer is made of transition metal, FeSi₂Amorphous silicon, or noble metals; the transition metal is preferably Cr, Ni and Ti, and the noble metal is preferably Au and Pt;

and/or the thickness of the broadband absorption layer is 5-50 nm, preferably 5-15 nm; the line width of the mesh hollow-out part is 0.1-20 mu m, and preferably 1-10 mu m.

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

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

sequentially forming a metal reflecting layer, a dielectric layer and a broadband absorbing layer on a first substrate to obtain a first substrate;

sequentially forming a transparent conductive electrode and an electrochromic layer on a second substrate to obtain a second substrate;

sealing the first substrate and the second substrate along the peripheral region thereof 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, including: such as the multicolor electrochromic devices described above.

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

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

The invention has the following beneficial effects:

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.

Drawings

FIG. 1 is a schematic structural diagram of a multicolor electrochromic device according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a first substrate (metal reflective layer/dielectric layer/broadband absorbing layer) according to an embodiment of the present invention;

fig. 3 is a schematic view of a mesh-like hollow-out structure of a reflective metal layer or a broadband absorbing layer according to an embodiment of the invention;

fig. 4 is a schematic structural diagram of another first substrate (metal reflective layer/dielectric layer/metal nanopore structure layer) according to an embodiment of the invention;

fig. 5 is a schematic structural diagram of another first substrate (broadband absorbing layer/dielectric layer/metal nanopore structure layer) according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a second substrate according to an embodiment of the invention;

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;

fig. 8 is a schematic structural diagram of a display panel composed of three multicolor electrochromic devices according to an embodiment of the present invention;

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

FIG. 10 shows a resonant cavity (Ag/WO) according to an embodiment of the present invention₃Au nano-pore film) and a Prussian blue-like complementary type electrochromic device;

fig. 11 is a schematic diagram of a colloid etching process for preparing a non-uniform Au nanopore array according to an embodiment of the present invention;

FIG. 12 shows a resonant cavity (Al/WO) according to an embodiment of the present invention₃/Cr) and Prussian blue-like thin film complementary multicolor flexible electrochromic device;

FIG. 13 shows an example of the present invention providing Glass/ITO/Al/WO with different tungsten trioxide thicknesses₃Reflectance spectrum of/Cr;

FIG. 14 shows a reflection type (Glass/Cr/WO) according to an embodiment of the present invention₃a/Al nano-pore film) bottom color development multicolor electrochromic device structure schematic diagram;

fig. 15 is a schematic diagram of a non-uniform Au nanopore array prepared by a nanoimprint process provided by an embodiment of the invention;

reference numerals: 1 a first substrate; 11 a first substrate; 12 a working electrode; 121 a metal reflective layer; 122 a dielectric layer; 123 broadband absorbing layer; 124 a metal nanopore structure layer; 2 a second substrate; 21 a second substrate; 22 pairs of electrodes; 221 a transparent conductive electrode; 222 an electrochromic layer; 3 an electrolyte layer; and 4, sealing the frame glue.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, specific embodiments of a multicolor electrochromic device, a manufacturing method thereof, a display panel and a display device according to embodiments of the present invention are described in detail below with reference to the accompanying drawings.

The embodiment of the invention provides a multicolor electrochromic device in a first aspect, and aims to solve the problems that in the prior art, the electrochromic device is few in changeable color types, low in reflectivity, low in light efficiency utilization rate and incapable of being used in mature industrial application.

In view of the above technical problems, an embodiment of the present invention provides the following technical solutions:

fig. 1 is a schematic structural diagram of a multicolor electrochromic device according to an embodiment of the present invention, and fig. 2 is a schematic structural diagram of a first substrate according to an embodiment of the present invention. Referring to fig. 1 and 2, the multicolor electrochromic device includes: the liquid crystal display panel comprises a first substrate 1 (comprising a first substrate 11 and a working electrode 12), a second substrate 2 (comprising a second substrate 21 and a counter electrode 22), an electrolyte layer 3 positioned between the working electrode 12 and the counter electrode 22, and frame sealing glue 4 for sealing the working electrode 12 and the counter electrode 22.

The working electrode 12 is a resonant cavity structure, and includes a metal reflective layer 121, a dielectric layer 122, and a broadband absorbing layer 123, which are stacked in sequence, and the resonant cavity structure can realize color adjustment of different reflective structures by adjusting the thickness of the dielectric layer, and can realize multiple color changes by modulating an external electric field.

The invention discovers that the wavelength selection function can be realized by adopting the resonant cavity structure, and further full color can be obtained.

Specifically, referring to fig. 2, the first substrate 1 includes a first substrate 11, a metal reflective layer 121, a dielectric layer 122, and a broadband absorbing layer 123, which are sequentially stacked. Wherein the content of the first and second substances,

the first substrate is glass, polymer plastic material, metal foil (such as stainless steel foil).

The metal reflecting layer is made of non-active metal; the non-active metal preferably comprises Au, Ag, Cu, Pt, Al or Ti and a composite metal formed by a plurality of metals; the thickness of the metal reflecting layer is more than 20nm, preferably 50 to 500 nm. The invention further discovers that the resonant cavity structure formed by adopting the nonreactive metal not only can realize the wavelength selection function, but also has higher reflectivity.

The dielectric layer mainly comprises electrochromic materials, including inorganic electrochromic materials and/or organic electrochromic materials. Wherein, the inorganic electrochromic material comprises any one or more of transition metal oxide, Prussian blue or derivatives thereof and heteropoly acid; transition metal oxides are preferred, and include compounds formed by combining any one or more of the elements W, Ni, Ti, Nb, Fe, Co or Mo with oxygen. The organic electrochromic material comprises any one or combination of organic small molecules, conductive polymers and metal organic compounds. By way of example, small organic molecules include viologen, methyl viologen; the conductive polymer comprises any one or combination of polyaniline, polythiophene and polypyrrole; the metal organic compound is a metal organic chelate. The thickness of the dielectric layer is 10-3000 nm, preferably 50-800 nm.

The material of the broadband absorbing layer comprises transition metal such as Cr, Ni, Ti, FeSi₂Amorphous silicon or noble metals such as Au, Pt. The thickness of the broadband absorption layer is 5-50 nm, preferably 5-15 nm.

In some preferred embodiments, the broadband absorbing layer has a mesh-like hollow structure, and fig. 3 is a schematic view of the mesh-like hollow structure of the broadband absorbing layer; the material of the broadband absorbing layer is transition metal such as Cr, Ni, Ti and the like, FeSi₂Amorphous 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 mesh hollow line width is 0.1-20 μm, preferably 1-10 μm. The invention further discovers that the hollow-out area of the mesh hollow-out structure broadband absorbing layer is communicated with the electrochromic material and the electrolyte, so that the multicolor electrochromic is reducedThe response time of the device.

In some preferred embodiments, to increase the adhesion of the metal reflective layer to the first substrate, a transition layer may be added between the first substrate and the metal reflective layer. Preferably, the transition layer is made of 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 nanopore structure layer) according to an embodiment of the 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 nanopore structure layer 124, which are sequentially stacked. Wherein the content of the first and second substances,

The metal reflecting layer is made of non-active metal; preferred non-reactive metals include gold, silver, copper or titanium; the thickness of the metal layer is 20nm or more, preferably 50 to 500 nm.

The dielectric layer mainly comprises electrochromic materials, including inorganic electrochromic materials and organic electrochromic materials. Wherein, the inorganic electrochromic material comprises any one or more of transition metal oxide, Prussian blue or derivatives thereof and heteropoly acid; transition metal oxides are preferred, and include compounds formed by combining any one or more of the elements W, Ni, Ti, Nb, Fe, Co or Mo with oxygen. The organic electrochromic material comprises any one or combination of organic small molecules, conductive polymers and metal organic compounds; by way of example, small organic molecules include viologen, methyl viologen; the conductive polymer comprises any one or combination of polyaniline, polythiophene and polypyrrole; the metal organic compound is a metal organic chelate. The thickness of the dielectric layer is 1 to 3000nm, preferably 50 to 500 nm.

The metal nanopore structure layer is made of noble metal, preferably gold or platinum. The thickness of the metal nano-pore structure layer is 5-50 nm, preferably 10-20 nm. The diameter of the nano-pore of the metal nano-pore structure layer is 50-500 nm, preferably 100-300 nm.

The invention further discovers that the metal nano-pore structure layer has the following functions: a resonant cavity structure is formed, the wavelength selection function is realized, and the reflectivity is high; the plasma enhancement effect is achieved, and the reflectivity of the resonant cavity can be increased; the light scattering effect can be achieved, and the viewing angle of the resonant cavity can be increased; the effect of eliminating color cast can be achieved; the nano holes in the metal nano hole structure are communicated with the electrochromic layer and the electrolyte layer, so that ions can be rapidly injected into or separated from the electrochromic layer, and the response time of electrochromic is prolonged.

Similarly, to increase the adhesion of the metal reflective layer to the first substrate, a transition layer may be disposed between the first substrate and the metal reflective layer. Preferably, the transition layer is made of 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 absorbing layer/dielectric layer/metal nanopore structure layer) according to an embodiment of the invention. The present invention further finds that the metal reflective layer and the broadband absorbing layer can be reversed, and referring to fig. 5, the first substrate includes a first substrate 11, a broadband absorbing layer 123, a dielectric layer 122 and a metal nanopore structure layer 124, which are sequentially stacked. By adjusting the thickness of the dielectric layer, color adjustment of different reflection-type structures can be realized. The reflection structure color of the broadband absorption layer/dielectric layer/metal nanopore thin film structure of this embodiment belongs to a bottom reflection type structure, i.e., both incident light and outgoing light pass through the first substrate. Wherein the content of the first and second substances,

the material of the broadband absorption layer comprises Cr, Ni, Ti and FeSi₂And amorphous silicon. The thickness of the broadband absorption layer is 5-50 nm, preferably 5-15 nm.

The dielectric layer mainly comprises electrochromic materials, including inorganic electrochromic materials and organic electrochromic materials. The inorganic electrochromic material comprises any one or more of transition metal oxide, Prussian blue or derivatives thereof and heteropoly acid; transition metal oxides, including compounds formed from oxygen and any one or more combinations of W, Ni, Ti, Nb, Fe, Co or Mo elements are preferred. The organic electrochromic material comprises any one or combination of organic small molecules, conductive polymers and metal organic compounds; preferably, the organic small molecules comprise viologen and methyl viologen; the conductive polymer comprises any one or combination of polyaniline, polythiophene and polypyrrole; the metal organic compound is a metal organic chelate. The thickness of the dielectric layer is 0-3000 nm, preferably 50-500 nm.

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

In some preferred embodiments, the metal reflective layer has a mesh-like hollow structure, and fig. 3 is a schematic view of the mesh-like hollow structure of the metal reflective layer; the material of the reflecting layer is non-active metal; the non-active metal material comprises Au, Ag, Cu, Pt, Al or Ti and composite metal formed by a plurality of metals; the thickness of the metal reflecting layer is more than 20nm, preferably 50-500 nm; the line width of the mesh hollow-out part is 0.1-20 mu m, and preferably 1-10 mu m. The invention further discovers that the hollow-out area of the reflecting layer with the reticular hollow-out structure is communicated with the electrochromic material and the electrolyte, so that the response time of the multicolor electrochromic device is reduced.

Fig. 6 is a schematic structural diagram of a second substrate according to an embodiment of the invention. Referring to fig. 6, the second substrate includes a second substrate 21, a transparent conductive electrode 221, and an electrochromic layer 222, which are sequentially stacked. Wherein:

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

The transparent conductive electrode comprises any one of Indium Tin Oxide (ITO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), a silver nanowire film and a carbon nanotube film.

The material of the electrochromic layer comprises an inorganic electrochromic material and/or an organic electrochromic material. Preferably, the material of the electrochromic layer is an anodic electrochromic material, and comprises prussian blue and nickel oxide. More preferably, the anodic electrochromic material is prussian-like blue; further, the prussian-like blue includes at least one of prussian blue, prussian blue analogues and derivatives thereof. The thickness of the Prussian-like blue film is preferably 50-800 nm.

Wherein the chemical formula of Prussian blue is Fe₄[Fe(CN)₆]₃·mH₂O (m is 14 to 16); the general formula of the Prussian blue analogue is A_xM_A[M_B(CN)₆]_y·nH₂O (x, y, n are stoichiometric ratios) and A is K⁺、Na⁺Conducting ions, M_AAnd M_BIs a transition metal element, such as Mn, Fe, Co, Ni or Cu; or Na_xM[Fe(CN)₆]·nH₂O (n is stoichiometric ratio), wherein M is one of Mn, Fe, Co, Ni or Cu; the derivative of the Prussian blue and the analogue thereof is a general name for designing various core-shell, hollow shell and other nano-structure materials with different shapes, components, sizes, shapes and chemical properties by using the Prussian blue and the analogue thereof as a sacrificial template.

The electrolyte layer provided by the invention has the functions of providing interconnected active ion channels for the color-changing electrodes and isolating electronic conduction in the multicolor electrochromic device. The material of the electrolyte layer comprises a liquid electrolyte, a gel electrolyte and a solid electrolyte; preferably, the liquid electrolyte takes propylene carbonate as a solvent, and lithium perchlorate and organic weak acid as solutes, and more preferably, the liquid electrolyte takes 0.08-0.12 mol/L of lithium perchlorate and 0.008-0.012 mol/L of organic weak acid by molar concentration meter.

The invention further discovers that the lithium-based lithium-ion battery is based on Li⁺Organic weak acid is introduced into the electrolyte system to optimize the pH value of the electrolyte and inhibit OH in the electrolyte^–And the iron ions in the Prussian blue are combined, so that the stability of the electrochromic performance of the Prussian blue film is improved. Preferably, the weak organic acid is at least one of citric acid, oxalic acid and acetic acid. The organic weak acid can effectively inhibit OH in electrolyte^–The iron ions in the Prussian blue are combined, other chemical reactions cannot be damaged, and the failure of an electrolyte system is avoided.

The second aspect of the embodiments of the present invention provides a method for preparing the above-mentioned multicolor electrochromic device, including the following steps:

an electrolyte is disposed in the cavity.

The preparation method of the metal reflecting layer comprises any one of the modes of magnetron sputtering, thermal evaporation, electron beam evaporation, ion plating and electrochemical deposition;

the preparation method of the dielectric layer comprises any one of magnetron sputtering, thermal evaporation, electron beam evaporation, ion plating, electrochemical deposition and chemical vapor deposition.

When the material of the broadband absorbing layer comprises Cr, Ni, Ti and FeSi₂Or amorphous silicon, the preparation method of the broadband absorbing layer includes but is not limited to any one of magnetron sputtering, thermal evaporation, electron beam evaporation, ion plating, chemical vapor deposition and electrochemical deposition.

When the broadband absorbing layer is a metal nano-pore structure layer, the preparation method thereof includes, but is not limited to, colloid etching and nano-imprinting.

When the broadband absorbing layer is in a mesh hollow structure, the preparation method includes but is not limited to mask evaporation and common exposure, development and etching processes in a semiconductor process.

A third aspect of embodiments of the present invention provides a display panel based on the above-described multicolor electrochromic device.

The traditional color display generally introduces sub-pixels to form a displayed pixel, the number of the sub-pixels is generally three, namely, a display mode of three primary colors is adopted, and the three primary colors are red, green and blue or cyan, magenta and yellow. Taking the electronic ink display which is most widely applied in the reflective display as an example, the gray scale is adjusted by the area ratio of the black particles, and the color is realized by adding a color film. The reflectivity of each sub-pixel displayed by the electronic ink is less than 50%, and the reflectivity of the pixel is reduced by more than 3 times for forming color, so that the color display effect is poor.

Since a single multicolor electrochromic device of the present invention can display a plurality of colors. Therefore, the display mode of the display panel composed of the multicolor electrochromic device is different from the display mode of the conventional display. 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 can be greatly improved. The invention designs a display panel based on a multicolor electrochromic device.

The first display panel based on a multicolor electrochromic device employs 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 fig. 7, each sub-pixel may display other colors such as red, yellow, green, and blue, and 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 blue, the pixel displays blue; when the two sub-pixels respectively display blue and yellow, the pixel displays white; the multicolor electrochromic device can display colors such as orange, yellow green, blue-green and the like besides red, yellow, green and blue, so that the pixel can display abundant colors by combining the two sub-pixels.

Fig. 8 is a schematic structural diagram of a display panel composed of 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 of which can display other colors such as red, green, and blue, and when all three sub-pixels display red, the pixel displays red; when all three sub-pixels display green, the pixel displays green; when all three sub-pixels display blue, the pixel displays blue; when the three sub-pixels respectively display red, green and blue, the pixel displays white; when the three sub-pixels respectively display red, red and green, the pixel displays yellow; since the multicolor electrochromic device can display colors such as orange, yellow-green, and cyan in addition to red, green, and blue, the pixel can display abundant colors by the combination of the three sub-pixels.

Fig. 9 is a schematic structural diagram of another display panel composed of three multicolor 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 including red, green and blue pixels, which may 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 on, the pixel displays white; when the red, green and blue sub-pixels are all off, the pixel displays black; since the multi-color electrochromic device can adjust the reflectivity by adjusting the voltage or time, the pixel can be freely switched between color and black by combining the three sub-pixels, and abundant colors can be displayed.

A fourth aspect of the embodiments of the present invention provides a display device based on the display panel described above. 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 television, a display, a notebook computer, a digital photo frame or a navigator and the like.

Example 1

As shown in FIG. 10, the present embodiment provides a resonant cavity (Ag/WO)₃Au nano-pore film) and a Prussian blue-like film, belongs to a reflection type top color development structure, and comprises:

the first substrate comprises a first substrate 11, a metal reflecting layer 121, a dielectric layer 122 and a metal nano-pore structure layer 124 in a stacking sequence, wherein the first substrate is glass, the metal reflecting layer is a metal Ag thin film, the dielectric layer is a tungsten trioxide thin film, and the metal nano-pore structure layer is a gold nano-pore thin film;

the second substrate comprises a second substrate 21, a transparent conductive electrode 221 and an electrochromic layer 222 in a lamination 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 blue film;

the frame sealing glue 4 is arranged between the peripheral regions of the first substrate and the second substrate along the circumferential direction basically so as to combine the upper surface of the metal nanopore structure layer 124 and the lower surface of the electrochromic layer 222 with each other in a sealing way and limit a cavity; and

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

The working mechanism of the resonant cavity and the prussian blue complementary electrochromic device of the embodiment is as follows: tungsten trioxide in the resonant cavity is a cathode color-changing material, when the resonant cavity is electrified, the tungsten trioxide obtains electrons, the optical constant of the material is changed, and the resonant cavity has an opaque structural color; prussian blue is an anode electrochromic material which is a coordination compound capable of reacting with Li in electrolyte⁺And H⁺Coordination bonding, when energized, coordination bonding of Li⁺And H⁺The Prussian blue film loses electrons and is changed into a blue coloring state from a transparent state; li in electrolyte⁺And H⁺The ion transmission synergistic effect is achieved; the resonant cavity is compounded by structural color regulated by an electric field and the electrochromism of Prussian blue, so that the effect of regulating and controlling various colors of a single device is realized.

The preparation method of the resonant cavity and prussian blue complementary multicolor electrochromic device comprises the following steps:

preparation of the first substrate:

placing the glass substrate in a vacuum chamber, and vacuumizing to 3 × 10^-4The method comprises the following steps of (1) depositing an Ag film layer on a glass substrate by direct current sputtering under the conditions that the flow of argon is below 50sccm, the deposition pressure is 1.5Pa, the sputtering power is 50W, a target material is a metal Ag target, and the thickness of the Ag film layer is controlled to be 150 nm;

vacuum-pumping to 3 × 10^-4Less than Pa, argon gas flow of 80sccm, oxygen gas flow of 10 sccm, deposition pressure of 3.0Pa, sputtering power of 50W, tungsten trioxide target as target material,depositing a tungsten trioxide film layer on the Ag film layer by radio frequency sputtering, wherein the thickness of the tungsten trioxide film layer is controlled to be 120 nm;

treating the tungsten trioxide film in a weak oxygen plasma (50W) for 60 seconds to increase surface wettability; then the glass/Ag/WO₃Soaking the tungsten trioxide film 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, carefully washing the substrate in deionized water to remove redundant PDDA, and drying the substrate with nitrogen; secondly, a layer of 20 muL/cm is covered on the PDDA modified substrate ²30 minutes later, the base was tilted to nearly 90 ° and held for 5 seconds to allow excess solution to flow out, and then the substrate was immersed in boiling water for 5 seconds and blown dry with nitrogen; then, DC sputtering is adopted, the target material is Au target, and the back bottom is vacuumized to 3 multiplied by 10^-4Depositing an Au film on the surface of the polystyrene nanopore array with the thickness of the Au film controlled to be 20nm under the conditions that the argon flow is 50sccm, the deposition pressure is 1.5Pa and the sputtering power is 50W; 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. The preparation method of the polystyrene nanoparticle solution comprises the following steps: adding 90mL of deionized water into a 250mL three-neck round-bottom flask, and heating to 80 ℃ in an oil bath; then 8.5mL of clean styrene was added to form 200nm nanospheres and the mixed solution was held at 80 ℃ for 5 minutes under constant nitrogen purge and reflux; dissolving 350mg of potassium persulfate and 50mg of sodium dodecyl sulfate in 10mL of deionized water, keeping the temperature at 65 ℃, then adding the solution into a three-neck flask to start synthesis, and finishing the synthesis after 4 hours; the synthetic polystyrene nanosphere solution was centrifuged at 6000rpm, washed 4 times with deionized water before use, and the resulting polystyrene solution was mixed with ethanol 1:1 and adjusted to approximately 1 wt.% (see fig. 11 for a specific procedure).

The manufactured resonant cavity film layer is red under natural light.

Preparation of the second substrate:

preparing a Prussian blue-like electrochromic film by magnetron sputtering deposition of an ITO transparent conductive electrode on a glass substrate and an electrochemical deposition method;

configuring FeCl with the concentration of 10mmol/L₃·6H₂O, 10mmol/L K₃Fe(CN)₆A precursor solution consisting of 0.1mol/L KCl and 0.1mol/L HCl; then, a second conductive substrate is used as a working electrode, a Pt sheet is used as a counter electrode to form an electrochemical deposition working pool, and a prepared precursor solution is added; performing electrochemical deposition by using a direct current stabilized voltage power supply under the condition of 9V, and depositing Fe on the ITO transparent conductive electrode₄[Fe(CN)₆]₃The Prussian-like blue film is 500nm thick;

the Prussian-like blue film formed by the manufacturing process is dark blue;

and (4) processing the cartridges: bonding the first substrate and the second substrate along the peripheral area thereof by frame sealing glue and defining a cavity;

electrolyte pouring: adding 0.1mol/L of lithium perchlorate and 0.01mol/L of acetic acid into propylene carbonate to prepare electrolyte with the pH value of 3; then vacuum pouring the mixture into the cavity of the paired boxes; and (5) packaging to obtain the resonant cavity and Prussian blue complementary multicolor electrochromic device.

The resonant cavity and the prussian blue complementary multicolor electrochromic device of the embodiment can obtain full colors such as red, orange, yellow, green, blue-green and blue by adjusting voltage. The method specifically comprises the following steps: when a positive voltage is applied by using a direct-current stabilized voltage supply, the Prussian blue fades, and the device is changed from blue to red; when a negative voltage is applied, the device can display red, orange, yellow, green, cyan, and blue colors by adjusting the voltage or time.

Example 2

As shown in FIG. 12, the present embodiment provides a resonant cavity (Al/WO)₃/Cr) and Prussian blue-like film, belonging to a reflective top color structure, comprising:

the first substrate comprises a first substrate 11, a metal reflecting layer 121, a dielectric layer 122 and a broadband absorbing layer 123 in a stacking sequence, wherein the first substrate is a polyimide film, the metal reflecting layer is a metal Al film, the dielectric layer is a tungsten trioxide film, and the broadband absorbing layer is a metal Cr film;

a second substrate including a second substrate 21, a transparent conductive electrode 221, and an electrochromic layer 222 in a laminated order, wherein the second substrate is a transparent polyimide film; the transparent conductive electrode is an ITO transparent conductive layer; the electrochromic layer is a Prussian-like blue film;

frame sealing glue which is basically arranged between the peripheral areas of the first substrate and the second substrate along the circumferential direction so as to combine the upper surface of the broadband absorbing layer 123 and the lower surface of the electrochromic layer 222 with each other in a sealing way and limit a cavity; and

an electrolyte is disposed in the cavity. The electrolyte takes propylene carbonate as a solvent, lithium perchlorate and acetic acid as solutes, and the molar concentration of the electrolyte is 0.1mol/L, and the molar concentration of the acetic acid is 0.01 mol/L; the pH value 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.

preparation of the first substrate:

the electron beam evaporation method is used for preparing metal Cr/Al/WO₃The manufacturing steps of the/Cr film layer are as follows: metal Cr, Al and WO are filled in₃The crucible for evaporating the material and the first polyimide substrate are placed in a vacuum chamber, and the back bottom of the vacuum chamber is vacuumized to 3 multiplied by 10^-4Keeping the substrate temperature below 250 ℃ and controlling the accelerated working voltage of an electron gun to carry out electron beam evaporation deposition on Cr, Al and WO in sequence at 6kV₃And Cr; the obtained Cr film, Al film, WO₃The thicknesses of the film and the Cr film are respectively controlled to be 20nm, 150nm, 250nm and 10 nm;

the manufactured resonant cavity film layer is red under natural light.

Preparation of the second substrate: depositing a Prussian blue-like film on a polyimide/FTO substrate by a hydrothermal method; the Prussian blue-like film is specifically Na_1.92Fe[Fe(CN)₆]·nH₂O (n is stoichiometric ratio);

the Prussian blue-like film Na_1.92Fe[Fe(CN)₆]·nH₂The preparation method of the O comprises the following steps: adding 3 mmol of Na₄Fe(CN)₆Dissolving in 100mL of deionized water, and adjusting the pH value of the solution to 6.5 by using ascorbic acid; then transferring the solution into a high-pressure reaction kettle, and putting a polyimide/FTO flexible conductive substrate; maintaining the sealed reaction kettle at 140 ℃ for 20 hours; after the reaction kettle is naturally cooled, taking out the second conductive substrate, washing with deionized water for 2 times, and rinsing with acetone for 1 time; then putting the obtained product into a vacuum drying oven, and vacuum-drying the obtained product for 12 hours at 120 ℃ to obtain the Prussian-like blue film Na_1.92Fe[Fe(CN)₆]·nH₂O; the thickness of the Prussian-like blue film is 120 nm;

the cartridge aligning treatment steps are the same as the cartridge aligning process described in example 1;

adding 0.08mol/L of lithium perchlorate and 0.008mol/L of citric acid into a propylene carbonate solvent to prepare electrolyte with the pH value of 2; then vacuum-pouring the electrolyte into the cavity of the pair of boxes; and packaging to obtain the resonant cavity and Prussian blue-like complementary multicolor electrochromic device.

Resonant Cavity (Al/WO) of this example₃/Cr) and Prussian blue complementary multicolor electrochromic devices can obtain full colors by adjusting voltage.

Example 3

As shown in FIG. 14, the present embodiment provides a resonant cavity (Cr/WO)₃a/Al nano-pore film) and a NiO film, belongs to a reflective bottom color development structure, and comprises:

the first substrate comprises a first substrate 11, a broadband absorbing layer 123, a dielectric layer 122 and a metal nanopore structure layer 124 in a stacking sequence, wherein the first substrate is made of glass; the broadband absorption layer is a metal Cr film with the thickness of 10 nm; the dielectric layer is a tungsten trioxide film with the thickness of 250 nm; the metal nano-pore structure layer is a metal Al nano-pore film with the thickness of 100 nm;

a second substrate including a second substrate 21, a transparent conductive electrode 221, and an electrochromic layer 222 in a lamination order, wherein the second substrate is glass; the transparent conductive electrode is an ITO transparent conductive layer; the electrochromic layer is a NiO ion storage layer;

the frame sealing glue is basically arranged between the peripheral regions of the first substrate and the second substrate along the circumferential direction so as to hermetically combine the upper surface of the metal nanopore structure layer 124 and the lower surface of the electrochromic layer 222 with each other and define a cavity; and

an electrolyte is disposed in the cavity. The electrolyte takes propylene carbonate as a solvent and lithium perchlorate as a solute, and the lithium perchlorate is 0.1mol/L by a molar concentration meter.

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

Example 4

This embodiment provides a resonant cavity (Al/SiO)₂Au nano-pore film) and a polypyrrole film, which belongs to a reflection type top color development structure, the structure of the multi-color electrochromic device is the same as that of the embodiment 1, and the multi-color electrochromic device comprises:

the first substrate comprises a first substrate 11, a metal reflecting layer 121, a dielectric layer 122 and a metal nanopore structure layer 124 in a stacking sequence, wherein the first substrate is made of glass; the metal reflecting layer is a metal Al film with the thickness of 150nm, and the dielectric layer is SiO with the thickness of 50nm₂The metal nanopore structure layer is an Au nanopore film with the thickness of 20 nm;

a second substrate comprising a second substrate 21, a transparent conductive electrode 221 and a polypyrrole film 222 with a thickness of 500nm in the order of lamination, wherein the second substrate is glass; the transparent conductive electrode is an FTO transparent conductive layer; the electrochromic layer is a polypyrrole film;

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

The Au nano-pore film can adopt a nano-imprinting process, and the nano-imprinting process can be used for manufacturing a large-area metal nano-pore array.

As shown in fig. 15, the preparation steps of the Au nanopore array thin film by the nanoimprint process are as follows: 1. manufacturing a hard template and performing surface treatment; 2. copying a soft template; 3. a pattern imprinting process; 4. and (5) dry etching the pattern.

The hard template manufacturing and surface treatment method comprises the following specific steps: firstly, manufacturing a master template pattern on a silicon wafer by adopting an electron beam exposure etching process; after the pattern of the master template is manufactured, coating an anti-sticking agent on the surface of the master template; the master template coated with the anti-sticking agent was baked on a heating table at 120 ℃ for 10 minutes.

The soft template replication method comprises the following specific steps: coating template glue on the master template treated by the anti-sticking agent, and pre-baking for 5-10 s at 120 ℃; placing a substrate on the master template coated with the template glue, and imprinting by using a roller; and (4) after imprinting, carrying out ultraviolet illumination and demoulding to obtain the soft template.

The specific steps of the pattern imprinting are as follows: cleaning the substrate deposited with the 20nm Au film, and coating the imprinting glue; after pre-baking, placing a soft template for imprinting; after ultraviolet irradiation treatment, demoulding is carried out at the speed of 40 mm/s; after demolding, the soft film pattern is transferred to a substrate;

the pattern dry etching comprises the following specific steps: etching the substrate subjected to pattern transfer to the height required by the pattern on the substrate by adopting Inductively Coupled Plasma (ICP) etching; and (3) ashing the substrate to remove the residual stamping glue to obtain the non-uniform Au nanopore array.

The preparation method of the electrodeposited polypyrrole film comprises the following steps: the constant current method in electrochemical oxidation is adopted, an Au nano-pore conductive matrix 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 0.05mA/cm²The deposition time is 15 s;

the preparation method of the deposition solution of the electrodeposited polypyrrole film comprises the following steps: 1.05mL pyrrole was added to 150mL deionized water; after the pyrrole was dissolved, 1.92g of sodium p-benzenesulfonate was added; and after the sodium p-benzenesulfonate is dissolved, obtaining the deposition solution of the electrodeposited polypyrrole film.

Resonant Cavity (Al/SiO) of this example₂Au nano-pore film) and a polypyrrole film, and can be switched between red and black by controlling voltage value and time.

The polypyrrole film can also be positioned on the top of the Au nanopore film and towards the electrolyte side, and the same effect as the embodiment can be achieved.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A multicolor electrochromic device, comprising:

the electrolyte layer is arranged between the first base plate and the second base plate, and the first base plate comprises a first substrate and a working electrode arranged on the side, facing the electrolyte layer, of the first substrate; the second base plate comprises a second substrate and a counter electrode arranged on the side, facing the electrolyte layer, of the second substrate;

the working electrode is of a resonant cavity structure, the resonant cavity structure comprises a metal reflecting layer, a dielectric layer and a broadband absorbing layer which are sequentially stacked, color adjustment of different reflection-type structures can be achieved through adjustment of the thickness of the dielectric layer, and multiple color changes can be achieved through modulation of an external electric field.

2. The multicolor electrochromic device according to claim 1,

the metal reflecting layer is made of non-active metal; preferably, the non-active metal comprises Au, Ag, Cu, Pt, Al or Ti, and a composite metal formed by a plurality of metals; the thickness of the metal reflecting layer is more than 20nm, preferably 50-500 nm;

3. The multi-color electrochromic device according to claim 2, wherein said metallic reflective layer is a mesh-like hollowed-out structure; the metal reflecting layer is made of non-active metal; preferably, the non-active metal comprises Au, Ag, Cu, Pt, Al or Ti, and a composite metal formed by a plurality of metals;

4. The multicolor electrochromic device according to claim 2, wherein said broadband absorbing layer is a metal nanoporous structural layer; the metal is a noble metal, preferably Au and Pt;

5. The multicolor electrochromic device according to claim 2, wherein said broadband absorbing layer is a mesh-like hollowed-out structure; the broadband absorbing layer is made of transition metal, FeSi₂Amorphous silicon, or noble metals; the transition metal is preferably Cr, Ni and Ti, and the noble metal is preferably Au and Pt;

6. The multicolor electrochromic device according to any one of claims 1 to 5, wherein the materials of said first and second substrates comprise glass, polymeric plastic material, metal foil.

7. A method of making a multicolour electrochromic device as in any of claims 1 to 6, comprising the steps of:

an electrolyte is disposed in the cavity.

8. A display panel, comprising: the multicolor electrochromic device according to any one of claims 1 to 7.

9. The display panel according to claim 8, characterized in that the display panel comprises: a plurality of sub-pixels, each of the sub-pixels including at least one of the multicolor electrochromic devices stacked in sequence.

10. A display device, comprising: a display panel as claimed in claim 8 or 9.