Patent Application
20240317675
The technical field relates to an oxidizable compound, and relates to an electrochromic composition including the same and an electrochromic device utilizing the same.
Electrochromic related products are attractive in green energy industries due to their low driving voltage (<3.0 V) and bistable properties. This technology is regarded as an important industry in the next decades, in which electrochromic materials will play a critical role. Major electrochromic materials are inorganic oxides. The inorganic oxide has shortcomings such as a slow electrochromic rate and less color variation. In organic systems, the electrochromic conjugated polymer has more color variation and fast electrochromic rates. The electrochromic conjugated polymer in a neutral state has an appearance of a deep color due to its conjugated length. Although the deep color can be lightened by applying voltage, the conjugated polymer cannot be fully transparent. In manual dynamic control selections, the electrochromic conjugated polymer must be electrified to enter a transparent state, thereby leading to high energy consumption. A general electrochromic composition containing a small organic molecule has an overly high driving voltage, thereby limiting the application of the small organic molecule in the electrochromic field. Accordingly, for application in electrochromic related products, a novel electrochromic material is called for.
One embodiment of the disclosure provides an oxidizable compound, having a chemical structure of
wherein each R1 is independently C1-3 alkyl group.
One embodiment of the disclosure provides an electrochromic composition, including: an oxidizable compound; a reducible compound; and a solvent. The oxidizable compound includes
wherein each R2 is independently —N(R1)2, —OR1, or —R1, and R1 is C1-3 alkyl group. The reducible compound has a chemical structure of
and each R3 is independently C4-12 alkyl group, —OCnH2n+1,
and n=0˜7.
One embodiment of the disclosure provides an electrochromic device, including a first transparent conductive layer, a second transparent conductive layer; and the described electrochromic composition disposed between the first transparent conductive layer and the second transparent conductive layer.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
The disclosure can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
One embodiment of the disclosure provides an oxidizable compound, having a chemical structure of
wherein each R1 is independently C1-3 alkyl group. For example, the oxidizable compound has a chemical structure of
In some embodiments, the oxidizable compound can be synthesized by coupling 4-bromophenyl alkyl ether and 4-dialkylamino-4′-nitro diphenylamine to form a nitro triphenyl amine compound. It should be understood that the three R1s in the below Formula can be the same or different from each other as necessary.
Subsequently, the nitro group of the nitro triphenyl amine is reduced to form amino triphenyl amine, as shown in below Formula.
The reaction is used to illustrate a possible path to synthesize the oxidizable compound such as triphenyl amine, which is not the only applicable synthesis path. One skilled in the art may adopt any applicable synthesis way as necessary to form the disclosed oxidizable compound in the disclosure.
One embodiment of the disclosure provides an electrochromic composition, including: an oxidizable compound; a reducible compound; and a solvent. The oxidizable compound includes
wherein each R2 is independently —N(R1)2, —OR1, or —R1, and R1 is C1-3 alkyl group. The reducible compound has a chemical structure of
and each R3 is independently C4-12 alkyl group, —OCnH2n+1,
and n=0˜7.
In some embodiments, the oxidizable compound is
such as
In some embodiments, the oxidizable compound is
such as
In some embodiments, the oxidizable compound is
such as
In some embodiments, the solvent includes propylene carbonate, γ-butyrolactone, acetonitrile, propionitrile, glutaronitrile, methylglutaronitrile, 3,3′-oxydipropionitrile, hydroxypropionitrile, dimethylformamide, N-methyl tetrahydropyrrolidone, sulfolane, 3-methylsulfolane, or a combination thereof.
In some embodiments, the electrochromic composition further includes an electrolyte such as an ammonium salt. For example, the ammonium salt can be TBABF4 ((N(C4H9)4)+BF4−), TBAP ((N(C4H9)4+ClO4−), another suitable ammonium salt, or a combination thereof. The electrolyte is beneficial to balance charge and transfer current.
In the electrochromic composition, the oxidation potential of the oxidizable compound matches the reduction potential of the reducible compound, such as viologen (e.g. the potential difference therebetween is less than 0.15 V), thereby improving the cycling stability and lowering the driving voltage.
In some embodiments, the concentration of the oxidizable compound and the concentration of the reducible compound in the electrochromic composition can be independently 0.003 M (mole/L) to 0.1 M, preferably 0.005 M to 0.05 M, more preferably of 0.01 M to 0.025 M, and most preferably 0.012 M to 0.0.18 M.
In some embodiments, the oxidizable compound and the reducible compound in the electrochromic composition may have a molar ratio of 7:3 to 3:7, preferably 6:4 to 4:6, and most preferably 5:5.
One embodiment of the disclosure provides an electrochromic device, including a first transparent conductive layer, a second transparent conductive layer; and the described electrochromic composition disposed between the first transparent conductive layer and the second transparent conductive layer. In some embodiments, the first transparent conductive layer and the second transparent conductive layer include indium tin oxide, indium zinc oxide, aluminum zinc oxide, cadmium tin oxide, tin oxide, or zinc oxide. In general, the first transparent conductive layer can be formed on a first transparent substrate, and the second transparent conductive layer can be formed on a second transparent substrate. The first transparent substrate and the second transparent substrate are assembled, and their edges are adhered by a gap glue to define the space between the first transparent substrate and the second transparent substrate. The electrochromic composition is injected into the space through a hole in the gap glue, and the hole is then sealed to complete the electrochromic device. It should be understood that the above method of forming the electrochromic device is only for illustration rather than limiting the disclosure thereto. One skilled in the art may adopt any applicable way to put the electrochromic composition between the first transparent conductive layer and the second transparent conductive layer to form the so-called electrochromic device. The electrochromic device is transparent when not powered. When a positive voltage is applied to the electrochromic device, the color of the electrochromic composition is gradually deeper. Once the power is off, the electrochromic composition will return to the original transparent state in a short time (<1 second).
Below, exemplary embodiments will be described in detail with reference to accompanying drawings so as to be easily realized by a person having ordinary knowledge in the art. The inventive concept may be embodied in various forms without being limited to the exemplary embodiments set forth herein. Descriptions of well-known parts are omitted for clarity, and like reference numerals refer to like elements throughout.
In following Examples, the triphenyl amine TAP-1N
was prepared according to Macromolecules, 2008, 41 (5), 1667-1674, the triphenyl amine TPA-2N
was prepared according to Journal of Materials Chemistry, 2007, 17 (10), 1007-1015, the triphenyl amine TPA-3N
was prepared according to Journal of Materials Chemistry C, 2018, 6 (48), 13345-13351, and triphenyl amine 3PiAB
was prepared according to Taiwan Patent No. TWI551574. The ammonium salt TBABF4 (N(C4H9)4)+BF4−) was commercially available from Uni-Onward Co., and the ammonium salt TBAP (N(C4H9)4+ClO4−) was commercially available from Uni-Onward Co.
4,4′-bipyridine (1.56 g, 0.01 mole) and 1-bromoheptane (3.58 g, 0.02 mole) were dissolved in solvent of 60 g of water and 40 g of ethanol, and reacted at room temperature for 2 hours in the presence of acetonitrile (0.01 mole) serving as catalyst, and excess amount of sodium fluoroborate (2.19 g, 2 mole) was then added to the reaction to perform ion-exchange. The mixture was then stirred for 1 hour, and ethanol was then removed. The crude was precipitated by ice-bath, and then filtered by a filter paper with a pore size of 1 μm to collect white crystal. The white crystal was dried in an oven at 80° C. to obtain heptyl viologen HV, which had a hydrogen spectrum as below: 1H NMR (400 MHz, D2O): δ 9.02 (d, J=5.2 Hz, 4H, viologen), 8.44 (d, J=5.2 Hz, 4H, viologen), 4.59 (t, J=6.0 Hz, 4H, —CH2—), 1.93 (m, 4H, —CH2—), 1.18 (m, 12H, —CH2—), 0.79 (t, J=6.4 Hz, 6H, —CH3). The heptyl viologen HV had a chemical structure of
4-Bromoanisole (2.24 g, 1.51 mL, 12.00 mmole) and 4-dimethylamino-4′-nitro diphenylamine (2.57 g, 10.00 mmole, synthesized according to China Patent No. CN105924361B) were dissolved in 30 mL of 1,3-dichlorobenzen under nitrogen. Copper powder (0.76 g, 12.00 mole), potassium carbonate (3.32 g, 24.00 mmole) and 18-crown-6 ether (0.26 g, 1.00 mmole) were added to the above solution. The reaction mixture was heated to 160° C. and then stirred for 2 days, and then filtered while hot by Celite® to remove the residual copper powder and salts. The filtrate was cooled and then poured into 200 mL of water, and then extracted by 100 mL of dichloromethane 3 times to obtain an organic layer. The organic layer was concentrated using a rotatory pump to remove solvent and obtain crude. The crude was purified by chromatography to obtain a red crystal product TPA-NDM (0.78 g, yield=21%). The chromatography was performed with a silica gel column and an eluent of chloroform/hexane (1/1). TPA-NDM had a melting point of 108° C. to 111° C. TPA-NDM had a hydrogen spectrum as below: 1H NMR (600 MHz, DMSO-d6) δ (ppm): 7.99 (d, J=9.4 Hz, 2H), 7.23 (d, J=9.0 Hz, 2H), 7.12 (d, J=8.9 Hz, 2H), 7.00 (d, J=8.8 Hz, 2H), 6.76 (d, J=9.0 Hz, 2H), 6.61 (d, J=9.4 Hz, 2H), 3.77 (s, 3H), 2.91 (s, 6H). TPA-NDM had a carbon spectrum as below: 13C NMR (150 MHz, DMSO-d6) δ (ppm): 157.44, 154.39, 148.92, 137.67, 137.36, 133.28, 128.33, 128.02, 125.65, 115.28, 114.10, 113.36, 55.30, 40.06. The reaction is shown below:
TPA-NDM (0.73 g, 2.00 mole) was dissolved in 15 mL of ethanol under nitrogen, and Pd/C (10% Pd, 0.036 g) was added to the solution. The reaction mixture was heated to reflux, and hydrazine hydrate (1.00 mL, 20 mmole) was dropwise added into the reaction mixture. After reacting and being refluxed for 12 hours, the reacted mixture was filtered while hot by Celite® to remove Pd/C. The filtrate was cooled and stood for 1 day to obtain crystal such as white solid TPA-ADM (0.60 g, yield=91%). The TPA-ADM had a melting point of 97° C. to 99° C. TPA-ADM had a hydrogen spectrum as below: 1H NMR (600 MHz, DMSO-d6) δ (ppm): 6.80 (d, J=9.0 Hz, 2H), 6.77-6.71 (m, 4H), 6.70 (d, J=8.6 Hz, 2H), 6.64 (d, J=9.0 Hz, 2H), 6.50 (d, J=8.6 Hz, 2H), 4.85 (s, 2H), 3.67 (s, 3H), 2.82 (s, 6H). TPAD-ADM had a carbon spectrum as below: 13C NMR (150 MHz, DMSO-d6) δ (ppm): 153.20, 146.16, 144.51, 142.53, 138.36, 137.16, 125.81, 124.36, 121.88, 114.79, 114.33, 113.65, 55.15, 40.59. The reaction is shown below:
An electrochromic composition was prepared, which contained solvent of γ-butyrolactone (0.048 mL), 0.72 μmole of the triphenyl amine compound TPA-ADM (0.015 M), 0.72 μmole of the heptyl viologen HV (0.015 M), and 4.8 μmole of TBABF4 (0.1 M). The electrochromic composition was interposed between two ITO glasses (2 cm*2 cm), and analyzed by electrochemical analytical instrument CHI-6122E (commercially available from CH instruments) to measure the cyclic voltammetry (CV) spectrum of the electrochromic composition (scan rate was 50 mV/s). The CV spectrum of the electrochromic composition is shown in
In addition, different driving voltages were applied to the electrochromic composition to measure its absorption spectra, as shown in
When no driving voltage was applied, the electrochromic composition was colorless (L*=97.87, a*=−1.08, b*=6.72). When a driving voltage of 0.9 V was applied, the electrochromic composition changed to deep sky blue (L*=53.50, a*=−26.93, b*=−37.61). When a driving voltage of 1.2 V was applied, the electrochromic composition changed to grey blue (L*=47.57, a*=−34.86, b*=−35.81). For a definition of L*, a*, and b*, refer to the CIELAB color space. In general, a lower L* value means a deeper color. The driving voltages and the color variation effect of the electrochromic composition are tabulated in Table 1.
0.5 μmole of TPA-ADM was dissolved in 1 mL of γ-butyrolactone solution of TBAP (1M), and analyzed by a three-electrode system to measure the CV spectrum of TPA-ADM, as shown in
An electrochromic composition was prepared, which contained solvent of γ-butyrolactone (0.048 mL), 0.72 μmole of the triphenyl amine compound TPA-1N (0.015 M), 0.72 μmole of the heptyl viologen HV (0.015 M), and 4.8 μmole of TBABF4 (0.1 M). The electrochromic composition was interposed between two ITO glasses (2 cm*2 cm), and analyzed by electrochemical analytical instrument CHI-6122E (commercially available from CH instruments) to measure the cyclic voltammetry (CV) spectrum of the electrochromic composition (scan rate was 50 mV/s). The CV spectrum of the electrochromic composition is shown in
In addition, different driving voltages were applied to the electrochromic composition to measure its absorption spectra, as shown in
0.5 μmole of TPA-1 N was dissolved in 1 mL of γ-butyrolactone solution of TBAP (1M), and analyzed by a three-electrode system to measure the CV spectrum of TPA-1 N, as shown in
An electrochromic composition was prepared, which contained solvent of γ-butyrolactone (0.048 mL), 0.72 μmole of the triphenyl amine compound TPA-2N (0.015 M), 0.72 μmole of the heptyl viologen HV (0.015 M), and 4.8 μmole of TBABF4 (0.1 M). The electrochromic composition was interposed between two ITO glasses (2 cm*2 cm), and analyzed by electrochemical analytical instrument CHI-6122E (commercially available from CH instruments) to measure the cyclic voltammetry (CV) spectrum of the electrochromic composition (scan rate was 50 mV/s). The CV spectrum of the electrochromic composition is shown in
In addition, different driving voltages were applied to the electrochromic composition to measure its absorption spectra, as shown in
0.5 μmole of TPA-2N was dissolved in 1 mL of γ-butyrolactone solution of TBAP (1M), and analyzed by a three-electrode system to measure the CV spectrum of TPA-2N, as shown in
An electrochromic composition was prepared, which contained solvent of γ-butyrolactone (0.048 mL), 0.72 μmole of the triphenyl amine compound TPA-3N (0.015 M), 0.72 μmole of the heptyl viologen HV (0.015 M), and 4.8 μmole of TBABF4 (0.1 M). The electrochromic composition was interposed between two ITO glasses (2 cm*2 cm), and analyzed by electrochemical analytical instrument CHI-6122E (commercially available from CH instruments) to measure the cyclic voltammetry (CV) spectrum of the electrochromic composition (scan rate was 50 mV/s). The CV spectrum of the electrochromic composition is shown in
In addition, different driving voltages were applied to the electrochromic composition to measure its absorption spectra, as shown in
0.5 μmole of TPA-3N was dissolved in 1 mL of γ-butyrolactone solution of TBAP (1M), and analyzed by a three-electrode system to measure the CV spectrum of TPA-3N, as shown in
An electrochromic composition was prepared, which contained solvent of γ-butyrolactone (0.048 mL), 0.72 μmole of the triphenyl amine compound 3PiAB (0.015 M), 0.72 μmole of the heptyl viologen HV (0.015 M), and 4.8 μmole of TBABF4 (0.1 M). The electrochromic composition was interposed between two ITO glasses (2 cm*2 cm), and analyzed by electrochemical analytical instrument CHI-6122E (commercially available from CH instruments) to measure the cyclic voltammetry (CV) spectrum of the electrochromic composition (scan rate was 50 mV/s). The CV spectrum of the electrochromic composition is shown in
0.5 μmole of 3PiAB was dissolved in 1 mL of γ-butyrolactone solution of TBAP (1M), and analyzed by a three-electrode system to measure the CV spectrum of 3PiAB, as shown in
As known from Table 1, the electrochromic compositions in Examples had low driving voltages (e.g. 0.9 V to 1.2 V) and high contrasts (e.g. differences of L* were large).
The heptyl viologen in Examples above had a first reduction potential of 0.45 V and a second reduction potential of 0.85 V. As shown in Table 2, the oxidizable compounds in Examples had first oxidation potentials to match the first reduction potential of the heptyl viologen (e.g. differences therebetween were less than 0.15 V) and second oxidation potentials to match the second reduction potential of the heptyl viologen (e.g. differences therebetween were less than 0.15 V), thereby improving the oxidation-reduction cycling stability and lowering the driving voltage.
As known from the above Examples and the Comparative Example, not all the triphenyl amine compounds were suitable to collocate with the heptyl viologen to serve as the electrochromic composition. When some triphenyl amine compound (e.g. 3PiAB in Comparative Example 1) was collocated with the heptyl viologen, the electrochromic driving voltage will be obviously overly high (>1.2 V) and could not achieve the low driving voltage (e.g. 0.9 V to 1.2 V) of the electrochromic compositions in Examples. In addition, the electrochromic composition containing some triphenyl amine molecule (e.g. 3PiAB in Comparative example 1) had low contrast (i.e. the difference of L* before and after driving was small).
The oxidizable compound could be used in the electrochromic composition. The electrochromic device containing the electrochromic composition had a decreased driving voltage, an enhanced contrast before and after driving, and a cycling stability.
The electrochromic device could have a lower driving voltage, an enhanced contrast before and after driving, and a cycling stability through the electrochromic composition of the disclosure.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed methods and materials. It is intended that the specification and examples be considered as exemplary only, with the true scope of the disclosure being indicated by the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 112141713 | Oct 2023 | TW | national |
The present application claims the benefit of U.S. Provisional Application No. 63/491,807 filed on Mar. 23, 2023, and claims priority from Taiwan Application Serial Number 112141713, filed on Oct. 31, 2023, the disclosure of which are hereby incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63491807 | Mar 2023 | US |
