Electrolyte for a dye-sensitized solar cell with long-term stability and dye-sensitized solar cell for a vehicle using the same

Abstract

Electrolyte for a dye-sensitized solar cell, consisting of: a non-volatile ionic liquid; a low-viscosity liquid solvent with a viscosity of 0.1 g / cm s (10 cP) or less, tert-butylpyridine, GuSCN, and iodine, wherein the low-viscosity liquid solvent is added in an amount of 1 to 10 wt% of the non-volatile ionic liquid based on the total weight of the non-volatile ionic liquid.

Description

TECHNICAL AREA

[0001] The present invention relates to an electrolyte for a dye-sensitized solar cell which can be used to improve the performance and lifetime of a solar cell, and to a dye-sensitized solar cell for a vehicle using the electrolyte of the invention. BACKGROUND

[0002] Generating electricity from sunlight using a solar cell is environmentally friendly and has proven itself to be superior to fossil fuel-based electricity generation in that it produces no air pollution or noise, and the energy source, i.e., sunlight, is not consumed. Among various solar cells, a dye-sensitized solar cell based on nanocrystalline porous titanium oxide (TiO 2) has received special attention and has been extensively investigated due to its high energy conversion efficiency and low manufacturing costs.

[0003] The dye-sensitized solar cell, which can be a third-generation solar cell, has been particularly highlighted for its high energy conversion efficiency and low manufacturing costs, which can be approximately one-fifth of those of a silicon solar cell. Furthermore, since it uses a transparent conductive glass substrate and can produce modules in various colors using different dyes and electrolytes, the dye-sensitized solar cell can be applied to a building window or the like.

[0004] The dye-sensitized solar cell may be formed with a photoelectrode comprising an oxide semiconductor electrode having a dye adsorbed on one of its surfaces on a conductive substrate, an electrolyte capable of undergoing oxidation and reduction reactions, and a counter electrode, with a catalyst electrode formed on a conductive substrate. When light is irradiated onto the dye-sensitized solar cell, the dye adsorbs the light energy to generate an electron-hole pair, and the generated electron is injected into a conduction band of an oxide semiconductor. The injected electron is then transported through the oxide semiconductor to a transparent electrode and moves through an external circuit when the photoelectrode and the counterelectrode are connected, generating an electric current.The electron hole created in the dye receives electrons from the electrolyte, which can undergo oxidation and reduction, and is reduced back, thereby restoring the dye-sensitized solar cell and closing an electrical circuit of the dye-sensitized solar cell. In this case, the counter electrode can provide the electron moving through the external circuit, thereby triggering an oxidation-reduction reaction of the ions in the electrolyte. Since the electron must be efficiently transferred to the electrolyte, the counter electrode conventionally has a structure where the conductive substrate is coated with the catalyst.Furthermore, the catalyst may require high catalytic activity, increased surface area, and increased electrical conductivity or ionic conductivity to thereby exhibit minimal electrical resistance at the interface with the electrolyte, as well as long-term stability in the electrolyte. Furthermore, the electrolyte used in the dye-sensitized solar cell may have an elevated boiling point to achieve both long lifetime and improved ionic conductivity, which affects efficiency.

[0005] In the related art, compositions used as the electrolyte of the dye-sensitized solar cell were described as follows.

[0006] For example, an electrolyte for a dye-sensitized solar cell has been reported, and the electrolyte includes the imidazole-based oligomer-type ionic liquid N-(3-(1-methylimidazole)propyl)hexanam iodide (NMIPHI), wherein the imidazole-based oligomer-type ionic liquid has an N-alkylimidazolium propylhexanam iodide as the basic structure and contains an iodide ion (I - ), i.e., an inorganic anion. The electrolyte may be in a solid or liquid state according to the substitution of a reaction group of an organic cation, and the electrolyte is prepared by adding iodine, 4-tert-butylpyridine (TBP), and 3-methoxypropionitrile (MPN) to the ionic liquid (e.g., Korean Patent Application Laid-Open KR 10 2013 0 084 719 A

[0007] The related art also provides an electrolyte for a solar cell comprising a complex salt of imidazole and C1-C20 diiodoalkane and a cation of a complex of imidazole and C1-C20 diiodoalkane and of iodine (I 2 ) produced iodide ions (I - / I 3 - ), and a solar cell using the electrolyte has also been developed. The electrolyte further comprises 1 to 10 parts by weight of a non-volatile organic solvent such as acetonitrile, gamma-butyrolactane, and 3-methoxypropionitrile, in addition to the above-mentioned electrolyte (e.g., Korean Patent Application Laid-Open KR 10 2009 0 022 383 A

[0008] In another example of related art, an imidazole-based polymer-type or oligomer-type ion solution was developed. The ion solution comprises an iodide ion (I -) and 1 to 25 ethylene oxide monomers, and has a structure of ethylene oxide monomers and urethane in which urea is bonded to the ethylene oxide monomers, and an imidazolium structure at one end. The electrolyte for a dye-sensitized solar cell comprising an organic solvent selected from acetonitrile, 3-methoxypropionitrile, gamma-butyrolactone, ethylene glycol, and the like in addition to the aforementioned ion solution has also been disclosed (e.g., Korean Patent Application Laid-Open KR 10 2011 0 011 158 A

[0009] Furthermore, a dye-sensitized solar cell with an imidazolium-based liquid-type electrolyte has been reported. The imidazolium-based liquid-type electrolyte can be in a liquid state at room temperature and higher temperatures and exhibit excellent thermal stability and temperature stability without using an organic solvent in an electrolyte. Thus, the dye-sensitized solar cell has been provided, which comprises a semiconductor electrode; a counter electrode; and an iodine-based 1,3-vinylalkylimidazolium electrolyte interposed between the semiconductor electrode and the counter electrode (e.g., US Patent Publication US 2004 / 0 261 842 A1).

[0010] In another prior art example, an electrolyte solution for a dye-sensitized solar cell was developed. The electrolyte comprises an organic solvent; an oxidation-reduction derivative; a pyrrolidinium iodide-based ionic liquid selected from the group consisting of 1-butyl-1-methylpyrrolidinium iodide, 1-methyl-1-propylpyrrolidinium iodide (MPPyl), and 1-ethyl-1-methylpyrrolidinium iodide; and t-butylpyridine as an additive, in which the organic solvent is one or more mixed solutions selected from ethylene carbonate, 3-methoxypropionitrile, gamma-butyrolactone, diethyl carbonate, and the like (e.g., Korean Patent KR 10 1 088 676 B1).

[0011] Meanwhile, a polymer particle dispersing element, an electrolyte, and a cell have been provided, and the electrolyte comprises a polymer particle dispersing element containing polymer particles and an ionic liquid in which the polymer particles are monomer components and include methyl (meth)acrylate, isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, and the like, and the ionic liquid includes 1-ethyl-3-vinylimidazolium or 1-methyl-3-ethylimidazolium iodide (e.g., Japanese Laid-Open Patent Application JP 2004 - 256 711 A

[0012] In some other related prior art documents, an electrolyte for a dye-sensitized solar cell was proposed. The electrolyte comprises the imidazole-based oligomer-type ionic liquid N-(3-(1-methylimidazolium)propyl)hexanam iodide (NMIPHI) and 3-methoxypropionitrile as solvents. The solar cell also comprises the electrolyte with the complex salt of imidazole and C1-C20 diiodoalkane and a cation of the complex salt and of iodine (I 2 ) produced iodide ions (I - / I 3 - ), and further comprises the non-volatile solvent, such as acetonitrile. Furthermore, it has been proposed that the electrolyte for the solar cell be an imidazole-based polymer-type or oligomer-type ion solution comprising the iodide ion (I -) and 1 to 25 ethylene oxide monomers and the organic solvent, such as acetonitrile, and comprises the imidazole-based compound and the solvent. However, the electrolyte in such a dye-sensitized solar cell does not include the imidazolium-based compound, such as 1-propyl-3-methylimidazolium iodide, or the pyridinium-based compound, as the ionic liquid, and thus the stability may be significantly reduced (e.g., Korean Patent Application Laid-Open No. KR 10 2013 0 084 719 A; Korean Patent Application Laid-Open No. KR 10 2009 0 022 383 A; Korean Patent Application Laid-Open No. KR 10 2011 0 011 158 A

[0013] Furthermore, other related documents have disclosed a dye-sensitized solar cell using an iodide-based 1,3-vinylalkylimidazolium electrolyte. The electrolyte solution for the dye-sensitized solar cell includes an organic solvent, an oxidation-reduction derivative, a pyrrolidinium iodide-based ionic liquid, and an additive. Furthermore, the electrolyte includes a polymer particle dispersing element containing the polymer particles and the ionic liquid, but does not include the ionic liquid and the low-viscosity liquid solvent, and thus performance may deteriorate (e.g., US Patent Publication US 2004 / 0 261 842 A1; Korean Patent KR 10 1 088 676 B1; Japanese Patent Application Laid-Open JP 2004-256 711 A).

[0014] The above-described conventional related art technologies aim to prevent liquid leakage or volatilization of the electrolyte for the solar cell by using a conventional ionic liquid and maintaining its stability. However, no specific solution has been provided for an optimal electrolyte composition when using a low-viscosity solvent as an additive in the ionic liquid electrolyte, an effect of improving efficiency, and maintaining long-term stability.

[0015] In particular, to apply a dye-sensitized solar cell to vehicles, long-term stability in the actual vehicle environment in a temperature range of approximately -40 to 85°C may be required, which is achieved by using a high-durability material that maintains performance even under harsh environmental conditions.

[0016] However, in current related art technologies using a low-boiling-point liquid electrolyte, despite improved efficiency, the temperature stability in the actual vehicle environment may be poor due to the low boiling point and poor fluidity, and thus such a liquid electrolyte cannot be used for a vehicle. Meanwhile, if the electrolyte has an improved service life and a viscosity higher than that of a liquid solvent, ion mobility may decrease, and thus the solar energy conversion efficiency may be greatly reduced compared with the liquid electrolyte.

[0017] Therefore, for the development of a dye-sensitized solar cell for a vehicle, a novel electrolyte is desired that is stable under difficult evaluation conditions for the vehicle and has improved efficiency.

[0018] The above information disclosed in this background section is provided solely for the purpose of facilitating a better understanding of the background of the invention and may therefore contain information that does not constitute prior art as is already known to a person of ordinary skill in the art in this country.

[0019] DE 11 2011 102 797 T5 relates to an electrolyte for a photoelectric conversion element.

[0020] EP 2 453 516 A1 also describes a photoelectric conversion element.

[0021] WO 2012 / 151618 A1 relates to an electrolyte system suitable for use as an energy storage device. SUMMARY OF THE INVENTION

[0022] The present invention provides technical solutions to the above-mentioned technical problems and the need for a novel electrolyte that provides both durability under severe evaluation conditions for a vehicle and improved efficiency. Accordingly, the present invention relates to a non-volatile ionic liquid-based electrolyte and a dye-sensitized solar cell using the same.

[0023] In one aspect, an electrolyte for a dye-sensitized solar cell is provided. The electrolyte consists of: a non-volatile ionic liquid; and a low-viscosity liquid solvent having a viscosity of 0.1 g / cm s (10 cP) or below, tert-butylpyridine, GuSCN, and iodine. The low-viscosity liquid solvent is added to the non-volatile ionic liquid in an amount of 1 to 10 wt% based on the total weight of the non-volatile ionic liquid.

[0024] In certain exemplary embodiments, the electrolyte can maintain its stability during a durability test of a solar cell module. Furthermore, unlike existing liquid electrolytes, the electrolyte of the invention can prevent module seal breakage and maintain improved ion mobility, thus improving performance.

[0025] In further specific exemplary embodiments of the present invention, by using an ionic liquid, the boiling point of the electrolyte can be increased to approximately 300°C or higher, and the performance of the solar cell can be improved by using a liquid solvent as an additive in a predetermined ratio compared to the conventional solar cell in which the electrolyte is used without the liquid solvent. Furthermore, sealing stability can be maintained by controlling the vapor pressure of the liquid solvent, which can be added for an optimized composition at elevated temperatures.

[0026] Accordingly, according to various exemplary embodiments of the present invention, when the electrolyte for the dye-sensitized solar cell containing a low-viscosity liquid solvent such as acetonitrile, 3-methoxypropionitrile, or butyrolactone as an additive is added to the ionic liquid containing an imidazolium-based compound or a pyridinium-based compound, the dye-sensitized solar cell can maintain durability and conversion efficiency even in a harsh vehicle environment.

[0027] Further aspects and preferred embodiments of the invention are discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other features of the present invention will now be described in detail with reference to certain exemplary embodiments thereof which are illustrated in the accompanying drawings and which are given below by way of illustration only and thus do not limit the present invention, and in which: Fig. 1 illustrates an exemplary optimal level of an exemplary liquid solvent additive added to an exemplary electrolyte for an exemplary dye-sensitized solar cell according to an exemplary embodiment of the present invention; Fig. 2 illustrates a cross-sectional view of an exemplary structure of an exemplary dye-sensitized solar cell made in accordance with an exemplary embodiment of the present invention; Fig.3 shows the result of an exemplary impedance analysis obtained from Example 1 and Comparative Example 1 according to an exemplary embodiment of the present invention. As shown here, the electrolyte in Example 1 can exhibit the stability of a liquid electrolyte with high ion mobility. Fig. Figure 4 shows the result of exemplary thermogravimetric analysis obtained from Example 1 and Comparative Example 1 according to an exemplary embodiment of the present invention. As shown herein, an evaporation amount of the electrolyte can be improved in Example 1.

[0029] Reference numerals defined in the drawings refer to the following elements, as discussed below: 101: first substrate 102: UV-curing agent 103: inorganic oxide layer 104: Electrolyte layer of an ionic liquid 105: Counter electrode layer 106: second substrate

[0030] It should be understood that the attached drawings are not necessarily to scale, but are a somewhat simplified representation of various exemplary features illustrating the principles of the invention. The specific design features of the present invention as disclosed herein include, for example, specific dimensions, orientations, positions, and shapes, and will be determined in part by the particular application and usage environment.

[0031] In the figures, reference numerals refer to the same or equivalent parts of the present invention throughout the figures of the drawing. DETAILED DESCRIPTION

[0032] It is understood that the term "vehicle" or "vehicular" or other similar expressions as used herein include motor vehicles in general, such as passenger automobiles including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and encompasses hybrid vehicles, electric vehicles, plug-in hybrid-electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As noted herein, a hybrid vehicle is a vehicle that has two or more power sources, for example, both gasoline-powered and electric-powered vehicles.

[0033] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is further to be understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of the recited features, indicia, steps, operations, elements, ingredients, and / or components, but do not preclude the presence or addition of one or more other features, indicia, steps, operations, elements, ingredients, and / or groups thereof. The term "and / or," as used herein, includes all combinations of one or more of the related listed terms.

[0034] Unless specifically stated or obvious from the context, the term "about" as used herein is to be understood as within a range of normal tolerance in the art, for example, within 2 standard deviations of the mean. "Approximately" may be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise apparent from the context, all numerical values ​​provided herein are modified by the term "about."

[0035] Reference will now be made in detail to various exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in connection with exemplary embodiments, it is to be understood that the present description is not intended to limit the invention to these exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments which may be included within the spirit and scope of the invention as defined by the appended claims.

[0036] In one aspect, an electrolyte for a dye-sensitized solar cell is disclosed that can improve ion mobility, durability, and performance. The electrolyte consists of: a non-volatile ionic liquid; and a low-viscosity liquid solvent having a viscosity of approximately 0.1 g / cm s (10 cP) or less. The low-viscosity liquid solvent is added to the non-volatile ionic liquid, which has improved durability, in an amount of approximately 1 to 10 wt.%.

[0037] In certain exemplary embodiments, the non-volatile ionic liquid comprising the low-viscosity liquid solvent may be, but is not limited to, one or more of an imidazolium-based compound, a pyridinium-based compound, or combinations thereof. The imidazolium-based compound, as used herein, may comprise one or more selected from the group consisting of: 1-propyl-3-methylimidazolium iodide, 1-butyl-3-methylimidazolium iodide, 1-hexyl-3-methylimidazolium iodide, 1-hexyl-2,3-dimethylimidazolium iodide, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium thiocyanate, and 1-ethyl-3-methylimidazolium selenocyanate. Alternatively, the ionic liquid may be a pyridinium-based compound, but is not limited to this.The pyridinium-based compound can be selected from the group consisting of: 1-butylpyridinium iodide, 1-hexylpyridinium iodide and combinations.

[0038] The low-viscosity liquid solvent has a viscosity of approximately 0.1 g / cm s (10 cP) or less. In certain exemplary embodiments, the low-viscosity liquid solvent may be acetonitrile, 3-methoxypropionitrile, or mixtures thereof, which is particularly suitable for the electrolyte for a vehicle's dye-sensitized solar cell, but is not limited thereto. The content of the low-viscosity liquid solvent corresponds to an amount of approximately 1.0 to 10 wt.% based on the total weight of the ionic liquid.

[0039] If the low-viscosity liquid solvent content is less than approximately 1.0 wt%, sufficient improvement in the mobility of redox species in the ionic liquid cannot be obtained, and such an electrolyte cannot be used due to a reduction in the efficiency of the solar cell. If the low-viscosity liquid solvent content is more than approximately 10 wt%, the liquid solvent may evaporate, and the cell seal of a solar cell may be ruptured due to the generated vapor pressure when the electrolyte is used in a vehicle environment.

[0040] The electrolyte additionally consists of GuSCN, tert-butylpyridine, and iodine as an additive. The additive content can be in an amount of approximately 1 wt% to 10 wt% based on the total weight of the ionic liquid, taking into account the effect of improving efficacy and solubility. EXAMPLES

[0041] The following examples illustrate the invention but are not intended to limit it.

[0042] Hereinafter, the method for producing the dye-sensitized solar cell produced according to various examples of the present invention will be described below, but this does not determine the scope of the present invention.

[0043] The non-volatile ionic liquid in the following example may be 1-butyl-3-methylimidazolium iodide and an ionic liquid species as the equivalent material encompassed in the present invention.

[0044] Example 1: Preparing an exemplary ionic liquid electrolyte comprising an amount of approximately 1 to 10 parts by weight of the liquid solvent

[0045] A mixed solution was prepared by adding approximately 90 parts by weight of the ionic liquid, approximately 4 parts by weight of tert-butylpyridine, and approximately 3 parts by weight of GuSCN, and stirring for approximately 1 hour. Subsequently, approximately 3 parts by weight of iodine were added to the mixed solution and stirred for approximately 1 hour. Then, approximately 3 parts by weight of the low-viscosity liquid solvent were further added and stirred for approximately 24 hours. The low-viscosity liquid solvent may have a viscosity of approximately 10 cP or below, and examples thereof may include acetonitrile and 3-methoxypropionitrile, or a mixture thereof.

[0046] Comparative Example 1: Preparation of the ionic liquid electrolyte without the low-viscosity liquid solvent

[0047] A mixed solution was prepared by adding approximately 90 parts by weight of the ionic liquid, approximately 4 parts by weight of tert-butylpyridine, and approximately 32 parts by weight of GuSCN and stirring for approximately 1 hour. Subsequently, approximately 3 parts by weight of iodine was added to the mixed solution and stirred for 1 hour.

[0048] Comparative Example 2: Preparation of the ionic liquid electrolyte with an amount of about 10 parts by weight or more of the low-viscosity liquid solvent

[0049] A mixed solution was prepared by adding approximately 90 parts by weight of the ionic liquid, approximately 4 parts by weight of tert-butylpyridine, and approximately 3 parts by weight of GuSCN, and stirring for approximately 1 hour. Subsequently, approximately 3 parts by weight of iodine was added to the mixed solution and stirred for approximately 1 hour.

[0050] Thereafter, approximately 12 parts by weight or more of the low-viscosity liquid solvent was further added and stirred for approximately 24 hours. The low-viscosity liquid solvent may have a viscosity of approximately 10 cP or less, and examples thereof may include acetonitrile and 3-methoxypropionitrile, or a mixture thereof. Manufacturing example: Manufacturing of the solar cell

[0051] A titanium dioxide paste (Solaronix SA) was screen-printed onto a fluorine-doped tin oxide (FTO) substrate. The coated substrate was fired at a temperature of approximately 500°C for approximately 30 minutes. A dye (Solaronix SA, N719) was adsorbed onto the fabricated titanium dioxide photoelectrode at a conventional temperature for approximately 24 hours. Subsequently, a UV curing agent was applied to the exterior (outer skin) of the photoelectrode on which the dye was adsorbed. The platinum-coated and sintered counter electrode substrate was applied thereon, and curing was performed using UV curing equipment. After the electrolytes of Example 1 and Comparative Examples 1 and 2 were injected into the fabricated cells, their inlets were sealed with the same UV curing agent to compare the cell performances.

[0052] The fabricated solar cells comprising electrolytes of Example 1 and Comparative Examples 1-2 are compared as shown in Table 1. As shown below, the low-viscosity liquid solvent is added according to an exemplary embodiment of the present invention, and the efficiency of the cell can be improved. [Table 1] sample Jsc (mA / cm2) Voc (V) Fill factor Energy conversion efficiency (%) Comparison example 1 9,5 0,55 0,52 2,71 Example 1 13,4 0,61 0,61 5,00

[0053] Furthermore, as in Fig.3, the ion mobility in the electrolyte to which the liquid solvent according to an exemplary embodiment of the present invention has been added can be improved. Specifically, when an amount of approximately 1.0 to 10 parts by weight of the liquid solvent additive in Example 1 is added to the ionic liquid electrolyte having the high-resistance properties of high viscosity, the ion mobility of the electrolyte of the present invention can be improved by reducing the resistance value to a level similar to that of the low-viscosity liquid electrolyte.

[0054] Accordingly, the vapor pressure of the electrolyte can be controlled with the low-viscosity liquid solvent, as in Fig. 4 is shown.

[0055] When the content of low-viscosity liquid solvent is included in an amount of about 10 wt% or more, the photoelectric efficiency may be rapidly reduced due to the breakage of the seal during the accelerated durability evaluation, as shown in Table 2 and Fig. 1 shown. [Table 2] sample Energy conversion efficiency before accelerated durability assessment (%) Energy conversion efficiency after accelerated durability assessment (%) Example 1 5,00 4,40 Comparison example 2 2,71 0,31

Claims

[1] Electrolyte for a dye-sensitized solar cell, consisting of: a non-volatile ionic liquid; a low-viscosity liquid solvent with a viscosity of 0.1 g / cm s (10 cP) or less, tert-butylpyridine, GuSCN, and iodine, wherein the low-viscosity liquid solvent is added in an amount of 1 to 10 wt% of the non-volatile ionic liquid based on the total weight of the non-volatile ionic liquid. [2] The electrolyte of claim 1, wherein the non-volatile ionic liquid is one or more of an imidazolium-based compound, a pyridinium-based compound, or combinations thereof. [3] The electrolyte according to claim 2, wherein the imidazolium-based compound is selected from the group consisting of 1-propyl-3-methylimidazolium iodide, 1-butyl-3-methylimidazolium iodide, 1-hexyl-3-methylimidazolium iodide, 1-hexyl-2,3-dimethylimidazolium iodide, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium thiocyanate and 1-ethyl-3-methylimidazolium selenocyanate. [4] The electrolyte according to claim 2, wherein the pyridinium-based compound is selected from the group consisting of 1-butylpyridinium iodide and 1-hexylpyridinium iodide. [5] The electrolyte according to claim 1, wherein the low-viscosity liquid solvent having the viscosity of 0.1 g / cm·s (10 cP) or below is selected from the group consisting of acetonitrile, 3-methoxypropionitrile and combinations thereof. [6] Dye-sensitized solar cell comprising: the electrolyte according to claim 1. [7] Dye-sensitized solar cell for a vehicle, comprising: the electrolyte according to claim 1.

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