阅读说明：本技术 一种紫外固化紫精基电致变色器件及其制备方法 (Ultraviolet curing viologen-based electrochromic device and preparation method thereof ) 是由 王宏志 刘自豪 白智元 李耀刚 侯成义 张青红 李贤英 于 2019-09-29 设计创作，主要内容包括：本发明涉及一种紫外固化紫精基电致变色器件及其制备方法,通过在紫精基变色溶液中加入紫外固化剂和玻璃微珠,通过涂覆进行器件组装,最后紫外固化而得。本发明组装的电致变色器件结构简单,变色性能好,具有自动化、流程化、批量化生产应用的潜力。(The invention relates to an ultraviolet curing viologen-based electrochromic device and a preparation method thereof. The assembled electrochromic device has the advantages of simple structure, good color-changing performance and potential for automatic, flow and batch production and application.)

1. An ultraviolet curing viologen-based electrochromic device is characterized in that: the ultraviolet curing agent and the glass beads are added into the viologen-based color-changing solution, device assembly is carried out through coating, and finally ultraviolet curing is carried out to obtain the ultraviolet-curable color-changing solution.

2. A preparation method of an ultraviolet curing viologen-based electrochromic device comprises the following steps:

(1) dissolving 1, 1-diethyl-4.4-bipyridine dibromide EtVio and ferrocene Fc in propylene carbonate PC and 1-ethyl-3-methylimidazolium bistrifluoromethylsulfonyl imide salt [ EMIM]NTF₂Performing ultrasonic dispersion on the mixed solution to obtain a viologen-based color-changing solution;

(2) adding an ultraviolet curing agent and glass beads into the viologen-based color-changing solution obtained in the step (1), uniformly stirring, and performing vacuum defoaming to obtain a color-changing precursor mixed solution; wherein, the glass beads account for 0.4 to 0.5 percent of the total mass of the color-changing precursor solution;

(3) and (3) coating the color-changing precursor mixed liquor obtained in the step (2) between two pieces of ITO-PET, compacting, and finally carrying out ultraviolet curing to obtain the color-changing precursor mixed liquor.

3. The method of claim 2, wherein: the dosage of the Etvio in the step (1) is 20-40 mmol/L; the dosage of Fc is 10-20 mmol/L.

4. The method of claim 2, wherein: [ EMIM ] in the step (1)]NTF₂The volume ratio of the PC to the PC is 1: 1-1: 5.

5. The method of claim 2, wherein: the volume ratio of the ultraviolet curing agent to the viologen-based color-changing solution in the step (2) is 1: 1-1: 4.

6. The method of claim 2, wherein: and (3) the vacuum defoaming pressure in the step (2) is-0.8 to-1 KPa, and the defoaming time is 0.5 to 2 hours.

7. The method of claim 2, wherein: and (3) compacting two sheets of ITO-PET by adopting a pressing roller.

8. The method of claim 2, wherein: the ultraviolet curing in the step (3) adopts an LED ultraviolet curing device, the power is 20-30W, and the wavelength is 365 nm; the ultraviolet curing time is 0.5-3 min.

Technical Field

The invention belongs to the field of electrochromic materials, and particularly relates to an ultraviolet curing viologen-based electrochromic device and a preparation method thereof.

Background

Viologen materials are one of the most widely used electrochromic materials at present. People often compound the electrochromic material with inorganic fillers, polymers, organic solvents and the like, and encapsulate the electrochromic material among conductive substrates to construct an integrated structural electrochromic device. The viologen-based color-changing device not only has the advantages of rich colors, stable circulation and the like, but also is easy to prepare the electrochromic film with light weight and good flexibility. However, few researches on the preparation of the viologen-based flexible color-changing film are carried out, and the preparation process mostly adopts a heat curing mode. For example, patent CN109557740 discloses a method for preparing a viologen-based flexible color-changing sheet, wherein PVDF is added to prepare an electrochromic film with an integrated structure through thermal curing, and the method adopts an adhesive tape to control the thickness, so that the electrochromic device is difficult to prepare in batch and automatically, and has the problems of uneven coloring and the like.

Unlike the conventional thermal curing method, the photo-curing method is regarded as a more convenient and efficient film-forming method. The ultraviolet curing is one of the most common light curing modes, namely, light with the wavelength of 200-450 nm is used for irradiating curing glue, so that an internal photoinitiator absorbs light energy, and then intramolecular or intermolecular polymerization or crosslinking is induced to generate insoluble substances with a three-dimensional network structure. The ultraviolet curing method has the characteristics of high efficiency, wide adaptability, economy, energy conservation and environmental protection. Compared with a thermal curing method, the method is simpler and easier, can reduce the curing process, saves time, and realizes batch and automatic production. For example, patent CN103992434 discloses an ultraviolet curing electrolyte gel and its application in electrochromic devices, the method is through ultraviolet curing crosslinking, the process is simple, the formed gel has good stability, and shows excellent stability in electrochemical cycling of electrochromic devices. However, at present, few researches on preparing the viologen-based flexible color-changing device by using an ultraviolet curing method are available.

The glass beads are mainly processed from borosilicate, have the granularity of 10-250 mu m, have the advantages of light weight, low heat conduction, higher strength, good chemical stability and the like, have oleophylic hydrophobicity after the surface is specially treated, are easy to disperse in an organic material system, are usually applied to a PDLC liquid crystal film and are used for controlling the thickness of the film, and the patent CN106336875 discloses a preparation method of a trans-polymer dispersed liquid crystal film. The defects of the method are that the thermal polymerization time before the ultraviolet curing is long, the synthesis process of the ultraviolet curing agent is complicated, and the cost is high.

Disclosure of Invention

The invention aims to solve the technical problem of providing an ultraviolet curing viologen-based electrochromic device and a preparation method thereof, which adopt a convenient and efficient ultraviolet curing method and a process of doping glass beads, are beneficial to the improvement of the light modulation range of the electrochromic device, can effectively control the thickness of the electrochromic device, and are more beneficial to the automatic and batch production of the obtained electrochromic device.

The invention provides an ultraviolet curing viologen-based electrochromic device which is obtained by adding an ultraviolet curing agent and glass beads into viologen-based electrochromic solution, assembling the device through coating and finally performing ultraviolet curing.

The invention also provides a preparation method of the ultraviolet curing viologen-based electrochromic device, which comprises the following steps:

(1) dissolving 1, 1-diethyl-4.4-bipyridine dibromide EtVio and ferrocene Fc in propylene carbonate PC and 1-ethyl-3-methylimidazolium bistrifluoromethylsulfonyl imide salt [ EMIM]NTF₂Performing ultrasonic dispersion on the mixed solution to obtain a viologen-based color-changing solution;

(2) adding an ultraviolet curing agent and glass beads into the viologen-based color-changing solution obtained in the step (1), uniformly stirring, and performing vacuum defoaming to obtain a color-changing precursor mixed solution; wherein, the glass beads account for 0.4 to 0.5 percent of the total mass of the color-changing precursor solution;

(3) and (3) coating the color-changing precursor mixed liquor obtained in the step (2) between two pieces of ITO-PET, compacting, and finally carrying out ultraviolet curing to obtain the color-changing precursor mixed liquor.

The dosage of the Etvio in the step (1) is 20-40 mmol/L; the dosage of Fc is 10-20 mmol/L (based on the total volume of the viologen-based color-changing solution).

[ EMIM ] in the step (1)]NTF₂The volume ratio of the PC to the PC is 1: 1-1: 5.

The volume ratio of the ultraviolet curing agent to the viologen-based color-changing solution in the step (2) is 1: 1-1: 4.

The ultraviolet curing agent does not have special requirements, and the conventional ultraviolet curing agent in the industry can be used.

And (3) the vacuum defoaming pressure in the step (2) is-0.8 to-1 KPa, and the defoaming time is 0.5 to 2 hours.

And (3) compacting two sheets of ITO-PET by adopting a pressing roller.

The ultraviolet curing in the step (3) adopts an LED ultraviolet curing device, the power is 20-30W, and the wavelength is 365 nm; the ultraviolet curing time is 0.5-3 min.

The experimental environment in the step (1), the step (2) and the step (3) is free of strong light, and the stirring time in the step (2) is 1-5 hours.

Advantageous effects

(1) The invention adopts the ultraviolet curing method to prepare the electrochromic device, and has the advantages of high efficiency, wide application range, simple process, cost saving and the like.

(2) The invention realizes the regulation and control of the thickness of the electrochromic device by adding the glass beads.

(3) According to the invention, the electrochromic device with good film forming property, adjustable mechanical property and adjustable light modulation range can be prepared by adjusting and controlling the proportion of the ultraviolet curing agent and the color-changing solution, and the obtained device has excellent color-changing property (the maximum light modulation range can reach 79 percent) and good bending resistance, has good comprehensive performance and is suitable for market application.

Drawings

FIG. 1 is a digital photograph of a quasi-solid hybrid color-changing gel prepared according to the present invention.

FIG. 2 is a schematic structural diagram of a color-changing device according to the present invention.

Figure 3 is a digital photograph of the assembled electrochromic device of example 1 in the bleached and colored states.

Fig. 4 is a graph of the uv-vis spectra of the colored and bleached states of the assembled electrochromic device of example 1.

FIG. 5 is a graph of in situ light transmittance at 605nm for a colored state versus a faded state for an assembled electrochromic device of example 1.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.