A spirobifluorene derivative, a preparation method thereof and application thereof in electrochromic devices

Abstract

The application provides a spirobifluorene derivative, a preparation method thereof and application thereof in an electrochromic device, and belongs to the technical field of organic polymer chemistry. The application successfully prepares electrochromic materials with different colors by exploring the difference between nitro and amino and combining fine regulation of the side chain electronic structure. The materials have the characteristics of high neutral state transmittance and bistability, and are expected to be applied in the fields of display, anti-counterfeiting and biological analysis. Specifically, the spirobifluorene derivative of the application not only endows the material with the electrochromic function, but also embeds the methoxy unit with high stability, so that the stability of the electrochromic small molecule device is significantly enhanced, and the material also has the characteristics of neutral state transparency and long-lasting bistability after coloring.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic polymer chemistry, and particularly relates to a spirobifluorene derivative, a preparation method thereof and application thereof in electrochromic devices. BACKGROUND

[0002] Electrochromism (EC) refers to a phenomenon that a material reversibly changes optical properties under voltage driving. Specifically, an electrochromic material reversibly changes light absorption properties in an electrochemical redox process, and the change is manifested as a color conversion between a transparent (or referred to as “bleaching”) state and a colored state, or a conversion between two colored states. Due to the very ideal physical and chemical properties of the electrochromic material, such as low operating voltage, multi-stable characteristics, static power consumption, low color change power consumption, continuous adjustable light transmittance / reflection, optical modulation amplitude, the material is widely used in optical display, information encryption, military camouflage, sensors and intelligent light windows and the like.

[0003] Spirofluorene is a common organic small molecule compound with a large conjugated system and a special rigid fused ring structure. Under voltage driving, it exhibits obvious color change, good optical contrast, high coloring efficiency and redox stability, and is therefore widely used as an organic optoelectronic functional material in the field of electrochromism. Spirofluorene compounds can be used as electron transport materials (ETMs), which is usually achieved by combining with strong electron-attracting groups, such as in the structure of “(A)n–D–(A)n”, by combining spirofluorene with two strong electron-attracting terpyridine groups, an electron transport material with high triplet energy level, suitable frontier orbital energy level, excellent thermal stability and electrochemical stability can be formed. Studies on the photoelectric properties of spirofluorene show that as the polymerization length increases, the energy gap narrows, the hole injection and electron transfer capabilities are improved accordingly, the energy required for light absorption decreases, the absorption intensity increases, and the spectrum red shifts. In addition, the 9-spiro carbon atom in the spirofluorene skeleton significantly blocks the conjugation effect of the two conjugated fragments, making them two independent conjugated links. This structural characteristic affects the photophysical properties of spirofluorene in different redox states, thereby determining its color change. In dilute solutions of tetrahydrofuran, as the effective conjugation length increases, the maximum absorption peak and emission peak of these compounds show obvious red shift. These characteristics make spirofluorene and its derivatives have great application potential in the field of electrochromic devices.

[0004] At present, the spirobifluorene compound in neutral state generally shows yellow color, the color is single, and the color fades quickly after coloring. It is found that the color display of the spirobifluorene compound is also related to the type of the triphenylamine connecting group combined therewith, and various colors can be obtained by modifying the side chain group combined with the spirobifluorene compound, and the rich color range and slow fading will be beneficial to expanding the application field of the spirobifluorene compound. SUMMARY

[0005] The purpose of the present application is to provide a spirobifluorene derivative, a preparation method thereof and an application in an electrochromic device, so as to solve the technical problem that the color of the spirobifluorene compound in the prior art is single, fades quickly and leads to limited application range.

[0006] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical scheme:

[0007] The present application provides a spirobifluorene derivative, and the structure of the spirobifluorene derivative is selected from the following structural formula:

[0008] Monomer I: Monomer II:

[0009] The present application provides a preparation method of a spirobifluorene derivative, comprising the following steps:

[0010] Step 1), p-methoxyaniline and p-fluoronitrobenzene are mixed in dimethyl sulfoxide, and reacted under the action of triethylamine to obtain compound I;

[0011] Step 2), fluorene and liquid bromine are reacted in toluene to obtain compound II;

[0012] Step 3), compound II and N-bromosuccinimide are subjected to bromination reaction in chloroform to obtain compound III;

[0013] Step 4), compound I, compound III, copper powder and 18-crown-6 ether-6 are mixed in o-dichlorobenzene, and subjected to condensation reaction under the action of potassium carbonate to obtain monomer I;

[0014] Step 5), monomer I, ethanol, 1,4-dioxane and hydrazine hydrate are mixed and subjected to reaction under the catalysis of Pd / C catalyst to obtain monomer II;

[0015] The structural formula of the compound I is:

[0016] The structural formula of the compound II is:

[0017] The structural formula of the compound III is:

[0018] Further, in step 1), the molar ratio of p-methoxyaniline, triethylamine and p-fluoro nitrobenzene is 8-9:8-9:6-7; the reaction temperature is 80-100℃.

[0019] The molar volume ratio of p-methoxyaniline and dimethyl sulfoxide is 5-10 mmol:25-35 mL.

[0020] Further, in step 2), the molar ratio of fluorene and liquid bromine is 0.8-1.2:2.5-3.5; the reaction temperature is 80-110℃.

[0021] Further, in step 2), the molar volume ratio of fluorene and toluene is 8-15 mmol:20-40 mL.

[0022] Further, in step 3), the molar ratio of compound II and N-bromosuccinimide is 1:1.8-3.

[0023] Further, in step 3), the molar volume ratio of compound II and chloroform is 5-10 mmol:20-40 mL.

[0024] Further, in step 4), the molar ratio of compound III and compound I is 1:2.5-3;

[0025] The molar ratio of compound I, potassium carbonate and copper powder is 1:3-5:3-5;

[0026] The molar ratio of compound I and 18-crown-6 is 1:0.7-1.

[0027] Further, in step 5), the ratio of the amount of monomer I, ethanol and 1,4-dioxane is 0.5-1 g:8-12 mL:8-12 mL;

[0028] The mass ratio of monomer I and Pd / C catalyst is 1:0.8-1.2;

[0029] The mass ratio of monomer I and hydrazine hydrate is 1:4-7.

[0030] The application also provides a spirobifluorene derivative in an electrochromic device.

[0031] The application has the following beneficial effects:

[0032] The application not only obtains a spirobifluorene derivative by modifying monomers through an amino group and a nitro group, but also prepares a corresponding electrochromic device, and the spirobifluorene derivative obtained by modifying the nitro group has a bistable characteristic of a neutral state and a long retention time after coloring. The application expands the application of the spirobifluorene derivative electrochromic material in the fields of smart glasses, smart windows, smart sky curtains, automobile sunroofs and the like. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A cyclic voltammogram of monomer I of Example 1 at 0-2.5V;

[0034] Figure 2 A cyclic voltammogram of monomer II of Example 1 at 0-2.5V;

[0035] Figure 3 An ultraviolet-visible absorption spectrum of monomer I of Example 1 at different voltages;

[0036] Figure 4 An ultraviolet-visible absorption spectrum of monomer II of Example 1 at different voltages;

[0037] Figure 5 A chromaticity change graph of monomer I of Example 1 at different voltages;

[0038] Figure 6 A chromaticity change graph of monomer II of Example 1 at different voltages. DETAILED DESCRIPTION

[0039] The application provides a spirobifluorene derivative, and a structure of the spirobifluorene derivative is selected from the following structural formulae:

[0040] Monomer I: Monomer II:

[0041] The application provides a preparation method of a spirobifluorene derivative, and the method comprises the following steps:

[0042] Step 1), p-methoxyaniline and p-fluoronitrobenzene are mixed in dimethyl sulfoxide, and a reaction is carried out under the action of triethylamine to obtain compound I;

[0043] Step 2), fluorene and liquid bromine are reacted in toluene to obtain compound II;

[0044] Step 3), compound II and N-bromosuccinimide are subjected to a bromination reaction in chloroform to obtain compound III;

[0045] Step 4), compound I, compound III, copper powder and 18-crown-6 ether-6 are mixed in o-dichlorobenzene, and a condensation reaction is carried out under the action of potassium carbonate to obtain monomer I;

[0046] Step 5), mixing monomer I, ethanol, 1,4-dioxane and hydrazine hydrate, and performing a reaction under catalysis of Pd / C catalyst to obtain monomer II;

[0047] The structural formula of the compound I is:

[0048] The structural formula of the compound II is:

[0049] The structural formula of the compound III is:

[0050] In the present application, in step 1), the molar ratio of p-methoxyaniline, triethylamine and p-fluoronitrobenzene is 8-9:8-9:6-7, preferably 8.5:8.5:6.5; the temperature of the reaction is 80-100°C, preferably 85-95°C, further preferably 90°C.

[0051] The molar volume ratio of the p-methoxyaniline and dimethyl sulfoxide is 5-10 mmol:25-35 mL, preferably 6-8 mmol:28-32 mL, further preferably 7 mmol:30 mL.

[0052] In the present application, in step 1), the reaction is performed under heating reflux.

[0053] In the present application, in step 1), after the reaction is completed, natural cooling to room temperature is performed, and then extraction, washing, drying, filtration and recrystallization are performed in sequence to obtain the compound I.

[0054] In the present application, in step 1), the recrystallization is to drop a small amount of dimethyl sulfoxide and a large amount of ethanol into the crude product.

[0055] In the present application, the mass ratio of the dimethyl sulfoxide and ethanol is preferably 1:4.

[0056] In the present application, in step 2), the molar ratio of the fluorene and liquid bromine is 0.8-1.2:2.5-3.5, preferably 0.9-1.1:2.8-3.2, further preferably 1.0:3.0; the temperature of the reaction is 80-110°C, preferably 90-100°C, further preferably 95°C.

[0057] In the present application, in step 2), the molar volume ratio of the fluorene and toluene is 8-15 mmol:20-40 mL, preferably 10-13 mmol:28-35 mL, further preferably 12 mmol:30 mL.

[0058] In the present application, in step 2), the reaction is performed under heating reflux.

[0059] In the present application, in step 3), the molar ratio of the compound II to N-bromosuccinimide is 1:1.8-3, preferably 1:2-2.5, and further preferably 1:2.3.

[0060] In the present application, in step 3), the molar volume ratio of the compound II to chloroform is 5-10 mmol: 20-40 mL, preferably 8 mmol: 25-35 mL, and further preferably 8 mmol: 30 mL.

[0061] In the present application, in step 3), the compound II and N-bromosuccinimide are preferably mixed, shielded from light, and chloroform is added under a nitrogen atmosphere.

[0062] In the present application, in step 3), the bromination reaction is preferably performed at -2-5°C for 1.5-4 h, and then stirred at room temperature for 6-14 h.

[0063] The reaction temperature is preferably 0°C, and the reaction time is preferably 2-3 h, and further preferably 2.5 h; the stirring time at room temperature is preferably 8-12 h, and further preferably 10 h.

[0064] In the present application, in step 3), after the completion of the bromination reaction, purification is preferably performed by column chromatography (stationary phase: fine silica gel having a particle size of 300-400 mesh, mobile phase: dichloromethane and petroleum ether at a volume ratio of 1:1).

[0065] In the present application, in step 4), the molar ratio of the compound III to the compound I is 1:2.5-3, and preferably 1:2.8.

[0066] The molar ratio of the compound I, potassium carbonate, and copper powder is 1:3-5:3-5, and preferably 1:4:4.

[0067] The molar ratio of the compound I to 18-crown-6 is 1:0.7-1, and preferably 1:0.85.

[0068] In the present application, in step 4), after the condensation reaction, extraction, washing, drying, filtration, and reduction of pressure are sequentially performed, and then purification is performed by column chromatography.

[0069] The stationary phase of the column chromatography is preferably silica gel, and the mobile phase is preferably composed of ethyl acetate and petroleum ether at a volume ratio of 1:12.

[0070] In the present application, in step 5), the amount of the monomer I, ethanol, and 1,4-dioxane is 0.5-1 g: 8-12 mL: 8-12 mL, and preferably 0.75 g: 10 mL: 10 mL.

[0071] The mass ratio of monomer I and Pd / C catalyst is 1:0.8-1.2, preferably 1:1.

[0072] The mass ratio of monomer I and hydrazine hydrate is 1:4-7, preferably 1:6.

[0073] In the present application, in step 5), the condensation reaction is that monomer I, Pd / C catalyst, ethanol and 1,4-dioxane are mixed, heated to 70-90℃ under nitrogen atmosphere, hydrazine hydrate is added and refluxed for 10-14h, and then naturally cooled to room temperature.

[0074] In the present application, hydrazine hydrate is preferably used to reduce monomer I, and the reduction effect is poor when iron powder is used.

[0075] In the present application, the heating temperature is preferably 75-85℃, and further preferably 80℃, and the reflux time is preferably 11-13h, and further preferably 12h.

[0076] In the present application, in step 5), the Pd / C catalyst is preferably 10% Pd / C catalyst.

[0077] The present application also provides a use of a spirobifluorene derivative in an electrochromic device.

[0078] In the present application, the electrochromic device comprises an electrochromic material, further comprises a cathodic electrochromic material and an anodic electrochromic material.

[0079] In the present application, the anodic electrochromic material is a spirobifluorene derivative, and the cathodic electrochromic material is preferably a diallyl violet derivative.

[0080] In the present application, the mass ratio of the cathodic electrochromic material and the anodic electrochromic material is 10-12:20-30, preferably 11:25.

[0081] The technical solutions provided by the present application are described in detail below in combination with examples, but they should not be understood as limiting the scope of protection of the present application.

[0082] Example 1

[0083] A mixture of 8.12 mmol of p-methoxyaniline, 8.25 mmol of triethylamine and 6.24 mmol of p-fluoronitrobenzene was added to 30 mL of dimethyl sulfoxide and heated to 90°C under a nitrogen atmosphere for 24 hours, after which it was cooled to room temperature. The resulting reaction mixture was extracted with dichloromethane, the extracted organic phase was washed three times with saturated brine, then dried over anhydrous sodium sulfate, filtered and the filtrate was recrystallized by adding 10 mL of dimethyl sulfoxide and 30 mL of ethanol, obtaining 1.2 g of orange needle-shaped crystals, which were compound I, with a yield of 90%.

[0084] A mixture of 10 mmol of fluorene and 30 mmol of liquid bromine was added to 30 mL of toluene and heated to 100°C under a nitrogen atmosphere for 10 hours, after which it was cooled to room temperature. The resulting reaction mixture was extracted with dichloromethane, the extracted organic phase was washed three times with saturated brine, then dried over anhydrous sodium sulfate, filtered and the filtrate was rotary evaporated with methanol, obtaining compound II, with a yield of 93%;

[0085] A mixture of 6.28 mmol of compound II and 13.82 mmol of N-bromosuccinimide was added to 30 mL of chloroform under a nitrogen atmosphere, and reacted at 0°C for 2 hours, then stirred at room temperature for 12 hours. After the reaction was completed, it was purified by column chromatography (stationary phase: fine silica gel 300-400 mesh, mobile phase: dichloromethane and petroleum ether in a volume ratio of 1:1), obtaining 2.02 g of white solid, which was compound III, with a yield of 90%.

[0086] A mixture of 0.63 mmol of compound III, 1.6 mmol of compound I, 5.04 mmol of potassium carbonate, 5.04 mmol of copper powder and 0.63 mmol of 18-crown-6 ether was added to 20 mL of o-dichlorobenzene and heated to 180°C under a nitrogen atmosphere for 30 hours, after which it was cooled to room temperature. The resulting reaction mixture was extracted with dichloromethane, the extracted organic phase was washed three times with saturated brine, then dried over anhydrous sodium sulfate, filtered, and the resulting liquid was column chromatographed (stationary phase: silica gel, mobile phase: ethyl acetate and diethyl ether in a volume ratio of 1:12), obtaining 0.75 g of red-brown solid, which was monomer I.

[0087] A mixture of 0.875 mmol of monomer I and 0.80 g of 10% Pd / C catalyst was added to 10 mL of ethanol and 10 mL of 1,4-dioxane, respectively, and 3.90 g of hydrazine hydrate was added to the mixture while heating to 80°C under a nitrogen atmosphere, and refluxed for 12 hours, after which it was cooled to room temperature. The filtrate was precipitated in a saturated sodium chloride solution, obtaining 0.6 g of orange-red solid, which was monomer II, with a yield of 88%.

[0088] Example 2

[0089] 8 mmol of p-methoxyaniline, 9 mmol of triethylamine and 6 mmol of p-fluoronitrobenzene were mixed, 35 mL of dimethyl sulfoxide was added, and the mixture was heated to 90°C under a nitrogen atmosphere for 24 hours, and then cooled to room temperature. The resulting mixture was extracted with dichloromethane, the extracted organic phase was washed with saturated brine three times, and then dried with anhydrous sodium sulfate. After filtration, the filtrate was recrystallized by adding 10 mL of dimethyl sulfoxide and 30 mL of ethanol to obtain orange needle-shaped crystals, which were compound I.

[0090] 8 mmol of fluorene and 35 mmol of liquid bromine were mixed with 30 mL of toluene, and the mixture was heated to 100°C under a nitrogen atmosphere for 10 hours, and then cooled to room temperature. The resulting reaction system was extracted with dichloromethane, the obtained organic phase was washed with saturated brine three times, and then dried with anhydrous sodium sulfate. After filtration, the filtrate was rotary evaporated with methanol to obtain compound II.

[0091] 6.28 mmol of compound II and 11.30 mmol of N-bromosuccinimide were mixed, and 40 mL of chloroform was added under a nitrogen atmosphere. The mixture was reacted at 0°C for 2 hours, and then stirred at room temperature for 12 hours. After the reaction was completed, the mixture was purified by column chromatography (stationary phase: fine silica gel having a particle size of 300-400 mesh, mobile phase: dichloromethane and petroleum ether at a volume ratio of 1:1) to obtain compound III.

[0092] 0.63 mmol of compound III, 1.6 mmol of compound I, 4.8 mmol of potassium carbonate, 4.8 mmol of copper powder and 1.12 mmol of 18-crown-6 were mixed, and then 20 mL of o-dichlorobenzene was added. The mixture was heated to 180°C under a nitrogen atmosphere for 30 hours, and then cooled to room temperature. The resulting reaction system was extracted with dichloromethane, the extracted organic phase was washed with saturated brine three times, and then dried with anhydrous sodium sulfate. After filtration, the obtained liquid was column chromatographed (stationary phase: silica gel, mobile phase: ethyl acetate and diethyl ether at a volume ratio of 1:12) to obtain monomer I.

[0093] 1 mmol of compound monomer I and 1.2 g of 10% Pd / C catalyst were mixed, and then 10 mL of ethanol and 10 mL of 1,4-dioxane were added, respectively. When the mixture was heated to 80°C under a nitrogen atmosphere, 7 g of hydrazine hydrate was added, and the mixture was refluxed for 12 hours, and then cooled to room temperature. The filtrate was precipitated in a saturated sodium chloride solution to obtain monomer II.

[0094] Example 3

[0095] Mix 9 mmol of p-methoxyaniline, 8 mmol of triethylamine and 7 mmol of p-fluoronitrobenzene, then add 25 mL of dimethyl sulfoxide, heat to 90°C under nitrogen atmosphere for 24 hours, then cool to room temperature. Extract the resulting mixture with dichloromethane, wash the extracted organic phase with saturated brine for 3 times, then dry it with anhydrous sodium sulfate, filter to obtain the filtrate, then recrystallize the filtrate by adding 10 mL of dimethyl sulfoxide and 30 mL of ethanol to obtain compound I.

[0096] Mix 12 mmol of fluorene and 42 mmol of liquid bromine with 40 mL of toluene, heat to 100°C under nitrogen atmosphere for 10 hours, then cool to room temperature. Extract the resulting reaction system with dichloromethane, wash the obtained organic phase with saturated brine for 3 times, then dry it with anhydrous sodium sulfate, filter to obtain the filtrate, then add methanol to the filtrate and rotary evaporate to obtain compound II.

[0097] Mix 6.28 mmol of compound II and 18.84 mmol of N-bromosuccinimide, shield from light, add 20 mL of chloroform under nitrogen atmosphere, react at 0°C for 2 hours, then stir at room temperature for 12 hours, then purify by column chromatography (stationary phase: fine silica gel with particle size of 300-400 mesh, mobile phase: dichloromethane and petroleum ether with a volume ratio of 1:1) to obtain compound III.

[0098] Mix 0.63 mmol of compound III, 1.89 mmol of compound I, 9.45 mmol of potassium carbonate, 9.45 mmol of copper powder and 1.89 mmol of 18-crown-6 ether-6, then add 20 mL of o-dichlorobenzene, heat to 180°C under nitrogen atmosphere for 30 hours, then cool to room temperature. Extract the resulting reaction system with dichloromethane, wash the extracted organic phase with saturated brine for 3 times, then dry it with anhydrous sodium sulfate, filter, then reduce pressure, then purify the obtained liquid by column chromatography (stationary phase: silica gel, mobile phase: ethyl acetate and ethyl ether with a volume ratio of 1:12) to obtain monomer I.

[0099] Mix 0.5 g of compound monomer I and 0.40 g of 10% Pd / C catalyst, then add 10 mL of ethanol and 10 mL of 1,4-dioxane respectively, add 2.0 g of hydrazine hydrate under nitrogen atmosphere when heated to 80°C, reflux for 12 hours, then cool to room temperature. Pour the filtrate into a saturated sodium chloride solution to precipitate to obtain monomer II.

[0100] Example 4

[0101] Add 93wt% propylene carbonate and 7wt% lithium perchlorate to a beaker, ultrasonic mix uniformly to obtain an electrolyte material;

[0102] Take 1.12 mmol of monomer I prepared in Example 1 and 0.51 mmol of diallyl violane derivative to mix in 5 mL of electrolyte material, ultrasonic treatment for 10 min, to obtain a color-changing active layer material;

[0103] First, apply a heat-curing glue around the transparent conductive layer of the transparent conductive electrode b, then cover the conductive layer of the transparent conductive electrode a on the glue layer. Then, put the whole device into an oven for heat curing at a temperature of 85°C for 3h. Subsequently, inject the color-changing active layer material into the space sealed by the transparent conductive electrode a and the transparent conductive electrode b by means of needle cylinder injection, to obtain the electrochromic device.

[0104] Example 5

[0105] Different from Example 4, in this embodiment, monomer II prepared in Example 1 is used as an anodic electrochromic material.

[0106] The electrochromic device prepared in Example 4 is tested for full-wave transmittance, using the electrochemical workstation and ultraviolet spectrometer combined technology, the electrochemical workstation is set to constant potential mode, the ultraviolet spectrum is set to full-wave absorption rate, and the scanning range is 300-1000 nm. The test results are shown in Figure 3 As can be seen from the figure, the device in the neutral state has substantially no absorption in the visible light region, and the device presents high transparency; with the increase of voltage, the device begins to color, and when the voltage is 1.8V, the device reaches the fully colored state, at this time, the ultraviolet absorption curve presents full absorption in the visible light region, and the device presents orange yellow.

[0107] Performance test

[0108] Take 0.074 g of tetrabutylammonium hexafluorophosphate into a 10 mL volumetric flask, and use γ-butyrolactone to make up the volume, to obtain a blank supporting electrolyte solution (0.1 mol / L). Take the monomer I and the monomer II prepared in Example 1 as working electrodes, platinum sheet as counter electrode, and Ag / AgCl as reference electrode, to test the performance of the monomer I and the monomer II.

[0109] 1) Cyclic voltammetry performance test. Figure 1 、 Figure 2 The cyclic voltammograms of the monomers I and II at 0-2.5V are shown in the figures, respectively. As can be seen from the figures, the monomers have obvious redox peaks, which indicates that the monomers have good redox activity, and the redox behavior of the monomer I is reversible.

[0110] 2) Ultraviolet-visible absorption spectrum test. Figure 3 、 Figure 4The figures show the UV-Vis absorption spectra of monomers I and II under different voltages. As can be seen from the figures, monomer I is colorless in the neutral state and orange-yellow in the oxidized state, showing a significant color change. Monomer II is orange in the neutral state and brown in the oxidized state, also showing a significant color change.

[0111] 3) Colorimetric test. Figure 5 , Figure 6 These are chromaticity variation diagrams for monomers I and II under different voltages, respectively. Figure 5 It can be seen that monomer I remains essentially colorless between 0 and 1.4V, but begins to change color after 1.5V, changing from colorless to orange-yellow; from Figure 6 It can be seen that monomer II remains essentially unchanged in the range of 0–1.6V, but begins to change color from orange to brown after 1.7V. Both monomers I and II exhibit good electrochromic properties.

[0112] As can be seen from the above embodiments, the present invention provides a spirodifluorene derivative, its preparation method, and its application in electrochromic devices. The spirodifluorene derivative of the present invention possesses bistable characteristics of neutral transparency and long-lasting coloring time, good redox activity, significant color change, and excellent electrochromic performance. It is of great significance in solving the technical problems of limited application range caused by the single color and rapid fading of spirodifluorene compounds in the prior art, and is expected to be widely used in fields such as display, anti-counterfeiting, and bioanalysis.

[0113] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Use of a spirobifluorene derivative in an electrochromic device, characterized in that, The electrochromic device comprises a cathodic electrochromic material and an anodic electrochromic material; The anodic electrochromic material is a spirobifluorene derivative, and the cathodic electrochromic material is a diallyl ionone derivative; The structure of the spirobifluorene derivative is: Monomer I: .

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