KR20180099415A - Electrochromic Compound, Electrochromic Device, and, Method of Driving Electrochromic Device - Google Patents
Electrochromic Compound, Electrochromic Device, and, Method of Driving Electrochromic Device Download PDFInfo
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- KR20180099415A KR20180099415A KR1020170049852A KR20170049852A KR20180099415A KR 20180099415 A KR20180099415 A KR 20180099415A KR 1020170049852 A KR1020170049852 A KR 1020170049852A KR 20170049852 A KR20170049852 A KR 20170049852A KR 20180099415 A KR20180099415 A KR 20180099415A
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/15—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on an electrochromic effect
- G02F1/1514—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material
- G02F1/1523—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material comprising inorganic material
- G02F1/1525—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material comprising inorganic material characterised by a particular ion transporting layer, e.g. electrolyte
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- G—PHYSICS
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- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/15—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on an electrochromic effect
- G02F1/153—Constructional details
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- G02F2001/1512—
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/15—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on an electrochromic effect
- G02F1/1514—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material
- G02F2001/15145—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material the electrochromic layer comprises a mixture of anodic and cathodic compounds
Abstract
An electrochromic compound, an electrochromic device, and a driving method thereof, the electrochromic device comprising: a core part; And an electrochromic compound having an asymmetric structure and a substituent at one side bonded to the core, and an electrochromic device comprising the electrochromic compound. In addition, such an electrochromic device can have multicolor (color) and can be driven at a low power.
Description
An electrochromic device, and a driving method thereof.
Electrochromism is a phenomenon that reversibly changes color when electrochemically oxidizing or reducing the electrode material. A device made of an organic or inorganic electrochromic material can be manufactured as a wide area device at a low cost even though the response speed is slower than that of a conventional cathode ray tube (CRT), a liquid crystal display (LCD), or a light emitting diode (LED) Because it has low power consumption, it can be applied to many fields such as smart window, smart mirror, and electronic paper.
In addition, the development of smart windows / films using electrochromic materials can reduce the emission of fossil fuel emissions through alternative energy utilization, save energy, and contribute to environmental conservation. Therefore, The development of a new concept window that can control the active function such as the effect and the heat transmission can improve the quality of life by improving the residential culture and office environment.
And to provide electrochromic compounds having improved properties.
From this, it is possible to provide a multi-color and low-power electrochromic device.
Further, it is intended to provide a low power driving method using such an electrochromic device.
Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.
In one embodiment of the present invention, the core portion; And a substituent at one side bonded to the core portion, wherein the electrochromic compound has an asymmetric structure.
When such an asymmetric structure compound is used as an electrochromic device, it does not form a radical dimer, and color purity can be maintained even after a color change cycle.
A description of such dimer formation will be described later in more detail in the embodiment section.
The substituent on one side is composed of a cation component and an anion component, and the molecular weight of the anion component may be from 145 to 280. [ As a specific example, PF 6 can be used, and its molecular weight is 145. Or TFSI (bis (trifluoromethane) sulfonimide) may be used, and the molecular weight is 280. As another example, BF 4 may be used. This is to control the size of the anion component so that it can be melted into the ion gel described later. This may be selected depending on the type of ion gel used, but is not limited thereto.
The compound may be represented by the following general formula (1).
[Chemical Formula 1]
Wherein R is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C5 to C20 hetero aryl group, and R 1 to R 8 are independently of each other , Hydrogen, deuterium, or a substituted or unsubstituted C1 to C6 alkyl group, and A means an anion.
As used herein, unless otherwise defined, at least one of the substituents or at least one hydrogen in the compound is substituted with one or more substituents selected from the group consisting of deuterium, a halogen group, a hydroxy group, an amino group, a substituted or unsubstituted C1 to C30 amine group, a nitro group, C1 to C10 alkyl groups such as a C1 to C40 silyl group, a C1 to C30 alkyl group, a C1 to C10 alkylsilyl group, a C3 to C30 cycloalkyl group, a C6 to C30 aryl group, a C1 to C20 alkoxy group, a fluoro group, A trifluoroalkyl group or a cyano group.
A substituted or unsubstituted C1 to C20 amine group, a nitro group, a substituted or unsubstituted C3 to C40 silyl group, a C1 to C30 alkyl group, a C1 to C10 alkylsilyl group, a C3 to C10 alkylsulfinyl group, A C1 to C10 trifluoroalkyl group such as a C30 cycloalkyl group, a C6 to C30 aryl group, a C1 to C20 alkoxy group, a fluoro group or a trifluoromethyl group, or a cyano group may be fused together to form a ring . Specifically, the substituted C6 to C30 aryl group may be fused with another adjacent substituted C6 to C30 aryl group to form a substituted or unsubstituted fluorene ring.
Means one to three heteroatoms selected from the group consisting of N, O, S and P in one functional group, and the remainder is carbon, unless otherwise defined.
As used herein, the term "alkyl group" means an aliphatic hydrocarbon group, unless otherwise defined. The alkyl group may be a "saturated alkyl group" which does not contain any double or triple bonds.
The alkyl group may be an alkyl group having from 1 to 20 carbon atoms. More specifically, the alkyl group may be a C1 to C10 alkyl group or a C1 to C7 alkyl group. For example, C1 to C4 alkyl groups mean that one to four carbon atoms are included in the alkyl chain and include methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec- ≪ / RTI >
Specific examples of the alkyl group include a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, heptyl group, cyclopropyl group, cyclobutyl group, , A cyclohexyl group, and the like.
The term "aryl group" as used herein means a substituent in which all the elements of the cyclic substituent have a p-orbital and the p-orbital forms a conjugation, and the monocyclic or fused ring Polycyclic (i. E., Rings that divide adjacent pairs of carbon atoms) functional groups.
As used herein, the term " heteroaryl group "means that the aryl group contains 1 to 3 heteroatoms selected from the group consisting of N, O, S, and P, and the remainder is carbon. When the heteroaryl group is a fused ring, it may contain 1 to 3 heteroatoms in each ring.
More specifically, the substituted or unsubstituted C6 to C30 aryl group and / or the substituted or unsubstituted C2 to C30 heteroaryl group may be substituted or unsubstituted phenyl group, substituted or unsubstituted naphthyl group, substituted or unsubstituted anthra A substituted or unsubstituted phenanthryl group, a substituted or unsubstituted naphthacenyl group, a substituted or unsubstituted pyrenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted p-terphenyl group, a substituted or unsubstituted naphthacenyl group, An unsubstituted m-terphenyl group, a substituted or unsubstituted chrysenyl group, a substituted or unsubstituted triphenylenyl group, a substituted or unsubstituted perylenyl group, a substituted or unsubstituted indenyl group, a substituted or unsubstituted furan A substituted or unsubstituted thiophenyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted pyrazolyl group, a substituted or unsubstituted imidazolyl group, a substituted or unsubstituted thiazolyl group, a substituted or unsubstituted pyrazolyl group, A substituted or unsubstituted thiazolyl group, a substituted or unsubstituted thiadiazolyl group, a substituted or unsubstituted thiadiazolyl group, a substituted or unsubstituted pyridyl group, a substituted or unsubstituted pyrimidyl group, Substituted or unsubstituted pyrazinyl, substituted or unsubstituted pyrazinyl, substituted or unsubstituted pyrazinyl, substituted or unsubstituted thiazinyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted benzothiophenyl, substituted or unsubstituted benzimidazolyl, A substituted or unsubstituted quinolinyl group, a substituted or unsubstituted quinolinyl group, a substituted or unsubstituted quinazolinyl group, a substituted or unsubstituted quinolinyl group, a substituted or unsubstituted quinazolinyl group, a substituted or unsubstituted quinazolinyl group, Substituted or unsubstituted pyrazinyl groups, substituted or unsubstituted pyrazinyl groups, substituted or unsubstituted benzoxazinyl groups, substituted or unsubstituted benzothiazyl groups, substituted or unsubstituted acridinyl groups, Phenothiazine group, may be a substituted or unsubstituted phenoxazine group, or a combination thereof, are not limited.
In one embodiment of the present invention, a pair of electrodes; And an electrochromic layer disposed between the pair of electrodes, wherein the electrochromic layer comprises an ion gel and a plurality of electrochromic compounds.
The plurality of electrochromic compounds means a compound which is discolored into a distinct color according to different applied voltages.
By using such a device, it is possible to control the applied voltage and adjust the color of the discoloration of the device.
More specifically, the plurality of electrochromic compounds are symmetric compounds which are symmetrical with respect to the axis of the compound; And asymmetric compounds forming asymmetry.
The asymmetric compound may be represented by the following general formula (1).
[Chemical Formula 1]
The description of Formula 1 will be described in an embodiment of the present invention, and a duplicate description will be omitted.
The symmetrical compound may be represented by the following formula (2).
(2)
In
The definition of the substituent in the above formula (2) is the same as that of the embodiment of the present invention described above.
More specifically, the electrochromic layer includes an ion gel and a plurality of electrochromic compounds, wherein the ion gel is an electrolyte matrix, and the electrochromic compound in the ion gel is uniformly dissolved.
The ion gel may be a heterogeneous polymer copolymer.
The heterogeneous polymer copolymer may be a poly (vinylidene fluoride) poly (styrene) or a combination thereof, which has a property of improving the mechanical strength of the ion gel by not mixing with an ionic liquid; And
Poly (ethylene oxide), poly (alkylmethacrylate), poly (alkyl (meth) acrylate), which act as a part of the ionic liquid, Acrylate) or a combination thereof.
In addition, the electrochromic layer may further comprise an ionic salt, that is, an ionic liquid, in a liquid state at room temperature.
The ionic liquid can be prepared by reacting 1-alkyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, [AMI] [TFSI] The alkyl group has 1 to 10 carbon atoms, 1-butyl-3-methylimidazolium tetrafluoroborate, [BMI] [BF 4 ], 1-butyl- (1-butyl-3-methylimidazolium hexafluorophosphate, [BMI] [PF 6 ]), or a combination thereof.
Such an ionic salt is a substance that can help the movement of ions in the electrolyte, and can be effectively applied to an ionic gel in a liquid state at room temperature. It was confirmed that the decarbonylation of these ionic salts up to 10 carbon atoms was still a liquid, although the viscosity became higher at room temperature.
The ionic gel may further comprise an anode redox compound.
The anodoredox compound may be ferrocene (Fc), dimethyl ferrocene (dmFc), or a combination thereof.
For 100 mol% of the plurality of electrochromic compounds, the asymmetric compound may include more than 0 mol% and less than 100 mol%. However, the present invention is not limited thereto, and can be variously selected according to a change in required color. Specific experimental data will be described later.
The electrochromic device may be flexible. For this purpose, the substrate itself can also be a plastic substrate. Specific examples of the plastic that can be used include transparent plastic such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyethersulfone, polyimide, glass fiber reinforced plastics and the like.
However, when the product is not required to have a flexible characteristic, the substrate may be made of glass.
The pair of electrodes includes an inorganic or organic conductive material, and may be transparent. For example, inorganic materials such as indium tin oxide (ITO), indium zinc oxide (IZO) and tin oxide doped with florine, and organic materials such as polythiophene and phenylpolyacetylene.
In another embodiment of the present invention, a pair of electrodes; And an electrochromic layer disposed between the pair of electrodes, wherein the electrochromic layer comprises an ion gel and a plurality of electrochromic compounds, wherein the electrochromic device comprises an electrochromic device, An ON step of supplying the electric power; And turning off the current for a predetermined period of time; The ON step; And an OFF step are performed at an intersection, and the electrochromic device has a transmittance of 30% or less with respect to light of a specific wavelength of the electrochromic device.
The predetermined time of the ON step may be 2 to 4 seconds, and the predetermined time of the OFF step may be 20 to 60 seconds.
With this driving method, it is possible to control the time of power application and ultimately drive the device with low power.
More specifically, in another embodiment of the present invention, a pair of electrodes; And an electrochromic layer disposed between the pair of electrodes, wherein the electrochromic layer comprises an ion gel and a plurality of electrochromic compounds; An ON step; And an OFF step of shutting off power; And the transmittance of the electrochromic device to light of a specific wavelength is 30% or less, and the consumed power range may be 300 μW / cm 2 or less.
This range can be understood as the ultra low power consumption level of the display field.
An electrochromic compound having improved properties can be provided.
From this, it is possible to provide a multi-color and low-power electrochromic device.
Further, a low-power driving method using such an electrochromic device can be provided.
FIG. 1 is a schematic view of a process for producing a gel-based electrochromic device and a chemical formula of the electrochromic material used in the examples.
FIG. 2 (a) shows the frequency dependency of the storage modulus (G ') and the loss coefficient (G'') of the gel applied to the embodiment, and the internal view of FIG. 2 (b) Metal-insulator (ion-gel) -metal (MIM) structure.
Figure 3 is cyclic voltammograms of an electrochromic device containing MHV + or DHV 2 + with dmFc.
Fig. 4 shows UV-vis absorption spectra at various voltages in an electrochromic device comprising (a) MHV + and (d) DHV 2 + .
5 shows the results of recording the instantaneous transmittance profiles at 546 nm and 602 nm in order to evaluate the discoloration and off-white velocities of the electrochromic devices including MHV + and DHV 2 + .
6 is a plot of the optical density vs. injected charge density at -1.3 V and -0.7 V of the electrochromic device comprising (a) MHV + and (b) DHV 2 + .
7 shows instantaneous changes in current density and transmittance at? Max in an electrochromic device comprising (a) MHV + and (b) DHV 2 + .
8 is a photograph of an electrochromic device at various mixing compositions and applied voltages of an electrochromic material.
FIG. 9 (a) shows the applied voltage dependency of the absorption spectrum, and FIG. 9 (b) shows the voltage tuning characteristic of the electrochromic device based on the mixed composition of the electrochromic material.
Hereinafter, examples and comparative examples of the present invention will be described. However, the following examples are only illustrative of the present invention and are not intended to limit the scope of the present invention.
In the present invention, voltage-tunable multicolor electrochromic devices (ECDs) were fabricated on the basis of a flexible ion gel made of a copolymer as an electrolyte layer and an ionic liquid.
In the present invention, two electrochromic (EC) substances, monoheptyl viologen (MHV + ) and diheptyl viologen (DHV 2 + ) were applied. Particularly, it is essential to replace the anion part with PF 6 - and TFSI - so that it can be uniformly mixed with the ion gel.
The electrochromic studies involving both MHV + and DHV 2 + are pale yellow in the bleached state, while magenta and blue in the colored states, respectively. Each device can exhibit excellent color tone efficiency of 87.5 cm 2 / C (magenta) and 91.3 cm 2 / C (blue).
In addition, in order to maintain the discoloration state, the power required for the ion gel in the electrochromic device is ~ 248 μW / cm 2 (magenta) and ~ 72 μW / cm 2 (blue), which is a very low level of display power consumption.
Used material
All materials in this example were purchased from Sigma-Aldrich.
Diheptyl viologen bis (hexafluorophosphate), DHV (PF 6 ) 2 ), and monoheptyl viologen hexafluorophosphate (MHV (PF 6 )), Anion exchange reaction.
For example, diheptyl viologen dibromide (DHV (Br) 2 ) (1.0 g, 1.94 mmol) was dissolved in distilled water (DI water, 120 ml).
An aqueous solution (10 ml) containing separately prepared ammonium hexafluorophosphate (NH 4 PF 6 ) (0.697 g, 4.28 mmol) was dropwise added to the solution.
After 30 hours of reaction for 24 hours, the DHV (PF 6 ) 2 was obtained as a precipitate, which was washed with distilled water. Then, it was dried at 50 캜 for 24 hours under vacuum condition.
MHV (PF 6 ) was also prepared by the same method using monoheptyl viologen bromide (MHV (Br)).
(1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, [EMI] [TFSI]) of 1-ethyl-3-methyldiimidazolium bis (trifluoromethylsulfonyl) Ethyl-3-methylimidazolium bromide [EMI] [Br] and an excess of LiTFSI.
A sheet resistance (10 Ω / sq) coated with ITO, a sheet resistance (60 Ω / sq, Sigma-Aldrich) coated with Asahi Glass Co. and ITO were successively ultrasonically mixed with acetone (5 minutes) (5 min) and 2-propanol (5 min), then treated with UV / ozone for 10 min.
Manufacture of electrochromic gel and device
FIG. 1 is a schematic view of a process for producing a gel-based electrochromic device and a chemical formula of the electrochromic material used in the examples.
More specifically, the electrochromic device was prepared by the following method.
First, poly (vinylidene fluoride-co-hexafluoropropylene), PVDF-co-HFP) and 1-ethyl-3-methylimidazolium bis (trifluoromethyl 3-methylimidazolium bis (trifluoromethylsulfonyl) imide, [EMI] [TFSI]) was completely dissolved in 50 acetone. (Mixture ratio 4: 36 weight ratio (typical polymer mass: ~ 80 mg))
DHV (PF 6 ) 2 (or MHV (PF 6 )) and dimethyl ferrocene (dmFc) (3 (or 1.87): 1 weight ratio) previously measured were added to the acetone solution.
The solution according to the reaction was cast on a substrate coated with ITO. Then, it was dried at room temperature.
Another ITO coated substrate was placed on the formed gel, and the device was fabricated in the form of ITO / EC gel / ITO as shown in FIG.
The two electrodes were fixed with a double-sided tape having a thickness of 60 mu m.
Character rating
The mechanical properties of the gels were measured on parallel plates of 25 nm diameter, using an Advanced Rheometric Expansion System (TI Instrument).
Dynamic isothermal frequency sweeps (ω = 0.1 to 100 rad / s) of the storage modulus (G ') and the loss factor (G' ') were performed at a strain of 0.05 and at a temperature of 20 ° C.
The ionic conductivity of the gel was measured at 20 ° C. using an electrochemical impedance spectrometer (IM6, ZAHNER). With a frequency range of 0.1 to 10 6 Hz at 10 mV AC amplitude.
The redox potentials of DHV (PF 6 ) 2 and MHV (PF 6 ) were measured by cyclic voltammetry (CV).
dmFc; And cyclic voltammetric curves of electrochromic gels containing the chromogenic compounds DHV (PF 6 ) 2 or MHV (PF 6 ) were measured using a potentiostat (
PT disk, Ag wire, and ITO coated glass were used as working electrode, reference electrode, and counter electrode, respectively.
dmFc was used as an anode component and an internal reference material.
The UV-vis spectra of the electrochromic devices at various voltages were measured using a UV-vis spectrometer (V-730, Jasco) at a resolution of 1.0 nm in the range of 400 to 1100 nm. The scanning speed was 400 nm / min.
At a fixed wavelength, the dynamic characteristics of the device, the instantaneous transmittance, and the current profile of the device could be obtained with a combination of the same UV-vis spectra and potentiostat.
Square wave and DC voltages were supplied from a Potentiostat (
Experimental Example 1
FIG. 2 (a) shows the frequency dependency of the storage modulus (G ') and the loss coefficient (G' ') of the gel applied to the embodiment, and the internal view of FIG. 2 (b) Metal-insulator (ion-gel) -metal (MIM) structure.
More specifically, FIG. 2 (a) is a dynamic isothermal frequency sweep of the storage modulus (G ') and the loss modulus (G ") at a strain of 0.05 and (b) (VDF-co-HFP) and 90 wt% [EMI] [TFSI]. This experiment was carried out at 20 캜.
G 'is larger than G' ', which is not a significant frequency dependence in the entire frequency range (0.1 - 100 rad / s).
The results show that the gel serves as an elastic solid, and its network structure remains substantially unchanged.
The 10 wt% P (VDF-co-HFP) based gel had a G 'value (> 10 4 Pa) 10 times higher than the commercialized ion gel. The compatibilized gel is an ABA type block copolymer, for example, polystyrene-b-poly (methyl methacrylate) -b-polystyrene, PS-b B-polystyrene, PS-b-PEO-b-PS, SOS), or polystyrene-b-poly (ethylene oxide) to be.
These results led to gels that could be applied to mechanically rigid, 'cut-and-stick' protocols.
In order to produce an electrochemical device with low voltage and fast response speed, a high ionic conductivity of the gel is essentially required, which enables an active electrochemical reaction.
Figure 2 (b) shows the frequency dependence of Z '.
The bulk gel resistance (R) can be obtained from a flat Z 'plateau value at high frequencies. At this time, the impedance can be regarded as a pure resistance and measured to ~ 235 Ω.
Considering the thickness (h) of the gall of 2 mm to 4 mm diameter, the ionic conductivity (?) Of ~ 6.7 mS / cm is calculated as? = H / AR. Where A corresponds to the crossing area.
These values are comparable to about 5-6 mS / cm values of other ion gels containing 10 wt% SMS or SOS.
That is, a high-stiffness ion gel containing 10 wt% of P (VDF-co-HFP) has improved mechanical properties and a similar level of ionic conductivity as compared to conventional commercial ion gels. The ion gel of this study can be suitable for a flexible electrochromic device.
Experimental Example 2
Figure 3 is cyclic voltammograms of an electrochromic device containing MHV + or DHV 2 + with dmFc.
More specifically, FIG. 3 shows the results of the measurement of the electrochromic gel containing dmFc at a scanning rate of 20 mV / s, using a PT disk, Ag wire, and ITO coated glass as working electrodes, reference electrodes, a) MHV + and (b) DHV 2 + cyclic voltage-current plot (CVs). dmFc was used as an internal reference and an anode component.
MHV + / MHV and oxidation-reduction reaction (Fig. 3 (a)) and DHV 2 + / + and DHV oxidation-reduction reaction (Fig. 3 (b)) are each -1.2V and -0.75V (vs. dmFc of + / dmFc).
Since dmFc not only provides an anode component but also an internal reference material, the difference between the redox potential of the electrochromic material and dmFc corresponds to the voltage required for discoloration of the electrochromic device.
Therefore, the electrochromic device including MHV + is expected to be discolored at a relatively high voltage.
Experimental Example 3
Fig. 4 shows UV-vis absorption spectra at various voltages in an electrochromic device comprising (a) MHV + and (d) DHV 2 + .
(B) and (c) are photographs of the off-color and color state of the electrochromic device including MHV + , and (e) and (f) are photographs of the off-color and color state of the electrochromic device including DHV 2 + .
To evaluate the voltage dependence of the optical characteristics of the electrochromic device, UV-vs absorption spectra were recorded at various voltages.
4 (a) shows the change of absorption spectrum of an electrochromic device including MHV + according to an externally applied voltage. There is a broad and slightly peaks at ~ 450 nm from dmFc dissolved in the gel, which appears as a pale yellow visible in the off-color electrochromic device. (Fig. 4 (b)
Does not have a change in the voltage change -1.0V, -1.1V in the absorption peak (λ max ~ 546 nm) increases due to MHV and is observed.
It is a strong absorption band is observed As voltage increases, due to increased and MHV.
As mentioned in previous studies, magenta can be achieved using DHV 2 + in a hydrophilic ionic gel containing [BMI] [BF 4 ], but an electrochemically unstable radical cation dimer is generated, It was disadvantageous to drive.
On the other hand, in the electrochromic device including MHV + , characteristic absorption peaks at wavelengths larger than ~ 750 nm did not appear. (Figure 4a), indicating that the source of magenta is not an unstable radical dimer.
The change in the color dramatically in the electrochromic device can be seen in Fig. 4 (c).
On the other hand, two strong peaks at ~ 602 nm and ~ 553 nm are observed from the color state of the electrochromic device including DHV 2 + even though the pale yellow in the off-white state is the same (Figure 4 (e)). (Fig. 4 (d)).
As a result, in the electrochromic device containing DHV 2 + , a blue-based color state was observed.
As expected from the electrochemical analysis (Fig. 3), the discoloration occurred at a voltage of -0.6 V lower than that of the electrochromic device containing MHV + .
Experimental Example 4
5 shows the results of recording the instantaneous transmittance profiles at 546 nm and 602 nm in order to evaluate the discoloration and off-white velocities of the electrochromic devices including MHV + and DHV 2 + .
More specifically, Figure 5, -1.3V (a) and -0.7V (b) the applied voltage and the electrochromic containing (a) and MHV + (b) + DHV 2 at the maximum absorption wavelength (λ max) It is the instantaneous transmittance profile of the device. Each including a profile of an open circuit condition and a short circuit condition.
As can be seen from Fig. 5 (a), in the electrochromic device including MHV + , the time required to change to the maximum transmittance of 90% (? T 90% ) was 11 seconds.
In another aspect, the evaluation was performed under two different conditions for undercolorization. These two conditions are an open circuit and a short circuit.
When an external voltage is applied, the reduced electrochromic material (MHV and or + and DHV) and dmFc + are respectively generated in the cathode and the anode.
As a result, the concentration of the electrochromic material and dmFc + shows a concentration gradient from the electrode to the center gel.
These two species eventually meet and respond spontaneously due to negative ΔG. As a result, the off-coloring progresses even under the open circuit condition.
If the circuit is short-circuited, the reoxidation of the electrochromic material in addition to the off-coloring route in the open circuit occurs simultaneously near the electrodes.
Therefore, the uncoloring time (? T 90% to 22 s) in the short-circuit condition is faster than the uncoloring time (? T 90% to 125 s) in the open circuit condition. (Fig. 5 (a))
Electrochromic devices containing DHV 2 + also show similar trends. (Fig. 5 (b)).
More specifically, at -0.7 V, the discoloration? T 90% was ~ 17 seconds, the uncolorizing time at the open condition was ~ 146 seconds, and the uncoloring time at the shorting condition was ~ 32 seconds.
Experimental Example 5
6 is a plot of the optical density vs. injected charge density at -1.3 V and -0.7 V of the electrochromic device comprising (a) MHV + and (b) DHV 2 + .
Another important factor for evaluating the performance of electrochromic devices is the discoloration efficiency (?). This discoloration efficiency can be expressed by the following equation (1).
[Equation 1]
In Equation (1),? OD is a change in optical density. The optical density can be defined as a log of the ratio of the transmittance Tb in the off-white state to the transmittance Tc in the discolored state.
DELTA Q is the amount of charge injected corresponding to DELTA OD.
The discoloration efficiency? Can be calculated from the linear slope of [Delta] Q. MHV + and color transfer efficiency in an electrochromic device comprising a DHV 2 + was measured in each -1.3V ~ 87.5cm 2 / C and -0.7V ~ to 91.3 cm 2 / C. (Fig. 6) This is comparable to the efficiency of a previously reported viologen-based type I electrochromic device.
Experimental Example 6
7 shows instantaneous changes in current density and transmittance at? Max in an electrochromic device comprising (a) MHV + and (b) DHV 2 + . More specifically, it is data when an external voltage is applied again every time the transmittance becomes at least 30% after the power is turned off after the first discoloration.
In contrast to a light emitting display such as an OLED or an ECL, an electrochromic device can provide information even after power is cut off because a part of the coloring material remains. Moreover, low power consumption in these areas is a crucial factor in real life applications.
In order to measure the power for maintaining the discoloration-state, an external voltage was applied for discoloration of the device. The voltage was then shut off when the permeability reached ~ 10%. Then, when the transmittance reached ~ 30%, the voltage was applied again. This process was repeated for 3,600 seconds.
FIGS. 7 (a) and 7 (b) show the instantaneous current density and transmittance profile of change in λ max in the electrochromic device comprising (a) MHV + and (b) DHV 2 + .
In order to evaluate the average current density, the total injected charge amount was calculated as the integral of the instantaneous current density profile. In this case, the electrochromic device (magenta) containing MHV + was calculated to be 191 μA / cm 2 , and the electrochromic device (blue) containing DHV 2 + was calculated to be 90 μA / cm 2 .
Considering the experimental voltages of -1.3V and -0.8V, the power consumption of the electrochromic device is ~ 248 μW / cm 2 (magenta) and ~ 72 μW / cm 2 (blue) ).
Such an electrochromic device may belong to an ultra low power consumption display field such as an e-paper display (~ 2 mW / cm 2 ).
Experimental Example 7
8 is a photograph of an electrochromic device at various mixing compositions and applied voltages of an electrochromic material. More specifically, FIG. 8 shows the electrochromic properties of the electrochromic device at 20, 80, 50/50, and 80/20 (MHV + / DHV 2 + ) molar ratios, It is a photograph of the device.
It is necessary to pay attention to the different coloring voltage ranges distinguished here. More specifically, in the case of magenta, it was in the range of -1.1V or more, and in the case of blue, it was -0.6V or more. (See Figures 3 and 4)
This means that in the case of a device including both MHV + and DHV 2 + , multi-color can be realized by adjusting the voltage.
To prove the above hypothesis, an electrochromic device comprising three different types of electrochromic material mixture was prepared. These devices were each adjusted to a molar ratio of 20/80, 50/50, and 80/20, respectively, including a mixture of MHV + / DHV 2 + .
Regardless of the composition, all devices show blue color at -0.8V.
However, from the second discoloration state, the characteristics dependent on the composition are shown. For example, as the MHV + fraction increases at -1.3V, a darker maroon color is induced.
Since the amount of the entire electrochromic material was fixed in the above-mentioned experiment, this result is a reasonably reasonable result. That is, when MHV + / DHV 2 + of 80/20 molar ratio is selected, a voltage-tuned electrochromic device of two colors, which are flexible and distinguishable, can be described. The second reduction takes place (that is, DHV +, and from 0 DHV) at the same time in the DHV of -1.2V 2+. However, the absorption peak of the DHV DHV 0 +, and , Which means a reduction in blue color interference upon MHV + discoloration.
Therefore, it can be seen that the second reduction is advantageous for the voltage-tuned multicolor electrochromic device concept.
Experimental Example 8
FIG. 9 (a) shows the applied voltage dependency of the absorption spectrum, and FIG. 9 (b) shows the voltage tuning characteristic of the electrochromic device based on the mixed composition of the electrochromic material.
More specifically, FIG. 9A shows an absorption spectrum according to the voltage-dependent wavelength of the electrochromic device composed of MHV + (80 mol%) and DHV 2 + (20 mol%).
At a relatively low voltage (-1.0 V or less), the same spectrum as the electrochromic device containing DHV 2 + alone is shown.
Due to the reduction potential is greater than the voltage + MHV, MHV and (λ max ~ 546 nm) the absorption peak is observed.
Although MHV and DHV and +, and is at the same time affects the absorption spectrum, the peak at -546nm it is most affected by MHV + (MHV and and).
A flexible multicolor electrochromic device on a plastic can be manufactured using the blushing system and the rubbery properties of the gel.
The device clearly showed characteristics with voltage tuning multicolor. More specifically, in the off-white state, it was pale yellow. In the discolored state I of -0.8 V, blue was observed. In the discolored state II of -1.3 V, maroon was seen. (Fig. 9 (b)).
It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As will be understood by those skilled in the art. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.
Claims (21)
A core portion, and a core portion;
Asymmetric electrochromic compounds.
The substituent on one side is composed of a cation component and an anion component,
In this case, the electrochromic compound having an anionic component with a molecular weight of 145 to 280 is preferred.
Wherein said compound is represented by the following formula (1): < EMI ID =
[Chemical Formula 1]
In Formula 1,
R is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C5 to C20 heteroaryl group,
R 1 to R 8 independently represent hydrogen, deuterium, or a substituted or unsubstituted C1 to C6 alkyl group,
A means an anion.
The anion PF 6, TFSI, BF 4 or the electrochromic compound that is a combination thereof.
And an electrochromic layer disposed between the pair of electrodes,
Wherein the electrochromic layer comprises:
Ion gel, and a plurality of electrochromic compounds.
The plurality of electrochromic compounds may include,
A symmetric compound which is symmetric with respect to the axis of the compound; And an asymmetric compound forming asymmetry.
Wherein the asymmetric compound is represented by the following formula (1): < EMI ID =
[Chemical Formula 1]
In Formula 1,
R is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C5 to C20 heteroaryl group,
R 1 to R 8 independently represent hydrogen, deuterium, or a substituted or unsubstituted C1 to C6 alkyl group,
A means an anion.
Wherein the symmetrical compound is represented by the following formula (2): < EMI ID =
(2)
In Formula 2,
R is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C5 to C20 heteroaryl group,
R 1 to R 8 independently represent hydrogen, deuterium, or a substituted or unsubstituted C1 to C6 alkyl group,
A means an anion.
Wherein the electrochromic layer comprises:
Ion gel and a plurality of electrochromic compounds,
Wherein the ion gel is an electrolyte matrix, and the electrochromic compound in the ion gel is uniformly dissolved.
Wherein the ion gel is a heteropolymer copolymer.
The heterogeneous polymer copolymer may be a copolymer
Poly (vinylidene fluoride) poly (styrene), or a combination thereof; And
Wherein the polymer is a copolymer of poly (hexafluoropropylene), poly (ethylene oxide), poly (alkyl methacrylate), poly (alkyl acrylate), or a combination thereof.
Wherein the electrochromic layer comprises:
Further comprising an ionic salt in a liquid state at room temperature.
The ionic salt may be,
Alkyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, [AMI] [TFSI] wherein the alkyl group has 1 to 3 carbon atoms, 10), 1-butyl-3-methylimidazolium tetrafluoroborate, [BMI] [BF 4 ], 1-butyl-3-methylimidazolium hexafluorophosphate (1-butyl-3-methylimidazolium hexafluorophosphate, [BMI] [PF 6 ]), or a combination thereof.
Wherein the ion gel further comprises an anode redox compound.
The above-mentioned anode redox compound,
Ferrocene (Fc), dimethyl ferrocene (dmFc), or a combination thereof.
With respect to 100 mol% of the plurality of electrochromic compounds,
Wherein the asymmetric compound is contained in an amount of more than 0 mol% and less than 100 mol%.
Wherein the electrochromic device is flexible.
An ON step of supplying an electric current for a predetermined time; And
Turning off the current for a predetermined time; Lt; / RTI >
The ON step; And the OFF step are performed at an intersection,
Wherein the transmittance of the electrochromic device to light of a specific wavelength is 30% or less.
And the predetermined time of the ON step is 2 to 4 seconds.
And the predetermined time of the OFF step is 20 to 60 seconds.
An ON step of supplying a predetermined electric power; And an OFF step of shutting off power; Are intersected,
Wherein the electrochromic device has a transmittance of 30% or less with respect to light of a specific wavelength, and a consumed power range is 300 μW / cm 2 or less.
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| WO2023063490A1 (en) * | 2021-10-14 | 2023-04-20 | 한국기술교육대학교 산학협력단 | Electrochromic element composition having light transmissability, high flexibility, and high moisture resistance, and method for producing electrochromic member |
| KR20230053123A (en) * | 2021-10-14 | 2023-04-21 | 한국기술교육대학교 산학협력단 | Electrochromism element composite based on Poly(butyl acrylate) having light transmissibility and stretchability, and manufacturing method of electrochromism member |
| KR20230053122A (en) * | 2021-10-14 | 2023-04-21 | 한국기술교육대학교 산학협력단 | Electrochromism element composite having improved light- light transmissibility and stretchable, and manufacturing method of electrochromism member |
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