Electro-reflective device

Abstract

An electro-reflective device, comprising an electro-reflective layer. The electro-reflective layer comprises an ionic liquid. The ionic liquid has a hydrophobic ionic group. The present application solves the problem that existing electro-reflective devices are prone to short circuits.

Description

An electroluminescent device Technical Field

[0001] This invention relates to the field of electroluminescence technology, and more particularly to an electroluminescence device. Background Technology

[0002] Electroluminescent devices generally refer to optoelectronic devices that change the reflectivity of light by applying a certain voltage. The main way to achieve this is through the reversible electrodeposition technology of metals.

[0003] In practical applications of electroluminescent devices, after energization, metal ions are oxidized and dissolved in the electrolyte on the electrodes or reduced to elemental metals and deposited on the electrodes. This process often requires repeated deposition and dedeposition. Existing electroluminescent devices use hydrophilic ionic liquids for deposition. Although these liquids have high electrodeposition efficiency and fast color change, they are easily affected by ambient temperature and humidity, which can lead to short circuits and device failure, affecting the device's lifespan. The risk of short circuits during device cycling also limits its application areas and large-scale industrial production. Summary of the Invention

[0004] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide an electroluminescent device to solve the problem that existing electroluminescent devices are prone to short circuits.

[0005] This invention discloses an electroluminescent device, including an electroluminescent layer comprising an ionic liquid; the ionic liquid having hydrophobic ionic groups.

[0006] The term "hydrophobic" refers to a group that has no affinity for water, is insoluble in water, or has very low solubility. It is usually composed of long-chain alkyl, aryl, or non-polar functional groups such as ester or ether groups.

[0007] It is understandable that the ionic liquids used in the electroreflective layer of existing electroreflective devices are hydrophilic ions, such as halogen ionic liquids. The purpose is to dissolve metal ions in the electrolyte during the oxidation / reduction process, thereby achieving the removal of deposits in the electroreflective device. However, the electroreflective layer contains a large number of hydrophilic ions, which can easily exchange substances with moisture in the environment, thereby causing uneven local conductivity and ultimately increasing the risk of short circuits in local electrode areas. Based on this, in this embodiment, hydrophobic ionic groups are applied / added / introduced into the ionic liquid that forms the electrolyte.

[0008] The presence of the hydrophobic ionic group can be the hydrophobic ionic liquid itself, or it can be a hydrophobic ionic group introduced based on the ionic liquid of an existing application (i.e., a mixture of two types of ionic liquids).

[0009] Specifically, the hydrophobic ionic groups include, but are not limited to, anions and / or cations having fluorinated groups.

[0010] The aforementioned anions include, but are not limited to, one or more of the following: tetrafluoroborate ions [BF4], such as 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), hexafluorophosphate ions [PF6], such as 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), 1-octyl-3-methylimidazolium hexafluorophosphate ([OMIM][PF6]), and bis(trifluoromethanesulfonyl)imide ions ([Tf2N]), such as 1 Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ([BMIM][Tf₂N]) and trifluoroacetate ion are used as examples. The hydrophobicity order of the aforementioned anions is [BMIM][BF₄] < [BMIM][Tf₂N] < [BMIM][PF₆], meaning [BF₄] is the most hydrophilic and [PF₆] is the most hydrophobic, which can be selected according to the device application. Further, the cations include, but are not limited to, one or more of the following: fluoroalkylimidazolium ions, fluoroalkylpyridine ions, fluoroalkyl quaternary ammonium ions, and fluoroalkyl quaternary phosphine ions. Imidazole cations generally have better hydrophilicity than pyridine or quaternary ammonium salts.

[0011] The aforementioned anions / cations with fluorinated groups all have a certain degree of hydrophobicity. They can be selected as ionic liquids used as the electroreflective layer of the electroreflective device in this embodiment, or they can be added to the existing ionic liquid of the electroreflective layer of the electroreflective device to form a mixed ionic liquid with hydrophobic ionic groups in this embodiment.

[0012] Specifically, optionally, the aforementioned ionic liquids having hydrophobic ionic groups include (selected from) one or more of the following: pyridine tetrafluoroborate, pyridine trifluoroacetate, pyridine trifluoromethanesulfonate, pyridine bis(trifluoromethanesulfonyl)imide salt, pyridine hexafluorophosphate, pyridine chloride, pyrrole tetrafluoroborate, pyrrole trifluoroacetate, pyrrole trifluoromethanesulfonate, pyrrole bis(trifluoromethanesulfonyl)imide salt, pyrrole hexafluorophosphate, tetrafluoroborate quaternary ammonium salt, trifluoroacetate quaternary ammonium salt, trifluoromethanesulfonate quaternary ammonium salt, bis(trifluoromethanesulfonyl)imide quaternary ammonium salt, hexafluorophosphate quaternary ammonium salt, quaternary ammonium chloride, tetrafluoroborate quaternary phosphine salt, trifluoroacetate quaternary phosphine salt, trifluoromethanesulfonate quaternary phosphine salt, bis(trifluoromethanesulfonyl)imide quaternary phosphine salt, hexafluorophosphate quaternary phosphine chloride, fluoroalkylimidazolium tetrafluoroborate, fluoroalkylimidazolium trifluoroacetate, fluoroalkylimidazolium trifluoro Methanesulfonates, fluoroalkylimidazolium bis(trifluoromethanesulfonyl)imide salts, fluoroalkylimidazolium hexafluorophosphates, fluoroalkylimidazolium chloride salts, fluoroalkylpyridine tetrafluoroborate, fluoroalkylpyridine trifluoroacetate, fluoroalkylpyridine trifluoromethanesulfonate, fluoroalkylpyridine bis(trifluoromethanesulfonyl)imide salts, fluoroalkylpyridine hexafluorophosphates, fluoroalkylpyridine chloride salts, tetrafluoroborate fluoroalkyl quaternary ammonium salts, trifluoroacetate fluoroalkyl quaternary ammonium salts, trifluoromethanesulfonate fluoroalkyl quaternary ammonium salts, bis(trifluoromethanesulfonyl)imide fluoroalkyl quaternary ammonium salts, hexafluorophosphate fluoroalkyl quaternary ammonium salts, fluoroalkyl quaternary ammonium chloride salts, tetrafluoroborate fluoroalkyl quaternary phosphine salts, trifluoroacetate fluoroalkyl quaternary phosphine salts, trifluoromethanesulfonate fluoroalkyl quaternary phosphine salts, bis(trifluoromethanesulfonyl)imide fluoroalkyl quaternary phosphine salts, hexafluorophosphate fluoroalkyl quaternary phosphine salts, fluoroalkyl quaternary phosphine chloride salts.

[0013] Further optionally, in addition to the aforementioned hydrophobic ionic groups, the ionic liquid may also include one or more of the following: imidazole salts, pyridinium salts, pyrrole salts, quaternary ammonium salts, quaternary phosphine salts, piperidine salts, morpholine salts, thiophene salts, carbazole salts, and guanidine salts. The addition of the aforementioned hydrophobic ionic groups (ionic liquids containing hydrophobic ionic groups) to the ionic liquids based on these salts can enhance the interfacial energy between the electroluminescent layer and the interface, thereby reducing the short-circuit rate. This allows the device to achieve good electroluminescence performance and excellent cycle stability even under simple packaging conditions.

[0014] Optionally, the electroreflective layer of the electroreflective device described above may also include a metal source, which provides metal ions to form a metal complex with metal ion ligands provided by the ionic liquid, so as to achieve rapid oxidation / reduction of metal ions during the deposition and dedeposition processes.

[0015] The metal source includes one or more of the following metal compounds: silver chloride, silver bromide, silver iodide, silver acetate, silver nitrate, silver perchlorate, silver perbromate, silver periodate, silver sulfate, silver cyanide, silver sulfide, silver hexafluorophosphate, silver tetrafluoroborate, silver tetrachloroaluminate, silver trifluoromethanesulfonate, silver bis(trifluoromethanesulfonyl)imide, copper fluoride, copper chloride, copper bromide, copper iodide, copper cyanide, copper sulfate, copper acetate, copper aluminate, cuprous fluoride, cuprous chloride, cuprous bromide, cuprous iodide, cuprous cyanide, gold chloride, gold cyanide, gold sulfide, gold chloride, gold sulfide, nickel chloride, nickel sulfate, cobalt chloride, and platinum chloride.

[0016] It is understandable that the metal source mentioned above may also contain hydrophobic ions (hydrophobic ionic groups) such as trifluoromethanesulfonate ions and bis(trifluoromethanesulfonyl)imide ions, in order to further increase the content of hydrophobic ionic groups in the electrolyte and reduce the risk of electrode short circuit.

[0017] Optionally, the electroreflective layer further includes one or more of a polymer compound, a solvent, and additives to form the polymer framework of the electroreflective layer. Specifically, the additives include one or more of antioxidants, light stabilizers, thickeners, electrolyte supplements, and spacers; the polymer compound is generated by polymerization of one or more of a monomer, initiator, crosslinking agent, catalyst, and polymerization inhibitor.

[0018] Optionally, the polymerizing monomer includes one or more of the following: acrylic acid and its derivatives, acrylates and their derivatives, hydroxyethyl acrylate and its derivatives, N-vinyl-2-pyrrolidone and its derivatives, diphenylmethane diisocyanate and its derivatives, toluene diisocyanate and its derivatives, isophorone diisocyanate and its derivatives, dicyclohexylmethane diisocyanate and its derivatives, hexamethylene diisocyanate and its derivatives, L-lysine diisocyanate and its derivatives, polyols and their derivatives, polyamines and their derivatives, phenyl dioxide epoxy resin and its derivatives, glycidyl ether and its derivatives;

[0019] The polymer compound is generated by an integrated polymerization reaction of one or more of the above-mentioned polymerizing monomers, initiators, crosslinking agents, catalysts and polymerization inhibitors inside the device.

[0020] Optionally, the solvent includes one or more of the following: γ-butyrolactone and its derivatives, dimethyl sulfoxide and its derivatives, N-methylpyrrolidone and its derivatives, N,N-dimethylacetamide and its derivatives, N,N-dimethylformamide and its derivatives, cyclopentyl methyl ether and its derivatives, sulfolane and its derivatives, propylene carbonate and its derivatives, ethylene carbonate and its derivatives, and ethylene glycol dimethyl ether and its derivatives.

[0021] The initiator preferably includes one or more of the following: potassium persulfate, ammonium persulfate, azobisisobutyronitrile, benzoyl peroxide, benzaldehyde-formaldehyde trimer, acryloylcarboxylate diester, 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, 2,4,6-trimethylbenzoyl phosphate ethyl ester, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, lithium phenyl(2,4,6-trimethylbenzoyl)phosphate, 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone, 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone, 1-hydroxyphenylcyclohexanone, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin dimethyl ether, and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylpropanone.

[0022] The crosslinking agent preferably includes one or more of the following: ethylene glycol dimethacrylate and its derivatives, polyethylene glycol dimethacrylate and its derivatives, polydipentaerythritol pentaacrylate and its derivatives, ethoxylated trimethylolpropane triacrylate and its derivatives, N,N'-methylenebisacrylamide and its derivatives.

[0023] The catalyst preferably includes one or more of the following: dibutyltin dilaurate and its derivatives, di(dodecylthio)dibutyltin and its derivatives, dibutyltin diacetate and its derivatives, stannous octoate and its derivatives.

[0024] The polymerization inhibitor preferably includes one or more of the following: hydroquinone, p-tert-butylcatechol, 2,6-di-tert-butyl-p-methylphenol, 4,4'-dibutylbiphenyl, bisphenol A, tetrachlorobenzoquinone, 1,4-naphthoquinone, aromatic nitro compounds, p-toluidine, diphenylamine, benzidine, p-phenylenediamine, N-nitrosodiphenylamine, 1,1-diphenyl-2-trinitrophenylhydrazine, sodium sulfate, sodium sulfide, ammonium thiocyanate, and sodium dithiocarbamate.

[0025] The aforementioned electroluminescent layer can be formed by integrating a metal source, an ionic liquid, and a polymer compound. The metal source and the ionic liquid are essential components. The polymer monomers, initiators, crosslinking agents, catalysts (optionally added), polymerization inhibitors (optionally added), solvents (optionally added), and other additive components that form the polymer compound (polymer backbone) are optional when preparing different types of devices.

[0026] The electroluminescent device of this embodiment further includes a first substrate layer, a first electrode layer, the electroluminescent layer, a second electrode layer, and a second substrate layer arranged sequentially, wherein at least one of the first substrate layer and the second substrate layer is a transparent material.

[0027] The present invention does not have any special limitation on the material of the first substrate layer and the second substrate layer, and can be any substrate material known to those skilled in the art.

[0028] Preferably, the first substrate layer and / or the second substrate layer comprises an inorganic substrate, an organic substrate, or an inorganic-organic substrate composite; the inorganic substrate comprises one or more of the following: glass, diamond, ceramic; the thickness is preferably 500-50000 μm; the organic substrate comprises one or more of the following: polymethyl methacrylate and its derivatives, polyethylene terephthalate and its derivatives, polyethylene terephthalate and its derivatives, cyclic olefin copolymers and their derivatives; the thickness is preferably 20-50000 μm.

[0029] Optionally, the conductive layer of the first electrode includes one or more of the following materials (prepared to form a transparent metallic conductive electrode): a mesh or film made of copper nanowires, silver nanowires, or aluminum nanowires; a copper mesh; a silver mesh; an aluminum mesh; an indium tin oxide-copper multilayer composite film or mesh; an indium tin oxide-silver multilayer composite film or mesh; or an indium tin oxide-aluminum multilayer composite film or mesh.

[0030] Optionally, the conductive layer of the second electrode includes one or more of the following materials (prepared to form a transparent conductive metal electrode): a silver mesh, a mesh or film made of silver nanowires, or an indium tin oxide-silver multilayer composite film or mesh.

[0031] The first electrode and the second electrode are the working electrode and the counter electrode, respectively.

[0032] Compared with existing technologies, the above technical solution has the following advantages:

[0033] The electroreflective device provided in this application utilizes an ionic liquid with hydrophobic ionic groups, or it can be based on a commonly used ionic liquid in the prior art with the addition of an ionic liquid with hydrophobic ionic groups. Specifically, one or more of the above-mentioned (anions and / or cations with fluorinated groups) such as pyridine tetrafluoroborate, pyridine trifluoroacetate, and pyridine trifluoromethanesulfonate can be used to enhance the interfacial energy between the electroreflective layer and the interface, thereby reducing the short-circuit rate and solving the problem of easy short circuits in existing electroreflective devices.

[0034] The electroreflective device provided in this application, after being in an ionic liquid with hydrophobic ionic groups, reduces current fluctuations and has a more stable reflectivity difference during cycling, alleviating short circuits in the device. Furthermore, the coloring and fading time changes little after more than 2000 cycles, indicating better device stability. Attached Figure Description

[0035] Figure 1 is a schematic diagram of the structure of an electroluminescent device according to the present invention.

[0036] Reference numerals: 1-First substrate layer; 2-First electrode; 3-Electroluminescent layer; 4-Second electrode; 5-Second substrate layer. Detailed Implementation

[0037] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0038] 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.

[0039] 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.

[0040] It should be understood that these examples are merely for further illustrating the features and advantages of the invention, and not for limiting the scope of the invention claims.

[0041] To demonstrate the effect of this invention in improving the interface energy between the electroreflective layer and the electrode by adding a hydrophobic ionic liquid (with hydrophobic ionic groups) during the preparation of the electroreflective layer in an electroreflective device, multiple examples and comparative examples are provided. Each example and comparative example uses a different ionic liquid. In the examples, a hydrophobic ionic liquid is added to the ionic liquid of the comparative example, and the devices prepared with different ionic liquids (before and after adding the hydrophobic ionic liquid) are mixed. The difference in current (mean ± standard deviation) and reflectance (%) during cycling in the visible and infrared ranges (380–2500 nm) is then used to verify the effect of adding the hydrophobic ionic liquid on the electroreflective layer and the electrode interface in the devices prepared before and after the addition of the hydrophobic ionic liquid. (The change in reflectance under different currents reflects whether there is a short circuit, and the coloring time and fading time determine the device stability.)

[0042] Specifically, for each embodiment and comparative example, the embodiment is a device prepared after adding an ionic liquid with hydrophobic ionic groups, and the comparative example is a device prepared before adding an ionic liquid with hydrophobic ionic groups; the preparation process of each device is similar, and other existing preparation methods can also be used. The metal source, ionic liquid, polymer framework (monomer, additive, solution) / preparation method used in different embodiments are different.

[0043] The fabricated devices, as shown in Figure 1, all include a first substrate layer, a first electrode layer, an electroluminescent layer, a second electrode layer, and a second substrate layer.

[0044] The electroreflective device has a working electrode (first electrode) and a counter electrode (second electrode) respectively modified on a first substrate layer and a second substrate layer. When an electric current is applied to the device, metal cations undergo a reduction reaction on the working electrode to form a metal thin film. Meanwhile, the metal plate, metal mesh, or foil of the counter electrode undergoes an oxidation reaction, turning into metal cations and releasing them into the electrolyte. When the voltage polarity is reversed, the metal thin film formed on the working electrode is oxidized back into metal cations, leaving the working electrode and redissolving into the electrolyte. A corresponding reduction reaction also occurs on the counter electrode, where metal ions are reduced to elemental metals and adhere to the counter electrode, thus achieving a process from a reflective state to a decolorized state.

[0045] In device applications, the above process is repeated to achieve the deposition / deposition of metal ions.

[0046] 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.

[0047] It is understood that the presence of the hydrophobic ionic group can be directly present in the applied ionic liquid, or it can be achieved by adding / introducing the hydrophobic ionic group to an existing (hydrophilic) ionic liquid (i.e., mixing the two types of ionic liquids). The following examples, to demonstrate the effect, show the addition of ionic liquids with hydrophobic ionic groups in relatively comparative proportions to test the devices before and after the addition of the ionic liquid with hydrophobic ionic groups. In practical applications, ionic liquids with hydrophobic ionic groups can also be directly selected, as long as they do not affect the metal ion deposition / deposition process.

[0048] The formulations and test results of each embodiment and comparative example are disclosed below:

[0049] Example 1: 0.5g silver nitrate, 7g mixture of 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium tetrafluoroborate (mass ratio 5:2), 4g hydroxyethyl acrylate, 1g ethylene glycol diacrylate, 0.01g lithium phenyl (2,4,6-trimethylbenzoyl)phosphate, 5g propylene carbonate, 0.1g vinylsiloxane, and 1g polyglycerol.

[0050] Comparative Example 1: 0.5g silver nitrate, 5g 1-butyl-3-methylimidazolium chloride, 4g hydroxyethyl acrylate, 1g ethylene glycol diacrylate, 0.01g lithium phenyl (2,4,6-trimethylbenzoyl)phosphate, 5g propylene carbonate, 0.1g vinylsiloxane, 1g polyglycerol.

[0051] The preparation process for each product is as follows:

[0052] S1: Mix the compounds of the corresponding mass from Example 1 or Comparative Example 1;

[0053] S2: Add 0.03g of spacers (the spacers are spherical in shape, made of polyacrylic acid resin, and have a particle size of 100μm) to the mixed solution, stir evenly, and then quickly coat them onto the working electrode PET-ITO-Au composite conductive film using a two-roller coating method.

[0054] S3: Combine the counter electrode silver mesh film with the coated PET-ITO-Au composite conductive film, and cure the slurry by irradiating it with ultraviolet light for 1 minute.

[0055] S4: Roller slicing, electrode attachment, and encapsulation yield a flexible photo-solid integrated gel electroluminescent device.

[0056] In Example 1, 1-butyl-3-methylimidazolium tetrafluoroborate was added relative to Comparative Example 1 to form a mixture (ionic liquid).

[0057] The devices prepared using the above-described methods based on the above-described components were subjected to cyclic testing.

[0058] Under the conditions of an active area of ​​100mm*100mm and an electroluminescent layer thickness of 100μm, the coloring time and fading time were determined as follows: The electroluminescent devices prepared in Example 1 and Comparative Example 1 were placed in an ultraviolet-visible spectrometer, and the maximum and minimum transmittance values ​​were detected at 550nm. The time taken for the transmittance to change from the maximum to the minimum value was recorded as the coloring time, and the time taken for the transmittance to change from the minimum to the maximum value was recorded as the fading time.

[0059] The differences in current (mean ± standard deviation) and reflectance (%) in the visible and infrared ranges (380–2500 nm) before and after the addition of the hydrophobic ionic liquid during cycling are shown in Table 1 below. Specifically, the reflectance was measured according to the method in GB / T 33234-2016 "Test Method for Reflectance of Solar Thermal Power Generation Glass Mirrors". The difference in reflectance represents the change in reflectance between the colored state and the initial state. The short-circuit criterion is that when the device is driven by the same amount of electrical charge, the difference in colored reflectance is greater than or equal to 5%.

[0060] Table 1. Current and reflectivity changes in Example 1 and Comparative Example 1

[0061] By comparing Example 1 and Comparative Example 1, it was found that adding a hydrophobic ionic liquid can reduce current fluctuations and provide a more stable reflectivity difference during cycling, thus alleviating device short circuits.

[0062] With an active area of ​​100mm*100mm, simple encapsulation, and a 100μm electroreflective layer, the coloring time and fading time with and without the addition of hydrophobic ionic liquid are shown in Table 2 below:

[0063] Table 2. Changes in fading time for Example 1 and Comparative Example 1.

[0064] By comparing Example 1 and Comparative Example 1 (Tables 1 and 2), it was found that the coloring time and fading time of the two were not exactly the same. The time of Example 1 was more stable, which reduced the pressure on circuit control and packaging, laying the foundation for large-scale industrial production.

[0065] Example 2: 0.5g silver bromide, 8g mixture of 1-vinyl-3-butylimidazolium chloride and trifluoromethanesulfonylimide salt (mass ratio 3:1), 5g acrylic acid, 1g N,N'-methylenebisacrylamide, 0.01g 2-hydroxy-2-methylphenylacetone, 0.005g hydroquinone, 0.1g γ-glycidoxypropyltrimethoxysilane.

[0066] Comparative Example 2: 0.5g silver bromide, 6g 1-vinyl-3-butylimidazolium chloride, 5g acrylic acid, 1g N,N'-methylenebisacrylamide, 0.01g 2-hydroxy-2-methylphenylacetone, 0.005g hydroquinone, 0.1g γ-glycidoxypropyltrimethoxysilane.

[0067] The preparation process is the same as in Example 1 above.

[0068] Example 2: Trifluoromethanesulfonylimide salt was added to Comparative Example 2 to form a mixture (ionic liquid).

[0069] The differences in current and reflectivity in the visible and infrared ranges (380–2500 nm) are shown in Table 3 below. The test method is the same as in Example 1.

[0070] Table 3. Current and reflectivity changes in Example 2 and Comparative Example 2

[0071] Compared with Comparative Example 2 (see Table 3), the addition of hydrophobic ionic liquid can reduce current fluctuations, reduce short-circuit rate, and has a more stable reflectivity difference during cycling.

[0072] With an active area of ​​100mm*100mm, simple encapsulation and a 100μm electroreflective layer were used. The coloring time and fading time with and without the addition of hydrophobic ionic liquid are shown in Table 4 below. The test method is the same as in Example 1.

[0073] Table 4. Changes in fading time in Example 2 and Comparative Example 2

[0074] Comparing Example 2 with Comparative Example 2 (see Table 4), it was found that under simplified packaging conditions, the coloring and fading times of the devices prepared by the formulation of Example 2 varied during the cycling process. Furthermore, the coloring and fading times of the devices prepared by the formulation of Example 2 were more stable, which reduced the pressure on circuit control and packaging.

[0075] Example 3: 0.6g bis(trifluoromethanesulfonyl)imide silver, 7g N-butylpyridine chloride and hexafluorophosphate mixed ionic liquid (mass ratio 5:2), 5g ethylene glycol monoethyl ether, 0.1g aminosiloxane, 2g acrylate polyol, 0.1g isophorone diisocyanate, 0.01g dibutyltin diacetate, and 0.2g lithium nitrate.

[0076] Comparative Example 3: 0.6g bis(trifluoromethanesulfonyl)imide silver, 5g N-butylpyridine chloride, 5g ethylene glycol monoethyl ether, 0.1g aminosiloxane, 2g acrylate polyol, 0.1g isophorone diisocyanate, 0.01g dibutyltin diacetate, 0.2g lithium nitrate.

[0077] The preparation process is as follows:

[0078] S1: Mix the compounds of the corresponding mass from Example 3 or Comparative Example 3;

[0079] S2: Add 0.03g of spacers (the spacers are spherical in shape, made of polyacrylic acid resin, and have a particle size of 100μm) to the mixed solution, stir evenly, and then quickly coat them onto the working electrode PET-ITO-Au composite conductive film using a two-roller coating method.

[0080] S3: Combine the counter electrode silver mesh film with the coated PET-ITO-Au composite conductive film, and bake the slurry in an 85℃ oven for 30 minutes to solidify the slurry;

[0081] S4: Roller slicing, electrode attachment, and encapsulation yield a flexible photo-solid integrated gel electroluminescent device.

[0082] Example 3: Compared with Comparative Example 3, hexafluorophosphate was added to form a mixture (ionic liquid).

[0083] The reflectivity difference and current variation data are shown in Table 5 below. The test method is the same as in Example 1.

[0084] Table 5. Current and reflectivity changes in Example 3 and Comparative Example 3

[0085] Table 5 above shows that the device in Example 3 has lower current fluctuations and a more stable reflectivity difference during cycling, further reducing the short-circuit rate.

[0086] With an active area of ​​100mm*100mm, simple encapsulation was used, and a 100μm electroreflective layer was applied. The coloring and fading times of Example 3 and Comparative Example 3 are shown in Table 6 below. The test method is the same as that of Example 1.

[0087] Table 6. Changes in fading time for Example 3 and Comparative Example 3.

[0088] Comparing Example 3 and Comparative Example 3, it was found that under simplified packaging conditions, the coloring time and fading time of Example 3 and Comparative Example 3 were not entirely the same. The coloring and fading time of the device in Example 3 was more stable, which also reduced the short circuit rate of the device, circuit control and packaging pressure.

[0089] Example 4: 0.5g copper chloride, 7g mixture of 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium trifluoroacetate (mass ratio 5:2), 2g polyethylene glycol 1000, 0.2g lithium nitrate;

[0090] Comparative Example 4: 0.5g copper chloride, 5g 1-butyl-3-methylimidazolium chloride, 2g polyethylene glycol 1000, 0.2g lithium nitrate;

[0091] S1: Mix the compounds of the corresponding mass from Example 4 or Comparative Example 4;

[0092] S2: A laser is used to cut injection holes in the ITO glass, adhesive is applied, and the working electrode ITO and the counter electrode conductive silver glass are bonded face to face. Spacers (spherical in shape, made of polyacrylic acid resin, with a particle size of 200μm) or spacer strips (strip-shaped, with a thickness of 500μm or 3000μm) are used to control the distance between the two electrode surfaces to be 200μm, 500μm, or 3000μm.

[0093] S3: Inject the solution into the device through a pre-made hole in the conductive glass;

[0094] S4: Apply adhesive to seal the product, resulting in a rigid, integrated liquid electroluminescent device.

[0095] Example 4: 1-Butyl-3-methylimidazolium trifluoroacetate was added to Comparative Example 4 to form a mixture (ionic liquid).

[0096] The changes in current and reflectivity difference are shown in Table 7 below. The test method is the same as in Example 1.

[0097] Table 7. Current and reflectivity changes in Example 4 and Comparative Example 4

[0098] Table 7 shows that Example 4 has a low short-circuit rate and a more stable reflectivity difference during cycling.

[0099] With an active area of ​​100mm*100mm, simple encapsulation, and a 100μm electrolytic layer, the coloring and fading times of Example 4 and Comparative Example 4 are shown in Table 8 below. The test method is the same as that of Example 1.

[0100] Table 8. Changes in fading time for Example 4 and Comparative Example 4

[0101] Table 8 shows that, under simplified packaging conditions, the coloring and fading times of Example 4 and Comparative Example 4 are not the same. The coloring and fading times of Example 4 are more stable, which also reduces the short circuit rate, circuit control and packaging pressure.

[0102] Example 5: 0.5g silver trifluoromethanesulfonate, 8g mixture of 1-vinyl-3-butylpyrrole chloride and bis(trifluoromethanesulfonyl)imide salt (mass ratio 3:1), 5g methyl methacrylate, 1g N,N'-methylenebisacrylamide, 0.01g 2-hydroxy-2-methylphenylacetone, 0.008g hydroquinone, 0.3g polyethylene glycol 1000.

[0103] Comparative Example 5: 0.5g silver trifluoromethanesulfonate, 6g 1-vinyl-3-butylpyrrole chloride, 5g methyl methacrylate, 1g N,N'-methylenebisacrylamide, 0.01g 2-hydroxy-2-methylphenylacetone, 0.008g hydroquinone, 0.3g polyethylene glycol 1000.

[0104] The preparation process is referenced in Example 1.

[0105] Example 5, compared to Comparative Example 5, added bis(trifluoromethanesulfonyl)imide salt to form a mixture (ionic liquid).

[0106] The differences in current and reflectivity in the visible and infrared ranges (380–2500 nm) are shown in Table 9 below.

[0107] Table 9. Current and reflectivity changes in Example 5 and Comparative Example 5

[0108] The testing method was the same as in Example 1. Compared with Example 5 and Comparative Example 5 (see Table 9), the addition of hydrophobic ionic liquid can reduce current fluctuations, reduce short-circuit rate, and exhibit a more stable reflectivity difference during cycling.

[0109] With an active area of ​​100mm*100mm, simple encapsulation and a 100μm electroreflective layer were used. The coloring time and fading time with and without the addition of hydrophobic ionic liquid are shown in Table 10 below. The test method is the same as in Example 1.

[0110] Table 10. Changes in fading time for Example 5 and Comparative Example 5

[0111] Comparing Example 5 with Comparative Example 5 (see Table 10), it was found that under simplified packaging conditions, the coloring and fading times of the devices prepared by the formulation of Example 5 varied during the cycling process. Furthermore, the coloring and fading times of the devices prepared by the formulation of Example 5 were more stable, which reduced the pressure on circuit control and packaging.

[0112] Example 6: 0.6g silver sulfate, 8g tetrabutylammonium chloride and pyridine trifluoroacetate mixture (mass ratio 3:1), 5g hydroxybutyl methacrylate, 1g polyethylene glycol diacrylate, 0.01g 2-hydroxy-2-methylphenylacetone, 0.008g propylene carbonate, 0.4g polypropylene glycol 400.

[0113] Comparative Example 6: 0.6g silver sulfate, 8g tetrabutylammonium chloride, 5g hydroxybutyl methacrylate, 1g polyethylene glycol diacrylate, 0.01g 2-hydroxy-2-methylphenylacetone, 0.008g propylene carbonate, 0.4g polypropylene glycol 400.

[0114] The preparation process is referenced in Example 1.

[0115] Example 6 was prepared by adding pyridine trifluoroacetate to Comparative Example 6 to form a mixture (ionic liquid).

[0116] The differences in current and reflectivity in the visible and infrared ranges (380–2500 nm) are shown in Table 11 below. The test method is the same as in Example 1.

[0117] Table 11 Current and reflectivity changes in Example 6 and Comparative Example 6

[0118] Compared with Comparative Example 6 (see Table 11), the addition of hydrophobic ionic liquid can reduce current fluctuations, reduce short-circuit rate, and has a more stable reflectivity difference during cycling.

[0119] With an active area of ​​100mm*100mm, simple encapsulation and a 100μm electroreflective layer were used. The coloring time and fading time with and without the addition of hydrophobic ionic liquid are shown in Table 12 below. The test method is the same as in Example 1.

[0120] Table 12 Changes in fading time for Example 6 and Comparative Example 6

[0121] Comparing Example 6 with Comparative Example 6 (see Table 12), it was found that under simplified packaging conditions, the coloring and fading times of the devices prepared by the formulation of Example 6 varied during the cycling process. Furthermore, the coloring and fading times of the devices prepared by the formulation of Example 6 were more stable, which reduced the pressure on circuit control and packaging.

[0122] Based on the above six sets of embodiments and comparative examples, each embodiment and comparative example demonstrates the changes in refractive index and fading time of devices with and without hydrophobic ionic liquid, thereby verifying the improvement effect of adding hydrophobic ionic liquid to enhance device stability and reduce short-circuit risk in this application.

[0123] Based on the above, it can be seen that the reflectivity, coloring, and fading time of electroluminescent devices prepared with different metal sources, ionic liquids, and polymer frameworks (monomers, additives, solutions) / preparation methods are all improved before and after the addition of ionic liquids with hydrophobic ionic groups. Therefore, providing ionic liquids with hydrophobic ionic groups is beneficial to solving the problem of easy short circuits in the electroluminescent devices proposed in this application, and improving the safety and stability of use.

[0124] It is also understood that the electroluminescent device of this application improves the ionic liquid (formulation / component / ion (group) type) used in the application, increasing the influence of hydrophobic ionic groups. The specific mass ratios in the mixtures in the above embodiments are only examples to illustrate the improvement of short-circuit problems by hydrophobic ionic groups. The specific settings can be made according to the actual device application.

[0125] 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. An electroluminescent device, characterized in that, Includes an electroreflective layer, wherein the electroreflective layer comprises an ionic liquid; The ionic liquid has hydrophobic ionic groups.

2. The electroluminescent device according to claim 1, characterized in that: The hydrophobic ionic groups include anions and / or cations having fluorinated groups.

3. The electroluminescent device according to claim 2, characterized in that: The anions and / or cations having fluorinated groups include one or more of the following: tetrafluoroborate ion, hexafluorophosphate ion, bis(trifluoromethanesulfonyl)imide ion, trifluoroacetate ion, fluoroalkylimidazolium ion, fluoroalkylpyridine ion, fluoroalkylquaternary ammonium ion, and fluoroalkylquaternary phosphine ion.

4. The electroluminescent device according to any one of claims 1-3, characterized in that: The ionic liquid comprises one or more of the following: pyridine tetrafluoroborate, pyridine trifluoroacetate, pyridine trifluoromethanesulfonate, pyridine bis(trifluoromethanesulfonyl)imide salt, pyridine hexafluorophosphate, pyridine chloride, pyrrole tetrafluoroborate, pyrrole trifluoroacetate, pyrrole trifluoromethanesulfonate, pyrrole bis(trifluoromethanesulfonyl)imide salt, pyrrole hexafluorophosphate, tetrafluoroborate quaternary ammonium salt, trifluoroacetate quaternary ammonium salt, trifluoromethanesulfonate quaternary ammonium salt, bis(trifluoromethanesulfonyl)imide quaternary ammonium salt, hexafluorophosphate quaternary ammonium salt, quaternary ammonium chloride, tetrafluoroborate quaternary phosphine salt, trifluoroacetate quaternary phosphine salt, trifluoromethanesulfonate quaternary phosphine salt, bis(trifluoromethanesulfonyl)imide quaternary phosphine salt, hexafluorophosphate quaternary phosphine chloride, fluoroalkylimidazolium tetrafluoroborate, fluoroalkylimidazolium trifluoroacetate, fluoroalkylimidazolium trifluoromethanesulfonate ... tetrafluoromethanesulfonate, fluoroalkylimidazolium tetrafluoroborate, fluoroalkylimidazolium trifluoromethanesulfonate, fluoroalkylim Azole bis(trifluoromethanesulfonyl)imide salt, fluoroalkylimidazolium hexafluorophosphate, fluoroalkylimidazolium chloride salt, fluoroalkylpyridine tetrafluoroborate, fluoroalkylpyridine trifluoroacetate, fluoroalkylpyridine trifluoromethanesulfonate, fluoroalkylpyridine bis(trifluoromethanesulfonyl)imide salt, fluoroalkylpyridine hexafluorophosphate, fluoroalkylpyridine chloride salt, tetrafluoroborate fluoroalkyl quaternary ammonium salt, trifluoroacetate fluoroalkyl quaternary ammonium salt, trifluoromethanesulfonate fluoroalkyl quaternary ammonium salt, bis(trifluoromethanesulfonyl)imide fluoroalkyl quaternary ammonium salt, hexafluorophosphate fluoroalkyl quaternary ammonium salt, fluoroalkyl quaternary ammonium chloride salt, tetrafluoroborate fluoroalkyl quaternary phosphine salt, trifluoroacetate fluoroalkyl quaternary phosphine salt, trifluoromethanesulfonate fluoroalkyl quaternary phosphine salt, bis(trifluoromethanesulfonyl)imide fluoroalkyl quaternary phosphine salt, hexafluorophosphate fluoroalkyl quaternary phosphine salt, fluoroalkyl quaternary phosphine chloride salt.

5. The electroluminescent device according to claim 1, characterized in that: The ionic liquid also includes one or more of the following: imidazole salts, pyridine salts, pyrrole salts, quaternary ammonium salts, quaternary phosphine salts, piperidine salts, morpholine salts, thiophene salts, carbazole salts, and guanidine salts.

6. The electroluminescent device according to claim 1, characterized in that: The electroluminescent layer also includes a metal source; The metal source includes one or more of the following metal compounds: silver chloride, silver bromide, silver iodide, silver acetate, silver nitrate, silver perchlorate, silver perbromate, silver periodate, silver sulfate, silver cyanide, silver sulfide, silver hexafluorophosphate, silver tetrafluoroborate, silver tetrachloroaluminate, silver trifluoromethanesulfonate, silver bis(trifluoromethanesulfonyl)imide, copper fluoride, copper chloride, copper bromide, copper iodide, copper cyanide, copper sulfate, copper acetate, copper aluminate, cuprous fluoride, cuprous chloride, cuprous bromide, cuprous iodide, cuprous cyanide, gold chloride, gold cyanide, gold sulfide, gold chloride, gold sulfide, nickel chloride, nickel sulfate, cobalt chloride, and platinum chloride.

7. The electroluminescent device according to claim 1, characterized in that: The electroreflective layer further includes one or more of a polymer compound, a solvent, and an additive; The additives include one or more of antioxidants, light stabilizers, thickeners, electrolyte supplements, and spacers; the polymeric compounds are generated by polymerization of monomers with one or more of initiators, crosslinking agents, catalysts, and polymerization inhibitors.

8. The electroluminescent device according to claim 7, characterized in that: The polymeric monomers include one or more of the following: acrylic acid and its derivatives, acrylates and their derivatives, hydroxyethyl acrylate and its derivatives, N-vinyl-2-pyrrolidone and its derivatives, diphenylmethane diisocyanate and its derivatives, toluene diisocyanate and its derivatives, isophorone diisocyanate and its derivatives, dicyclohexylmethane diisocyanate and its derivatives, hexamethylene diisocyanate and its derivatives, L-lysine diisocyanate and its derivatives, polyols and their derivatives, polyamines and their derivatives, phenyl dioxide epoxy resin and its derivatives, glycidyl ether and its derivatives. And / or, the crosslinking agent includes one or more of the following: ethylene glycol dimethacrylate and its derivatives, polyethylene glycol dimethacrylate and its derivatives, polydipentaerythritol pentaacrylate and its derivatives, ethoxylated trimethylolpropane triacrylate and its derivatives, N,N'-methylenebisacrylamide and its derivatives. And / or, the initiator comprises one or more of the following: potassium persulfate, ammonium persulfate, azobisisobutyronitrile, benzoyl peroxide, benzaldehyde-formaldehyde trimer, acryloylcarboxylate diester, 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, 2,4,6-trimethylbenzoyl phosphate ethyl ester, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, lithium phenyl(2,4,6-trimethylbenzoyl)phosphate, 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone, 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone, 1-hydroxyphenylcyclohexanone, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin dimethyl ether, and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone; And / or, the solvent comprises one or more of the following: γ-butyrolactone and its derivatives, dimethyl sulfoxide and its derivatives, N-methylpyrrolidone and its derivatives, N,N-dimethylacetamide and its derivatives, N,N-dimethylformamide and its derivatives, cyclopentyl methyl ether and its derivatives, sulfolane and its derivatives, propylene carbonate and its derivatives, ethylene carbonate and its derivatives, and ethylene glycol dimethyl ether and its derivatives.

9. The electroluminescent device according to claim 1, characterized in that: The electroluminescent device includes a first base layer, a first electrode layer, the electroluminescent layer, a second electrode layer, and a second base layer arranged sequentially, wherein at least one of the first base layer and the second base layer is a transparent material.

10. The electroluminescent device according to claim 9, characterized in that: The first substrate layer and / or the second substrate layer comprises an inorganic substrate, an organic substrate, or an inorganic-organic substrate composite; the inorganic substrate comprises one or more of the following: glass, diamond, ceramic; the organic substrate comprises one or more of the following: polymethyl methacrylate and its derivatives, polyethylene terephthalate and its derivatives, polyethylene terephthalate and its derivatives, cyclic olefin copolymers and their derivatives. And / or, the conductive layer of the first electrode includes one or more of the following materials: a mesh or film made of copper nanowires, silver nanowires, aluminum nanowires, metallic copper mesh, metallic silver mesh, metallic aluminum mesh, indium tin oxide-copper multilayer composite film or mesh, indium tin oxide-silver multilayer composite film or mesh, indium tin oxide-aluminum multilayer composite film or mesh. And / or, the conductive layer of the second electrode includes one or more of the following materials: a metallic silver mesh, a mesh or film made of silver nanowires, or an indium tin oxide-silver multilayer composite film or mesh.

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