JP2004277736A - Conductive polymer, its producing method and organic solar cell using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive resin with enhanced conductivity and charge separation ability and good mechanical properties and light resistance, and to provide an organic solar cell superior in electronic properties by using the conductive resin with such excellent properties. <P>SOLUTION: This conductive polymer is a polymer with a sequence of thiophene rings, the side chain of which is coupled with a cyano-fullerene group or a methylated fullerene group in which a cyano group or a methyl group is coupled to a fullerene skeleton. The thiophene rings may be an oligomer of a 2-5 polymerization degree. An additive of one thiophene ring oligomer may be used. A hetero-junctional material composed of the conductive polymer and an electron donor layer is held between a transparent electrode and a counter electrode to provide the organic solar cell. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a conductive polymer material, a method for producing the same, and an organic solar cell using the same.

In recent years, global warming has become a concern, and the importance of renewable energy has been recognized in place of conventional fossil fuel-based energy. Research on photovoltaic power generation is being actively conducted as one of the leading natural energies.
BACKGROUND ART Conventionally, a solar cell using a light conversion element has been known as a solar power generation device. In an example of a solar cell currently in practical use, a photoelectric conversion element using a single crystal, polycrystal, or amorphous substance of silicon is used.
However, in these conventional photoelectric conversion elements, high-purity silicon is used as a raw material, the manufacturing process is complicated, the cost is extremely high, and there is a problem that it is difficult to increase the area of the element due to its manufacturing method. I do.

  On the other hand, a photoelectric conversion element using an organic substance has also been proposed, but a photoelectric conversion element using an organic substance is easy to manufacture and excellent in economical efficiency, but unlike inorganic substances such as silicon, The probability of dissociation of electron-hole pairs generated by light induction is low, and the number of carriers is low. In addition, it has a drawback that it is difficult to efficiently extract carriers due to low electric conductivity. In a conventional photoelectric conversion element using a conductive polymer as an organic substance, a method of dispersing iodine (I) in a thiophene ring polymer is used as an acceptor, but iodine must be uniformly dispersed. Since iodine has sublimability, it is difficult to uniformly disperse it. In addition, there is a drawback that when iodine has uneven concentration, the conductivity becomes unstable. In addition, there is a disadvantage that even after the conductive polymer is formed, the conductivity changes due to the sublimability of iodine.

By the way, fullerenes such as carbon clusters (C ₆₀ , C ₇₀ , C ₈₄ ) having a closed shell structure are recently generated by the arc discharge of graphite, the high-frequency plasma treatment of carbon black, and the like, and the physical properties derived from these unique structures Is being revealed. As a material for the light conversion element, fullerene, which is one of these carbon compounds, in addition to silicon, has been attracting attention.

Fullerene is a series of carbon compounds consisting of only carbon atoms, like diamond and graphite. Fullerene is spherical carbon Cn (n = 60, 70, 76, 78, 80, 82, etc.) in which an even number of 60 or more carbon atoms are bonded spherically to form a molecular assembly. Among others typical is a _{C 70} to _{C 60} and 70 of the carbon atoms 60. Among C ₆₀ fullerene has a polyhedral structure called truncated icosahedron that issued the pentagon cut off all the vertices of the regular icosahedron, as it were footballs its 60 vertices were all occupied by carbon atoms It has a molecular structure of the type. In contrast, C ₇₀ has a rugby ball type molecular structure.

Crystals C ₆₀ is _{C 60} molecules are arranged in a face-centered cubic structure, regarded as the semiconductor bandgap be about 1.6 eV. In a pure state, it has an electrical resistance of about 10 ¹⁴ Ω / cm. At 500 ° C., there is a vapor pressure of about 1 mmTorr, and a thin film can be deposited by sublimation. The fullerene molecules not limited to C ₆₀ said because it can easily vaporize in a vacuum or under reduced pressure, to be easily material to form a deposited film.

However, most fullerene molecules C ₆₀ or C ₇₀ or the like rich in mass production since a dipole moment is zero, the deposition film obtained therefrom does not work only van der Waals forces between the molecules, the intensity fragile It is. Therefore, when this deposited film is exposed to the air, oxygen and water molecules and the like easily diffuse into gaps between the fullerene molecules, and as a result, not only structural deterioration but also adversely affect the electronic properties thereof. Such fragility of the fullerene-deposited thin film becomes a problem in terms of device stability when fullerene is applied to manufacture of a thin-film electronic device. In addition, since a paramagnetic center is developed by oxygen molecules diffused between the fullerene molecules, there is a problem in terms of stability of thin film characteristics.

  In order to overcome such problems, in recent years, a method for producing a so-called fullerene polymer film in which fullerene molecules are polymerized has been proposed. A typical example thereof is a method for forming a fullerene polymer film by light induction. In this method, a fullerene vapor-deposited film formed in advance is irradiated with light after vapor deposition. However, due to volume shrinkage generated during polymerization, countless cracks are easily formed on the surface of the film, and there is a problem in strength. Moreover, it is extremely difficult to form a uniform thin film having a large area by this method. It is also known that fullerene polymer films can be formed by applying pressure or heat to the fullerene molecules or by colliding the fullerene molecules with each other. It is difficult to get.

  Attention has been paid to plasma polymerization and microwave polymerization as fullerene polymerization alternatives to these conventional methods. The fullerene polymer film obtained by such a method is a thin film formed by polymerization of fullerene molecules through an electronically excited state, and has a remarkably increased strength as compared with a fullerene vapor-deposited thin film, and is dense and flexible. Rich in nature. Since the electronic properties hardly change even in vacuum or air, it is considered that the dense thin film structure effectively suppresses the diffusion of oxygen molecules into the inside of the film. In fact, generation of multimers of fullerenes constituting a thin film by such a method can be known by time-of-flight mass spectrometry by a laser ablation method.

Meanwhile, the physical properties due to the unique structure of the fullerene is also being revealed, a conductive polymer when irradiated with light to conductive polymer and C ₆₀ mixture of fullerenes as one of its properties under light irradiation C It has been found that electron transfer to ₆₀ occurs.
For example, MEH-PPV (poly [2-methoxy, 5- (2'-ethyl - hexyloxy) - p - phenylene vinylene]) and the weight ratio of poly (3-octyl thiophene) and _{C 60} 1: light on 1 mixture As a result of the induced ESR measurement, two ESR signals having g values of approximately 2 and smaller than 2 are observed. g value is the 2 following signals are is confirmed that the signal of C ₆₀ monovalent anions, that are occurring electron transfer to C ₆₀ of a conductive polymer under illumination from this it is suggested (For example, see Non-Patent Document 1).

As an application of the physical properties which the C ₆₀ has the study of the photoelectric conversion element is performed. For example, the MEH-PPV on the ITO film electrode to form a film to a thickness of 100nm by spin coating, a _{C 60} layer thick 100nm on the laminate by vacuum evaporation, further photoelectric conversion laminated by vacuum deposition of Au The device is being created. The argon ion laser is used as the irradiation light source, wavelength 514.5 nm, a negative potential with light of the irradiation light intensity of about 1 mW / cm ² positive potential to the irradiated ITO film electrode as a forward bias of an ITO film electrode _side, the _{C 60-layer} side , A short circuit current of 2.08 μA / cm ² , an open circuit voltage of 0.44 V, and a conversion efficiency of 0.02% are obtained (for example, see Non-Patent Document 2).

Based on these findings, heterojunction type organic solar cells have been proposed. As an example, there is a heterojunction solar cell in which a layer containing an organic electron donor and fullerene and an n-type semiconductor layer are joined on a transparent conductive substrate as an electrode reinforcing material (for example, see Patent Document 1). 1). In this solar cell, as an organic electron donor, for example, poly (3-alkylthiophene) obtained by subjecting polythiophene to alkyl group substitution, polyparaphenylene vinylene derivative obtained by subjecting polyparaphenylene vinylene to alkoxyl group substitution, and polythienylene vinylene are used. A conductive polymer made of a substance soluble in an organic solvent such as toluene, such as an alkoxyl-substituted polyparathienylenevinylene derivative, or an organic π such as tetrathiafulvalene (TTF) or tetraselenatetracene (TST). Examples thereof include a low molecular weight organic conductor that forms a conjugated molecular complex. A thin film obtained by spin coating a solution obtained by mixing and dissolving the electron donor and fullerene in a solvent is used.
Examples of the n-type semiconductor include a polythiophene derivative doped with a donor such as sodium, a polyparaphenylene vinylene derivative, and silicon doped with phosphorus or the like.

In addition, as an active layer, MDMO-PPV (poly [2-methyl, 5- (3,7 dimethyloctyloxy)]-para-phenylene vinylene) and PCBM ([6,6] -phenyl C61 butyric acid methyl ester) were used. A film spin-coated with a 1: 4 (weight ratio) mixture was used, and PEDOT (poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonate)) was used as an organic electron donor. A heterojunction solar cell has been reported (for example, see Non-Patent Document 3).
Each of these solar cells uses a thin film obtained by spin-coating a mixture of an organic electron donor and fullerene dissolved in a solvent.
When an organic electron donor such as a conductive polymer mixed with fullerene is used for the electrode, in addition to an increase in the probability of dissociation of a photoinduced electron-hole pair due to band bending formed in the electron donor layer, the It is said that the charge transfer to fullerene further suppresses carrier loss, that is, increases carrier generation.
L. Smilowitz et al., Physical Review B47, 13385 (1993) NSSariciftci et al., Appl.Phys.Lett., Vol.62, No.6, p.585-p.587, 8 Feb.1993 SEShaheen et al., `` Appl.Phys.Lett. '', Vol.78, No.6, p.841-p.843, 5 Feb. 2001 JP-A-8-222281 (page 5, FIG. 4)

However, in conventional conductive polymers mixed with fullerenes, it is difficult to control the thickness, and it is not possible to obtain sufficient mechanical strength and light resistance for use as an element, and also in terms of photoelectric conversion characteristics such as conversion efficiency. No satisfactory performance has been obtained. Accordingly, no practical light conversion element has been obtained.
An object of the present invention is to improve conductivity and charge separation ability, and to obtain a conductive polymer having excellent mechanical strength and light resistance. Another object of the present invention is to obtain an organic solar cell having excellent electronic properties by using a conductive polymer having such excellent characteristics.

In order to solve the above-mentioned problems, one of the conductive polymers of the present invention is a high-molecular polymer in which thiophene rings are linked, and a conductive polymer in which a cyanated fullerene group is linked to a side chain. Combined.
The other is a high molecular polymer in which thiophene rings are connected, and is a conductive polymer in which a methylated fullerene group is connected to a side chain.
In the conductive polymer of the present invention, a π-conjugated thiophene ring having a high donor property is used for a main chain, and a cyanated fullerene group or a methylated fullerene group having a high electron accepting property is used for a side chain. ing. Therefore, a cyanated fullerene group or a methylated fullerene group is covalently bonded at a predetermined position in the molecule, and the electron of the thiophene ring in the main chain is more strongly linked to the cyanated fullerene or methylated fullerene because of its high electron accepting property. Will always be pulled. Accordingly, the thiophene ring in the main chain has a stronger donor property. As a result, the thiophene ring becomes a polymer monomer having high conductivity, and charge separation by light easily occurs.

In the conductive polymer of the present invention, the thiophene ring may be a thiophene oligomer. In this case, the degree of polymerization of the thiophene oligomer is preferably from 2 to 5, and for example, an oligomer having a degree of polymerization of 3 is preferably used.
Further, the conductive polymer of the present invention may be a monoadduct of a thiophene oligomer or a diadduct of a thiophene oligomer.
Each of the conductive polymers having these molecular structures has high conductivity and is a conductive polymer having a property that charge separation by light easily occurs.

More specifically, the conductive polymer of the present invention is a polymer of a monomer in which a cyanated fullerene group or a methylated fullerene group is triple-bonded to a side chain of a thiophene oligomer having a degree of polymerization of 3. A conductive polymer consisting of
By using a polymer having such a structure, a conductive polymer having high conductivity and having a property of easily causing charge separation by light can be obtained.

The method for producing a conductive polymer of the present invention comprises the steps of coupling a thiophene derivative with 2,3,5-tribromothiophene to synthesize a bromota-thiophene derivative, and coupling trimethylsilylacetylene to the bromota-thiophene derivative. To synthesize an acetylene derivative, deprotection of the acetylene derivative with tetrabutylammonium fluoride, and then lithiation, and dissolving the lithiation derivative in orthocyclobenzene to which fullerene is added to form a fullerene anion. Forming a monomer comprising a terthiophene-fullerene linking compound by reacting the fullerene anion with tosyl cyanide or a methyl group, and polymerizing the monomer to form a polymer. And a manufacturing method It was.
According to this method, a conductive polymer having high conductivity and easily causing charge separation can be easily obtained with an arbitrary thickness and an arbitrary area.

The organic solar cell of the present invention is an organic solar cell in which an electron donor layer made of a conductive polymer and an active layer made of the conductive polymer of the present invention are joined.
The organic solar cell of the present invention may have a structure in which an electron donor layer made of a conductive polymer and an active layer made of the conductive polymer of the present invention are laminated between a transparent electrode and its counter electrode. it can.
Further, the organic solar cell of the present invention has a structure in which an electron donor layer made of a conductive polymer is joined to an active layer made of the conductive polymer of the present invention on a transparent substrate via a transparent electrode. You can also.
These organic solar cells of the present invention have a high conversion efficiency and a long service life because the active layer has a high conductivity and is likely to cause charge separation, and uses a conductive polymer excellent in mechanical strength and light resistance. Long organic solar cells can be obtained.

According to the present invention, a π-conjugated thiophene ring having a high donor property is used for the main chain, and a cyanated fullerene having a high electron-accepting property is used for the side chain. Has a covalent bond to the cyanofullerene, and because of its high electron accepting property, the electrons of the thiophene ring in the main chain are always pulled toward the cyanofullerene. Therefore, the thiophene ring in the main chain has a stronger donor property, and as a result, it becomes a polymer having high conductivity, and charge separation by light easily occurs.
In addition, some of the conductive copolymers of the present invention are crosslinked three-dimensionally, resulting in conductive polymers having excellent mechanical strength and light resistance.
When an organic solar cell is formed using the conductive polymer of the present invention, an organic solar cell having excellent mechanical strength and light resistance and high light conversion efficiency can be provided.

(1st Embodiment)
As a first embodiment of the present invention, a conductive polymer composed of a monomer polymer in which a main chain is a thiophene oligomer having a degree of polymerization (repetition number) of 3 and a cyanated fullerene group is triple-bonded to a side chain thereof. I will combine. The structural formula of the monomer that forms the basis of the conductive polymer is shown in Chemical Formula 1.

As shown in Chemical formula 1, the main chain of this conductive polymer is a π-conjugated thiophene ring having a high donor property, and a cyanated fullerene group having a high electron accepting property is used for a side chain.
In this conductive polymer, a cyanated fullerene is covalently bonded at a predetermined position in the molecule, and the electrons of the thiophene ring in the main chain are always pulled toward the cyanated fullerene due to its high electron accepting property. Will be. Therefore, the thiophene ring in the main chain has a stronger donor property, and as a result, it becomes a polymer having high conductivity, and charge separation by light easily occurs.

(Second embodiment)
As a second embodiment of the present invention, a conductive polymer consisting of a monomer polymer in which a methylated fullerene group is triple-bonded to a side chain of a thiophene oligomer having a polymerization degree (repetition number) of 3 as a main chain. I will combine. The structural formula of the monomer serving as the group of the conductive polymer is shown in Chemical formula 2.

  In this conductive polymer, methylated fullerene is covalently bonded to a predetermined position in the molecule, and the electrons of the main chain thiophene ring are always pulled toward the methylated fullerene due to its high electron accepting property. Will be. Therefore, the thiophene ring in the main chain has a stronger donor property. As a result, the polymer becomes a polymer having high conductivity, and charge separation by light easily occurs.

Next, a method for producing a conductive polymer according to the first embodiment and the second embodiment will be described.
First, a bromoterthiophene derivative represented by Chemical Formula 4 is synthesized by coupling a thiophene derivative represented by Chemical Formula 3 with 2,3,5-tribromothiophene in the presence of a palladium catalyst.

  Next, trimethyl serial acetylene is coupled to the obtained bromoterthiophene derivative under the catalyst of palladium and copper to synthesize an acetylene derivative represented by Chemical Formula 5.

  Next, the obtained acetylene derivative is detrimethylsilylated by reacting with tetrabutylammonium fluoride to synthesize ethynylta-thiophene shown in Chemical formula 6.

  Next, the obtained ethynyl terthiophene is lithiated with n-butyllithium to give lithium acetylide shown in Chemical formula 7.

Further, ortho-dichlorobenzene in a solution prepared by dissolving C _60, of 6 lithium acetylide shown in Chemical formula 7 was generated from ethynyl Terthiophene shown in by nucleophilic addition, blackish green fullerene anions represented by the formula 8 after forming the, by the action of Toshirushianido as electrophile, to synthesize terthiophene -C ₆₀ linking compound shown in chemical Formula 9.
Here, if the action of methyl iodide as electrophile instead of Toshirushianido, terthiophene -C ₆₀ linking compound shown in Chemical formula 10 is obtained.
The structure of such a _C60- linked compound is determined by analyzing various spectra such as ¹ H and ¹³ C NMR (nuclear magnetic resonance), UV-vis (ultraviolet-visible absorption spectrum), and MS (mass spectrometry). be able to.

Thus a monomer consisting resulting Terthiophene -C ₆₀ linking compound by polymerization, a conductive polymer of interest. As the polymerization method, a method of applying energy to the monomer by various methods to accelerate the polymerization reaction can be used. Specifically, in addition to an electrolytic polymerization method using an electrochemical process, a photopolymerization method using light irradiation, a plasma polymerization method, a microwave polymerization method, and the like can be used.

Next, an organic solar cell using the conductive polymer obtained as described above as an active layer will be described.
The organic solar cell of the present invention uses a conductive polymer comprising a thiophene ring and a cyanated fullerene group or a methylated fullerene group obtained according to the present invention as an active layer, and a heterojunction with an electron donor layer. Basic. FIG. 1 shows an example of a cross-sectional structure of the organic solar cell 8 of the present invention.
As the transparent substrate 1, a transparent substrate such as quartz or glass can be used. On a transparent substrate 1, a transparent electrode 2 such as ITO (Indium Tin Oxide: indium oxide doped with tin), a conductive film such as polythiophene to be an electron donor layer 3, and a conductive film It is desirable that the active layer 4 made of the conductive polymer of the present invention, which forms a heterojunction with the film, and the counter electrode made of the LiF layer 5 and the Al electrode 6 are laminated in this order.
The transparent electrode 2 is for transmitting light to the electron donor layer 3 together with the transparent substrate 1 for supporting the whole organic solar cell, and is transparent and forms a conductor for taking out the generated current to the outside. is there. The transparent electrode 2 may be made of a thin film of a metal oxide or a thin film of a metal such as gold, silver, platinum, and nickel, in addition to the ITO. In the process of forming a transparent electrode, it is general to form it on a substrate, and the above-mentioned electrode material such as ITO is formed on the substrate by a method such as vapor deposition or sputtering.

  The electron donor layer 3 has an electron donating property, and is preferably formed of a P-type conductive polymer containing a conjugated π-electron system. Some preferred specific examples thereof include polyvinyl carbazole, poly (p-phenylene) -vinylene, polyaniline, polyethylene oxide, polyvinyl pyridine, polyvinyl alcohol, polyfluorene, polyparaphenylene, poly (3 -Alkylthiophene), poly [2-methoxy-5- (2'-ethylhexoxy) -p-phenylene] -vinylene, poly [2-methoxy-5- (2'-ethylhexoxy) -1,4-paraphenylenevinylene] Poly (3-alkylthiophene), poly (9,9-dialkylfluorene), polyparaphenylene, poly (2,5-diheptyloxy-1,4-phenylene), polyphenylene, poly (p-phenylene), polyethylene oxide, Poly (2-vinylpyridine), At least one selected from such re (vinyl alcohol), or there are those polymers consisting of a derivative of at least one constituent monomer. In addition, a known dopant such as a sulfate group may be added to the conductive polymer in order to control the conductivity.

In the active layer 4, a π-conjugated thiophene ring having a high donor property is disposed in the main chain according to the present invention, and a cyanated fullerene group or a methylated fullerene group having a high acceptor property and a high electron accepting property is used in a side chain. A conductive polymer composed of a polymer of the above-mentioned monomer is used. The fullerenes contained in the polymer may be any of C ₆₀ , C ₇₀ , C _{84 and the} like.
The thickness of each of the electron donor layer 3 and the active layer 4 may be 1 to 50 nm, preferably 5 to 20 nm.

The organic solar cell 8 of the present invention has a structure in which the electron donor layer 3 and the active layer 4 are heterojunction sandwiched between the transparent electrode 2 and the counter electrode. The counter electrode is preferably composed of a LiF layer 5 for obtaining a complete ohmic junction with the conductive polymer, and an Al electrode 6 for easy connection of external leads.
The counter electrode is made of, for example, an oxide such as ITO, a metal such as magnesium or indium, or an alloy composed of two or more of these metals, in addition to LiF / Al. A thin film can be formed on the active layer 4 by using such a technique.

  In addition, as a conductive polymer that can be used as an active layer, a polymer in which a thiophene ring is connected as a main chain and a cyanated fullerene group is connected to a side chain, and a thiophene ring is connected as a main chain and a methylated fullerene group is connected to a side chain Is a polymer of a monomer of the structural formula shown in Chemical formula 11 to Chemical formula 14, or a monomer of Chemical formula 1 or Chemical formula 2 It is also possible to use copolymers of monomers containing the polymer.

The monomer shown in Chemical formula 11 is a polymer of a monomer having a main chain in which a cyanated fullerene group is triple-bonded to a side chain of a thiophene oligomer having a degree of polymerization (repetition number) of 5. This monomer is polymerized into a conductive polymer.
It should be noted that a methyl group may be added in place of the cyano group.

  Next, the monomer shown in Chemical formula 12 is a monomer having a main chain in which a cyanated fullerene group is single-bonded to a side chain of a thiophene oligomer having a degree of polymerization (repetition number) of 3. This monomer is polymerized into a conductive polymer. What added a methyl group instead of a cyano group may be used.

The monomer shown in Chemical formula 13 has a cyanofullerene group or a methylated fullerene group having two cyano or methyl groups on two side chains of two thiophene oligomers having a main chain of polymerization degree (repetition number) 3. Is a monomer having a triple bond. This monomer is polymerized into a conductive polymer.
This conductive polymer has an advantage that it can be cross-linked three-dimensionally because it has two main chains, and exhibits effects such as improvement of mechanical strength and improvement of weather resistance enough to withstand light irradiation. Become.

The monomer shown in Chemical formula 14 has a cyanofullerene group or a methylated fullerene group having two cyano groups or methyl groups on two side chains of two thiophene oligomers having a main chain of a degree of polymerization (repetition number) of 3. Is a monomer formed by a single bond. This monomer is polymerized into a conductive polymer.
This conductive polymer also has an advantage that it can crosslink three-dimensionally because it has two main chains, and exhibits effects such as improvement in mechanical strength and improvement in weather resistance enough to withstand light irradiation. Become.

In the organic solar cell of the present invention, a copolymer obtained by copolymerizing at least two types of monomers among the six types of monomers represented by the chemical formulas 1, 2, and 11 to 14 above. Polymers can also be used. These copolymers also have a pi-conjugated thiophene ring with a high donor property in the main chain, and a highly electron accepting cyanated fullerene group or methylated fullerene group with a high acceptor property in the side chain. . As a result, a polymer having high conductivity is obtained, and charge separation by light is easily caused.
For example, the main chain shown in Chemical Formula 1 is a thiophene oligomer having a degree of polymerization (repetition number) of 3, and a monomer in which a cyanated fullerene group is triple-bonded to the side chain, and the main chain shown in Chemical Formula 13 is (Repeated number) Conductive copolymer obtained by copolymerizing a monomer comprising two thiophene oligomers each having 3 and one triple bond of a cyanated fullerene group having two cyano groups in its side chain. Can be mentioned.
In particular, a conductive copolymer obtained by copolymerizing a monoadduct monomer as a main material and adding a diadduct monomer to the main material has a mechanical strength because the main chain is three-dimensionally crosslinked. Has the advantage of being further improved.

The conductive polymer of the present invention makes use of its properties such as high-performance conductivity and electrification separation ability, in addition to organic solar cells, organic transistors (TR), organic electroluminescent (EL) elements, and organic solid electrolytes. It can be used for capacitors and the like.
Next, an example in which the conductive polymer of the present invention is used for an active layer of an organic transistor will be described.
FIG. 2 is an example of a cross-sectional view illustrating the structure of the organic transistor 10-1. An insulating film 13 such as a silicon oxide film or an aluminum oxide film is formed on a glass substrate 11 on which an electrode 12 such as ITO (Indium Thin Oxide) is formed by using a thermal oxidation method, a CVD method, or a sputtering method. Next, a source electrode 14 and a drain electrode 15 made of gold, platinum or the like are formed, and then a conductive polymer of the present invention, for example, a thiophene ring polymer 16 containing cyanated fullerene or methylated fullerene is spin-coated and electrolytically coated. Formed using a legal method.
Conversely, a thiophene ring polymer containing the aforementioned cyanated fullerene or methylated fullerene is formed on a silicon or glass substrate, a source electrode and a drain electrode of gold or platinum are formed, and then a silicon oxide film or silicon nitride film is formed. An organic transistor can be formed by forming a film or a gate insulating film such as aluminum oxide and then forming a gate electrode.
In these organic transistors, high electron mobility can be obtained due to their high conductivity, and the operation speed of the transistor can be improved.

3 to 5 show other structural examples of the organic transistor in cross-sectional views.
The organic transistor 10-2 shown in FIG. 3 is a cross-sectional view showing another example of the structure of the organic transistor using the conductive polymer of the present invention for the active layer, and includes the cyanated fullerene or the methylated fullerene of the present invention. The thiophene ring polymer 16 and the thiophene polymer 17 have a heterojunction structure.

An organic transistor 10-3 shown in FIG. 4 is a cross-sectional view showing another example of the structure of the organic transistor using the conductive polymer of the present invention for an active layer, and a silicon oxide film or an aluminum oxide film on a glass substrate 11. And the like, a thiophene ring polymer 16 containing a cyanated fullerene or a methylated fullerene of the present invention is laminated on the insulating film 13, and a source electrode 14 and a drain electrode 15 are formed thereon. It is.
Further, an organic transistor 10-4 shown in FIG. 5 is a cross-sectional view showing another example of the structure of the organic transistor using the conductive polymer of the present invention for the active layer. Instead of mounting the thiophene ring polymer 16 containing a cyanated fullerene or methylated fullerene of the present invention, the thiophene ring polymer 16 containing a cyanated fullerene or methylated fullerene of the present invention and the thiophene This is a structure in which a heterojunction structure with the union 17 is mounted.

Next, a structural example of an organic electroluminescence (EL) device using the conductive polymer of the present invention will be described.
FIG. 6 is a cross-sectional view showing an example of an organic EL device using the conductive polymer of the present invention for a hole injection layer. On a glass substrate 21 on which a transparent electrode 22 such as ITO is formed, a thiophene ring polymer containing a cyanated fullerene or a methylated fullerene of the present invention is formed as a hole injection layer 26 by an electrolytic polymerization method or the like, and then an electron transport layer is formed. After laminating an aluminum quinolinol complex (Alq) as 27, a MgAg alloy layer 24 or a LiF layer having a low work function is formed, and a counter electrode 25 made of a metal such as Al for connection is formed to form an organic EL element 20-1. It is what it was.

  FIG. 7 is a cross-sectional view showing another example of the structure of the organic EL device using the conductive polymer of the present invention. In the example of the organic EL element 20-2 shown in FIG. 7, the hole injection layer 26 is formed on the insulating film 13 via the thiophene polymer 28 instead of forming the hole injection layer 26 directly on the insulating film 13 in FIG. 26 to form a heterojunction structure of a thiophene polymer and a thiophene ring polymer containing a cyanated fullerene or a methylated fullerene of the present invention.

Next, a structural example of an organic solid electrolytic capacitor using the conductive polymer of the present invention will be described.
FIG. 8 is a sectional view showing a structural example of an organic solid electrolytic capacitor using a thiophene ring polymer containing a cyanated fullerene or a methylated fullerene of the present invention as a cathode conductive layer.
A porous sintered body 31 of tantalum (Ta) is used as an anode, and the porous sintered body 31 of Ta is oxidized to form a tantalum oxide film (Ta ₂ O ₅ ) 32 serving as a dielectric layer on the surface. I do. An anode lead is embedded in a porous sintered body 31 of Ta, and a thiophene ring polymer containing a cyanated fullerene or a methylated fullerene of the present invention is filled as a cathode conductive layer 33, and then a carbon layer 34 and a silver paste are used. The formed Ag electrode 35 is formed, and a cathode lead is attached to the organic solid electrolytic capacitor 30.
Note that niobium (Nb) may be used instead of tantalum (Ta) as the anode metal.

(Example 1)
First, a bromoterthiophene derivative was synthesized by coupling the thiophene derivative shown in Chemical formula 3 with 2,3,5-tribromothiophene in the presence of a palladium catalyst.

Next, trimethyl serial acetylene was coupled to the obtained bromota-thiophene derivative under the catalyst of palladium and copper to synthesize an acetylene derivative.
Next, the resulting acetylene derivative was detrimethylsilylated by reacting with tetrabutylammonium fluoride to synthesize ethynylta-thiophene.

Next, the obtained ethynylta-thiophene was lithiated with n-butyllithium to obtain lithium acetylide.
Further, in a solution prepared by dissolving C ₆₀ in ortho-dichlorobenzene, the Echiniruta - that by the lithium acetylide was generated from thiophene to nucleophilic addition, after forming a fullerene anion, exerting Toshirushianido as electrophile the was synthesized terthiophene _{-C 60} linking compound.
Thus per _{C 60} linking compound obtained ^was 1 H-NMR, MS, IR and UV-vis measured. FIG. 9 shows the ¹ H-NMR spectrum, FIG. 10 shows the MS spectrum, FIG. 11 shows the IR spectrum, and FIG. 12 shows the UV-vis absorption spectrum.
In FIGS. 9 and 13, peaks were identified by reference to comparison with similar compounds, chemical shifts, and relative heights of peaks.
In FIG. 9, the peaks at 3.98 and 4.10 (δ / ppm) are peaks due to CH ₂ of the ethylenedioxy group. The peaks at 6.05 and 6.06 (δ / ppm) are peaks due to protons at the α-position of ethylenedioxythiophene. The peak at 7.49 (δ / ppm) is a peak due to the proton at the β-position of thiophene in the middle.
In FIG. 10, a peak of C ₇₉ H ₁₁ NO ₄ S ₃ is observed at 1133 (m / z).
In FIG. 11, the peak at 2219 (cm ⁻¹ ) is the absorption due to the cyano group.
In FIG. 12, when a curve magnified 10 times is observed, a peak is recognized at a position of 697 (nm).
From these results, the obtained _C60- linked compound is identified as a monomer having a structure in which a cyanated fullerene in which one cyano group is added to the side chain of a thiophene oligomer having a degree of polymerization of 3 is triple-bonded. I was able to.
Furthermore, to obtain a thus obtained Terthiophene -C ₆₀ linking compound monomer electropolymerization to electrically conductive polymers.

(Example 2)
Instead of exerting Toshirushianido as electrophile in Example 1, it was synthesized monomers terthiophene -C ₆₀ linking compound is reacted with methyl iodide.
In this way, every monomer of the obtained _{C 60} linking compound ^{was 1 H-NMR, 13 C-} NMR, MS, IR, and UV-vis and cyclic voltammetry was measured. In the cyclic voltammetry, a redox potential (CV) was measured by a cyclic voltammetry in orthodichlorobenzene.
The ¹ H-NMR spectrum of this compound is shown in FIG. 13, the ¹³ C-NMR spectrum is shown in FIG. 14, the MS spectrum is shown in FIG. 15, the IR spectrum is shown in FIG. FIG. 17 shows a spectrum diagram, and FIG. 18 shows a chart of cyclic voltammetry.
In FIG. 14 as well, the peak was identified with reference to the comparison with the similar compound, the chemical shift, and the relative height of the peak.
In FIG. 13, the peak at 3.34 (δ / ppm) is the peak of the methyl group. The peaks at 3.92 and 4.03 (δ / ppm) are peaks due to CH ₂ of the ethylenedioxy group. The peaks at 6.03, 6.13 (δ / ppm) are peaks due to the α-position proton of ethylenedioxythiophene. The peak at 7.35 (δ / ppm) is a peak due to the proton at the β-position of thiophene in the middle.
In FIG. 14, peaks at 93.22 and 82.83 (δ / ppm) indicating a carbon triple bond are observed.
In FIG. 15, a peak of C ₇₉ H ₁₄ O ₄ S ₃ is observed at 1122 (m / z).
In FIG. 16, the peak at 2328 (cm ⁻¹ ) is absorption due to acetylene bonds.
In FIG. 17, when a curve magnified 10 times is observed, a peak is recognized at a position of 704 (nm).
FIG. 18 shows a reversible reduction wave at −1.14, −1.53, −2.08 V, and an irreversible oxidation wave at +0.49 V.
From these results, the obtained _C60- linked compound is identified as a monomer having a structure in which a methylated fullerene having one amino group added to the side chain of a thiophene oligomer having a degree of polymerization of 3 is triple-bonded. I was able to.

It was further polymerized using electrolytic polymerization method the terthiophene -C ₆₀ linking compound monomer. The cyclic voltammetry of this polymer was also measured. The results are shown in FIGS. As shown in FIG. 19, a reversible reduction wave was shown at −0.98, −1.44, and −1.94 V, and an irreversible oxidation wave was shown at +0.20 V. It was repeated sweep measurement, the current amount is increased to reduction wave both the oxidation side and C ₆₀ moiety as shown in FIG. 20. This indicates that electropolymerization has occurred on the electrode.

(Example 3)
An organic solar cell using the conductive polymer of the present invention obtained in Example 1 was produced.
First, PEDOT (poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonate)) is spin-coated as an electron donor layer 3 on a glass transparent substrate 1 on which a transparent electrode 2 made of ITO is formed. did. Next, the monomer shown in Chemical formula 1 was dissolved in acetonitrile, and the substrate on which the PEDOT film was formed, the platinum counter electrode and the saturated calomel reference electrode were immersed in the solution. Each electrode and the substrate were connected to a potentiostat, and a potential of 1 V was applied for 10 seconds to cause electropolymerization on the PEDOT film on the surface of the ITO transparent electrode of the transparent substrate, whereby the thiophene ring containing a cyanated fullerene group was produced. An active layer 4 was formed by forming a thin film of a conductive polymer composed of a united body, and a counter electrode composed of a LiF layer 5 and an Al electrode 6 was formed thereon to form an element having a cross-sectional structure shown in FIG.
When light was irradiated from the transparent electrode side, current flowed between the Al electrode and the transparent electrode with high efficiency, and it was found that an organic solar cell was configured.

  In the present invention, a thiophene ring derivative containing a cyanated fullerene group or a methylated fullerene group is used.Comparing these two derivatives, a thiophene ring derivative having a cyanated fullerene group in the side chain is considered to have an electron-accepting strength. When used, a polymer having higher charge separation property and higher conductivity than a thiophene ring derivative having a methylated fullerene group in a side chain is obtained, and also has a high value of charge separation ability by light.

(Example 4)
Created the organic solar cell of the structure shown in FIG. 21 by using the terthiophene -C ₆₀ linking compound fullerene 60 obtained is bound in Example 1.
First, terthiophene -C ₆₀ linking compound obtained in Example 1, ortho-dichlorobenzene tetrabutylammonium perchlorate is dissolved at a concentration of 0.1 M, was dissolved to a concentration of 0.1mM Was. Then, the solution was poured into an electrochemical cell, and an ITO electrode 41 obtained by forming an ITO film 41 on a glass substrate 41 was used as a working electrode, a platinum wire was used as a counter electrode, and a silver / silver chloride electrode was used as a reference electrode. The terthiophene derivative was electrolytically polymerized at 1 V for 1 hour to obtain a polymer thin film 43 on the ITO film. The electrode composed of the ITO film 41 and the polymer thin film 43 is called an ITO electrode.
A glass substrate (hereinafter, simply referred to as a platinum electrode) on which platinum 45 is sputtered is placed on the ITO electrode via an O (o) ring 47, and a 1M KCl solution 46 is placed between the ITO electrode and the platinum electrode. Thus, an organic solar cell having the structure shown in FIG. 21 was formed. When the ITO electrode and the platinum electrode were connected to an ammeter (manufactured by Keithley; remote source meter 6430) 48, and light was irradiated from the light source (manufactured by Hoyashot; HLS100UM) through the ITO electrode, a current of 100 nA was observed. The current stopped flowing when the light irradiation was stopped. FIG. 22 shows the result of the current measurement.

It is a figure showing an example of the section structure of the organic solar cell of the present invention. FIG. 3 is a cross-sectional view illustrating an example of the structure of an organic transistor. FIG. 11 is a cross-sectional view illustrating another example of the structure of the organic transistor. It is sectional drawing which shows the example of another structure of an organic transistor. It is sectional drawing which shows the example of another structure of an organic transistor. It is sectional drawing which shows an example of the structure of organic electroluminescence. It is sectional drawing which shows the example of another structure of organic electroluminescence. It is sectional drawing which shows an example of a structure of an organic electrolytic solid capacitor. FIG. 2 is a ¹ H-NMR spectrum diagram of a monomer constituting the conductive polymer according to the first embodiment. FIG. 3 is an MS spectrum diagram of a monomer constituting the conductive polymer according to the first embodiment. FIG. 2 is an IR spectrum diagram of a monomer constituting the conductive polymer according to the first embodiment. FIG. 3 is a UV-vis spectrum diagram of a monomer constituting the conductive polymer according to the first embodiment. FIG. 5 is a ¹ H-NMR spectrum diagram of a monomer constituting a conductive polymer according to a second embodiment. FIG. ¹³ is a ¹³ C-NMR spectrum diagram of a monomer constituting a conductive polymer according to a second embodiment. FIG. 7 is an MS spectrum diagram of a monomer constituting a conductive polymer according to a second embodiment. It is an IR spectrum figure of the monomer which comprises the conductive polymer concerning 2nd Embodiment. It is a UV-vis spectrum figure of the monomer which comprises the conductive polymer concerning 2nd Embodiment. It is a figure showing cyclic voltammetry of a monomer which constitutes a conductive polymer concerning a 2nd embodiment. It is another figure which shows the cyclic voltammetry of the conductive polymer concerning 2nd Embodiment. It is another figure which shows the cyclic voltammetry of the conductive polymer concerning 2nd Embodiment. It is a figure showing the section structure of the organic solar cell concerning a 4th example. It is a figure showing the current measurement result of the organic solar cell concerning a 4th example.

Explanation of reference numerals

1 ... Transparent substrate, 2 ... Transparent electrode, 3 ... Electron donor layer, 4 ... Active layer, 5 ... LiF Layer, 6 ... Al electrode, 8 ... Organic solar cell, 10-1, 10-2, 10-3, 10-4 ... Organic transistor, 13 ... ... insulating film, 16 ... thiophene ring polymer, 17 ... thiophene polymer, 20-1, 20-2 ... organic electroluminescent element, 22 ... ····· Transparent electrode, 26 ···· Hole injection layer, 27 ···· Electron transport layer, 28 ···· Thiophene polymer, 30 ···· Organic solid electrolysis Capacitor, 31: tantalum porous sintered body, 32: tantalum oxide film, 33: cathode conductive layer

Claims (9)

  What is claimed is: 1. A conductive polymer comprising a thiophene ring linked, wherein a cyanated fullerene group is linked to a side chain.   What is claimed is: 1. A conductive polymer comprising a thiophene ring and a methylated fullerene group connected to a side chain.   3. The conductive polymer according to claim 1, wherein the thiophene ring is a thiophene oligomer.   The conductive polymer according to claim 3, wherein the thiophene oligomer has a degree of polymerization of 3.   The conductive polymer according to any one of claims 1 to 4, wherein the conductive polymer is an adduct of a thiophene oligomer.   Coupling a thiophene derivative with 2,3,5-tribromothiophene to synthesize a bromoterthiophene derivative; coupling the tribromosilylacetylene to the bromoterthiophene derivative to synthesize an acetylene derivative; Lithiating the derivative with tetrabutylammonium fluoride, dissolving the lithiated derivative in orthocyclobenzene to which fullerene has been added to form a fullerene anion, and reacting the fullerene anion with a tosyl cyano or methyl group. A step of forming a monomer comprising a terthiophene-fullerene linking compound, and a step of polymerizing the monomer to obtain a polymer, thereby producing a conductive polymer. Method.   An organic solar cell, comprising an electron donor layer made of a conductive polymer and an active layer made of the conductive polymer according to any one of claims 1 to 5.   An electron donor layer made of a conductive polymer and an active layer made of the conductive polymer according to any one of claims 1 to 5, which are laminated between a transparent electrode and its counter electrode. An organic solar cell, comprising: An electron donor layer made of a conductive polymer and an active layer made of the conductive polymer according to any one of claims 1 to 5 are bonded on a transparent substrate via a transparent electrode. An organic solar cell according to claim 7 or claim 8, wherein

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