KR20110044089A - Polymer electrolyte doped with quantum dot and dye-sensitized solar cell using the same - Google Patents

Abstract

PURPOSE: A polymer electrolyte doped with a quantum dot and dye-sensitized solar battery using the same are provided to apply a gel type or solid type polymer electrolyte doped with a quantum dot as an electrolyte of the dye-sensitized solar battery, thereby increasing the photoelectric efficiency of a solar battery. CONSTITUTION: A metal oxide semiconductor layer(14) is formed on a first substrate(12). An optical electrode(10) includes a dye absorbed in the metal oxide semiconductor layer. A counterpart electrode(20) includes a second conductive substrate(22) and the metal layer(24) of the second conductive substrate. A polymer electrolyte(52) doped with a quantum dot is interposed between the optical electrode and the counter electrode. The polymer electrolyte doped with the quantum dot is in gel solid form.

Description

POLYMER ELECTROLYTE DOPED WITH QUANTUM DOT AND DYE-SENSITIZED SOLAR CELL USING THE SAME}

The present application is a polymer electrolyte doped with a quantum dot. And a dye-sensitized solar cell using the same and a method of manufacturing the same .

As one of the technical fields for solving the problems caused by environmental pollution and energy depletion, interest in solar cells that generate electricity without generating environmental pollutants is gradually increasing. In particular, since solar cells using solar energy have infinite resources and are environmentally friendly, unlike other energy sources, silicon solar cells have been in the spotlight recently since the development of silicon solar cells in 1983. However, such a silicon solar cell is difficult to commercialize because of the high manufacturing cost, and there are many difficulties in improving battery efficiency. In order to overcome this problem, development of dye-sensitized solar cells having low manufacturing costs has been actively studied in recent years.

Accordingly, dye-sensitized solar cells (DSSC = Dye-Sensitized Solar Cell) have recently emerged in the field of material science due to low cost and high efficiency. Dye-sensitized solar cells, unlike silicon solar cells, contain photosensitive dye molecules capable of absorbing visible light to produce electron-hole pairs, and transition metal oxides for transferring the generated electrons. It is a photoelectrochemical solar cell. A representative example of the dye-sensitized solar cells known to date is known in 1991 by Gratzel et al., Switzerland. These batteries have been attracting attention because they have a functionality that can replace the conventional solar cells because the manufacturing cost per power is cheaper than conventional silicon solar cells.

Specifically, one example of a DSSC is a fluorine-doped tin oxide (FTO) electrode (photoelectrode) coated with a dye-sensitized porous TiO ₂ film (photoelectrode), a platinum-coated counter electrode, and an oxide sandwiched between the electrodes. It includes an electrolyte containing a redox couple. TiO ₂ porous films show superiority over other common photoelectrodes because the high specific surface area of TiO ₂ allows the adsorption of large numbers of dye molecules. With regard to the synthesis of photoelectrodes, the doctor-blade method is often used because it provides a good film free of cracks [W. Chen, X. Sun, Q. Cai, D] Weng, H. Li, Electrochem. Commun. 9 (2007) 382.].

The DSSCs for achieving high efficiency reported so far are based on liquid electrolytes (organic solvents containing iodide / iodine) and ruthenium-based dyes. However, disadvantages of liquid electrolytes, such as corrosion, leakage, evaporation, etc., limit the long-term stability of DSSC. In addition, there have been problems such as the use of expensive dyes conventionally used in dye-sensitized solar cells.

Accordingly, there is a growing interest and demand for a technology for improving the light conversion efficiency of dye-sensitized solar cells by developing a solid electrolyte that can replace the liquid electrolyte having the above problems and developing a new low-cost dye.

In order to solve the above problems, the present application is a dye-sensitized type formed by injecting a polymer electrolyte doped with a quantum dot and a polymer electrolyte doped with the quantum dot in a predetermined space between the photoelectrode and the counter electrode. It is intended to provide a solar cell and a method of manufacturing the same.

However, the problem to be solved by the present application is not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, an aspect of the present application provides a polymer electrolyte doped with a quantum dot, including a polymer for an electrolyte and a quantum dot dispersed as a dopant in the polymer.

Another aspect of the present application provides a dye-sensitized solar cell comprising:

An optical electrode including a conductive first substrate, a metal oxide semiconductor layer formed on the first substrate, and a dye adsorbed on the metal oxide semiconductor layer;

A counter electrode comprising a conductive second substrate and a metal layer formed on the second substrate; And

A polymer electrolyte interposed between the photoelectrode and the counter electrode and doped with the quantum dots.

Another aspect of the present application provides a method of manufacturing the dye-sensitized solar cell, comprising:

Preparing a photoelectrode by forming a metal oxide semiconductor layer on the conductive first substrate and adsorbing a dye on the metal oxide semiconductor layer;

Forming a metal layer on the conductive second substrate to prepare a counter electrode;

Arranging the photoelectrode and the counter electrode such that the metal oxide semiconductor layer on which the dye of the photoelectrode is adsorbed and the metal layer of the counter electrode face each other with a predetermined space therebetween;

The polymer electrolyte doped with the quantum dots is injected into a predetermined space between the photoelectrode and the counter electrode.

Another aspect of the present application can provide a method of manufacturing the dye-sensitized solar cell, including:

Preparing a photoelectrode by forming a metal oxide semiconductor layer on the conductive first substrate and adsorbing a dye on the metal oxide semiconductor layer;

Forming a polymer electrolyte membrane doped with the quantum dots on the metal oxide semiconductor layer on which the dye of the photoelectrode is adsorbed;

Forming a metal layer on the conductive second substrate to prepare a counter electrode;

Contacting the metal layer of the counter electrode with the polymer electrolyte membrane doped with a quantum dot formed on the metal oxide semiconductor layer on which the dye of the photoelectrode is adsorbed, and fixing the photoelectrode and the counter electrode.

According to the present invention, a polymer electrolyte doped with quantum dots can be prepared, and the polymer electrolyte exhibits excellent electrical and photochemical properties due to the doped quantum dots. Thus, by applying the gel-type or solid-type polymer electrolyte doped with the quantum dots as the electrolyte of the dye-sensitized solar cell, it is possible to improve the problem of the conventional liquid electrolyte. In addition, the dye-sensitized solar cell incorporating the polymer electrolyte doped with the quantum dots can improve the photoelectric efficiency of the dye-sensitized solar cell by improving and improving the electrical and photochemical properties.

DETAILED DESCRIPTION Hereinafter, embodiments and examples of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present disclosure.

It should be understood, however, that the present invention may be embodied in many different forms and is not limited to the embodiments and examples described herein. In the drawings, parts irrelevant to the description are omitted for simplicity of explanation, and like reference numerals designate like parts throughout the specification.

In one aspect of the present application, a polymer electrolyte doped with a quantum dot, including a polymer for the electrolyte and a quantum dot (quantum dot) dispersed as a dopant in the polymer can be provided.

In an exemplary embodiment, the quantum dots may have a core / shell structure, for example, the quantum dots may be a II-VI compound semiconductor, a II-V compound semiconductor, a III-VI compound semiconductor, or III-V. A compound semiconductor selected from the group consisting of group compound semiconductors, group IV-VI compound semiconductors, group I-III-VI compound semiconductors, group II-IV-VI compound semiconductors, group II-IV-V compound semiconductors, and combinations thereof It may be. In the quantum dot having the core / shell structure, the core and the shell may each include the compound semiconductor described above.

In an exemplary embodiment, the electrolyte polymer is polyethylene (poly (ethylene oxide): PEO), polyvinylidene fluoride (poly (vinylidene fluoride): PVDF), polyethylene glycol (poly (ethylene glycol): PEG) And, but may include one or more polymers selected from the group consisting of, but is not limited thereto. For example, the polymer electrolyte may be gel or solid, but is not limited thereto.

In an exemplary embodiment, the polymer electrolyte doped with the quantum dots may further include a redox pair.

The polymer electrolyte doped with the quantum dots according to the present application may be stabilized in the long term by improving the ionic conductivity, etc. by being doped with the quantum dots may be improved electrical characteristics and photoelectrochemical properties.

In another aspect of the present application, it is possible to provide a dye-sensitized solar cell comprising:

An optical electrode including a conductive first substrate, a metal oxide semiconductor layer formed on the first substrate, and a dye adsorbed on the metal oxide semiconductor layer;

A counter electrode comprising a conductive second substrate and a metal layer formed on the second substrate; And

And a polymer electrolyte doped with the quantum dots interposed between the photoelectrode and the counter electrode.

In still another aspect of the present disclosure, a method of manufacturing the dye-sensitized solar cell, which includes the following, may be provided:

Preparing a photoelectrode by forming a metal oxide semiconductor layer on the conductive first substrate and adsorbing a dye on the metal oxide semiconductor layer;

Forming a metal layer on the conductive second substrate to prepare a counter electrode;

Arranging the photoelectrode and the counter electrode such that the metal oxide semiconductor layer on which the dye of the photoelectrode is adsorbed and the metal layer of the counter electrode face each other with a predetermined space therebetween;

The polymer electrolyte doped with the quantum dots is injected into a predetermined space between the photoelectrode and the counter electrode.

In still another aspect of the present disclosure, a method of manufacturing the dye-sensitized solar cell, which includes the following, may be provided:

Preparing a photoelectrode by forming a metal oxide semiconductor layer on the conductive first substrate and adsorbing a dye on the metal oxide semiconductor layer;

Forming a polymer electrolyte membrane doped with the quantum dots on the metal oxide semiconductor layer on which the dye of the photoelectrode is adsorbed;

Forming a metal layer on the conductive second substrate to prepare a counter electrode;

Contacting the metal layer of the counter electrode with the polymer electrolyte membrane doped with a quantum dot formed on the metal oxide semiconductor layer on which the dye of the photoelectrode is adsorbed, and fixing the photoelectrode and the counter electrode.

In an exemplary embodiment, the first substrate and the second substrate may be indium tin oxide (ITO), fluorine-doped tin oxide (FTO), a glass substrate coated with SnO ₂ on a surface thereof, or a conductive polymer substrate. However, it is not limited thereto.

In an exemplary embodiment, the metal oxide semiconductor layer may use all known metal oxide semiconductors used in the production of a photoelectrode of a dye-sensitized solar cell. For example, titanium dioxide (TiO ₂ ), tin dioxide ( SnO ₂ ), zinc oxide (ZnO), or a combination thereof, but is not limited thereto.

In an exemplary embodiment, the polymer electrolyte may further include a redox pair. For example, the polymer electrolyte may further include an iodine-based redox species as the redox pair, but is not limited thereto.

According to the present application, in the case of a liquid electrolyte, the problem of long-term stability that may be caused by an increase in temperature due to external factors is solved by using a polymer electrolyte, while the ion conductivity in the polymer electrolyte doped by the quantum dots is improved. As a result, it is possible to provide a dye-sensitized solar cell which is stable in the long term and has improved energy conversion efficiency.

Hereinafter, embodiments and examples of the present application will be described in detail with reference to the accompanying drawings. However, the present application is not limited thereto.

The polymer electrolyte doped with the quantum dots may be prepared by adding a desired amount of quantum dots to a solution in which an appropriate polymer is dissolved in the electrolyte for agitation so that the quantum dots are uniformly dispersed. The stirred solution may exhibit a unique color due to dispersed quantum dots and may exhibit viscosity.

The polymer electrolyte doped with the quantum dots may further include a redox pair. If necessary, the polymer for providing an electrolyte and a redox pair may be prepared by stirring a solution in which an appropriate solvent is dissolved, and then adding a desired amount of quantum dots to stir the quantum dots to be homogeneously dispersed.

The redox pair may be iodine-based, and may include, for example, I ^{3 −} / I ⁻ redox pairs. For example, the iodine-based redox pair may be a 1: 10 wt% mixture of KI and I ₂ , or 0.7 M of 1-vinyl-3-methyl-imidazolium iodide (1-vinyl-3-methylimidazolium iodide), 0.1 M LiI and 40 mM I ₂ dissolved in 3-methoxypropionitrile or N-methyl-2-pyrrolidone (NMP) solvent It can be obtained using a mixture.

The electrolyte polymer may be, for example, polyethylene (poly (ethylene oxide): PEO), polyvinylidene fluoride (poly (vinylidene fluoride): PVDF), polyethylene glycol (poly (ethylene glycol): PEG), and It may be at least one polymer selected from the group consisting of derivatives thereof.

In an exemplary embodiment, the quantum dots in the polymer electrolyte may be included in an amount of about 1 to 30% by weight, preferably about 15 to 25% by weight, based on the total weight of the polymer electrolyte 50. If the content of the quantum dots in the polymer electrolyte is too high, the viscosity of a solution containing a polymer, an iodine-based redox species and a quantum dot in a solvent increases during the preparation of the electrolyte, so that the uniform dispersion distribution of the quantum dots in the electrolyte Difficulties in securing them can be followed.

In an exemplary embodiment, in order to prepare the polymer electrolyte, for example, a polymer for electrolyte such as salt (KI and I- ₂ ) and polyethylene oxide (PEO), which provides an iodine-based redox pair, may be appropriately organic. A homogeneous solution can be prepared by dissolving in a solvent and mixing. Then, the polymer electrolyte doped with quantum dots may be formed by adding the quantum dots described above to the homogeneous solution and stirring until the desired viscosity is obtained to uniformly disperse the quantum dots. If necessary, the polymer electrolyte solution in which the quantum dots are dispersed may be cast into a suitable container, and the solvent may be removed to cast a film or other desired shape.

In an exemplary embodiment, the polymer electrolyte 52 doped with the quantum dots may be gel or solid.

In an exemplary embodiment, the quantum dots may have a core / shell structure.

The quantum dots are, for example, group II-VI compound semiconductors, group II-V compound semiconductors, group III-VI compound semiconductors, group III-V compound semiconductors, IV-VI compound semiconductors, I-III-VI compound semiconductors, II It may include a compound semiconductor selected from the group consisting of -IV-VI compound semiconductor, II-IV-V compound semiconductor and combinations thereof. In the quantum dot having the core / shell structure, the core and the shell may each include the compound semiconductor described above.

For example, the quantum dots or the core and shell of the quantum dots are MgO, MgS, MgSe, MgTe, CaO, CaS, CaSe, CaTe, SrO, SrS, SrSe, SrTe, BaO, BaS, BaSe, BaTE, ZnO, ZnS , ZnSe, ZnTe, CdO, CdS, CdSe, CdTe, HgO, HgS, HgSe, HgTe, Al ₂ O ₃ , Al2S ₃ , Al ₂ Se ₃ , Al ₂ Te ₃ , Ga ₂ O ₃ , Ga ₂ S ₃ , Ga ₂ Se ₃ , Ga ₂ Te ₃ , In ₂ O ₃ , In ₂ S ₃ , In ₂ Se ₃ , In ₂ Te ₃ , SiO ₂ , GeO ₂ , SnO ₂ , SnS, SnSe, SnTe, PbO, PbO ₂ , PbS , A compound semiconductor selected from the group consisting of PbSe, PbTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, BP, Si, Ge, and combinations thereof It may be, but is not limited thereto.

In an exemplary embodiment, the quantum dot having the core / shell structure may be one in which the core and the shell each include a II-VI compound semiconductor, such as CdSe / ZnS core / shell quantum dots, but are not limited thereto. It is not.

In an exemplary embodiment, the quantum dots may have a particle size of about 1 to 20 nm, for example, about 5 to 20 nm, or about 5 to 10 nm, but is not limited thereto.

1 is a cross-sectional view schematically showing the configuration of a dye-sensitized solar cell 100 including a polymer electrolyte doped with the quantum dots according to an embodiment of the present application.

Referring to FIG. 1, the dye-sensitized solar cell 100 including the polymer electrolyte doped with the quantum dots according to the present disclosure may include a photoelectrode 10 and a counter electrode 20 facing each other.

The photoelectrode 10 may include a conductive first substrate 12 and a metal oxide semiconductor layer 14 formed on the first substrate 12. A dye (not shown) may be adsorbed onto the metal oxide semiconductor layer 14.

In an exemplary embodiment, the metal oxide semiconductor layer 14 may include, for example, titanium dioxide (TiO ₂ ), tin dioxide (SnO ₂ ), zinc oxide (ZnO), or a combination thereof. . Preferably, the metal oxide semiconductor layer 14 may be formed of nanoparticle titanium dioxide (TiO ₂ ) having a particle diameter of about 5 to 30 nm, and may have a thickness of about 5 to 30 μm, but is not limited thereto. It is not.

As the dye adsorbed on the metal oxide semiconductor layer 14, all dyes generally used in the manufacture of DSSC can be used. Non-limiting examples include ruthenium complexes, xanthine dyes, cyanine dyes, phenosafranin, and carbrie. Blue, thiocin, basic dyes, porphyrin-based compounds, azo dyes, phthalocyanine compounds, Ru trisbipyridyl complex compounds, anthraquinone dyes, polycyclic quinone dyes, or mixtures thereof.

The counter electrode 20 may include a conductive second substrate 22 and a metal layer 24 formed on the second substrate 22, and the metal layer 24 may be formed of, for example, platinum. .

The first substrate 12 and the second substrate 22 may be made of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), a glass substrate coated with SnO ₂ on the surface, or a conductive polymer substrate, respectively. However, it is not limited thereto.

The photoelectrode 10 and the counter electrode 20 may be disposed such that the metal oxide semiconductor layer 14 of the photoelectrode 10 and the metal layer 24 of the counter electrode 20 face each other. The photoelectrode 10 and the counter electrode 20 are spaced apart from each other by a predetermined support polymer layer 40 supported therebetween.

The space between the photoelectrode 10 and the counter electrode 20 may be filled with the polymer electrolyte 50 doped with the above-mentioned quantum dots. Alternatively, the polymer electrolyte 50 film doped with the quantum dots may be formed on the photoelectrode 10, and then bound to the counter electrode 20 to fix them.

2 is a flowchart illustrating a method of manufacturing a dye-sensitized solar cell including a polymer electrolyte doped with a quantum dot according to an embodiment of the present application.

Referring to FIG. 2, the photoelectrode 10 including the metal oxide semiconductor layer 14 on which the dye is adsorbed and the counter electrode 20 including the metal layer 24 may be prepared, respectively (S210).

For this purpose, for example, the following procedure can be performed.

To fabricate the photoelectrode 10, first, a colloidal TiO ₂ paste is used, for example, using a doctor-blade technique, for example FTO, ITO or SnO ₂ as the first substrate. Is coated on a transparent conductive glass substrate coated with and then sintered to form a porous TiO ₂ film. The thickness of the porous TiO ₂ film can be controlled by Scotch tape having a thickness of ˜50 μm.

The first substrate 12 on which the metal oxide semiconductor layer 14 such as the titanium dioxide film is formed is, for example, a ruthenium complex, a xanthine dye, a cyanine dye, phenosafranin, cabrio blue, The dye is adsorbed by impregnation for a predetermined time or more in a dye solution containing a thiocine, a basic dye, a porphyrin compound, an azo dye, a phthalocyanine compound, a Ru trisbipyridyl complex compound, an anthraquinone dye, a polycyclic quinone dye, or a mixture thereof. The photoelectrode including the metal oxide semiconductor layer 14 can be completed.

If necessary, a dye-sensitized solar cell (DSSC) having an active region may be manufactured by the following procedure.

For example, for use as a blocking layer, a Ti (IV) bis (ethyl acetoacetateto) -diisopropoxide [Ti (IV) bis (ethyl acetoacetato) -diisopropoxide] solution (1- 2% by weight in butanol is added dropwise onto the first substrate (e.g., transparent conductive glass substrate coated with FTO, ITO or SnO ₂ ) on which the porous TiO ₂ film is formed and spin-coated It can apply uniformly using. The photoelectrode may be manufactured by adsorbing a dye by impregnating the porous TiO ₂ film having the blocking layer in a dye solution.

In order to form the counter electrode 20, a platinum layer may be coated on the transparent conductive glass substrate coated with the second substrate 20, for example, FTO, ITO, or SnO ₂ .

Thereafter, the polymer electrolyte doped with the quantum dots is described in reference [P.K. Singh, K.W. Kim, H.W. Rhee, Electrochem. Commun. 10 (2008) 1769; A.F. Nogueira, J. R. Durrant, M.A. De Paoli, Adv. Mater. 13 (2001) 826.] can be cast on the photoelectrode including the metal oxide semiconductor layer 14, the dye is adsorbed according to the two-step casting method. The dye-sensitized solar cell can be completed by firmly clamping the photoelectrode and the counter electrode including the polymer electrolyte doped with the quantum dots thus obtained and vacuum drying before measurement.

Alternatively, the photoelectrode 10 and the counter electrode 20 are aligned such that the dye-adsorbed metal oxide semiconductor layer 14 and the metal layer 24 face each other (S220), and then the photoelectrode 10 ) And the counter electrode 20, for example, a polymer layer 40 having a thickness of about 30 to 50 µm made of, for example, SURLYN (trade name manufactured by Du Pont), and about 1 to 3 on a heating plate of about 100 to 140 ° C. Atmospheric pressure may be used to bring the two electrodes into close contact. Next, the polymer electrolyte 50 doped with the quantum dots may be injected into a predetermined space between the photoelectrode 10 and the counter electrode 20 (S230). In more detail, the polymer electrolyte 50 doped with the quantum dots is formed between the photoelectrode 10 and the counter electrode 20 through a minute hole (not shown) formed in the counter electrode 20. It can be injected into the space to completely fill the predetermined space. Finally, the dye-sensitized solar cell of the present application can be completed by blocking the micropores.

One. QD Doped  Polymer electrolyte and film production thereof

Poly (ethylene oxide) PEO (Mw˜1 × 10 ⁶ , Aldrich), potassium iodide and iodine (KI, I- ₂ , Aldrich, USA) were prepared and used. CdSe / ZnS core / shell quantum dots (QD, size ca. 5.8 nm) dispersed in chloroform were purchased from Evident Technologies. A 75: 25: 2.5 composition (w / w) of polymer (PEO) and salts (KI and I- ₂ ) were dissolved in an acetonitrile solvent at 50 ° C. overnight to prepare a homogeneous solution. The iodide / iodine salt ratio was fixed at 10: 1 (weight ratio%) because the electrolyte film in this composition was stable and showed maximum ionic conductivity. A desired amount of quantum dots (QD) was added to the polymer electrolyte solution and the final solution was again thoroughly stirred to give a colored viscous solution. Before the quantum dots were doped, the bare polymer electrolyte solution (PE) and the quantum dot doped polymer electrolyte (QDPE) solution were each cast into a polypropylene dish. The solvent was evaporated slowly at room temperature, and the polymer electrolyte film obtained was dried under vacuum to remove solvent traces.

2. Porosity using doctor-blade technology TiO ₂  Manufacture of film

Porous TiO ₂ films with good properties were prepared by the doctor-blade technique. In this method, a colloidal TiO ₂ paste [Ti-Nanoxide: D, purchased from Solaronix (Switzerland)] was spread on a conductive FTO glass substrate using the doctor-blade method and sintered at 500 ° C. for 30 minutes. To form a porous TiO ₂ film having a ˜10-15 nm pore diameter and a thickness of 10 μm. The thickness of the porous TiO ₂ film was controlled by Scotch tape with a thickness of ˜50 μm.

3. Fabrication of Dye-Sensitized Solar Cell

0.25 cm ² A dye-sensitized solar cell (DSSC) having an active region of was prepared by the following procedure. Ti (IV) bis (ethyl acetoacetateto) -diisopropoxide [Ti (IV) bis (ethyl acetoacetato) -diisopropoxide] solution (2-weight in 1-butanol) for use as a blocking layer %) Was added dropwise onto the FTO-substrate on which the porous TiO ₂ film described above was formed and uniformly applied using the spin-coating method. The porous TiO ₂ film with the blocking layer was sensitized by immersion in a 0.5 mM dye (N 719, Solaronix, Switzerland) solution in ethanol. Pt counter electrode was prepared by spin-coating a H ₂ PtCl ₆ solution (0.05 moldm ^{−3 in} isopropyl solvent) onto a conductive FTO glass (sintered at 400 ° C. for 30 minutes). Then, the polymer / quantum dot electrolyte is described in reference [PK Singh, KW Kim, HW Rhee, Electrochem. Commun. 10 (2008) 1769; AF Nogueira, JR Durrant, MA De Paoli, Adv. Mater. 13 (2001) 826.] was cast on the sensitized TiO ₂ electrode according to the two-step casting method described. The sensitized TiO ₂ electrode and the counter electrode comprising the polymer / quantum point (maximum sigma) thus obtained were firmly clamped and vacuum dried prior to measurement.

4. Characterization of Dye-Sensitized Solar Cell

The ion conductivity (σ) of the polymer electrolyte film was measured using a Solartron bridge (SI 1287 and 1252 FRA) coupled to a computer in the frequency range 0.65 Hz to 65 kHz. The surface morphology of the electrolyte film was obtained using atomic force microscopy (AFM, atomic mode microscope IV Digital Instruments, Canada) operated in tapping mode. CHI 600 potentiostat was used for cyclic voltammetry in 0.1 phosphate buffer solution at pH 7. Dye-sensitized solar cell performance (JV curve) was measured with a Keithley 2400 source meter under solar intensity (100 mWcm ⁻² ) simulated by a solar simulator (Olar, 91193).

(1) conductivity measurement

Complex impedance spectroscopy was used to calculate the room temperature ion conductivity of the polyethylene oxide electrolyte (QDPE) film and the polyethylene oxide electrolyte (PE) film doped by the quantum dots. Referring to Table 1 and FIG. 3, the calculated value can be confirmed.

Referring to Table 1, the host polymer electrolyte (not doped with a quantum dot) having a composition of 75: 25: 2.5 shows an σ value of 2.02 x 10 ^-5 Scm ^-1 , which means that the σ value of the original PEO polymer film is 10 ^It is a much higher value compared to those within ^-8 Scm ^-1 to 10 ^-9 Scm ^-1 . Doping the quantum dots (QD) into the polymer electrolyte increases the sigma value, reaching up to 1.92 × 10 ⁻⁴ Scm ⁻¹ at a 20 wt% quantum dot concentration and then decreasing. σ vs. Such peaking, expressed in composition, is a general feature of the ionic conductivity of the "ionic conductor-semiconductor complex", where the maximum conductivity (peak) is the interfacial space-charge model [J. Maier, Prog. Solid State Chem. 23 (1995) 171.] and percolation threshold model [A. Bunde, W. Dieterich, E. Roman, Phys. Rev. Lett. 55 (1985) 5.].

(2) AFM  Measure

4 is a tapping mode AFM photograph showing a two-dimensional AFM topology for (a) a polymer electrolyte film undoped with QDs and (b) a polymer electrolyte film doped with quantum dots according to an embodiment of the present disclosure. Information on the surface characteristics of the polymer electrolyte film was shown. More specifically, FIG. 4 shows a two-dimensional AFM photograph for the [PEO: KI] polymer electrolyte film and the [PEO: KI + 20% QD] polymer electrolyte film. The polymer electrolyte (PE) morphology, which is not doped with QD, shows a relatively flat, continuous matrix free of pores / cracks (see FIG. 4A). Looking closely at the QDPE doped polymer electrolyte matrix (QDPE), the QD particles show a size distribution of 10-30 nm and clearly show that they are uniformly distributed within the polymer electrolyte matrix (see FIG. 4B). These results can be seen from the fact that during the doping of QD into the polymer matrix, the particle size obtained by wrapping the polymer around the QD is relatively large compared to the size of pure QD (average size ˜5.8 nm).

(3) electrochemical measurement

QD- doped PEO: KI: was, performing cyclic voltammetry experiments to confirm that the electrochemical reaction of I- _2: I- ₂ film as well as the PEO of the original state: KI. FIG. 5 shows the cyclic voltammograms of the polymer electrolyte films measured in 0.1 M phosphate buffer solution, with no quantum dots (black solid line) and with quantum dots at a scan rate of 50 mV / s. It is a graph which shows the cyclic voltage-current curve of the polymer electrolyte film in the case (red dotted line). The polymer electrolyte system (PE) without quantum dots shows two clear redox peaks (black solid line) around ΔE = 0.465 and 0.560 V, respectively. These peaks show the formation of triiodides generated from iodides and iodine. In the presence of quantum dots, the polymer electrolyte system (QDPE) shows two peaks, but they do not separate well. Interestingly, the two redox peaks observed in the quantum dot doped polymer electrolyte show about 100 mV positive shift at that peak position. This shift in peak position may be due to the interaction between the quantum dots, the polymer matrix and the iodide / iodine complex. In addition, it was observed that PEO and quantum dots were electrochemically inactive in the scanned electrochemical window.

(4) Performance Evaluation of Dye-Sensitized Solar Cell

The photovoltaic performance (JV curve) of a dye-sensitized solar cell prepared as described above was simulated by a solar simulator with an AM 1.5 G filter (Oriel, model 91193 including a 1000 W xenon lamp). (100 mWcm ^-2 ) measured with a Keithley 2400 source meter. The sunlight was controlled with a crystalline Si solar cell with a KG5 filter to match 1 solar intensity. FIG. 6 is a photoelectric of a dye-sensitized solar cell (DSSC) each comprising (a) a polymer electrolyte not doped with quantum dots and (b) a polymer electrolyte doped with quantum dots at 100 mWcm ⁻² light intensity according to an embodiment of the present disclosure As a graph showing the photovoltaic curve, the photocurrent density-voltage curve for the DSSC is presented. Dye-sensitized solar cells containing a polymer electrolyte undoped with quantum dots have a 2.01 mA cm ^-2 short-circuit current density (Jsc), an open circuit voltage (Voc) of 0.83 V and Fill factor (FF) was shown and the efficiency was 1.07%. On the other hand, dye-sensitized solar cells containing a solid polymer electrolyte (maximum sigma) doped with 20% weight ratio quantum dots have a 5.87 mA cm ^-2 short-circuit current density (Jsc) with an open circuit voltage of 0.71 V. (open circuit voltage, Voc) and a fill factor (FF) of 0.55, and the efficiency was improved to 2.33%. It was confirmed that the continuous resistance of the polymer electrolyte (QDPE) system doped with quantum dots is higher than the case where the quantum dots are absent. This may be related to a change in the Voc value. It can be seen that doping quantum dots improves the Jsc value (from 2.01 to 5.87 mA cm ⁻² ) and finally improves solar cell efficiency. Since the Jsc values are directly related to the mobility of charge carriers (ionic conductivity) and represent orders of magnitude higher in quantum dot doped electrolyte (QDPE) systems, the results are in good agreement with the conductivity data herein. Shows a match. However, some of the light may also be absorbed by the quantum dots to contribute to the improved Jsc value.

In summary, the doping of the quantum dots (QD) in the polymer electrolyte matrix enables the development of dye-sensitized solar cells with stable, good conductivity and excellent efficiency. As confirmed by AFM measurement, the quantum dots are uniformly dispersed in the electrolyte. Conductivity measurements show that σ improves due to the additional charge provided by the quantum dots. Cyclic voltammetry shows two well separated peaks related to oxidation / reduction reactions. The new dye-sensitized solar cell developed by applying a solid electrolyte doped with a quantum dot having a maximum sigma according to the present invention exhibits a high efficiency of 2.33%, which is the efficiency of the conventional dye-sensitized solar cell without quantum dots. 1.07). This improvement in photovoltaic properties is due to the improvement in ionic conductivity of the polymer electrolyte doped with quantum dots (~ 1 order of magnitude).

As described above, the present application has been described in detail, but the present disclosure is not limited to the above embodiments, and may be modified in various forms, and may be modified by those skilled in the art within the technical spirit of the present disclosure. It is obvious that many other variations are possible.

1 is a cross-sectional view schematically showing the configuration of a dye-sensitized solar cell 100 using a polymer electrolyte doped with a quantum dot according to an embodiment of the present application,

2 is a flowchart illustrating a method of manufacturing a dye-sensitized solar cell using a polymer electrolyte doped with a quantum dot according to an embodiment of the present application.

3 is a graph showing the ion conductivity according to the weight ratio of the quantum dots in the polymer electrolyte according to an embodiment of the present application,

4 is a photograph showing a two-dimensional AFM topology for (a) a quantum dot doped polymer electrolyte film and (b) a polymer electrolyte film doped with quantum dots according to an embodiment of the present application,

FIG. 5 is a graph showing cyclic voltage current curves of a quantum dot doped polymer electrolyte film (solid black line) and a quantum dot doped polymer electrolyte film (red dotted line) at a scan rate of 50 mV / s according to an embodiment of the present disclosure. ,

Figure 6 is a photoelectric of a dye-sensitized solar cell comprising (a) a polymer electrolyte when the quantum dots are not doped, and (b) a polymer electrolyte doped with quantum dots at 100 mWcm ^-2 light intensity according to an embodiment of the present application This graph shows the photovoltaic curve.

<Explanation of symbols for the main parts of the drawings>

10: photoelectrode

12: first substrate

14: metal oxide semiconductor layer

20: counter electrode

22: second substrate

24: metal layer

40: polymer layer

50: electrolyte

52: polymer electrolyte

54: quantum dots

100: dye-sensitized solar cell

Claims (15)

A polymer electrolyte doped with a quantum dot comprising a polymer for an electrolyte and a quantum dot dispersed as a dopant in the polymer. The method of claim 1, The quantum dots include group II-VI compound semiconductors, group II-V compound semiconductors, group III-VI compound semiconductors, group III-V compound semiconductors, IV-VI compound semiconductors, I-III-VI compound semiconductors, and II-IV-VI group semiconductors. A compound electrolyte doped with a quantum dot, comprising a compound semiconductor selected from the group consisting of compound semiconductors, group II-IV-V compound semiconductors and combinations thereof. The method of claim 2, The quantum dots include MgO, MgS, MgSe, MgTe, CaO, CaS, CaSe, CaTe, SrO, SrS, SrSe, SrTe, BaO, BaS, BaSe, BaTE, ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, CdTe , HgO, HgS, HgSe, HgTe, Al ₂ O ₃ , Al2S ₃ , Al ₂ Se ₃ , Al ₂ Te ₃ , Ga ₂ O ₃ , Ga ₂ S ₃ , Ga ₂ Se ₃ , Ga ₂ Te ₃ , In ₂ O ₃ , In ₂ S ₃ , In ₂ Se ₃ , In ₂ Te ₃ , SiO ₂ , GeO ₂ , SnO ₂ , SnS, SnSe, SnTe, PbO, PbO ₂ , PbS, PbSe, PbTe, AlN, AlP, AlAs, AlSb And a compound semiconductor selected from the group consisting of GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, BP, Si, Ge, and combinations thereof. The method of claim 1, Wherein the quantum dots have a core / shell structure. The method of claim 4, wherein The core and the shell of the quantum dot are II-VI compound semiconductor, II-V compound semiconductor, III-VI compound semiconductor, III-V compound semiconductor, IV-VI compound semiconductor, I-III-VI compound semiconductor, II A polymer electrolyte doped with a quantum dot, comprising a compound semiconductor selected from the group consisting of a group IV-VI compound semiconductor, a group II-IV-V compound semiconductor, and a combination thereof. The method of claim 5, The core and the shell of the quantum dot each comprises a II-VI compound semiconductor, doped with a quantum dot polymer electrolyte. The method of claim 1, The electrolyte polymer is composed of polyethylene (poly (ethylene oxide): PEO), polyvinylidene fluoride (poly (vinylidene fluoride): PVDF), polyethylene glycol (poly (ethylene glycol): PEG), and derivatives thereof A polymer electrolyte doped with a quantum dot, comprising at least one polymer selected from the group. The method of claim 1, A polymer electrolyte doped with a quantum dot further comprising a redox couple. An optical electrode including a conductive first substrate, a metal oxide semiconductor layer formed on the first substrate, and a dye adsorbed on the metal oxide semiconductor layer; A counter electrode comprising a conductive second substrate and a metal layer formed on the second substrate; And A dye-sensitized solar cell comprising a polymer electrolyte doped with a quantum dot according to any one of claims 1 to 8 interposed between the photoelectrode and the counter electrode. The method of claim 9, The polymer electrolyte doped with the quantum dot is a gel or solid type, dye-sensitized solar cell. The method of claim 9, The first substrate and the second substrate are indium tin oxide (ITO), fluorine-doped tin oxide (FTO), a glass substrate coated with SnO ₂ on its surface, or a conductive polymer substrate. The method of claim 9, The metal oxide semiconductor layer comprises titanium dioxide (TiO ₂ ), tin dioxide (SnO ₂ ), zinc oxide (ZnO), or a combination thereof, dye-sensitized solar cell. The method of claim 9, The polymer electrolyte doped with the quantum dot will include an iodine-based redox pair, dye-sensitized solar cell. Method for manufacturing a dye-sensitized solar cell using a polymer electrolyte doped with quantum dots, including: Preparing a photoelectrode by forming a metal oxide semiconductor layer on the conductive first substrate and adsorbing a dye on the metal oxide semiconductor layer; Forming a metal layer on the conductive second substrate to prepare a counter electrode; Arranging the photoelectrode and the counter electrode such that the metal oxide semiconductor layer on which the dye of the photoelectrode is adsorbed and the metal layer of the counter electrode face each other with a predetermined space therebetween; A polymer electrolyte doped with a quantum dot according to any one of claims 1 to 8 is injected into a predetermined space between the photoelectrode and the counter electrode. Method for manufacturing a dye-sensitized solar cell using a polymer electrolyte doped with quantum dots, including: Preparing a photoelectrode by forming a metal oxide semiconductor layer on the conductive first substrate and adsorbing a dye on the metal oxide semiconductor layer; Forming a polymer electrolyte membrane doped with a quantum dot according to any one of claims 1 to 8 on the dye-adsorbed metal oxide semiconductor layer of the photoelectrode; Forming a metal layer on the conductive second substrate to prepare a counter electrode; Contacting the metal layer of the counter electrode with the polymer electrolyte membrane doped with a quantum dot formed on the metal oxide semiconductor layer on which the dye of the photoelectrode is adsorbed, and fixing the photoelectrode and the counter electrode.

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