KR101200766B1

KR101200766B1 - Dye-sensitized solar cell including blocking layer

Info

Publication number: KR101200766B1
Application number: KR20100098442A
Authority: KR
Inventors: 김성진
Original assignee: 주식회사 상보
Priority date: 2010-10-08
Filing date: 2010-10-08
Publication date: 2012-11-13
Also published as: KR20120036655A

Abstract

The present invention relates to a dye-sensitized solar cell including a blocking layer, comprising: a first substrate 110 and a second substrate 180 formed of glass or plastic; A first transparent conductive film 120 and a second transparent conductive film 170 formed of ITO or FTO on the first substrate 110 and the second substrate 180; A blocking layer 130 formed by depositing magnesium oxide (MgO) on the first transparent conductive film 120 with an e-beam evaporator to a thickness of 500 kV to 5,000 kV and crystallizing it; A porous film 140 formed of titanium (Ti) oxide or zirconium (Zr) oxide on the blocking layer 130; A conductive layer 160 formed of any one material of carbon black, carbon nanotubes, or platinum on the second transparent conductive film 170; And an electrolyte layer 150 sealed between the first substrate 110 and the second substrate 180 by a partition and made of an iodine-based redox liquid electrolyte.
In the dye-sensitized solar cell including the blocking layer according to the present invention, magnesium oxide is deposited and crystallized using an e-beam evaporator to form a blocking layer having a desired thickness and a uniform surface with a first transparent conductive film and a porous layer. By forming between the films, the electron recombination phenomenon in which electrons injected into the semiconductor compound are recombined by the electrolyte can be prevented, and the electrode corrosion phenomenon by the electrolyte can be prevented to improve the total light conversion efficiency.

Description

Dye-sensitized solar cell including blocking layer {DYE-SENSITIZED SOLAR CELL INCLUDING BLOCKING LAYER}

The present invention relates to a dye-sensitized solar cell, and more particularly to a dye-sensitized solar cell comprising a blocking layer.

Amid global consensus on the climate change crisis, the demand for renewable energy using clean nature such as the sun, wind, and water instead of existing fossil fuel-based energy is increasing. In particular, technology development and commercialization around the world of solar energy have been developing in recent years, and if 100% of the solar energy delivered to the earth can be used for one hour without loss, it can be used by humankind for one year. The sun has enormous energy that is enough to generate electricity. Solar cells that convert sunlight into electricity have been mostly made of silicon semiconductors, but recently, interest in 'dye-sensitized solar cells' that use sunlight to convert sunlight into electricity without using silicon at all is increasing. have.

Although dye-sensitized solar cells are only half the efficiency of converting sunlight into electricity, they have the advantage of lowering manufacturing costs to less than one-fifth, and operate regardless of seasonal changes. It is attracting attention because it can be done. Currently, the efficiency of dye-sensitized solar cells is known to reach about 11%. In the future, the battery has a commercialization efficiency of 20% and has various applications, and thus intensive research by many researchers and companies around the world is being conducted.

Dye-sensitized solar cells were first introduced in 1991 by Michael Gratzel, a professor of chemistry at Lausanne Institute of Technology (EPFL) in Switzerland. Due to its simple structure, dye-sensitized solar cells are easier to manufacture than conventional silicon solar cells. Typically, crystalline silicon solar cells cost around $ 2.5 per watt, and dye-sensitized solar cells can be manufactured for less than $ 1 per watt, industry experts say. However, in terms of efficiency, how much solar energy is converted into electricity, commercial crystalline silicon solar cells are about 14-17%, while commercial dye-sensitized solar cells are still only 4-7%.

The working principle of a conventional dye-sensitized solar cell is as follows.

The dyes excited by sunlight inject electrons into the conduction band of nanoparticle titanium dioxide. The injected electrons pass through the nanoparticle titanium dioxide to reach the conductive substrate and are transferred to the external circuit. Here, the energy conversion efficiency of electrons transferred from the nanoparticle titanium dioxide to the conductive substrate is greatly influenced by the contact area between the titanium dioxide nanoparticles constituting the semiconductor substrate and the conductive substrate. That is, some of the electrons transferred from the nanoparticle titanium dioxide to the conductive substrate disappear back into the electrolyte through the portion of the conductive substrate that is not in contact with the nanoparticle titanium dioxide and is exposed to the electrolyte solution.

However, in the conventional dye-sensitized solar cell, since the particle shape of the titanium dioxide constituting the semiconductor electrode has a spherical shape, an elliptical shape, or a similar particle shape, the contact area between the titanium dioxide and the conductive substrate is secured. There is a limit. As a result, there is a limit in securing desired energy conversion efficiency due to electron loss through the surface exposed to the electrolyte in the conductive substrate of the semiconductor electrode.

Accordingly, the present invention has been made to solve the above problems, and includes a blocking layer for improving the light conversion efficiency by depositing and crystallizing magnesium oxide using an E-BEAM Evaporater equipment. The purpose is to provide a dye-sensitized solar cell.

Dye-sensitized solar cell comprising a blocking layer according to the present invention for achieving the above object, the first substrate and the second substrate formed of glass or plastic; A first transparent conductive film and a second transparent conductive film formed of ITO or FTO on the first substrate and the second substrate; A barrier layer formed by depositing magnesium oxide (MgO) on the first transparent conductive film with an e-beam evaporator to an thickness of 500 kV to 5,000 kV and crystallizing it; A porous film formed of titanium (Ti) oxide or zirconium (Zr) oxide on the blocking layer; A conductive layer formed of any one material of carbon black, carbon nanotubes, or platinum on the second transparent conductive film; And an electrolyte layer sealed between the first substrate and the second substrate by a partition and made of an iodine-based redox liquid electrolyte.

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As described above, the dye-sensitized solar cell including the blocking layer according to the present invention is deposited and crystallized magnesium oxide using an E-BEAM Evaporater, the desired thickness and uniform surface By forming a blocking layer between the first transparent conductive film and the porous film, it is possible to prevent the electron recombination phenomenon that the electrons injected into the semiconductor compound are recombined by the electrolyte, and to prevent the electrode corrosion phenomenon caused by the electrolyte, the total light conversion efficiency There is an advantage that can be improved.

1 is a view showing an embodiment of a dye-sensitized solar cell including a blocking layer according to the present invention
FIG. 2 is a view showing an embodiment of an E-BEAM Evaporater device for forming a blocking layer of a dye-sensitized solar cell including a blocking layer according to the present invention.
Figure 3 is a surface and side view of the FTO deposited using CVD in a dye-sensitized solar cell according to the prior art
Figure 4 is a surface and side photograph of the barrier layer deposited using the E-BEAM Evaporater equipment of a dye-sensitized solar cell including a barrier layer according to the present invention
5 is an AFM photograph of FIGS. 3 and 4
Figure 6 is a view showing the transmittance comparison analysis of Figures 3 and 4
Figure 7 shows the difference in efficiency with or without the barrier layer according to the present invention

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, a dye-sensitized solar cell including a blocking layer according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing an embodiment of a dye-sensitized solar cell including a blocking layer according to the present invention.

As shown in FIG. 1, a dye-sensitized solar cell including a blocking layer includes a first substrate 110, a first transparent conductive film 120, a blocking layer 130, a porous film 140, and an electrolyte. The layer 150, the conductive layer 160, the second transparent conductive film 170, and the second substrate 180 are provided.

The first substrate 110, the first transparent conductive film 120, the porous film 140, the electrolyte layer 150, the conductive layer 160, and the second transparent conductive film 170 ) And the second substrate 180 may be selected and used conventionally in the art to which the present invention pertains, and are not limited by the following examples.

The first substrate 110 and the second substrate 180 are plastic substrates or glass substrates.

The first transparent conductive layer 120 or the second transparent conductive layer 170 may be formed on indium tin oxide (ITO) or fluorine-doped tin oxide (FTO) on the first or second substrates 110 and 180. Is formed.

The blocking layer 130 is formed by depositing a metal oxide by E-Beam Evaporator (E-BEAM Evaporator) equipment and crystallization, the metal oxide is a magnesium oxide (MgO) thin film, the blocking layer, A layer deposited to a thickness of 500 kV to 5,000 kPa, which improves the adhesion between the first substrate 110 and the porous membrane 140, and at the same time, the layer of the first substrate 110 and the electrolyte layer 150. Blocks direct contact to prevent electron transitions to improve energy conversion efficiency, and to prevent scattering of light due to the rough surface of the first substrate 110, and as a component of the blocking layer 130. It is desirable to select and use components that have sufficient blocking force to block the electron transition between the substrate 110 and the electrolyte 30 and do not affect the performance of the dye-sensitized solar cell.

The porous membrane 140 is formed on the blocking layer 130, absorbs sunlight, serves to catalyze (oxidation-reduction reaction) and electrical conduction, and the metal included in the porous membrane 140 Oxide nanoparticles are titanium (Ti) oxide or zirconium (Zr) oxide, the photosensitive dye for absorbing sunlight is adsorbed on the surface of the porous membrane 140, the ruthenium (Ru) or ruthenium complex as the photosensitive dye It can be used to absorb visible light, including, and can be used to select and use a photosensitive dye commonly used in the art to which the present invention belongs is not particularly limited.

The electrolyte layer 150 is sealed by a partition (not shown) between the first substrate 110 and the second substrate 180, and is made of an iodine-based redox liquid electrolyte.

The conductive layer 160 is made of carbon black, a carbon material such as carbon nanotubes, or platinum.

FIG. 2 is a view showing an embodiment of an E-BEAM Evaporater device for forming a blocking layer of a dye-sensitized solar cell including a blocking layer according to the present invention.

As shown in FIG. 2, the E-BEAM Evaporator apparatus 200 includes a wafer carousel 210, a substrate 220, a crucible 230, and a vacuum pump. The valve 240 and the filament 250 are provided.

3 is a side view and a photograph of the surface of the FTO deposited using CVD in the dye-sensitized solar cell according to the prior art, Figure 4 is a two-beam evaporator (E) of the dye-sensitized solar cell comprising a blocking layer according to the present invention -BAM Evaporater) and the barrier layer deposited using the equipment is a picture of the side, Figure 5 is an AFM picture of Figures 3 and 4, Figure 6 is a view showing the comparative analysis data of the transmission of Figures 3 and 4, 7 is a view showing the difference in efficiency with or without the barrier layer according to the present invention.

Such a dye-sensitized solar cell including a blocking layer according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the first substrate 110 on which the first transparent conductive film 120 is formed is mounted on the wafer carousel 220 as the substrate 220, and the crucible 230 is shown in FIG. 2. The metal oxide deposited on the first substrate 110 is inserted into the groove on the (), and then the oxygen atmosphere is created through the vacuum pump valve 210, and then the wafer carousel mounted on the first substrate 110 ( At the same time as the rotation of the 220 and a very high voltage is applied to the metal oxide to the thickness of 500 ~ 5,000Å to the first substrate 110 by the heat generated by emitting hot electrons from the filament 250 and collides with the metal oxide The deposition is performed to form the blocking layer 130. The metal oxide is magnesium oxide (MgO).

Hereinafter, the dye-sensitized solar cell is formed by sealing the porous membrane 140, the electrolyte layer 150, the conductive layer 160, the second transparent conductive film 170, and the second substrate 180. Since a conventional process is performed in the technical field to which the invention belongs, a description thereof will be omitted.

Referring to the dye-sensitized solar cell formed with the blocking layer according to the present invention formed as described above are as follows.

First, sunlight passing through the first substrate 110 and the first transparent conductive film 120 from the outside is absorbed by the dye molecule layer adsorbed on the surface of the metal oxide particles of the porous film 140.

In this case, light may also be absorbed in the dye molecule layers respectively adsorbed on the upper surface of the blocking layer 130. Each dye molecule of the dye molecule layer that absorbs light is excited to inject electrons into the conduction band of the porous membrane 140. Electrons injected into the porous membrane 140 are transferred to the blocking layer 130 and the first transparent conductive layer 120 through an interparticle interface in the porous membrane 140, and are electrically connected to each other through an external wire (not shown). After the operation is moved to the second transparent conductive film 170. The second transparent conductive film electrons reach 170 through the conductive layer 160, the oxidation-reduction action of the iodine-based electrolyte in the electrolyte layer ^{(150) (3I - → I3} - + 2e -) in the porous by Electrons are injected into the film 140. Each dye molecule in the dye molecule layer oxidized as a result of electron transition in the first transparent conductive film 120 is reduced again by receiving electrons provided by the redox action in the electrolyte layer 150 and oxidized iodine ions (I3 ^-) is the second is reduced again by the electron reaching the transparent conductive film 170 is completed the operation of the dye-sensitized solar cell. In this process, since the blocking layer 130 is formed between the first substrate 110 and the porous film 140 in the first transparent conductive film 120, the porous film 140 may be formed. The blocking layer 130 prevents the electrolyte solution of the electrolyte layer 150 flowing into the region adjacent to the first substrate 110 from contacting the first substrate 110 through the pores. As the electron loss on the surface of the first substrate 110 is blocked, the energy conversion efficiency may be improved.

Hereinafter, preferred embodiments of the present invention will be described. Herein, the following examples are merely illustrated to aid the understanding of the present invention, but the contents of the present invention are not limited by the following examples.

(Example)

In order to form a blocking layer of a dye-sensitized solar cell, a magnesium oxide (MgO) thin film is coated on a glass substrate with an MgO thin film using an e-beam evaporator. It is deposited in the range of 500 kHz to 5000 kHz on (1000 Å to 6000 Å). The substrate temperature is 300 ° C. to realize the crystalline thin film, the base vacuum is about 3 × 10 ^-6 Torr, and the working pressure is 1,6 × 10 ^-4 Torr )to be. The substrate is fixed at a temperature of 300 ° C. while being rotated, the deposition rate is in the range of 5 s / sec, and the atmosphere is an oxygen partial pressure.

Experimental conditions as described above are as follows.

Backgroundpressure: 3 * 10 ^-6 Torr

Operating pressure: 1.6 * 10 ^-4 Torr

MgSource: 99.99%

MgsourceDepositionrate: 0.5Å / sec

Oxygengasratio: 2sccm

Substratetemperature: 300 ℃

k-CellImpingingAngle: 35 °

Coolingcondition: Water

Ionbeampowersupplycondition Plasmadischargecurrent: 200㎃ ~ 1,000㎃

In general, in the case of the oxide film, not only the internal crystallinity and internal structure of the thin film but also the transmittance and efficiency are influenced by the characteristics of the surface of the magnesium oxide (MgO) thin film, which is a blocking layer. The conventional FTO thin film is deposited by the CVD method, and as shown in Fig. 3, adversely affect the surface roughness. Therefore, by depositing a magnesium oxide (MgO) thin film on a transparent conductive oxide (TCO) substrate, as shown in Figure 4, it contributes to the surface roughness control and the improvement of transmittance. In the present invention, the characteristics of the magnesium oxide (MgO) thin film, which is a blocking layer, by deposition by an e-beam evaporator device is analyzed through AFM and SEM.

As shown in Fig. 5, when looking at the FTO surface photograph and the side photograph, the surface roughness seems to be quite bad. This is due to the diffuse reflection of the surface to reduce the transmittance of light seems to be the cause of the decrease in efficiency. According to the present invention, the photographs of the surface and the side surface of the thin film coated with magnesium oxide (MgO) as a blocking layer according to the present invention showed that the surface roughness was significantly controlled and the improvement of the transmittance was shown. The reason for this is that the grain size of the FTO substrate without the use of the e-beam evaporator equipment is not uniform, but the magnesium oxide is a blocking layer using the e-beam evaporator equipment. The (MgO) thin film has a larger grain size and has a circular shape.

In order to examine the characteristics of the blocking layer of the dye-sensitized solar cell using the magnesium oxide (MgO) thin film deposited by the e-beam evaporator, the emission luminance and The optical transmittance is measured, as shown in FIG.

The optical transmittance was measured by u-visible, and the magnesium oxide (MgO) thin film, which is a barrier layer, improved the transmittance of the pure FTO thin film. This is because scattering of light is suppressed by surface roughness control, and it seems that the transmittance is improved due to the growth of grain size.

In addition, in order to confirm whether the blocking-layer (MgO) thin film of the dye-sensitized solar cell is the cause of the improvement of the efficiency, the luminance value was measured by using the (BM-7) luminance meter, The values were compared by data.

The comparison value is measured by comparing the values of Raw glass, Raw + ITO, ITO + MgO, as shown in Table 1 below.

Configuration Thickness Luminance value Raw glass 1.629 Raw + ITO 1,000 Å (ITO) 1.618 Raw + ITO + MgO (1,500 Å) 1,000 Å (ITO) + 1,500 Å (MgO) 1.686 Raw + ITO + MgO (2,500 Å) 1,000 Å (ITO) + 2,500 Å (MgO) 1.656

As a result of measuring the brightness, the coating of magnesium oxide (MgO) as a blocking layer and the uncoated thin film were different as shown in Table 2 below. This can be seen that the luminance value increases with the thickness of the area according to the length of the magnesium oxide (MgO) bridge (blocking layer). Due to this cause, the efficiency of dye-sensitized solar cells including a blocking layer can be expected.

division Jsc (㎃ / cm) Voc (V) Fillfactor (%) Efficiency (η%) 1. Layer without barrier layer 8.69 0.516 54.5 3.56 2. Layer with blocking layer 9.93 0.619 69.7 5.52

A solar cell system using a magnesium oxide (MgO) thin film, which is a blocking layer structured with such a blocking network, improves the efficiency and solar optoelectronic efficiency at the same oxide thickness as the cell system sintered with conventional titanium dioxide. Can be.

In addition, as a result of comparative test experiments showing the difference between a film having a blocking layer and a film having a blocking layer, as shown in FIG. I can see high

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims and their equivalents.

110: first substrate 120: first transparent conductive film
130: blocking layer 140: porous membrane
150: electrolyte layer 160: conductive layer
170: second transparent conductive film 180: second substrate
200: E-BEAM Evaporater
210: wafer carousel 220: substrate
230: crucible 240: vacuum pump valve
250 filament

Claims

A first substrate 110 and a second substrate 180 formed of glass or plastic;
A first transparent conductive film 120 and a second transparent conductive film 170 formed of ITO or FTO on the first substrate 110 and the second substrate 180;
A blocking layer 130 formed by depositing magnesium oxide (MgO) on the first transparent conductive film 120 with an e-beam evaporator to a thickness of 500 kV to 5,000 kV and crystallizing it;
A porous film 140 formed of titanium (Ti) oxide or zirconium (Zr) oxide on the blocking layer 130;
A conductive layer 160 formed of any one material of carbon black, carbon nanotubes, or platinum on the second transparent conductive film 170; And
And an electrolyte layer 150 sealed between the first substrate 110 and the second substrate 180 by a partition and made of an iodine-based redox liquid electrolyte.
The e-beam evaporator is a dye-sensitized solar cell comprising a blocking layer, characterized in that the crystallization after depositing magnesium oxide on the first transparent conductive film 120 under the following conditions .

Backgroundpressure: 3 * 10 ^-6 Torr
Operating pressure: 1.6 * 10 ^-4 Torr
MgSource: 99.99%
MgsourceDepositionrate: 0.5Å / sec
Oxygengasratio: 2sccm
Substratetemperature: 300 ℃
k-CellImpingingAngle: 35 °
Coolingcondition: Water
Ionbeampowersupplycondition Plasmadischargecurrent: 200㎃ ~ 1,000㎃

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