JP2011040435A - Method for manufacturing photoelectric transducer material, and method for manufacturing organic solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a photoelectric transducer material excellent in light collection ability and having a high energy conversion efficiency, to provide an organic solar cell using the photoelectric transducer material, and to provide a method for manufacturing the organic solar cell. <P>SOLUTION: A porphyrin-fullerene coupled body is formed at first by coupling a fullerene with a compound having a porphyrin skeleton, a poor solvent is injected into an organic solvent dissolved with the porphyrin-fullerene coupled body and a soluble single layer carbon nanotube, to form the photoelectric transducer material coupled cluster-likely with the large number of the porphyrin-fullerene coupled bodies and the single layer carbon nanotubes. Then, the photoelectric transducer material is deposited on an optical transparent electrode mounted with a metal oxide, by an electrophoretic electro-deposition method, and an integration structure integrated with the photoelectric transducer material on the metal oxide is formed thereby, to manufacture the solar cell. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a photoelectric conversion element material and a method for producing an organic solar cell.

As global warming, environmental pollution, and energy problems become more serious, solar cells are attracting attention as environmentally friendly electrical energy sources. At present, inorganic semiconductors typified by amorphous silicon are widely used as semiconductor materials for photovoltaic elements of solar cells. However, inorganic solar cells manufactured using inorganic semiconductors are expensive and have not been widely used in general households. The high cost factor is mainly in the process of manufacturing a semiconductor thin film under vacuum and high temperature.
In contrast, organic solar cells using organic semiconductors and organic dyes such as conjugated polymers and organic crystals are easy to mass-produce their raw materials, and are easy to reduce the thickness and area. Therefore, practical application is being studied.

  Among such organic solar cells, there is a dye-sensitized solar cell (Gretzel cell) that is considered to be close to practical use at present (Patent Document 1). However, the Grezel cell is a practical bottleneck because the electrolyte is a solution and its durability is low.

  Therefore, an organic solar cell using a bulk heterojunction, which has a new concept different from that of the Gretzel cell, has recently attracted attention. Here, the bulk heterojunction means a state in which the semiconductor interface (depletion layer) is not two-dimensional like a normal heterojunction but spreads three-dimensionally inside the film.

  Salichifuchi, Heger et al. Have produced organic solar cells using bulk heterojunctions from thin films obtained by mixing conjugated polymers that can be regarded as p-type semiconductors and n-type semiconductors and fullerene derivatives. References 1, 2). In an organic solar cell using a bulk heterojunction, unlike an organic solar cell based on a normal heterojunction, a depletion layer is formed in the entire region inside the mixed thin film, so that charge separation occurs very efficiently.

  However, in spite of this very high-efficiency charge separation, in fact, the energy conversion efficiency of this type of solar cell is very low compared to inorganic ones, which is about several percent. It has only been obtained. This is considered to be caused by the fact that in the conventional method using the bulk heterojunction, even if charge separation occurs, electrons and holes are immediately recombined. For this reason, it is possible to prevent recombination of electrons and holes, and to achieve high energy even in organic solar cells using bulk heterojunctions if the transport of electrons and holes separated by charge is performed efficiently. It is estimated that conversion efficiency can be obtained.

  Accordingly, the present inventor forms a composite cluster composed of single-walled carbon nanotubes and fullerenes, and constructs a photoelectric conversion system using the composite cluster, thereby preventing recombination of electrons and holes, and efficiently. It has been found that stable charge transport is possible (Non-patent Document 3).

  Single-walled carbon nanotubes (SWNTs) are known as highly efficient charge transport materials, and are expected to be applied to organic photoelectric conversion elements (organic solar cells, photosensors, etc.) together with fullerenes. Yes. Since single-walled carbon nanotubes are poorly soluble in both aqueous and organic solvents due to π-π interaction, the present inventors have solubilized single-walled carbon nanotubes by chemical modification. Single-walled carbon nanotubes (functionalized-SWNT, f-SWNT) were combined with fullerenes in a mixed solvent and deposited on a metal tin electrode. When the film structure of the obtained modified electrode was observed using a scanning electron microscope, it was revealed that fullerene molecules were densely arranged on the side wall of the solubilized single-walled carbon nanotube. It was considered that such a characteristic film structure enabled efficient charge transport and markedly improved photocurrent generation efficiency.

International Publication No. 94/05045 Pamphlet

"Science", 1995, Volume 270, pp.1789-1791 "Advanced Functional Materials", 2003, Vol. 13, No. 1, pp.85-88 “Chemistry-A European Journal”, 2008, Volume 14, pp. 4875-4885

  By the way, although the single-walled carbon nanotube is known as a photoelectric conversion element material having an excellent charge transport capability, it has been required to be improved for use as an organic solar cell material because of its low light collecting ability.

  The problem to be solved by the present invention is a method for producing a photoelectric conversion element material having excellent light collection ability and high energy conversion efficiency, an organic solar cell using the photoelectric conversion element material, and production of the organic solar cell Is to provide a method.

The manufacturing method of the photoelectric conversion element material which is the first aspect of the present invention made to solve the above problems is as follows.
a) forming a porphyrin-fullerene conjugate by bonding fullerenes to a compound having a porphyrin skeleton;
b) dissolving the porphyrin-fullerene conjugate in an organic solvent;
c) a step of forming a photoelectric conversion element material in which a number of the porphyrin-fullerene conjugates are connected in a cluster by injecting a poor solvent into the organic solvent in which the porphyrin-fullerene conjugate is dissolved. It is characterized by.

Moreover, the manufacturing method of the photoelectric conversion element material which is the 2nd aspect of this invention is the following.
a) forming a porphyrin-fullerene conjugate by bonding fullerenes to a compound having a porphyrin skeleton;
b) dissolving the porphyrin-fullerene conjugate and the soluble single-walled carbon nanotube in an organic solvent;
c) By injecting a poor solvent into an organic solvent in which the porphyrin-fullerene conjugate and the soluble single-walled carbon nanotube are dissolved, the porphyrin-fullerene conjugate and the single-walled carbon nanotube are joined in a cluster. And a step of forming a photoelectric conversion element material.

  Moreover, the manufacturing method of the organic solar cell which is the 3rd aspect of this invention is the light by which the metal oxide was mounted in the photoelectric conversion element material manufactured by the method of the said 1st aspect or the 2nd aspect. It is characterized by being interposed between the transparent electrode and the counter electrode.

  Furthermore, the method for producing an organic solar cell according to the fourth aspect of the present invention is a method in which a photoelectric conversion element material produced by the method of the first aspect or the second aspect is oxidized by electrophoretic electrodeposition. An integrated structure in which the photoelectric conversion element material is integrated on the metal oxide is formed by depositing on an optically transparent electrode on which an object is placed.

  Fig. 2 shows how a cluster-like photoelectric conversion element material and an integrated structure are formed from a porphyrin-fullerene conjugate obtained by bonding fullerenes to a compound having a porphyrin skeleton (hereinafter also referred to as porphyrins). 1 will be used for explanation. 1A shows a process of manufacturing an integrated structure of a photoelectric conversion element material and an organic solar cell by the method of the first aspect, and FIG. 1B shows a process of manufacturing the photoelectric conversion element material and the organic solar cell integrated structure by the method of the second aspect. 3 shows a process for manufacturing an integrated structure of an organic solar cell.

  In both the first and second embodiments, first, the porphyrin-fullerene linkage is obtained by reacting the side chain portion of the porphyrins with the fullerenes in the presence of a reducing agent, etc., and linking the porphyrins with the fullerenes. Form the body.

As porphyrins, general porphyrins can be used as appropriate, and the structure thereof is not limited, but in consideration of stability, the general formula (1)
It is preferable to use what is represented by these. In the formula, R _{1 to} R ₂₀ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, an alkenyl group, a cycloalkyl group or an alkoxy group, a hydroxyl group, a halogen atom, a nitro group, an amino group, Represents a sulfonyl group, a cyano group, a silyl group, a phosphonic acid group, a diazo group, a mercapto group, etc. In particular, as R _{1 to} R ₂₀ , a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group, or a cycloalkyl group Alternatively, it is preferable to use an alkoxy group.

  The alkyl group, alkenyl group or cycloalkyl group having 1 to 15 carbon atoms is such that the hydrogen atom is a halogen group (F, Cl, Br, I), hydroxyl group, nitro group, amino group, sulfonyl group, cyano group, silyl group. , A phosphonic acid group, a diazo group, a mercapto group and the like. Further, an ether, ester, or ketone structure may be formed by interposing one or more —O—, —COO—, or —CO— between C—C single bonds at arbitrary positions.

Of the side chain parts R _{1 to} R ₂₀ of the porphyrins, the side chain part to which fullerenes are bonded preferably has a flexible structure, in particular, an alkyl group having 1 to 6 carbon atoms, an alkoxy group, or these It is desirable to select from these derivatives. FIG. 2 shows a synthesis example of a porphyrin-fullerene conjugate. The porphyrin-fullerene conjugate obtained by the synthesis method shown in FIG. 2 has a flexible structure because there is no double bond or triple bond at the junction between the porphyrins and fullerenes.

  In the first embodiment, a large number of porphyrin-fullerene conjugates are clustered by rapidly injecting a poor solvent (eg acetonitrile) into an organic solvent (eg o-dichlorobenzene) solution in which many porphyrin-fullerene conjugates are dissolved. A photoelectric conversion element material (also referred to as a composite cluster) bonded to is formed.

  In the second embodiment, by rapidly injecting a poor solvent (eg, acetonitrile) into an organic solvent (eg, o-dichlorobenzene) solution in which a large number of porphyrin-fullerene conjugates and a large number of soluble single-walled carbon nanotubes are dissolved, A photoelectric conversion element material (composite cluster) in which a porphyrin-fullerene conjugate and a large number of single-walled carbon nanotubes are bonded in a cluster form is formed.

  Single-walled carbon nanotubes are sparingly soluble in both aqueous and organic solvents, but single-walled carbon nanotubes are treated with an acid so that both ends of the single-walled carbon nanotubes are open ends, and the open ends thereof are opened. It becomes soluble by introducing a long-chain alkyl group having 4 or more carbon atoms. FIG. 3 shows an example of a process for forming soluble single-walled carbon nanotubes.

The composite cluster which is the photoelectric conversion element material formed in this way is placed on a transparent conductive metal oxide such as SnO ₂ and TiO ₂ placed on a transparent electrode such as an FTO (fluorine-tin oxide) electrode. By depositing by electrophoretic electrodeposition, an integrated structure in which the composite clusters are integrated is formed. In this integrated structure, it is considered that the composite clusters are aggregated to form a network. In particular, when porphyrins and fullerenes are bonded via a side chain portion having a flexible structure, the composite cluster is easily accumulated on the transparent conductive metal oxide, and a regular network can be constructed.

Porphyrins are not only excellent electron donors but also good light collecting molecules. For this reason, in an integrated structure, charge separation occurs easily by light irradiation, electron transfer from porphyrins to fullerenes, transport of holes by a network formed by porphyrins, and electron transfer by a network formed by fullerenes. Each transport will be carried out efficiently.
Further, in an organic solar cell using a composite cluster including single-walled carbon nanotubes, single-walled carbon nanotubes exist in the integrated structure so as to connect the clusters composed of porphyrin-fullerene linkages. For this reason, the single-walled carbon nanotube functions as an electron transfer path and a charge transport path, and more efficiently transports electrons.

  According to the present invention, porphyrins having excellent light collection ability are linked to fullerenes to form porphyrin-fullerene linkages, and a large number of porphyrin-fullerene linkages are linked in a cluster to produce a photoelectric conversion element material. In addition, a solar cell having high energy conversion efficiency can be obtained by combining the photoelectric conversion element material and an electrode. Moreover, in the photoelectric conversion element material containing a single-walled carbon nanotube, charge transport is performed more efficiently, so that the energy conversion efficiency can be further improved.

The figure (a) explaining the formation process of the organic solar cell using the photoelectric conversion element material of the 1st aspect of this invention, The formation process of the organic solar cell using the photoelectric conversion element material of a 2nd aspect is demonstrated. Figure (b). The figure which shows an example of the synthetic | combination path | route of a 2nd structure. The figure which shows an example of the synthetic | combination path | route of a soluble single wall carbon nanotube. Scanning electron microscope images ((a) to (c) of clusters ((f-SWNT + H ₂ PC ₆₀ ) _m , (H ₂ PC ₆₀ ) _m , (f-SWNT) _m ) according to one embodiment of the present invention. )). An absorption spectrum (a) before acetonitrile injection and an absorption spectrum (b) after acetonitrile injection are shown. (f-SWNT + H ₂ PC ₆₀ ) A diagram for explaining a process of integrating _m on the FTO / SnO ₂ electrode. Scanning electron microscope images of (f-SWNT + H ₂ PC ₆₀ ) _m , (H ₂ PC ₆₀ ) _m , and (f-SWNT) _m integrated on the FTO / SnO ₂ electrode ((a) to (c) ). Scanning electron micrographs of (f-SWNT + H ₂ PC ₆₀ ) _m integrated on the FTO / SnO ₂ electrode when the electrophoretic deposition time was 10 seconds and 120 seconds ((a), (b) ). Absorption spectra of (f-SWNT + H ₂ PC ₆₀ ) _m , (H ₂ PC ₆₀ ) _m and (f-SWNT) _m integrated on the FTO / SnO ₂ electrode are shown. A configuration diagram (a) of the photocurrent measurement system and a configuration diagram (b) of a cell according to the system are shown. Wavelength of IPCE value of the system using FTO / SnO ₂ / (f-SWNT + H ₂ PC ₆₀ ) _m , FTO / SnO ₂ / (f-SWNT) _m , FTO / SnO ₂ / (H ₂ PC ₆₀ ) _m A graph showing dependencies. The figure for demonstrating the charge transport (a) in the photoelectric conversion element material which a porphyrin-fullerene coupling body connects in a cluster form, and the charge transport (b) in an integrated structure. The figure which shows the structure (a) of porphyrin-fullerene conjugate (H ₂ PC ₆₀ ), the structure (b) of porphyrin (TBPP), and their fluorescence decay curves (c)

Hereinafter, specific examples of the present invention will be described.
[Example]
(Production of photoelectric conversion element material and performance evaluation)
Chemical formula (2)
To the porphyrins represented by the formula (compound having a porphyrin skeleton), formaldehyde (HCHO) and fullerene (C ₆₀ ) are added and refluxed with toluene to obtain a chemical formula (3)
A porphyrin-fullerene conjugate (hereinafter referred to as “H ₂ PC ₆₀ ”) represented by

Next, H ₂ PC ₆₀ (0.55 mM) and soluble single-walled carbon nanotubes (hereinafter also referred to as “f-SWNT (functionalized-single-walled carbon nanotube)”) (0.044gl ⁻¹ ) dissolved By rapidly injecting acetonitrile (1.14 ml) into a chlorobenzene solution (0.46 ml), a composite cluster in which H ₂ PC ₆₀ and f-SWNT are linked in a cluster (hereinafter referred to as “(f-SWNT + H ₂ PC ₆₀ ) _m ”).
In addition, by the same method, a composite cluster in which H ₂ PC ₆₀ is connected in a cluster (hereinafter referred to as “(H ₂ PC ₆₀ ) _m ”), and a single cluster in which f-SWNT is connected in a cluster (hereinafter referred to as “ (f-SWNT) _m ”).

The (f-SWNT + H ₂ PC ₆₀ ) _m , (H ₂ PC ₆₀ ) _m , and (f-SWNT) _m obtained as described above were observed using a scanning electron microscope. The result is shown in FIG. As is clear from FIG. 4 (a), in (f-SWNT + H ₂ PC ₆₀ ) _m , the surface of an aggregate of H ₂ PC ₆₀ (elongated rhombus-shaped lump, corresponding to (H ₂ PC ₆₀ ) _m ) It was revealed that a large number of f-SWNTs were attached to the surface.

Moreover, the result of having measured the absorption spectrum before and behind inject | pouring acetonitrile into an o-dichlorobenzene solution is shown in FIG. Before injecting acetonitrile, the absorption spectrum before f-SWNT + H ₂ PC ₆₀ , H ₂ PC ₆₀ , and f-SWNT form a cluster.After injecting acetonitrile, (f-SWNT + H ₂ PC ₆₀ ) _m , (H ₂ PC ₆₀ ) _m , and (f-SWNT) _m absorption spectra. In FIG. 5 (a), the broken line indicates the sum of the absorption spectra of H ₂ PC ₆₀ and f-SWNT, and in FIG. 5 (b), the broken line indicates (H ₂ PC ₆₀ ) _m and (f-SWNT). _The sum of the absorption spectra of _m is shown respectively.

As is clear from FIG. 5, the absorption spectra of (f-SWNT + H ₂ PC ₆₀ ) _m and (H ₂ PC ₆₀ ) _m are broader than the absorption spectrum before cluster formation. In particular, the absorption band called the Q band near 500-700 nm found in porphyrins was split into four before cluster formation, but it was not split by cluster formation. On the other hand, a sharp absorption band called a Soret band near 400-500 nm found in porphyrin shifted to the long wavelength side (red shift) due to cluster formation.
In addition, no absorption spectrum was observed for f-SWNT before and after cluster formation, indicating that the light collection ability was low.

(Production of solar cells and performance evaluation)
Three types of clusters ((f-SWNT + H ₂ PC ₆₀ ) _m , (H ₂ PC ₆₀ ) _m , (f-SWNT) _m ), SnO ₂ transparent conductive metal on fluorine-tin oxide (FTO) electrode It was deposited on the FTO / SnO ₂ electrode on which the oxide was placed by electrophoretic deposition (DC 200 V, 120 seconds), and each cluster was integrated on the FTO / SnO ₂ electrode (see FIG. 6). Integrated structure (FTO / SnO ₂ / (f-SWNT + H ₂ PC ₆₀ ) _m , FTO / SnO ₂ / (H ₂ PC ₆₀ ) _m , FTO / SnO ₂ / (f-SWNT) the) _m) to) the results of observation with the scanning electron microscope are shown in Figure 7. As apparent from FIG. 7 (c), in FTO / SnO ₂ / (f-SWNT + H ₂ PC ₆₀ ) _m , (H ₂ PC ₆₀ ) _m (elongated rhombus-shaped lump) accumulates and accumulates. It became clear that many f-SWNTs were attached to the surface of (H ₂ PC ₆₀ ) _m constituting the structure. It was also clarified that a large number of f-SWNTs were attached across (H ₂ PC ₆₀ ) _m .

The adhesion state of f-SWNT near the bottom of the integrated structure (FTO / SnO ₂ / (f-SWNT + H ₂ PC ₆₀ ) _m ) (side closer to the electrode) For comparison, the integrated structure was observed with a scanning electron microscope when the electrophoretic deposition time was 10 seconds. The result is shown in FIG. FIG. 8 (a) shows an integrated structure when the electrophoretic electrodeposition time is 10 seconds, and FIG. 8 (b) shows a scanning electron microscope image of the integrated structure when the electrophoretic electrodeposition time is 120 seconds. FIG. 8 (b) shows the same scanning electron microscope image as FIG. 7 (c).

Since the amount of (f-SWNT + H ₂ PC ₆₀ ) _m accumulated when the electrophoretic electrodeposition time is 10 seconds is smaller than when the electrophoretic electrodeposition time is 120 seconds, FIG. FTO / SnO ₂ / (f-SWNT + H ₂ PC ₆₀ ) _m ) near the bottom, Figure 8 (b) shows the surface near (FTO / SnO ₂ / (f-SWNT + H ₂ PC ₆₀ ) _m ) It can be regarded as representing.
From comparison between (a) and (b) of FIG. 8, it is clear that a large number of f-SWNTs are attached to the surface of (H ₂ PC ₆₀ ) _m near the bottom as well as near the surface.

In addition, absorption spectra of FTO / SnO ₂ / (f-SWNT + H ₂ PC ₆₀ ) _m , FTO / SnO ₂ / (H ₂ PC ₆₀ ) _m , FTO / SnO ₂ / (f-SWNT) _m were measured ( (See FIG. 9). As a result, the absorption spectrum of FTO / SnO ₂ / (f-SWNT + H ₂ PC ₆₀ ) _m has a greater absorbance than the absorption spectrum of FTO / SnO ₂ / (H ₂ PC ₆₀ ) _{m in} a wide wavelength range. It was high.

  In order to measure the capability of the device fabricated as described above, a simulated solar cell was fabricated and a photoelectrochemical measurement was performed.

As shown in FIG. 10, the photoelectrochemical measurement is provided with a standard triode array composed of a working electrode, a Pt wire counter electrode, and an Ag / AgNO ₃ reference electrode, and the Pt wire counter electrode has 170 mV (vs SCE (Saturated Calomel Electrode). )) Bias voltage was applied using a Pyrex (registered trademark) UV cell (5 mL) containing an acetonitrile solution containing 0.5 M LiI and 0.01 M I ₂ as the electrolyte (photocurrent measurement) ALS 630A electrochemical analyzer was used). Here, FTO / SnO formed on _{SnO 2 2 / (f-SWNT} + H 2 PC 60) m, FTO / SnO 2 / (H 2 PC 60) m, FTO / SnO 2 / (f-SWNT) m Excitation of the film was performed by irradiating a monochromatic light that passed through a monochromator (Ritsu MC-10N) from a 500 W xenon lamp (Ushio XB-50101AA-A) through a cutoff filter.

The photoelectric conversion efficiency (IPCE) was determined by IPCE (%) = 100 × 1240 × I / (W _in × λ). I is the photocurrent (Acm ^-2), W _in the incident light intensity (Wcm ^-2), λ represents the excitation wavelength (nm).

FIG. 11 shows a system using FTO / SnO ₂ / (f-SWNT + H ₂ PC ₆₀ ) _m , FTO / SnO ₂ / (f-SWNT) _m , FTO / SnO ₂ / (H ₂ PC ₆₀ ) _m It is the figure which showed the measurement result of IPCE. (A) to (c) in FIG. 11 show FTO / SnO ₂ / (f-SWNT + H ₂ PC ₆₀ ) _m , FTO / SnO ₂ / (f-SWNT) _m , FTO / SnO ₂ / (H ₂ PC ₆₀ ) The IPCE value of the system using _m , (d) shows the sum of the IPCE values of FTO / SnO ₂ / (f-SWNT) _m and FTO / SnO ₂ / (H ₂ PC ₆₀ ) _m ing.

As shown in FIG. 11, the IPCE value of the system using FTO / SnO ₂ / (f-SWNT + H ₂ PC ₆₀ ) _m is FTO / SnO ₂ / (f-SWNT) _m , FTO / SnO ₂ / ( Increased compared to both the IPCE value of the system using H ₂ PC ₆₀ ) _m and the combined IPCE value. In particular, it greatly increases at a wavelength of 440 nm, while the FCE / SnO ₂ / (H ₂ PC ₆₀ ) _m system has an IPCE value of about 11%, while FTO / SnO ₂ / (f-SWNT + H ₂ The IPCE value of the PC ₆₀ ) _m system was about 22%. Moreover, since the IPCE value of the combined FTO / SnO ₂ / (f-SWNT) _m and FTO / SnO ₂ / (H ₂ PC ₆₀ ) _m systems was about 12%, the porphyrin-fullerene conjugate and the single layer It clearly shows that the formation of composite clusters of carbon nanotubes is very effective in improving the photoelectrochemical properties.

Since the IPCE value of the conventional photoelectric conversion element material was 0.4%, the system using FTO / SnO ₂ / (H ₂ PC ₆₀ ) _m was also sufficiently effective for improving the photoelectrochemical characteristics. It was.

The reason why the IPCE value of the system using FTO / SnO ₂ / (f−SWNT + H ₂ PC ₆₀ ) _m has increased greatly will be described with reference to FIGS.
In a photoelectric conversion element material (composite cluster, (H ₂ PC ₆₀ ) _m ) in which porphyrin-fullerene conjugates are linked in a cluster, porphyrin-fullerene conjugates (H ₂ PC ₆₀ ) are arranged in an orderly manner (FIG. 12 ( see a)). As a result, in (H ₂ PC ₆₀ ) _m ), holes are transported efficiently by a network formed by porphyrins and electrons are transported by a network formed by fullerenes.
In an integrated structure formed by integrating composite clusters ((H ₂ PC ₆₀ ) _m ), single-walled carbon nanotube clusters ((f-SWNT) _m ) are attached across the composite clusters (FIG. 12 ( b)). For this reason, in addition to transport of charges (holes and electrons) in each composite cluster, electron transfer and charge transport between the composite clusters are efficiently performed by (f-SWNT) _m .

(C) of FIG. 13 shows the fluorescence decay curves of the porphyrin-fullerene conjugate (H ₂ PC ₆₀ ) and porphyrin (TBPP) shown in (a) and (b). As shown in FIG. 13, the fluorescence intensity of TBPP gradually attenuated after excitation, whereas the fluorescence intensity of H ₂ PC ₆₀ disappeared immediately after excitation. This indicates that the electrons and holes separated by charge upon excitation recombined immediately in TBPP, whereas in H ₂ PC ₆₀ , rapid electron transfer from porphyrin to fullerene was performed.

  Therefore, organic solar cells in which an integrated structure in which composite clusters composed of porphyrin-fullerene conjugates are integrated is formed on a light transparent electrode on which a metal oxide is placed has excellent light collection ability and energy conversion efficiency. Has been shown to improve.

Claims (14)

a) forming a porphyrin-fullerene conjugate by bonding fullerenes to a compound having a porphyrin skeleton;
b) dissolving the porphyrin-fullerene conjugate in an organic solvent;
c) forming a photoelectric conversion element material in which a number of the porphyrin-fullerene conjugates are connected in a cluster by injecting a poor solvent into the organic solvent in which the porphyrin-fullerene conjugate is dissolved. The manufacturing method of the photoelectric conversion element material characterized by these. a) forming a porphyrin-fullerene conjugate by bonding fullerenes to a compound having a porphyrin skeleton;
b) dissolving the porphyrin-fullerene conjugate and the soluble single-walled carbon nanotube in an organic solvent;
c) By injecting a poor solvent into an organic solvent in which the porphyrin-fullerene conjugate and the soluble single-walled carbon nanotube are dissolved, the porphyrin-fullerene conjugate and the single-walled carbon nanotube are joined in a cluster. And a step of forming a photoelectric conversion element material. A method for producing a photoelectric conversion element material.   The soluble single-walled carbon nanotube is obtained by introducing a long-chain alkyl group having 4 or more carbon atoms into open ends on both sides formed by acid treatment of the single-walled carbon nanotube. Item 3. A method for producing a photoelectric conversion element material according to Item 1 or 2. The compound having a porphyrin skeleton has the general formula (1)
(Wherein R _{1 to} R ₂₀ are the same or different and each represents a hydrogen atom, an alkyl group or alkenyl group having 1 to 15 carbon atoms, a cycloalkyl group or an alkoxy group, a hydroxyl group, a halogen atom, a nitro group, an amino group, a sulfonyl group) A cyano group, a silyl group, a phosphonic acid group, a diazo group, and a mercapto group.) Of the photoelectric conversion element material according to any one of claims 1 to 3, Production method. Side chain portion porphyrin binds among the side chain R ₁ to R ₂₀ of the compound having a porphyrin skeleton, a photoelectric conversion device material according to claim 4, characterized in that it has a flexible structure Production method. Side chain portion porphyrin binds of the side chain portion R ₁ to R ₂₀ of a compound having a porphyrin skeleton, producing a photoelectric conversion device material according to claim 5, characterized in that an alkyl or alkoxy group Method. The porphyrin-fullerene conjugate has the chemical formula (3)
It has the structure represented by these. The manufacturing method of the photoelectric conversion element material in any one of Claims 1-6 characterized by the above-mentioned.   The method for producing a photoelectric conversion element material according to claim 1, wherein the organic solvent is o-dichlorobenzene and the poor solvent is acetonitrile.   The photoelectric conversion element material manufactured by the method in any one of Claims 1-8.   An organic solar cell comprising a photoelectric conversion element material produced by the method according to any one of claims 1 to 8 interposed between a light transparent electrode on which a metal oxide is placed and a counter electrode.   The organic solar cell according to claim 10, wherein the metal oxide is tin oxide or titanium oxide.   An organic solar element comprising a photoelectric conversion element material produced by the method according to claim 1 interposed between a transparent electrode on which a metal oxide is placed and a counter electrode. Battery manufacturing method.   The method for producing an organic solar cell according to claim 12, wherein the metal oxide is tin oxide or titanium oxide.   A photoelectric conversion element material produced by the method according to claim 1 is deposited on a light transparent electrode on which a metal oxide is placed by an electrophoretic electrodeposition method. The manufacturing method of the organic solar cell characterized by forming the integrated structure in which the said photoelectric conversion element material was integrated on the thing.