TWI438196B - Gelator and application therefore - Google Patents

Description

Gel compound and its application

The present invention relates to a gel compound for use in a colloidal electrolyte and its use, particularly in the field of solar cells.

As the price of crude oil climbs, research on energy has become the research direction of scholars in various countries. Among them, the research on solar cells is the first, and among the many types of solar cells, Dye-sensitized solar cells (Dye-sensitized solar cells) DSSC) enables large-area and low-cost battery manufacturing without the need for expensive ultra-high vacuum coating equipment. At present, the DSSC research published in the world has a pure liquid electrolyte efficiency of up to 10%, but the disadvantage is that the pure liquid electrolyte is prone to liquid leakage or volatilization in the packaging operation, thereby affecting the durability of the battery.

In particular, one of the reasons why the stability of solar cells cannot be improved is that the organic solvent in the liquid electrolyte has high volatility, and the existing sealant is more difficult to withstand the corrosion of iodine, so that the life of the battery is lowered, and the solution is solved. The method is to improve the effective coating of the electrolyte, or to develop an encapsulation technology resistant to iodine corrosion, and the time and cost of the latter may be higher than the former. Therefore, it is a preferred mode if the electrolyte can be effectively coated without being used, and the ionic conductivity can be improved while being used.

At present, a semi-solid electrolyte such as poly(ethylene oxide-co-epichlorohydrin) copolymer, which is referred to as P(EO-EPI), has been developed. Molecular film. By coating the liquid electrolyte with the microporous structure formed by the formation of the polymer, the risk of volatilization of the liquid electrolyte can be reduced, but the diffusion of I ^- /I ₃ ^- is hindered, and the photoelectric conversion efficiency is reduced to 2~3. %.

Hanabusa et al., 1999, published a low molecular weight gelling compound in which N-carbobenzyloxy-L-isoleucine and 1-amine are utilized. A guanamine compound synthesized by the reaction of 1-aminooctadecane (Hanabusa et al ., Chem Mater., 1999, 11, 649-655). Kubo et al. published a pseudo-solid dye-sensitized solar cell in 2001, which applied a gelatin compound of guanamine to the electrolyte of the battery, and found that a pseudo-solid solar cell using a colloidal electrolyte can improve the evaporation of liquid electrolyte. Problem (Kubo et al ., J. Phys. Chem. B, 2001, 105, 12809-12815).

US Patent No. 7,332,529 B2 discloses a thermoreversible organogel compound having a diurea group (-HN-C(O)-NH-) by a diuret group in one molecule The resulting intermolecular hydrogen bonding forces enhance the aggregation of such gel compounds, and the three-dimensional coating structure formed by intermolecular hydrogen bonding can effectively coat the liquid solvent.

However, the above-mentioned conventional techniques have not been able to achieve satisfactory results, so there is still a need to continuously develop colloidal electrolytes and prolong the service life of solar cells.

The invention develops a novel gel compound which provides abundant intermolecular hydrogen bonds, and it is unexpectedly found that the use of the gel compound in the electrolyte of the dye-sensitized solar cell can solve the problem of electrolyte volatilization and leakage, and at the same time, the battery can be improved. Years of use.

The present invention provides a gel condensation compound which is a condensate of a molecule of a triamine compound and a trisole of Ar-Q ¹ -Q ² -R'-COOH, wherein the triamine compound is selected from the group consisting of:

Wherein R is a C _1-18 alkyl group of a long aliphatic chain; and wherein Ar, Q ¹ , Q ² and R' in Ar-Q ¹ -Q ² -R'-COOH are defined as follows: Ar is unsubstituted Or a C _3-8 cycloalkyl group substituted by one or more C _1-4 alkyl groups, an amine group, a hydroxyl group, a C _5-8 cycloalkenyl group, a C _5-10 aromatic ring or containing 1 to 3 selected from N , C _5-10 heterocycle of O and S heteroatoms.

Q ¹ is C _1-6 alkylene, C _1-6 alkyloxy, C _1-6 alkyl or a bond; Q ² is -C(O)NH- or a bond; 'Substituted as unsubstituted or substituted by one or more groups selected from the group consisting of an amine group, a mercapto, a methylthio group, an carbamyl group, a carboxyl group, and a guanidino group. C _1-6 alkylene.

In the present invention, a one-molecular triamine compound and three molecules of Ar-Q ¹ -Q ² -R'-COOHAr-Q ¹ -Q ² -R'-COOH are subjected to a condensation reaction to obtain a gel condensation compound of the present invention.

According to the invention, a "triamine compound" is a compound having three amine groups.

According to the invention, "(C ₃ -C ₈ )cycloalkyl" means a saturated cyclic hydrocarbon having from 3 to 8 carbon atoms. Preferred (C ₃ -C ₈ )cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl and the like.

According to the present invention, "(C ₅ -C ₈ )cycloalkenyl" means a cyclic non-aromatic hydrocarbon having at least one carbon-carbon double bond in a cyclic system and having 5 to 8 carbon atoms. Preferred (C ₅ -C ₈ )cycloalkenyl groups include cyclopentenyl, cyclopentadienyl, cyclohexenyl, cyclohexadienyl, cycloheptenyl, cycloheptadienyl, cycloheptatriene Alkenyl, cyclooctenyl, cyclooctadienyl, cyclooctetylene, cyclooctyltetraenyl, and the like.

According to the present invention, the "C _5-10 aromatic ring" includes a 5- to 10-membered monocyclic or bicyclic ring system, and examples thereof include a phenyl group and a naphthyl group.

According to the present invention, "a C _5-10 heterocyclic ring having 1 to 3 hetero atoms selected from N, O and S" represents a saturated or unsaturated 5- to 10-membered heterocyclic ring system including at least one selected from the group consisting of N, The heteroatoms of O and S, each of which may be substituted with at least one substituent selected from the group consisting of nitro, hydroxy, oxo, halogen, C _1-6 alkyl, C _1-6 alkoxy. , C _1-6 alkylthio, C _1-6 alkylcarbonyl, C _1-6 alkoxycarbonyl and phenyl. Examples of the above heterocyclic ring include pyridine, piperazine, pyrimidine, pyrrole, pyrazole, imidazole, anthracene, thiazole, Azole Oxazole, thiadiazole, Diazoles, thiophenes, furans, quinolines, isoquines and their analogs.

According to the present invention, the Ar-Q ¹ -Q ² -R'-COOH compound is preferably selected from the group consisting of compounds of the following formulae:

According to a preferred embodiment of the invention, the gel condensation compound of the invention is selected from the group consisting of:

The present invention further provides a colloidal electrolyte comprising the gel compound as described above. The colloidal electrolyte can be used in a glass type dye-sensitized solar cell or in a flexible solar cell for a roll-to-roll process, in particular polyethylene terephthalate (polyethylene terephthalate). PET), a solar cell of poly(ethylene 2,6-naphthalate, PEN) or polyethylenimine (PEI).

The present invention further provides a method of gelling a liquid electrolyte by adding the above gel compound to a liquid electrolyte.

In the above method of the present invention, the solid content of the gel compound dissolved in the liquid electrolyte is in the range of 20 to 60 g/L, preferably 30 to 50 g/L.

In the above method of the present invention, the heating temperature of the gel compound to the liquid electrolyte is in the range of 70 to 100 °C.

The present invention also provides a method for preparing a colloidal dye-sensitized solar cell comprising the liquid electrolyte gelation method as described above.

The present invention has found that the triterpenoid gel compound according to the present invention is dissolved in an organic solvent and gelled with an intermolecular hydrogen bond between the organic solvent, and the present invention is The gel compound has a large molecular weight, and the formed three-dimensional structure is also large, so that more liquid electrolyte can be more effectively coated. In detail, since the gel compound has a rich hydrogen bond, and the amine group forms a guanamine bond with the aromatic carboxy group (Ar-Q ¹ -Q ² -R'-COOH) of the larger steric hindrance It exists in the form of a ribbon or a sheet structure, and the pores in the structure can effectively coat the electrolyte. A dye-sensitized solar cell using the colloidal electrolyte of the present invention is used after a long period of time, compared to the liquid electrolyte used in the prior art or the colloidal electrolyte using a disubstituted diamine gel compound. The invention can maintain a high level of photoelectric conversion efficiency, thereby increasing the service life of the battery.

The invention provides the following non-limiting examples for illustration. The examples are not to be construed as limiting the invention in any way. Modifications and variations of the embodiments discussed herein may be made without departing from the spirit and scope of the invention, and still fall within the scope of the invention.

The compounds and apparatus used in the following examples are as follows:

1. Conductive substrate: fluorine-doped tin dioxide conductive glass FTO, (SNO ₂ : F), manufactured by SONARONIX.

2. Titanium dioxide particles: manufactured by Degussa, Model P-25.

3. Cis-diisothiocyanato-bis (2,2,-bipyridyl-4,4'-dicarboxylato)ruthenium(II)bis (tetrabutylammonium), abbreviated as "N719 dye": manufactured by SOLARONIX.

4. Acetyl acetone: manufactured by Acros, with a purity greater than 99%.

5. Triton X-100 Nonionic Surfactant: manufactured by Roche Corporation.

6. Iodine: manufactured by Merck, with a purity of 99.8%.

7. Potassium iodide: manufactured by Merck, with a purity greater than 98%.

8. 3-Methoxypropionitrile (MPN): manufactured by Aldrich, with a purity of 99.5%.

9. 4-tert-butylpyridine: manufactured by Acros, with a reagent grade of 96% purity.

10. 1,2-dimethyl-3-propylimidazoliumiodide (DMPImI): manufactured by Aldrich, with a purity greater than 97%.

11. N-carbobenzyloxy-L-isoleucine (abbreviated as A ): The purity was 99.5% by Sigma.

12. 1,12-dodecane diamine (1,12-Diaminododecane, abbreviated as c): manufactured from the TCI a purity of 99%.

13. N,N-dicyclohexylcarbodiimide (DCC): Made by Acros, the purity is 99%.

14. Melamine ( M ): manufactured by Changchun Chemical Company.

15. Surlyn 1702 Encapsulation Film: Manufactured by DuPont

16. Dimethyl sulfoxide (DMSO): manufactured by Acros, HPLC grade purity 99.9%.

17. tris (2-aminoethyl) amine (Tris (2-aminoethyl) amine , abbreviated as T): manufactured by Acros Company, 98% purity.

18. Solar light source simulation test equipment: Xenon Short Arc, Model YSS-100A Specifications, Simulator class A, AM 1.5, 100mW/cm ²

Comparative Example 1 Solar cell containing a conventional liquid electrolyte

The cleaning method of the conductive glass is: using deionized water: ammonia water: hydrogen peroxide volume ratio of 5:1:1 to prepare a cleaning liquid for the conductive glass, the conductive glass is placed in the cleaning liquid, and heated to 50 ° C, It was washed with ultrasonic shock for 20 minutes, rinsed with deionized water, and dried with nitrogen to dry the conductive glass.

The TiO ₂ slurry is prepared by adding 6 g of P-25 titanium dioxide to 14 ml of deionized water, 0.2 ml of Triton X-100, 1.2 ml of acetamidine acetone, stirring with a magnet for 2 hours, and then placing it in super The sound wave is shaken for 1 hour to obtain a titanium dioxide slurry.

Take the cleaned FTO glass, first apply the TiO ₂ slurry on the FTO glass with a spin coater, set the rotation speed to 500 rpm, the coating time is 20 seconds, and then place the coated conductive glass in a high temperature furnace. After baking at 120 ° C for 15 minutes, the temperature was raised to 450 ° C for 30 minutes at a temperature increase rate of 20 ° C / min, and the second layer was repeatedly applied, and the sintering procedure was repeated, and finally a 10 μm thick TiO ₂ working electrode was obtained.

The preparation method of the electrolyte was: 0.1 M LiI, 0.05 M I ₂ , 0.6 M DMPII, and 0.5 M TBP MPN solution.

The platinum electrode is prepared by drilling a clean conductive glass hole as an electrolyte injection hole, applying it to a FTO conductive glass using a 0.05 M solution of hydrogenplatinic acid isopropanol, and sintering in a high temperature furnace at 400 ° C for 15 minutes. A platinum catalyst layer can be formed.

The dye is prepared by dissolving the N3 dye in absolute ethanol and MPN (the volume ratio of ethanol to MPN is 1:1) to prepare a 0.005 M N3 dye solution, and then immersing the TiO ₂ electrode in the N3 dye for 24 hours. TiO ₂ working electrode fabrication.

Dupont surlyn1702 was used as a spacer to heat the platinum electrode to the TiO2 electrode to 120 °C, so that the platinum counter electrode and the TiO2 working electrode can be adhered, and then the liquid electrolyte is poured into the small hole of the counter electrode, and the surlyn1702 encapsulation film will be used. The electrolyte perfusion hole of the platinum electrode is sealed, and then the cover glass is heated to 80 ° C to seal the electrolyte injection hole. Then, the epoxy around the cover slip and the edge around the electrode are sealed, that is, the battery is completed.

Example 2 A solar cell containing a colloidal electrolyte of AcA

The disubstituted bis-amine-based gel compound AcA of the following formula

The synthesis method is as follows: 1 mol of N-benzyloxycarbonyl-L-isoleucine (A) is dissolved in ethyl acetate, and 1 mol of N,N-dicyclohexylcarbodiimide (DCC) is added. The reaction was carried out at 0 ° C for 1 hour, and then 0.5 mol of 1,12-diaminododecane (c) was added to react at 0 ° C for 3 hours, then at room temperature for 18 hours, and then heated to 60 ° C for reaction. The reaction was terminated in 12 hours, filtered and the solvent in the filtrate was dried to give the product AcA. AcA was added to the electrolyte to raise the temperature to 80 ° C, and the AcA was completely dissolved to prepare 40 g / L. After the electrolyte was cooled, it became an AcA colloidal electrolyte. The battery assembly method is the same as that of the first embodiment.

Example 3 Solar cell containing A3M colloidal electrolyte

a tertiary triammine-based gel compound A3M of the following formula,

The synthesis method is as follows: 3 moles of A is dissolved in DMSO, 3 moles of DCC and 1 mole of melamine (M) are added and heated to 90 ° C, and after reacting for 72 hours, anhydrous ethanol is added to concentrate under reduced pressure to extract large After part of the DMSO, anhydrous ethanol was added, and the magnet was stirred for one hour, and the filter residue was filtered and dried to obtain A3M. Add A3M to the electrolyte and warm it up to 90 ° C to stir it to dissolve completely into 40 g / L. After cooling the electrolyte, it becomes A3M colloidal electrolyte. The battery assembly method is the same as that of the first embodiment.

Example 4 Solar Cell Containing A3T Colloidal Electrolyte

A tertiary triterpenoid gel compound A3T of the following formula

The synthesis method is as follows: 3 moles of A is dissolved in ethyl acetate, and 3 moles of DCC is added to react at 0 ° C for 1 hour, and then 1 mole of tris(2-aminoethyl) is added. The amine (T) was reacted at 0 ° C for 3 hours, then at room temperature for 18 hours, and then heated to 60 ° C for 12 hours to terminate the reaction. The mixture was filtered and dried to remove the solvent to give the product A3T. The A3T was added to the electrolyte to raise the temperature to 80 ° C, and the A3T was completely dissolved to form 40 g/L. After the electrolyte was cooled, it became an A3T colloidal electrolyte. The battery assembly method is the same as that of the first embodiment.

It can be confirmed from the above examples that the weather resistance properties of the three-stage triterpene colloidal electrolytes A3M and A3T of the present invention are better than those of the liquid electrolyte battery. Taking A3M as an example, from the perspective of photoelectric conversion efficiency, although the photoelectric conversion efficiency of liquid electrolyte (LE) is 0.43% higher than that of A3M, the efficiency of A3M can be improved after two weeks of aging test at 60 °C. Maintaining the original 76%, while LE's efficiency only maintains the original 57%; after 60 °C four weeks of aging test, A3M efficiency can maintain the original 75%, and LE can not measure efficiency because the electrolyte leaks out .

Comparing the results of AcA and A3M, the efficiency of AcA before aging was 4.21%, and that of A3M was 4.61%. After two weeks of aging test at 60 °C, AcA was 2.9%, the efficiency was maintained at 69% before aging, and A3M was 3.52%, the efficiency maintained 76% before aging; after 60 °C four weeks of aging test, AcA was 2.23%, the efficiency maintained 53% before aging; A3M was 3.48%, the efficiency remained 75% before aging, the reason is A3M has a larger molecular structure than AcA, so it can coat more liquid electrolytes. A3M contains three guanamine groups, so it has more hydrogen bonds than AcA. Therefore, it can coat the electrolyte more effectively. The tolerance is good, and the photoelectric conversion efficiency is also reduced by a small margin.

101. . . Conductive glass

102. . . Titanium dioxide porous film

103. . . dye

104. . . Electrolyte

105. . . Platinum catalytic layer

106. . . Conductive glass

107. . . Encapsulation film

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a view showing the apparatus used in the dye-sensitized solar cell of the present invention.

101. . . Conductive glass

102. . . Titanium dioxide porous film

103. . . dye

104. . . Electrolyte

105. . . Platinum catalytic layer

106. . . Conductive glass

107. . . Encapsulation film

Claims (11)

A gel condensation compound which is a condensate of a molecule of a triamine compound and a trisole of Ar-Q ¹ -Q ² -R'-COOH, wherein the triamine compound is selected from the group consisting of: Wherein R is a C _1-18 alkyl group of a long aliphatic chain; and wherein Ar, Q ¹ , Q ² and R' in Ar-Q ¹ -Q ² -R'-COOH are defined as follows: Ar is unsubstituted Or a C _3-8 cycloalkyl group substituted by one or more C _1-4 alkyl groups, an amine group, a hydroxyl group, a C _5-8 cycloalkenyl group, a C _5-10 aromatic ring or containing 1 to 3 selected from N , C _5-10 heterocycle of O and S heteroatoms. Q ¹ is C _1-6 alkylene, C _1-6 alkyloxy, C _1-6 alkyl or a bond; Q ² is -C(O)NH- or a bond; 'Substituted as unsubstituted or substituted by one or more groups selected from the group consisting of an amine group, a mercapto, a methylthio group, an carbamyl group, a carboxyl group, and a guanidino group. C _1-6 alkylene. The gel condensation compound of claim 1, wherein Ar is cyclopentenyl, cyclopentadienyl, cyclohexenyl, cyclohexadienyl or phenyl; Q ¹ is C _1-6 alkyl; Q ² is -C(O)NH-. The gel condensation compound of claim 1, wherein the Ar-Q ¹ -Q ² -R'-COOH is selected from the group consisting of the following formulae: A colloidal electrolyte comprising the gel condensation compound according to any one of claims 1 to 3. A colloidal electrolyte according to claim 3, which is used in a glass-type dye-sensitized solar cell. The colloidal electrolyte of claim 3, which is used in a flexible solar cell of a winding process. The colloidal electrolyte of claim 6, wherein the flexible solar cell is a solar cell of polyethylene terephthalate, polyethylene-2,6-naphthalate or polyethyleneimine. A method of gelling a liquid electrolyte by adding the gel condensation compound according to claim 1 or 2 to a liquid electrolyte. The method of claim 8, wherein the gel condensation compound is dissolved in the liquid electrolyte in a solid content ranging from 20 to 60 g/L. The method of claim 8 or 9, wherein the heating temperature of the gel condensation compound to the liquid electrolyte is in the range of 70 to 100 °C. A method of preparing a colloidal dye-sensitized solar cell, comprising the step of preparing a colloidal dye-sensitized solar cell using the method of any one of claims 8-10.