Preparation method for electroreflective gel, gel, and device

Abstract

The present invention relates to the technical field of electroreflection, and provides a preparation method for an electroreflective gel, a gel, and a device. The method comprises: mixing a metal source and an ionic liquid at a predetermined molar ratio to prepare a metal-based ionic liquid electrolyte, the molar ratio of the ionic liquid to the metal source being greater than or equal to 6:1; and mixing a polymerization additive with the metal-based ionic liquid electrolyte to prepare the electroreflective gel. Thus, the problem of poor light stability of existing ionic gels is solved.

Description

A method for preparing an electroreflective gel, the gel and the device Technical Field

[0001] This invention relates to the field of electroreflective technology, and more particularly to a method for preparing an electroreflective gel, the gel, and a device. Background Technology

[0002] In the current field of electroreflectivity, silver, as a metal source with excellent reflectance spectra, has been widely studied. One method involves using a multi-point visible light transmittance meter to detect the degree of attenuation at multiple points during cycling. Using silver-based ionogels for electroreflective devices from published literature and patents, cyclic testing under continuous LED illumination revealed bright spots of the same size as the LED light source after approximately two to three hundred cycles, particularly noticeable in the colored state of the device. This result indicates that the photostability of currently known silver-based ionogels used in electroreflectivity is generally poor.

[0003] Publicly available literature suggests that sufficient amounts of imidazole-based ionic liquid halides can fully dissolve silver halides, but it fails to explain the underlying dissolution mechanism or address the influence of coordination number on photostability. The slurry formulations in these examples generally exhibit poor photostability. The literature "AMonomeric Imidazol-2-ylidene-Silver(I)Chloride Complex: Synthesis, Structure, and Solid State" further clarifies this. 109 Ag and 13 The CCP / MAS NMR Characterization study indicates that coordination chemodissolution occurs when silver halides are dissolved by halogenated imidazole ionic liquids, forming new silver-imidazolium halide coordination complexes. However, the study does not address the effect of the coordination number on the photostability of the silver-based complex. Other literature suggests that polymerizable monomers containing coordination sites with metal ions in the polymer backbone of the gel can complex with silver ions, potentially improving the cycle life of the device to some extent. However, the study also does not investigate the effect of their coordination number on the photostability of the device.

[0004] In summary, based on relevant experimental verification, silver-based ion gels currently used in the field of electroreflective lighting generally exhibit poor photostability. During cyclic testing, bright spots of the same size as the LED light source appear within 800 cycles, especially noticeable in the colored state. Furthermore, there are currently no known and verified effective photostabilizing additives that can be used in silver-based ion gels to improve this photostability defect without affecting other device performance. Summary of the Invention

[0005] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide a method for preparing electroreflective gel, gel and device, so as to solve the problem of poor photostability of existing ionic gels.

[0006] This invention discloses a method for preparing an electroreflective gel, comprising: mixing a metal source and an ionic liquid at a predetermined molar ratio to prepare a metal-based ionic liquid electrolyte; wherein the molar ratio of the ionic liquid to the metal source is ≥6:1; and mixing a polymerization reaction aid with the metal-based ionic liquid electrolyte to prepare the electroreflective gel.

[0007] Optionally, the ionic liquid includes organic cations, inorganic or organic anions;

[0008] The organic cation includes one or more of the following:

[0009] Quaternary ammonium salt ions, quaternary phosphorus salt ions, imidazole salt ions, pyrrole salt ions, pyridine salt ions, piperidine salt ions, morpholine salt ions, thiophene salt ions, carbazole salt ions, and guanidine salts;

[0010] The inorganic or organic anions include one or more of the following:

[0011] Halogen ions, alkali salt ions, fluorine-containing anions, oxyacid anions, amino acid anions, ester anions, cyanide-containing anions, and halide metal salt anions.

[0012] Optionally, the ionic liquid comprises an organic cation having alkyl, aryl, or heterocyclic substituents; wherein the number of carbon atoms in the alkyl group does not exceed 18, and preferably, the number of carbon atoms in the alkyl group is 2-8.

[0013] Optionally, the metal source includes one or more of the following: silver chloride, silver cyanide, silver bis(trifluoromethanesulfonyl)imide, silver oxide, silver sulfate, silver bromide, silver perchlorate, silver nitrate, and silver iodide.

[0014] Optionally, the polymerization reaction aid includes one or more of the following: curable monomers, crosslinking agents, and initiators.

[0015] Optionally, the curable monomer includes one or more of the following: acrylic acid and its derivatives, acrylates and their derivatives, vinyl monomers, epoxy monomers, acryloylmorpholine and its derivatives, and N,N-dimethylacrylamide and its derivatives.

[0016] Optionally, the crosslinking agent includes one or more of the following: polyethylene glycol diacrylate and its derivatives, ethoxylated trimethylolpropane triacrylate and its derivatives, ethylene glycol dimethacrylate and its derivatives, and polydipentaerythritol pentaacrylate and its derivatives.

[0017] Optionally, the initiator includes one or more of the following: free radical initiators, cationic initiators, anionic initiators, and hybrid initiators.

[0018] The present invention also provides an electroreflective gel comprising a metal-based ionic liquid electrolyte formed by mixing a metal source and an ionic liquid in a specific molar ratio, wherein the molar ratio of the ionic liquid to the metal source is ≥6:1, and the gel is prepared using the preparation method described above.

[0019] The present invention also provides an electroluminescent device, comprising a first substrate layer, a working electrode layer, an electroluminescent layer formed from the above-described electroluminescent gel, a counter electrode layer, and a second substrate layer arranged sequentially.

[0020] Compared with existing technologies, the above technical solution has the following advantages:

[0021] 1. The electroreflective gel provided in this application forms an ionic liquid electrolyte with a stable coordination network by mixing a metal source and a corresponding ionic liquid ligand in a specific molar ratio, thereby significantly improving the photostability of the electroreflective gel and solving the problem of poor photostability of existing ionic gels;

[0022] 2. This application further limits the alkyl chain length of the ionic liquid ligand to prepare a silver-based ionic liquid electrolyte with as many high coordination structures as possible to improve photostability. After adding polymerization reaction aids and in-situ curing, a silver-based electroreflective gel can be obtained. There is no need to add additional photostability stabilizers or coat the device surface with a filter protective film to improve the photostability of the device, so the preparation efficiency is high.

[0023] 3. The electroreflective gel provided in this application can also be used to prepare electroreflective devices including but not limited to display devices, optical devices (such as light modulators, photodetectors, etc.), sensor devices, flexible devices, etc., and has good photostability. Attached Figure Description

[0024] Figure 1 is a flowchart of the electroreflective gel preparation method and device described in this invention;

[0025] Figures 2(a)-2(c) show the test structure of the electroreflective gel, preparation method and device according to Example 2 of the present invention under colored static xenon lamp irradiation test.

[0026] Figures 3(a)-3(c) show the test structure of the electroluminescent gel, its preparation method and device according to Comparative Example 1 under colored static xenon lamp irradiation test. Detailed Implementation

[0027] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0028] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0029] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0030] Example: This embodiment provides a method for preparing an electroreflective gel, comprising:

[0031] S10: Mix a metal source and an ionic liquid at a predetermined molar ratio to prepare a metal-based ionic liquid electrolyte; wherein the ionic liquid has an ionic liquid ligand that can coordinate with metal source ions, and the molar ratio of the ionic liquid to the metal source is ≥6:1;

[0032] Optionally, the metal source includes one or more of the following: silver chloride, silver cyanide, silver bis(trifluoromethanesulfonyl)imide, silver oxide, silver sulfate, silver bromide, silver perchlorate, silver nitrate, and silver iodide.

[0033] Optionally, the ionic liquid includes organic cations, inorganic or organic anions; the organic cations include one or more of quaternary ammonium salt ions, quaternary phosphonium salt ions, imidazole salt ions, pyrrole salt ions, pyridinium salt ions, piperidine salt ions, morpholine salt ions, thiophene salt ions, carbazole salt ions, and guanidine salts; the inorganic or organic anions include one or more of halide ions, alkali salt ions, fluorine-containing anions, oxyacid anions, amino acid anions, ester anions, cyanide-containing anions, and metal halide salt anions.

[0034] Based on the above, the ionic liquid ligands include, but are not limited to, imidazole ligands, pyrrole ligands, and pyridine ligands; the ionic liquids are selected from one or more of the following: imidazole salt ionic liquids, pyridine salt ionic liquids, pyrrole salt ionic liquids, quaternary ammonium salt ionic liquids, and quaternary phosphine salt ionic liquids. Preferably, they may also be selected from one or more of the following: alkyl imidazole salts, alkyl pyridine salts, alkyl pyrrole salts, alkyl quaternary ammonium salts, alkyl quaternary phosphine salts, fluoroalkyl imidazole salts, fluoroalkyl pyridine salts, fluoroalkyl pyrrole salts, fluoroalkyl quaternary ammonium salts, and fluoroalkyl quaternary phosphine salts. They may also be salts substituted with alkyl, aryl, or heterocyclic groups.

[0035] Based on the aforementioned optional metal sources and ionic liquids, silver-based ionic liquid electrolytes with different ligands can be formed.

[0036] It is understandable that ionic liquid ligands and metal ions (such as imidazole chloride ligands and silver ions) can form suitable ligand structures through feed control (the above molar ratio control) during the ionic liquid electrolysis preparation process, thereby improving photostability. For example, in this embodiment, it was found that the coordination number of imidazole chloride (like) ligands (ionic liquid ligands) and silver ions (metal ions) is positively correlated with the photostability of silver-based ionic gels. Therefore, by controlling the molar ratio of the metal source and the ionic liquid to a certain extent, the coordination structure can be controlled so that imidazole chloride ligands and silver ions can form as many structures with high coordination numbers as possible, thereby improving the photostability of the prepared electroreflective gel.

[0037] Preferably, the ionic liquid may further include organic cations substituted with alkyl, aryl, or heterocyclic groups (the organic cations include one or more of quaternary ammonium salts, quaternary phosphonium salts, imidazole salts, pyrrole salts, pyridinium salts, piperidine salts, morpholine salts, thiophene salts, carbazole salts, and guanidine salts).

[0038] In a preferred embodiment, when the ionic liquid contains alkyl-substituted cations, such as alkyl-substituted imidazole salts (alkylimidazolium salt ionic liquids), in order to achieve as many high coordination number-dominant structures as possible, the number of carbon atoms in the alkyl group does not exceed 18, and more preferably, the number of carbon atoms in the alkyl group is 2-8.

[0039] S20: The polymerization reaction aid is mixed with the metal-based ionic liquid electrolyte and then cured in situ to prepare an electroreflective gel.

[0040] In this embodiment, the preparation of the electroreflective gel also utilizes a polymerization reaction aid. For example, the polymerization reaction aid is used to polymerize and form the polymer backbone of the electroreflective gel. The polymerization reaction aid includes, but is not limited to, curable monomers (polymerizable monomers), crosslinking agents, and initiators, and may also include other additives, such as coupling agents.

[0041] Specifically, as optional, the above-mentioned curable monomers (which can be photocurable monomers or thermocurable monomers) include, but are not limited to, one or more of the following: acrylic acid and its derivatives, acrylates and their derivatives (such as hydroxyethyl methacrylate, methyl methacrylate), vinyl monomers (methyl vinyl ether), epoxy monomers (bisphenol A type epoxy acrylate, etc.), acryloylmorpholine and its derivatives, and N,N-dimethylacrylamide and its derivatives, etc.

[0042] The crosslinking agents mentioned above include, but are not limited to, one or more of the following: polyethylene glycol diacrylate and its derivatives, ethoxylated trimethylolpropane triacrylate and its derivatives, ethylene glycol dimethacrylate and its derivatives, and polydipentaerythritol pentaacrylate and its derivatives, etc.

[0043] The aforementioned initiators include, but are not limited to, one or more of the following: free radical initiators (such as 2,4,6-trimethylbenzoyl diphenylphosphine oxide, lithium phenyl (2,4,6-trimethylbenzoyl)phosphate, etc.), cationic initiators (such as diazonium salts), anionic initiators (such as benzoin sulfonates), and hybrid initiators.

[0044] The aforementioned curable monomers, crosslinking agents, and initiators are used to form the polymer backbone of the gel. In addition to the above, curable monomers, crosslinking agents, and initiators that do not affect the silver-based ionic liquid electrolyte can also be used. It is understood that curable monomers that also have crosslinking effects can also be used to polymerize and achieve the polymer backbone structure.

[0045] Based on the above preparation method, this embodiment also provides an electroreflective gel prepared therefrom. The electroreflective gel includes a metal-based ionic liquid electrolyte formed by mixing the above-mentioned ionic liquid and metal source in a specific molar ratio. The molar ratio of the ionic liquid and the metal source is ≥6:1. By controlling the feed molar ratio, as many ligand structures with high coordination numbers as possible are formed in the metal-based ionic liquid electrolyte, thereby improving structural stability.

[0046] The preparation method described above can be used to prepare a polymer backbone that is polymerized by the polymerization reaction aids described above.

[0047] It is understandable that the above-mentioned (silver-based) ionic liquid electrolyte is applied to three-dimensional networks formed by the polymerization of different polymer backbones (different curable monomers, crosslinking agents, and initiators) to generate reflective gels for use in different devices.

[0048] Taking the formation of silver-based ionic liquid electrolytes with imidazole chloride ligands from electroreflective gels as an example, the coordination number of the generated imidazole chloride ligands with silver ions may be 2-6. The silver ions are provided by the metal source, and the imidazole chloride ligands are provided by the ionic liquid. By controlling the conditions (specific molar ratio) during the preparation process of the silver-based ionic liquid electrolyte in the electroreflective gel, the coordination number can be controlled as much as possible to be dominated by high coordination number structures, that is, to form as many high coordination number ligand structures as possible. High coordination number can significantly improve photostability by enhancing the strength of metal-ligand bonds or forming a more stable coordination network.

[0049] Therefore, this embodiment can solve the problem of poor device photostability by adjusting the molar ratio of metal source and ionic liquid to form as many ligand structures with high coordination number as possible. Furthermore, its greater advantage over the prior art is that it does not require the addition of additional light stabilizers or additional coating of filter protective film on the device surface. It only needs to control the coordination design of the generated metal ions and metal ion ligands by controlling the feed molar ratio, thereby improving the photostability of the gel. The process is simple, the cost is controllable, and it is suitable for mass production.

[0050] Alternatively, a solvent, such as a polar / nonpolar solvent, can be added to the above preparation process to further optimize the coordination of the ionic liquid ligand and the metal ions (such as the above-mentioned imidazole chloride ligand and silver ions) and improve the stability of the prepared electroreflective gel.

[0051] This embodiment also provides an electroluminescent device, comprising a first substrate layer, a working electrode layer, an electroluminescent layer formed by electroluminescent gel obtained by the above preparation method (as, and / or with the addition of other additives, etc.), a counter electrode layer, and a second substrate layer arranged sequentially. Specifically, the electroluminescent device includes, but is not limited to, display devices, optical devices (such as light modulators, photodetectors, etc.), sensor devices, flexible devices, etc.

[0052] This application reveals through experiments that during cyclic testing (testing devices prepared from the aforementioned electroreflective gel), silver-based electroreflective gel devices with a predominantly low coordination number structure often exhibit bright spots of the same size as the lamp light source within 800 cycles (visible light transmittance variation range of 60%-10%), which is particularly noticeable in the colored state. In contrast, devices with a predominantly high coordination number structure, formed through specific feed molar ratio control, can guarantee that this spot phenomenon does not appear within 2000 cycles. In a 28-day static aging test under xenon lamp aging chamber illumination (one standard solar intensity) on the colored state of the devices (visible light transmittance of 10%), silver-based electroreflective gel devices with lower feed molar ratios all exhibited significant yellowing and optical failure phenomena such as decreased visible light transmittance in some areas. Devices with higher feed molar ratios, however, showed no significant optical failure after 28 days, and their overall visible light transmittance remained close to 10%, without significant decrease.

[0053] Therefore, the electroluminescent device provided in this embodiment can control the coordination number of metal ions and their ligands to be dominated by high coordination number structures by controlling the conditions (specific molar ratio) in the preparation process of silver-based ionic liquid electrolyte. Furthermore, it can select the ionic liquid structure (limiting the number of alkyl carbon atoms in alkyl-substituted ionic liquids) to reduce the spatial restriction of high coordination ligand structures, thereby further increasing the probability of the formation of high coordination number ligand structures and making the device have better photostability.

[0054] To demonstrate that the electroreflective device provided above achieves improved photostability by controlling the molar ratio of ionic liquid and metal source, several specific implementation examples (Examples 1-21 below) and comparative examples (Comparative Examples 1-11 below) for preparing electroreflective gels based on the above preparation method are provided.

[0055] It is understood that different embodiments 1-21 and comparative examples 1-11 differ only in the ratio and / or type of the metal source, ionic liquid, curable monomer, crosslinking agent and initiator, but all use similar preparation methods to prepare the corresponding electroreflective gels and devices.

[0056] The specific preparation method of the electroreflective gel is as follows: Under argon atmosphere, the metal source and ionic liquid are stirred and mixed at 120°C at a fixed molar ratio to form a colorless, transparent, homogeneous solution (pre-prepared silver-based ionic liquid electrolyte). When cooled to 90°C, a photocurable monomer and crosslinking agent are added, stirred and mixed to form a colorless, transparent, homogeneous solution, and then cooled to room temperature for storage. Before use, the solution is heated to 35°C, an initiator is added, and the solution is completely dissolved and homogeneous to obtain a silver-based electroreflective ionic gel that can be cured in situ.

[0057] For illustrative purposes, the use of argon atmosphere is to reduce the interference of external environmental impurities on the gel preparation process. The temperature control in the above steps is beneficial for the formation of as many highly coordinated structures as possible in the silver-based ionic liquid electrolyte. Increased temperature intensifies molecular thermal motion, accelerating the formation and breaking of coordination bonds; it also increases mixing efficiency, ensuring that the individual ions / coordination structures do not interfere with each other after the addition of photocurable monomers, crosslinking agents, and initiators, thereby improving the quality of the generated electroreflective gel. This process can also be carried out at room temperature and / or under other temperature conditions.

[0058] Specifically, a solution of silver-based ionic liquid electrolyte, photocurable monomer and crosslinking agent can be prepared in advance and stored at room temperature. Then, an initiator can be added before use, thereby improving the preparation efficiency of electroreflective gel.

[0059] The fabrication method of the device based on the above-mentioned electroreflective gel is as follows: the working electrode is a metal film material fabricated by metal magnetron sputtering, all using 5nm Au-ITO-PET; the counter electrode is a metallic silver mesh PET film. A flexible device is fabricated using a coating-composite method. The film thickness is controlled by adding spacer particles to the silver-based electroreflective ion gel before photocuring (except for Example 15, which is heat-cured at 60℃ for 1 hour). The spacer particles are 50μm in size. Immediately after roll-to-roll coating, the device is exposed to a UV lamp (21mW / cm²). 2 The film is cured for 16 minutes to ensure complete curing. After production, it is cut into approximately A5 size (148mm*210mm) thin-film devices. Then, it is laminated with tempered glass using an 80℃ EVA lamination process to isolate the silver-based electroreflective ionogel from the influence of airborne moisture and oxygen. All processing is carried out at room temperature. The visible light transmittance of the laminated device in its bleached state is approximately 60%.

[0060] Devices were fabricated based on the electroreflective gels obtained using the above preparation method under different implementation examples and comparative examples (provided components / ratios) for testing. Specifically, the photostability of the devices was characterized by monitoring the degree of decay at multiple points during cycling, such as performing the following cycling tests and xenon lamp irradiation aging tests.

[0061] Specifically, in this embodiment, the device prepared above is used for testing, and the circuit control method is as follows:

[0062] By applying a voltage of -0.6V to the device, its visible light transmittance is reduced from 60% to 10%. The total charge required for the coloring process at this voltage is calibrated using an electrochemical workstation. This charge level controls each coloring cycle of the corresponding device; that is, a voltage of -0.6V is applied at the start of the coloring process until the device reaches the calibrated total charge, at which point the voltage application stops. Conversely, by applying a voltage of 0.3V to the device, its visible light transmittance is increased from 10% to 60%, and the operating current is monitored by the electrochemical workstation to be less than 10 kJ / L. -5 At step A, pressure is stopped; this completes one bleaching process. One cycle of the device involves changing from a bleached state (60% visible light transmittance) to a colored state (10% visible light transmittance), stopping pressure for 1 minute, and then changing the device back from the colored state to the bleached state. The device rests for 1 minute between each cycle.

[0063] The cyclic testing process for the device fabricated above is as follows:

[0064] Under ambient air conditions, the relative humidity in the test room for the control device was 45-55%. Two sets of devices were prepared for each of the following embodiments and comparative examples, and placed in the perforated mesh illumination area (under continuous illumination by the LED backlight, the perforated mesh forms a multi-point illumination area, and the unilluminated areas form multi-point shielding areas). A cyclic test was initiated simultaneously, with a total of 2000 cycles. The visible light transmittance variation range for each device was 60%-10%. The LED lights were kept on throughout the test, and the difference in visible light transmittance between the irradiated and shielded areas was measured using a multi-point visible light transmittance meter. Each device is controlled by a circuit to check its overall optical state data every 100 cycles. If the difference in visible light transmittance between the irradiated area and the shaded area exceeds 1.5% when the coloring state occurs, it is considered that a light spot phenomenon has occurred. The cycle test of the device is stopped, and the number of cycles and the visible light transmittance of the irradiated area (i.e., the light spot) when the coloring state is completed are recorded. If no light spot phenomenon occurs, the cycle test continues until the device reaches 2000 cycles. The number of cycles and the visible light transmittance when the coloring state and the fading state are completed are also recorded.

[0065] The xenon lamp irradiation aging test process for the device prepared above is as follows:

[0066] The xenon lamp aging chamber was set at a temperature of 20°C and a relative humidity of 50%, with an irradiance equivalent to a standard sunbeam. The intensity was calibrated using a power density meter at the horizontal placement of the device. Two sets of devices were prepared for each embodiment and comparative example. Black tape was attached to the upper surface of each device at intervals to indicate whether it was exposed to light or not. After undergoing the aforementioned device coloring process (visible light transmittance of 10%), the devices were placed at the same horizontal position in the xenon lamp aging chamber. The entire xenon lamp irradiation aging test lasted 28 days (672 hours). After the test, the black tape was removed, and the reflection and transmission states of the device in its current colored state were recorded by photograph, along with the overall optical state of the device at this point. Finally, the device was tested again using the same cyclic method to verify whether it could undergo a normal cyclic process again.

[0067] Different implementation examples 1-21 and comparative examples 1-11 differ only in the ratio and / or type of the metal source, ionic liquid, curable monomer, crosslinking agent and initiator used. The specific metal source, ionic liquid, photocurable monomer, crosslinking agent, initiator and dosage used in specific implementation examples 1-21 and comparative examples 1-11 are shown below.

[0068] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0069] For each specific embodiment example 1-21 and comparative example 1-11, two devices were further fabricated using the silver-based electroreflective gel for parallel control, numbered A and B.

[0070] Implementation Example 1: Metal source and ionic liquid: 9331 mg of (1-butyl-3-methylimidazolium chloride) and 1276 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 6:1);

[0071] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0072] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0073] Example 2: Metal source and ionic liquid: 9418 mg of (1-butyl-3-methylimidazole) chloride, 1189 mg of silver chloride. (Molar ratio of imidazole chloride:silver chloride = 6.5:1);

[0074] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0075] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0076] Example 3: Metal source and ionic liquid: 9494 mg of (1-butyl-3-methylimidazole) chloride, 1113 mg of silver chloride. (Molar ratio of imidazole chloride:silver chloride = 7:1);

[0077] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0078] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0079] Example 4: Metal source and ionic liquid: 9803 mg of (1-butyl-3-methylimidazolium chloride) and 804 mg of silver chloride. (Molar ratio of imidazolium chloride to silver chloride = 10:1);

[0080] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0081] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0082] Example 5: Metal source and ionic liquid: 10020 mg of (1-butyl-3-methylimidazolium chloride), 587 mg of silver chloride. (Molar ratio of imidazolium chloride:silver chloride = 14:1);

[0083] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0084] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0085] Example 6: Metal source and ionic liquid: 9121 mg of (1-ethyl-3-methylimidazole) chloride, 1486 mg of silver chloride. (Molar ratio of imidazole chloride:silver chloride = 6:1);

[0086] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0087] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0088] Example 7: Metal source and ionic liquid: 9489 mg of (1-hexyl-3-methylimidazolium chloride) and 1118 mg of silver chloride. (Molar ratio of imidazolium chloride to silver chloride = 6:1);

[0089] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0090] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0091] Example 8: Metal source and ionic liquid: 9612 mg of (1-octyl-3-methylimidazole) chloride, 995 mg of silver chloride. (Molar ratio of imidazole chloride:silver chloride = 6:1);

[0092] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0093] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0094] Example 9: Metal source and ionic liquid: 9792 mg of (1-dodecyl-3-methylimidazole) chloride, 815 mg of silver chloride. (Molar ratio of imidazole chloride:silver chloride = 6:1);

[0095] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0096] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0097] Example 10: Metal source and ionic liquid: 9966 mg of (1-octadecyl-3-methylimidazole) chloride, 641 mg of silver chloride. (Molar ratio of imidazole chloride:silver chloride = 6:1);

[0098] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0099] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0100] Implementation Example 11: Metal source and ionic liquid: 10324 mg of (1-octadecyl-3-methylimidazole) chloride, 283 mg of silver chloride. (Molar ratio of imidazole chloride:silver chloride = 14:1);

[0101] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0102] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0103] Implementation Example 12: Metal source and ionic liquid: 9331 mg of (1-butyl-3-methylimidazolium chloride) and 1276 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 6:1);

[0104] Photocurable monomers and crosslinking agents: 3140 mg of 4-hydroxybutyl acrylate, 1253 mg of polyethylene glycol diacrylate;

[0105] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0106] Implementation Example 13: Metal source and ionic liquid: 9331 mg of (1-butyl-3-methylimidazolium chloride) and 1276 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 6:1);

[0107] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, ethoxylated trimethylolpropane triacrylate 1253 mg;

[0108] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0109] Implementation Example 14: Metal source and ionic liquid: 9331 mg of (1-butyl-3-methylimidazolium chloride) and 1276 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 6:1);

[0110] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0111] Initiator: 500 mg of an acrylic acid solution of 5% (w / w) 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide.

[0112] Implementation Example 15: Metal source and ionic liquid: 9331 mg of (1-butyl-3-methylimidazole) chloride, 1276 mg of silver chloride (molar ratio of imidazole chloride:silver chloride = 6:1);

[0113] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0114] Initiator: 500 mg of an acrylic acid solution containing 5% azobisisobutyronitrile.

[0115] Implementation Example 16: Metal source and ionic liquid: 9670 mg of 1-butyl-3-methylimidazolium thiocyanate, 937 mg of silver cyanide (molar ratio of imidazolium thiocyanate: silver cyanide = 7:1);

[0116] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0117] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0118] Implementation Example 17: Metal source and ionic liquid: 9632 mg of tributylmethylammonium chloride, 975 mg of silver chloride (molar ratio of quaternary ammonium chloride: silver chloride = 6:1);

[0119] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0120] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0121] Example 18: Metal source and ionic liquid: 7310 mg of (1-butyl-3-methylimidazolium chloride), 2064 mg of 1-butyl-3-methylimidazolium thiocyanate, 1000 mg of silver chloride, and 233 mg of silver cyanide (molar ratio of imidazolium chloride:imidazolium thiocyanate:silver chloride:silver cyanide = 4.8:1.2:0.8:0.2);

[0122] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0123] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0124] Implementation Example 19: Metal source and ionic liquid: 7464 mg of (1-butyl-3-methylimidazolium chloride), 2122 mg of 1-n-butyl-1-methylpyrrolidine di(trifluoromethanesulfonyl)imide, 1021 mg of silver chloride (molar ratio of imidazolium chloride:silver chloride = 6:1);

[0125] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0126] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0127] Implementation Example 20: Metal source and ionic liquid: 2611 mg of 1-ethyl-3-methylimidazole chloride, 3110 mg of 1-butyl-3-methylimidazole chloride, 3610 mg of 1-hexyl-3-methylimidazole chloride, 1276 mg of silver chloride (molar ratio of imidazole chloride:silver chloride = 6:1);

[0128] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0129] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0130] Implementation Example 21: Metal source and ionic liquid: 9518 mg of (1-benzyl-3-methylimidazolium chloride) and 1089 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 6:1);

[0131] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0132] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0133] Specifically, in Examples 1-5 above, the molar ratio of imidazole ligand to silver ions in the feed is different, all being ≥6:1; in Examples 6-10 above, imidazole ligands with different alkyl chain lengths are used compared to Example 1; in Example 11 above, a different feed molar ratio is used compared to Example 10, and a ligand with a different alkyl chain length (Example 11 has a longer alkyl chain length) is used compared to Example 5; in Examples 12-15 above, the curable monomer, crosslinking agent, or initiator is different compared to Example 1; in Example 16 above, the metal source and ionic liquid are different compared to Example 3; and in Examples 17-21 above, at least one of the ionic liquid and metal source is different compared to Example 1.

[0134] Comparative Example 1: Metal source and ionic liquid: 7626 mg of (1-ethyl-3-methylimidazole) chloride, 2981 mg of silver chloride (molar ratio of imidazole chloride: silver chloride = 2.5:1);

[0135] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0136] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0137] Comparative Example 2: Metal source and ionic liquid: 7986 mg of (1-butyl-3-methylimidazolium chloride) and 2621 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 2.5:1);

[0138] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0139] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0140] Comparative Example 3: Metal source and ionic liquid: 9188 mg of (1-octadecyl-3-methylimidazole) chloride, 1419 mg of silver chloride (molar ratio of imidazole chloride: silver chloride = 2.5:1);

[0141] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0142] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0143] Comparative Example 4: Metal source and ionic liquid: 8593 mg of (1-butyl-3-methylimidazolium chloride) and 2014 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 3.5:1);

[0144] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0145] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0146] Comparative Example 5: Metal source and ionic liquid: 8971 mg of (1-butyl-3-methylimidazolium chloride) and 1636 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 4.5:1);

[0147] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0148] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0149] Comparative Example 6: Metal source and ionic liquid: 9112 mg of (1-butyl-3-methylimidazolium chloride) and 1495 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 5:1);

[0150] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0151] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0152] Comparative Example 7: Metal source and ionic liquid: 8872 mg of (1-ethyl-3-methylimidazolium chloride) and 1735 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 5:1);

[0153] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0154] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0155] Comparative Example 8: Metal source and ionic liquid: 9846 mg of (1-octadecyl-3-methylimidazole) chloride, 761 mg of silver chloride (molar ratio of imidazole chloride: silver chloride = 5:1);

[0156] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0157] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0158] Comparative Example 9: Metal source and ionic liquid: 9230 mg of (1-butyl-3-methylimidazolium chloride) and 1377 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 5.5:1);

[0159] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0160] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0161] Comparative Example 10: Metal source and ionic liquid: 9230 mg of (1-butyl-3-methylimidazolium chloride) and 1377 mg of silver chloride (molar ratio of imidazolium chloride to silver chloride = 5.5:1);

[0162] Photocurable monomers and crosslinking agents: 3140 mg of 4-hydroxybutyl acrylate, 1253 mg of polyethylene glycol diacrylate;

[0163] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0164] Comparative Example 11: Metal source and ionic liquid: 9442 mg of 1-butyl-3-methylimidazolium thiocyanate, 1165 mg of silver cyanide (molar ratio of imidazolium thiocyanate: silver cyanide = 5.5:1);

[0165] Photocurable monomers and crosslinking agents: hydroxyethyl methacrylate 3140 mg, polyethylene glycol diacrylate 1253 mg;

[0166] Initiator: 500 mg of acrylic acid solution of 5% (w / w) lithium phenyl (2,4,6-trimethylbenzoyl) phosphate.

[0167] Specifically, in the above comparative examples 1-9, the molar ratio of imidazole ligands to silver ions is different, all <6:1 (compared to examples 1-5); comparative example 3 has an imidazole ligand with a longer alkyl chain length than comparative example 1; in the above comparative example 7, a different ionic liquid is used compared to comparative example 6; in the above comparative example 7, an imidazole ligand with a longer chain length is used compared to comparative example 6; and in the above comparative examples 10-11, different photocurable monomers, metal sources, or ionic liquids are used compared to comparative example 9.

[0168] Cyclic testing was performed on the devices fabricated using the above-described Examples 1-21 and Comparative Examples 1-11:

[0169] Both Implementation Example 1-21 and Comparative Example 1-11 participated in cyclic testing. The LED backlight used for illumination was kept on throughout the entire test process. The test results are shown in Table 1 below:

[0170] Based on the above test results, it can be concluded that, as in Example 1-21 and Comparative Example 1-11, by adjusting the molar ratio of the ionic liquid ligand to silver in the silver-based ionic liquid electrolyte pre-preparation process in the electroreflective gel, the purpose of controlling the coordination structure can be achieved (specifically, the molar ratio of ionic liquid to metal source during feeding is ≥6:1), thus obtaining an electroreflective gel with good photostability, which will not exhibit light spot phenomenon within 2000 cycles.

[0171] Among them, the above molar ratio control enables the metal ions and their ligands in the formed gel to form as many structures as possible with high coordination number. The high coordination number structure can significantly improve the photostability of the gel. For example, a 6-coordination number may form an octahedral complex structure, so that no light spot phenomenon appears after 2000 cycles of the device, and the transmittance of the colored state in the final irradiated area is less than 0.5%.

[0172] Examples 6-21 use photocurable monomers, crosslinking agents, and metal sources / ionic liquids that are different from those in Examples 1-5, respectively. They achieve similar test results to Examples 1-5 and can characterize the photostability of different gels. In conjunction with Comparative Examples 1-9, it can be seen that the preparation method of this embodiment, by controlling the molar ratio of ionic liquid to metal source during preparation, can make the electroreflective gels formed by photocurable monomers and crosslinking agents of different gels have a more stable coordination network, thereby significantly improving photostability.

[0173] The above implementation example 3 and comparative example 2 were used as examples in a xenon lamp irradiation aging test;

[0174] The test results of the colored state static xenon lamp irradiation experiment of the device are recorded in the form of photographs (see Figures 2(a)-3(c)) to show the difference in photostability of the colored state after 28 days.

[0175] Specifically, after 28 days of static xenon lamp irradiation in the colored state, there was no significant difference between the parts of the device prepared in Example 3 that were covered by black tape and the parts that were not covered (Fig. 2(a)-Fig. 2(c), Fig. 2(a)-Fig. 2(b) are in the transmission state, and Fig. 2(c) is in the reflection state). However, in the contrast of Example 2, the area where the black tape was not covered showed a very obvious yellowing phenomenon (Fig. 3(a)-Fig. 3(c), Fig. 3(a)-Fig. 3(b) are in the transmission state, and Fig. 3(c) is in the reflection state). This indicates that when the molar ratio of ionic liquid to metal source is less than 6, the photostability of the silver-based ionic gel is poor, and there may be a lot of coordination structures with low coordination numbers.

[0176] Referring to Table 1 above, the device fabricated in Example 3 showed a measured visible light transmittance of 10.1% in the colored state after 28 days, with almost no attenuation, and could still undergo one normal cycle test. After fading, the visible light transmittance was 59.8%. In contrast, the device fabricated in Example 2 could no longer undergo a normal cycle test, could not fade, and the unshaded area showed severe yellowing and discoloration failure.

[0177] Therefore, it can be seen that electroluminescent devices prepared by controlling the molar ratio of ionic liquid to metal source to exceed a specific ratio during the preparation process may have more structures dominated by high coordination number, which have a more stable coordination network and can significantly improve light stability.

[0178] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing an electroreflective gel, characterized in that, include: A metal-based ionic liquid electrolyte is prepared by mixing a metal source and an ionic liquid at a predetermined molar ratio; the molar ratio of the ionic liquid to the metal source is ≥6:

1. The polymerization reaction aid is mixed with the metal-based ionic liquid electrolyte to prepare an electroreflective gel.

2. The preparation method according to claim 1, characterized in that: The ionic liquid includes organic cations, inorganic or organic anions; The organic cation includes one or more of the following: Quaternary ammonium salt ions, quaternary phosphorus salt ions, imidazole salt ions, pyrrole salt ions, pyridine salt ions, piperidine salt ions, morpholine salt ions, thiophene salt ions, carbazole salt ions, and guanidine salts; The inorganic or organic anions include one or more of the following: Halogen ions, alkali salt ions, fluorine-containing anions, oxyacid anions, amino acid anions, ester anions, cyanide-containing anions, and halide metal salt anions.

3. The preparation method according to claim 2, characterized in that: The ionic liquid includes the organic cation having alkyl, aryl, or heterocyclic substituted groups; The number of carbon atoms in the alkyl group does not exceed 18.

4. The preparation method according to claim 3, characterized in that: The alkyl group has 2-8 carbon atoms.

5. The preparation method according to claim 1, characterized in that: The metal source includes one or more of the following: silver chloride, silver cyanide, silver bis(trifluoromethanesulfonyl)imide, silver oxide, silver sulfate, silver bromide, silver perchlorate, silver nitrate, and silver iodide.

6. The preparation method according to claim 1, characterized in that: The polymerization reaction aids include one or more of the following: curable monomers, crosslinking agents, and initiators.

7. The preparation method according to claim 6, characterized in that: The curable monomers include one or more of the following: acrylic acid and its derivatives, acrylates and their derivatives, vinyl monomers, epoxy monomers, acryloylmorpholine and its derivatives, and N,N-dimethylacrylamide and its derivatives.

8. The preparation method according to claim 6, characterized in that: The crosslinking agent includes one or more of the following: polyethylene glycol diacrylate and its derivatives, ethoxylated trimethylolpropane triacrylate and its derivatives, ethylene glycol dimethacrylate and its derivatives, and polydipentaerythritol pentaacrylate and its derivatives. And / or, the initiator includes one or more of the following: free radical initiators, cationic initiators, anionic initiators, and hybrid initiators.

9. An electroreflective gel, characterized in that: The electrolyte comprises a metal-based ionic liquid electrolyte formed by mixing a metal source and an ionic liquid in a specific molar ratio, wherein the molar ratio of the ionic liquid to the metal source is ≥6:1; Prepared using the preparation method described in any one of claims 1-8.

10. An electroluminescent device, characterized in that: It includes a first base layer, a working electrode layer, an electroreflective layer formed from the electroreflective gel of claim 9, a counter electrode layer, and a second base layer arranged sequentially.

Images