JP5243714B2 - Method for producing organic photoelectric conversion element and organic photoelectric conversion element - Google Patents

Description

  The present invention relates to a method for producing an organic photoelectric conversion element and an organic photoelectric conversion element. In particular, the present invention relates to an organic photoelectric conversion element suitable for use in an organic thin film solar cell and an optical sensor.

  Conventionally, as a solar cell which is one of organic photoelectric conversion elements, one using polycrystalline silicon has been developed and put into practical use. High-purity silicon is required for its manufacture, and the manufacturing process consists of a high-temperature process. Considering the energy required for manufacturing, it could not be said that the solar cell has sufficiently contributed to energy-saving technology. In addition to outdoor power generation applications, for example, problems remain in the fabrication of elements on plastic substrates that are required for portable solar cells.

  On the other hand, as an optical sensor which is another organic photoelectric conversion element, an image sensor in a facsimile or a copying machine can be cited. Such an optical sensor has been put into practical use in an image reading apparatus using a scanner based on a one-dimensional sensor using a silicon crystal. However, so far, large area two-dimensional sensors that do not require scanning have not been put to practical use.

  In recent years, in order to improve the above-described points, solar cells using organic materials have been developed that can be expected to save energy in manufacturing and can be applied with a coating process that can easily increase the area. For example, a dye-sensitized type has been studied as a wet solar cell using an organic material. However, since this wet solar cell is a system using an electrolyte solution, liquid leakage or iodine loss in the liquid may occur, and it has not yet been put into practical use.

Moreover, as another solar cell using an organic material, an all-solid-state organic thin film solar cell can be mentioned. This solar cell includes a heterojunction type and a bulk heterojunction type. In the heterojunction type, a layer made of an electron donor and a layer made of an electron acceptor are stacked, and charge transfer caused by light induction at the junction interface is used. For example, Non-Patent Document 1 reports a solar cell that achieves a conversion efficiency of 1% using copper phthalocyanine as an electron donor and a perylene derivative as an electron acceptor. In addition, condensed polycyclic aromatic compounds such as pentacene and tetracene have been studied as electron donors, and fullerene compounds such as C ₆₀ have been studied as electron acceptors.

On the other hand, the bulk heterojunction type is an active layer formed by mixing an electron donor and an electron acceptor at an appropriate ratio. What is a heterojunction type that forms an active layer with a two-layer structure? Different. The junction between the electron donor and the electron acceptor exists uniformly in the bulk of the mixed active layer, and sunlight can be used effectively. The bulk heterojunction type device can be produced by vacuum depositing an electron donor and an electron acceptor to form an active layer, or by applying a mixture of the two by spin coating or printing. There is something to form. In the vacuum evaporation method, an active layer composed of copper phthalocyanine and C ₆₀ has been reported (Non-patent Document 2). In the wet coating method, a typical example is a system in which polythiophene, which is a conjugated polymer, and [6,6] -phenyl C61-butyric acid methyl ester (abbreviated as PCBM), which is a soluble derivative of fullerene, are mixed. (Non-Patent Document 3).

  As for solar cells using a benzoporphyrin compound, there are Schottky junction type devices (Non-Patent Document 4) and heterojunction type devices using a perylene derivative as an electron acceptor layer (Non-Patent Documents 5 and 1). Although it has been reported, the conversion efficiency is low, and it can be said that there are still big problems in practical use.

JP 2003-304014 A C. W. Tang: Appl. Phys. Lett. 48, 183-185, 1986 S. Uchida et al .: Appl. Phys. Lett. 84, 4218-4220, 2004. S. E. Shahen et al .: Appl. Phys. Lett. 78, 841-843, 2001 K. Yamashita et al .: Bull. Chem. Soc. Jpn. 60, 803-805, 1987 D. Wohrle et al. Mater. Chem. 5: 1819-1829, 1995

In the conventional organic thin film solar cell described above, the effective contact area between the electron donor and the electron acceptor is not sufficient, and the charge mobility is low. For this reason, compared with a silicon-type solar cell, conversion efficiency is low and the improvement of the basic performance as a photoelectric conversion element has been a subject.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a method for producing an organic photoelectric conversion element and an organic photoelectric conversion element that are more excellent in photoelectric conversion characteristics than conventional ones.

  As a result of intensive studies to solve the above problems, the present inventors have improved the photoelectric conversion characteristics by using a benzoporphyrin compound thermally converted from a soluble precursor as an electron donor of an organic photoelectric conversion element. Found that is possible.

（前記式（Ｉ）及び（II）中、Ｚ^ia及びＺ^ib（ｉは１〜４の整数を表わす）は、各々独立に、１価の原子又は原子団を表わす。ただし、Ｚ^iaとＺ^ibとが結合して環を形成していてもよい。Ｒ¹〜Ｒ⁴は、各々独立に、１価の原子又は原子団を表わす。Ｍは、２価の金属原子、又は、３価以上の金属と他の原子とが結合した原子団を表わす。） That is, the gist of the present invention is that a substrate, a pair of electrodes formed on the substrate, at least one of which is transparent, an electron donor layer including an electron donor and formed between the electrodes, A benzoporphyrin compound represented by the following formula (I) or (II) having a bicyclo ring, which is a method for producing an organic photoelectric conversion element comprising an electron acceptor layer formed between the electrodes including a body The soluble precursor of is converted to the electron donor benzoporphyrin compound by thermal conversion to form the electron donor layer, and the electron donor layer is formed by thermal conversion. And the step of forming the electron acceptor layer by a coating method, wherein the electron acceptor layer contains a fullerene compound . (Claim 1)

(In the formulas (I) and (II), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represents a monovalent atom or atomic group, provided that Z ^ia and Z good .R ¹ to R ⁴ to form a ring and ^ib are bonded to each independently, .M representing a monovalent atom or atomic group, a divalent metal atom, or a trivalent or higher Represents an atomic group in which other metals are bonded to other atoms.)

（前記式（III）及び（IV）中、Ｚ^ia及びＺ^ib（ｉは１〜４の整数を表わす）は、各々独立に、１価の原子又は原子団を表わす。ただし、Ｚ^iaとＺ^ibとが結合して環を形成していてもよい。Ｒ¹〜Ｒ⁴は、各々独立に、１価の原子又は原子団を表わす。Ｙ¹〜Ｙ⁴は、各々独立に、１価の原子又は原子団を表わす。Ｍは、２価の金属原子、又は、３価以上の金属と他の原子とが結合した原子団を表わす。） In this case, the soluble precursor is preferably a compound represented by the following formula (III) or (IV) (Claim 2).

(In the formulas (III) and (IV), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represents a monovalent atom or atomic group, provided that Z ^ia and Z ^ib may be bonded to form a ring, R ^{1 to} R ⁴ each independently represents a monovalent atom or atomic group, and Y ¹ to Y ⁴ each independently represents a monovalent atom. M represents an atomic group in which a divalent metal atom or a trivalent or higher metal is bonded to another atom.

（前記式（Ｉ）及び（II）中、Ｚ ^ia 及びＺ ^ib （ｉは１〜４の整数を表わす）は、各々独立に、１価の原子又は原子団を表わす。ただし、Ｚ ^ia とＺ ^ib とが結合して環を形成していてもよい。Ｒ ¹ 〜Ｒ ⁴ は、各々独立に、１価の原子又は原子団を表わす。Ｍは、２価の金属原子、又は、３価以上の金属と他の原子とが結合した原子団を表わす。）
このとき、前記電子受容体層がフラーレン化合物を含むことが好ましい（請求項４）。
また、前記可溶性前駆体は、下記式（III）または（IV）で表される化合物である
ことが好ましい（請求項５）。

（前記式（III）及び（IV）中、Ｚ ^ia 及びＺ ^ib （ｉは１〜４の整数を表わす）は、各々独
立に、１価の原子又は原子団を表わす。ただし、Ｚ ^ia とＺ ^ib とが結合して環を形成していてもよい。Ｒ ¹ 〜Ｒ ⁴ は、各々独立に、１価の原子又は原子団を表わす。Ｙ ¹ 〜Ｙ ⁴ は、各々独立に、１価の原子又は原子団を表わす。Ｍは、２価の金属原子、又は、３価以上の金属と他の原子とが結合した原子団を表わす。） Another gist of the present invention is a substrate, a pair of electrodes formed on the substrate, at least one of which is transparent, an electron donor layer including an electron donor and formed between the electrodes, An organic photoelectric conversion device comprising an electron acceptor and an electron acceptor layer formed between the electrodes, the benzoate having a bicyclo ring represented by the following formula (I) or (II) A step of forming a porphyrin compound soluble precursor layer by a coating method and a step of forming the electron acceptor layer on the soluble precursor layer by a vacuum deposition method are performed, and then by the thermal conversion. The present invention resides in a method for producing an organic photoelectric conversion element , wherein the step of forming the electron donor layer is performed by converting the benzoporphyrin compound as the electron donor .

(In the formulas (I) and (II), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represents a monovalent atom or atomic group, provided that Z ^ia and Z good .R ¹ to R ⁴ to form a ring and ^ib are bonded to each independently, .M representing a monovalent atom or atomic group, a divalent metal atom, or a trivalent or higher Represents an atomic group in which other metals are bonded to other atoms.)
At this time, it is preferable that the electron acceptor layer contains a fullerene compound.
The soluble precursor is a compound represented by the following formula (III) or (IV)
(Claim 5).

(In the formulas (III) and (IV), Z ^ia and Z ^ib (i represents an integer of 1 to 4) are
Stands for a monovalent atom or atomic group. However, ^Zia and ^Zib may combine to form a ring. R ^{1 to} R ⁴ each independently represents a monovalent atom or atomic group. Y ¹ to Y ⁴ each independently represent a monovalent atom or group of atoms. M represents a divalent metal atom or an atomic group in which a trivalent or higher metal and another atom are bonded. )

  Another aspect of the present invention includes a substrate, a pair of electrodes formed on the substrate, at least one of which is transparent, and a benzoporphyrin compound represented by the formula (I) or (II). And an electron acceptor layer formed between the electrodes and containing a fullerene compound. (Claim 5)

  According to the method for producing an organic photoelectric conversion element and the organic photoelectric conversion element of the present invention, an organic photoelectric conversion element having excellent photoelectric conversion characteristics can be obtained.

  Hereinafter, the present invention will be described using embodiments and examples, but the present invention is not limited to the following embodiments and examples, and may be arbitrarily modified without departing from the gist of the present invention. Can be implemented.

（前記式（Ｉ）及び（II）中、Ｚ^ia及びＺ^ib（ｉは１〜４の整数を表わす）は、各々独立に、原子又は原子団を表わす。ただし、Ｚ^iaとＺ^ibとが結合して環を形成していてもよい。Ｒ¹〜Ｒ⁴は、各々独立に、原子又は原子団を表わす。Ｍは、２価の金属原子、又は、３価以上の金属と他の原子とが結合した原子団を表わす。） [1. Benzoporphyrin compound]
The benzoporphyrin compound according to the present invention is represented by the following formula (I) or (II).

(In the formulas (I) and (II), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represents an atom or an atomic group, provided that Z ^ia and Z ^ib are R ^{1 to} R ⁴ each independently represents an atom or an atomic group, and M represents a divalent metal atom, or a trivalent or higher metal and another atom. Represents an atomic group in which and are bonded.)

In formula (I) and formula (II), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represent a monovalent atom or atomic group.
As examples of Z ^ia and Z ^ib , examples of the atom include a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom;

  On the other hand, the atomic group includes: hydroxyl group; amino group; alkyl group, aralkyl group, alkenyl group, cyano group, acyl group, alkoxy group, alkoxycarbonyl group, aryloxy group, dialkylamino group, diaralkylamino group, haloalkyl group, And organic groups such as aromatic hydrocarbon ring groups and aromatic heterocyclic groups.

  Among the organic groups, the carbon number of the alkyl group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the alkyl group is too large, the semiconductor characteristics may deteriorate, the solubility may increase, and redissolution may occur during lamination, or the heat resistance may decrease. Examples of the alkyl group include a methyl group and an ethyl group.

  Among the above organic groups, the carbon number of the aralkyl group is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the aralkyl group is too large, the semiconductor characteristics may deteriorate, the solubility may increase, and redissolution may occur during lamination, or the heat resistance may decrease. Examples of the aralkyl group include a benzyl group.

  Among the above organic groups, the carbon number of the alkenyl group is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the alkenyl group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased, and redissolution may be performed at the time of lamination, or the heat resistance may be decreased. Examples of the alkenyl group include a vinyl group.

  Among the above organic groups, the carbon number of the acyl group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the acyl group is too large, the semiconductor characteristics may deteriorate, the solubility may increase, and redissolution may occur during lamination, or the heat resistance may decrease. Examples of this acyl group include formyl group, acetyl group, benzoyl group and the like.

  Among the organic groups, the number of carbon atoms of the alkoxy group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms of the alkoxy group is too large, the semiconductor characteristics may be lowered, the solubility may be increased, and redissolution may be performed at the time of lamination, or the heat resistance may be reduced. Examples of the alkoxy group include a methoxy group and an ethoxy group.

  Among the above organic groups, the carbon number of the alkoxycarbonyl group is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms of the alkoxycarbonyl group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased and redissolved during lamination, or the heat resistance may be decreased. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.

  Among the above organic groups, the carbon number of the aryloxy group is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms of the aryloxy group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased, and redissolution may be performed at the time of lamination, or the heat resistance may be decreased. Examples of the aryloxy group include a phenoxy group and a benzyloxy group.

  Among the above organic groups, the carbon number of the dialkylamino group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the dialkylamino group is too large, the semiconductor characteristics may deteriorate, the solubility may increase, and redissolution may occur during lamination, or the heat resistance may decrease. Examples of the dialkylamino group include a diethylamino group and a diisopropylamino group.

  Among the above organic groups, the carbon number of the diaralkylamino group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the diaalkylamino group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased, and redissolution may be performed during lamination, or the heat resistance may be decreased. Examples of the diaralkylamino group include a dibenzylamino group and a diphenethylamino group.

  Among the organic groups, the carbon number of the haloalkyl group is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms of the haloalkyl group is too large, the semiconductor characteristics may be reduced, the solubility may be increased, and redissolution may be performed at the time of lamination, or the heat resistance may be reduced. Examples of this haloalkyl group include α-haloalkyl groups such as a trifluoromethyl group.

  Among the organic groups, the number of carbon atoms of the aromatic hydrocarbon ring group is arbitrary as long as the effects of the present invention are not significantly impaired, but usually 6 or more, preferably 10 or more, and usually 30 or less, preferably 20 It is as follows. If the number of carbon atoms in the aromatic hydrocarbon ring group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased and redissolved during lamination, or the heat resistance may be decreased. Examples of the aromatic hydrocarbon ring group include a phenyl group and a naphthyl group.

  Among the organic groups, the carbon number of the aromatic heterocyclic group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 2 or more, preferably 5 or more, and usually 30 or less, preferably 20 or less. It is. If the number of carbon atoms in the aromatic heterocyclic group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased and redissolved during lamination, or the heat resistance may be decreased. Examples of the aromatic heterocyclic group include a thienyl group and a pyridyl group.

  Furthermore, the above atomic group may have an arbitrary substituent as long as the effects of the present invention are not significantly impaired. Examples of the substituent include a halogen atom such as a fluorine atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; an alkenyl group such as a vinyl group; and a carbon number of 1 such as a methoxycarbonyl group and an ethoxycarbonyl group. Alkoxy groups having ˜6; alkoxy groups having 1 to 6 carbon atoms such as methoxy group and ethoxy group; aryloxy groups such as phenoxy group and benzyloxy group; dialkylamino groups such as dimethylamino group and diethylamino group; acetyl group and the like An acyl group; a haloalkyl group such as a trifluoromethyl group; a cyano group, and the like. In addition, as for this substituent, 1 piece may be substituted by single or multiple, and 2 or more types may be substituted by arbitrary combinations and ratios.

Z ^ia and Z ^ib may be bonded to form a ring. When Z ^ia and Z ^ib are combined to form a ring, examples of the ring containing Z ^ia and Z ^ib (that is, a ring having a structure represented by Z ^ia —CH═CH—Z ^ib ) include benzene An aromatic hydrocarbon ring which may have a substituent such as a ring, naphthalene ring or anthracene ring; an aromatic which may have a substituent such as a pyridine ring, a quinoline ring, a furan ring or a thiophene ring A heterocyclic ring; a non-aromatic cyclic hydrocarbon such as a cyclohexane ring; and the like.

The above-mentioned substituents in the ring formed by combining Z ^ia and Z ^ib are optional as long as the effects of the present invention are not significantly impaired. Examples thereof include the same substituents as those exemplified as the substituent of the atomic group constituting Z ^ia and Z ^ib . In addition, as for this substituent, 1 piece may be substituted by single or multiple, and 2 or more types may be substituted by arbitrary combinations and ratios.

Among Z ^ia and Z ^ib described above, a hydrogen atom is particularly preferable. This is because the crystal packing is good and high semiconductor characteristics can be expected.

In formula (I) and formula (II), R ^{1 to} R ⁴ each independently represents a monovalent atom or atomic group.
Examples of R ¹ to R ^4, are the same as those of the Z ^ia and Z ^ib described above. Moreover, when R < ¹ > -R < ⁴ > is an atomic group, the said atomic group may have arbitrary substituents, unless the effect of this invention is impaired remarkably. Examples of the substituent include those similar to the substituents of Z ^ia and Z ^ib . In addition, as for this substituent, 1 piece may be substituted by single or multiple, and 2 or more types may be substituted by arbitrary combinations and ratios.
However, R ^{1 to} R ⁴ are preferably selected from atoms such as a hydrogen atom and a halogen atom in order to improve the planarity of the molecule.

In formula (I) and formula (II), M represents a divalent metal atom or an atomic group in which a trivalent or higher metal and another atom are bonded.
When M is a divalent metal atom, examples thereof include Zn, Cu, Fe, Ni, Co and the like. On the other hand, when M is a trivalent or more metal and other atomic group and is bonded atoms, ^{examples, Fe-B 1, Al-} B 2, Ti = O, and Si-B ³ B ⁴ Can be mentioned. Here, B ¹ , B ² , B ³ and B ⁴ each represent a monovalent group such as a halogen atom, an alkyl group, or an alkoxy group.

  Furthermore, the benzoporphyrin compound according to the present invention has, for example, one atom shared by two porphyrin rings and two porphyrin rings sharing one or more atoms or atomic groups. Or three or more of them joined together and connected on a long chain.

  Specific examples of preferable benzoporphyrin compounds according to the present invention are given below. However, the benzoporphyrin compound according to the present invention is not limited to the following examples. In addition, here, molecular structures with good symmetry are mainly exemplified, but an asymmetric structure based on a combination of partial structures can also be used.

[2. Soluble precursor of benzoporphyrin compound]
The benzoporphyrin compound according to the present invention described above can be obtained by performing thermal conversion on the soluble precursor of the benzoporphyrin compound according to the present invention. Hereinafter, the soluble precursor will be described.

The soluble precursor according to the present invention can be converted into the benzoporphyrin compound according to the present invention by thermal conversion. The structure is arbitrary as long as it has a bicyclo ring and can be converted into the benzoporphyrin compound according to the present invention by thermal conversion.
However, the soluble precursor according to the present invention is preferably a compound represented by the following formula (III) or (IV).

（前記式（III）及び（IV）中、Ｚ^ia及びＺ^ib（ｉは１〜４の整数を表わす）は、各々独立に、１価の原子又は原子団を表わす。ただし、Ｚ^iaとＺ^ibとが結合して環を形成していてもよい。Ｒ¹〜Ｒ⁴は、各々独立に、１価の原子又は原子団を表わす。Ｙ¹〜Ｙ⁴は、各々独立に、１価の原子又は原子団を表わす。Ｍは、２価の金属原子、又は、３価以上の金属と他の原子とが結合した原子団を表わす。）

(In the formulas (III) and (IV), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represents a monovalent atom or atomic group, provided that Z ^ia and Z ^ib may be bonded to form a ring, R ^{1 to} R ⁴ each independently represents a monovalent atom or atomic group, and Y ¹ to Y ⁴ each independently represents a monovalent atom. M represents an atomic group in which a divalent metal atom or a trivalent or higher metal is bonded to another atom.

In the formulas (III) and (IV), Z ^ia , Z ^ib , R ^{1 to} R ⁴ and M are the same as those in the formulas (I) and (II), respectively.

In the formulas (III) and (IV), Y ^{1 to} Y ⁴ each independently represent a monovalent atom or atomic group. In the formulas (III) and (IV), there are four Y ¹ to Y ^4, but Y ¹ , Y ² , Y ³ , and Y ⁴ may be the same, May be different.

Examples of Y ¹ to Y ^4, as the atom, such as hydrogen atom.
On the other hand, examples of the atomic group include a hydroxyl group and an alkyl group. Here, the carbon number of the alkyl group is arbitrary as long as the effects of the present invention are not significantly impaired, but it is usually 1 or more, usually 10 or less, preferably 6 or less, more preferably 3 or less. When the carbon number of the alkyl group is too large, the leaving group becomes large, so that the leaving group is difficult to volatilize and may remain in the film. Examples of the alkyl group include a methyl group and an ethyl group.

Moreover, when Y < ¹ > -Y < ⁴ > is an atomic group, the said atomic group may have arbitrary substituents, unless the effect of this invention is impaired remarkably. Examples of the substituent include those similar to the substituents of Z ^ia and Z ^ib . In addition, as for this substituent, 1 piece may be substituted by single or multiple, and 2 or more types may be substituted by arbitrary combinations and ratios.

Among Y ¹ to Y ⁴ described above, a hydrogen atom or an alkyl group having 10 or less carbon atoms is preferable. Further, among them, all of Y ^{1 to} Y ⁴ are hydrogen atoms, or at least one of (Y ¹ , Y ² ) and (Y ³ , Y ⁴ ) is an alkyl having 10 or less carbon atoms. Particularly preferred is a group. This is because the solubility is increased and the film formability is improved.

The soluble precursor according to the present invention is converted into the benzoporphyrin compound according to the present invention by thermal conversion. There is no limitation on what kind of reaction occurs during the conversion. For example, in the case of the soluble precursor represented by the above formula (III) or (IV), the compound of the following formula (V) is removed by the application of heat. Release. This elimination reaction proceeds quantitatively. And the soluble precursor which concerns on this invention is converted into the benzoporphyrin compound which concerns on this invention by this elimination reaction.

The heat conversion will be specifically described by taking the benzoporphyrin compound BP-1 exemplified above as an example. As a soluble precursor of the benzoporphyrin compound BP-1, for example, in the formula (III), Z ^ia , Z ^ib , R ^{1 to} R ⁴ and Y ^{1 to} Y ⁴ are all hydrogen atoms (hereinafter referred to as “BP”). -1 precursor "). However, the soluble precursor of the benzoporphyrin compound BP-1 is not limited to this BP-1 precursor.

When the BP-1 precursor is heated, the ethylene group is released from each of the four rings bonded to the porphyrin ring. A benzoporphyrin compound BP-1 is obtained by this deethyleneation reaction. This conversion is represented by the following reaction formula.

  When the soluble precursor according to the present invention is converted into the benzoporphyrin compound according to the present invention by heat conversion, the temperature condition is not limited as long as the above reaction proceeds, but is usually 100 ° C or higher, preferably 150 ° C or higher. . If the temperature is too low, the conversion takes time, which may be undesirable in practice. Although an upper limit is arbitrary, it is 400 degrees C or less normally, Preferably it is 300 degrees C or less. This is because decomposition may occur if the temperature is too high.

  When the soluble precursor according to the present invention is converted into the benzoporphyrin compound according to the present invention by heat conversion, the heating time is not limited as long as the reaction proceeds, but usually 10 seconds or longer, preferably 30 seconds or longer, Usually, it is 100 hours or less, preferably 50 hours or less. If the heating time is too short, the conversion may be insufficient, and if it is too long, it may be unpreferable in practice.

  When the soluble precursor according to the present invention is converted into the benzoporphyrin compound according to the present invention by thermal conversion, the atmosphere is not limited as long as the reaction proceeds, but an inert atmosphere is preferable. Examples of the inert gas that can be used at this time include nitrogen and rare gases. In addition, an inert gas may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The soluble precursor according to the present invention has high solubility in a solvent such as an organic solvent. The specific degree of solubility depends on the type of solvent, but the solubility in chloroform at 25 ° C. is usually 0.1 g / L or more, preferably 0.5 g / L or more, more preferably 1 g / L or more. . In addition, although there is no restriction | limiting in an upper limit, it is 1000 g / L or less normally.

While the soluble precursor according to the present invention is highly soluble in a solvent, the benzoporphyrin compound according to the present invention derived therefrom has very low solubility in a solvent such as an organic solvent. This is because the structure of the soluble precursor according to the present invention is not a planar structure, so the solubility is high and it is difficult to crystallize, whereas the benzoporphyrin compound according to the present invention has a planar structure. Inferred. Therefore, if the difference in solubility in such a solvent is utilized, the layer containing the benzoporphyrin compound can be easily formed by a coating method. For example, it can be produced by the following method. That is, the soluble precursor according to the present invention is dissolved in a solvent to prepare a solution, and the solution is applied to form an amorphous layer or a good layer close to amorphous. And the layer of the benzoporphyrin compound with high planarity can be obtained by heat-processing this layer and converting the soluble precursor which concerns on this invention by heat conversion. At this time, as in the example described above, among the compounds represented by the formula (III) or (IV), those in which Y ^{1 to} Y ⁴ are all hydrogen atoms are used as soluble precursors. Since it is a molecule, it is difficult to remain in the system, and it is suitable in terms of toxicity and safety.

There is no restriction | limiting in the manufacturing method of the soluble precursor which concerns on this invention, A well-known method is employable arbitrarily. For example, taking the BP-1 precursor as an example, it can be produced through the following synthesis route. Here, Et represents an ethyl group, and t-Bu represents a t-butyl group.

[3. Organic photoelectric conversion element]
[3-1. Outline of organic photoelectric conversion device]
The organic photoelectric conversion device of the present invention includes at least a substrate, a pair of electrodes (that is, a positive electrode and a negative electrode), an electron donor layer including an electron donor formed between the electrodes, and an electron acceptor. And an electron acceptor layer formed between the electrodes. However, the electron donor layer and the electron acceptor layer may be formed as separate layers, or a single layer may function as the electron donor layer and the electron acceptor layer. Good.

  The active layer is composed of the electron donor layer and the electron acceptor layer. That is, the active layer refers to a layered structure composed of an electron donor layer and an electron acceptor layer when the electron donor layer and the electron acceptor layer are formed as separate layers. When the electron donor layer and the electron acceptor layer are formed as a single layer, the electron donor layer and the electron acceptor layer are the same layer (bulk hetero Bonding type).

Moreover, the organic photoelectric conversion element of this invention is normally provided with the p-type semiconductor layer and the n-type semiconductor layer, and is provided with the said active layer between this p-type semiconductor layer and an n-type semiconductor layer.
Furthermore, when the electron donor layer and the electron acceptor layer are formed as a single active layer, the organic photoelectric conversion element of the present invention contains a benzoporphyrin compound separately from the active layer. It is preferable to provide an electron donor layer (benzoporphyrin compound layer).

Moreover, the organic photoelectric conversion element of this invention may be equipped with components other than the above-mentioned unless the effect of this invention is impaired remarkably.
However, in the organic photoelectric conversion element of the present invention, at least one layer of the electron donor layer (including the case where the active layer itself is an electron donor layer and the case where the electron donor does not constitute an active layer) The electron donor is formed by including the benzoporphyrin compound according to the present invention.

  Furthermore, when manufacturing the organic photoelectric conversion element of this invention, the soluble precursor which concerns on this invention is converted into the benzoporphyrin compound which concerns on this invention by heat conversion, and an electron donor layer is formed. Generally, the electron donor layer containing a benzoporphyrin compound can be formed by a vacuum deposition method or a wet coating method. However, in the case of the conventional wet coating method, the benzoporphyrin compound is difficult to apply because of its low solubility in organic solvents. On the other hand, if the soluble precursor according to the present invention is used to perform heat conversion after coating film formation, an electron donor layer made of a benzoporphyrin compound can be easily formed.

  In this case, it is also possible to control the crystallinity and shape of the resulting layer. That is, after forming a film by a wet method using a soluble precursor of a benzoporphyrin compound, the benzoporphyrin compound having high planarity can be used in a crystalline state by heat conversion to a benzoporphyrin compound by heat treatment. Thereby, while improving the mobility as an electron donor, it is possible to improve the photoelectric conversion characteristic of an organic photoelectric conversion element through making a contact with an electron acceptor effective. Moreover, it becomes possible to improve the characteristics of the organic photoelectric conversion element by providing the benzoporphyrin compound between the active layer and the positive electrode (in the case where a p-type semiconductor layer is provided, the p-type semiconductor).

  Hereinafter, the organic photoelectric conversion element of the present invention will be described in more detail with reference to embodiments. However, the present invention is not limited to the following embodiments. In addition, components appearing in the following embodiments can be implemented in any combination without departing from the gist of the present invention.

[3-2. First Embodiment]
In FIG. 1, typical sectional drawing of the organic photoelectric conversion element as 1st Embodiment of this invention is shown. As shown in FIG. 1, the organic photoelectric conversion element 1 of this embodiment includes a substrate 2, a positive electrode 3, a p-type semiconductor layer 4, an electron donor layer 5, an electron acceptor layer 6, and an n-type. The semiconductor layer 7 and the negative electrode 8 are provided. In the organic photoelectric conversion element 1, an active layer 9 is constituted by the electron donor layer 5 and the electron acceptor layer 6.

〔substrate〕
The substrate 2 serves as a support for the organic photoelectric conversion element 1. Accordingly, the positive electrode 3, the p-type semiconductor layer 4, the active layer 9 (that is, the electron donor layer 5 and the electron acceptor layer 6), the n-type semiconductor layer 7, and the negative electrode 8 are provided on the substrate 2.

  The material of the substrate 2 (substrate material) is arbitrary as long as the effects of the present invention are not significantly impaired. However, in this embodiment, since light is taken into the organic photoelectric conversion element 1 through the substrate 2, a transparent material is used as the substrate material. Since visible light is usually taken into the organic photoelectric conversion element 1 among light, the transparent substrate material has a visible light transmittance of 60% or more, particularly 80%, which is transmitted through the substrate 2. It is preferable to use one that is at least%.

  From this point of view, preferable examples of the substrate material include inorganic materials such as quartz and glass; organic materials such as plastic. Among these, glass; synthetic resins such as polyester, polymethacrylate, polycarbonate, polysulfone are preferable. In addition, only 1 type may be used for a board | substrate material and it may use 2 or more types together by arbitrary combinations and a ratio.

  However, when a synthetic resin is used as the substrate material, it is preferable to pay attention to gas barrier properties. If the gas barrier property of the substrate 2 is too low, the organic photoelectric conversion element 1 may be deteriorated by outside air passing through the substrate 2. For this reason, when forming the board | substrate 2 with a synthetic resin, it is preferable to form the layer (gas barrier layer) which has a gas barrier property in the one side or both sides of the said synthetic resin board | substrate. Examples of the gas barrier layer include a dense silicon oxide film.

There is no restriction | limiting in the shape of the board | substrate 2, For example, shapes, such as a board, a film, a sheet | seat, can be used.
There is no limitation on the thickness of the substrate 2. However, it is preferably 5 μm or more, especially 20 μm or more, and usually 20 mm or less, especially 10 mm or less. If the substrate 2 is too thin, the strength for holding the organic photoelectric conversion element 1 may be insufficient, and if it is too thick, the cost may increase or the weight may become too heavy.

[Positive electrode]
A positive electrode 3 is formed on the substrate 2. The positive electrode 3 is an electrode that plays a role of receiving holes separated by charge in the active layer 9 through the p-type semiconductor layer 4.
The material of the positive electrode 3 (positive electrode material) is arbitrary as long as it has conductivity, as long as the effects of the present invention are not significantly impaired. However, in this embodiment, since light is taken into the organic photoelectric conversion element 1 through the positive electrode 3, a transparent material is used as the positive electrode material. Since visible light is usually taken into the organic photoelectric conversion element 1 among light, the transparent positive electrode material has a visible light transmittance of usually 60% or more, particularly 80%. It is preferable to use one that is at least%.

  From this point of view, preferable examples of the positive electrode material include metal oxides such as indium tin oxide and indium zinc oxide. In addition, a positive electrode material may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no limitation on the thickness of the positive electrode 3. However, it is usually preferably 10 nm or more, especially 50 nm or more, and usually 1000 nm or less, especially 300 nm or less. If the positive electrode 3 is too thick, the transparency may be reduced and the cost may be high. If the positive electrode 3 is too thin, the series resistance may be large and the performance may be deteriorated.

[P-type semiconductor layer]
A p-type semiconductor layer 4 is usually provided on the positive electrode 3.
As a material of the p-type semiconductor layer 4 (p-type semiconductor material), a material that can efficiently transport holes generated in the active layer 9 (in particular, the electron donor layer 5 in the present embodiment) to the positive electrode 3 is preferable. For this purpose, the p-type semiconductor material has high hole mobility, high conductivity, a small hole injection barrier between the positive electrode 3 and the active layer 9 (particularly, in this embodiment, electron donation). It is preferable that the hole injection barrier from the body layer 5) to the p-type semiconductor layer 4 has a small property.

  Furthermore, in this embodiment, since light is taken into the organic photoelectric conversion element 1 through the p-type semiconductor layer 4, a transparent material is used as the p-type semiconductor material. Since visible light is usually taken into the organic photoelectric conversion element 1 among the light, the transparent p-type semiconductor material has a visible light transmittance of normally 60 through the p-type semiconductor layer 4. %, More preferably 80% or more.

  Furthermore, in order to reduce the manufacturing cost and increase the area of the organic photoelectric conversion element 1, an organic semiconductor material is used as the p-type semiconductor material, and the p-type semiconductor layer is formed as a p-type organic semiconductor layer. Is preferred.

  From this point of view, a suitable example of the p-type semiconductor material includes a porphyrin compound or a phthalocyanine compound. These compounds may have a central metal or may be metal-free. Specific examples thereof include 29H, 31H-phthalocyanine, copper (II) phthalocyanine, zinc (II) phthalocyanine, titanium phthalocyanine oxide, copper (II) 4,4 ′, 4 ″, 4 ′ ″-tetraaza-29H. , 31H-phthalocyanine and the like; and porphyrin compounds such as tetrabenzoporphyrin, tetrabenzocopper porphyrin, and tetrabenzozinc porphyrin;

Examples of preferable p-type semiconductor materials other than porphyrin compounds and phthalocyanine compounds include a system in which a dopant is mixed with a hole transporting polymer. In this case, examples of the hole transporting polymer include poly (ethylenedioxythiophene), polythiophene, polyaniline, polypyrrole, and the like. On the other hand, examples of the dopant include iodine; acids such as poly (styrene sulfonic acid) and camphor sulfonic acid; Lewis acids such as PF ₅ , AsF ₅ and FeCl ₃ ;
In addition, a p-type semiconductor material may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no limitation on the thickness of the p-type semiconductor layer 4. However, it is usually preferably 3 nm or more, especially 10 nm or more, and usually 200 nm or less, especially 100 nm or less. If the p-type semiconductor layer 4 is too thick, the transmittance may decrease or the series resistance may increase. If the p-type semiconductor layer 4 is too thin, a non-uniform film may be formed.

(Electron donor layer)
Of the layers constituting the active layer 9, the electron donor layer 5 is a layer formed including an electron donor, and is provided on the p-type semiconductor layer 4. The electron donor contained in the electron donor layer 5 has properties such as efficiently absorbing visible light and having high mobility to efficiently transport light-induced holes. It is preferable. Furthermore, in addition to the general requirements described above, when considering outdoor applications, the electron donor preferably has a heat resistance of usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 150 ° C. or higher.

  Examples of such electron donors include benzoporphyrin compounds according to the present invention. And in the organic photoelectric conversion element 1 of this embodiment, the benzoporphyrin compound according to the present invention is contained in the electron donor layer 5 as an electron donor. In addition, the benzoporphyrin compound concerning this invention may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, the electron donor layer 5 may contain other electron donors as long as the effects of the present invention are not significantly impaired. For example, condensed aromatic hydrocarbons such as naphthacene, pentacene, pyrene and fullerene; oligomers such as α-sexithiophene; macrocyclic compounds such as phthalocyanine and porphyrin; α-sexithiophene and dialkylsexithiophene And oligothiophenes containing four or more thiophene rings represented by the above; those having a total of four or more thiophene rings, benzene rings, fluorene rings, naphthalene rings, anthracene rings, thiazole rings, thiadiazole rings, and benzothiazole rings; Condensed thiophene such as anthradithiophene, dibenzothienobisthiophene, α, α′-bis (dithieno [3,2-b ′: 2 ′, 3′-d] thiophene) and derivatives thereof; polythiophene, polyfluorene, polythieni Lembinylene, polyphenylenevinylene, polyphe Ren, polyacetylene, polypyrrole, polyaniline, and the like. Among these, polymers exhibiting self-organization such as regioregular polythiophene, and polymers exhibiting liquid crystallinity represented by polyfluorene and copolymers thereof are preferable. In addition, only 1 type may be used also for another electron donor, and 2 or more types may be used together by arbitrary combinations and a ratio.

  However, when the electron donor layer 5 contains the benzoporphyrin compound according to the present invention, it is preferable to use a large amount of the benzoporphyrin compound according to the present invention as the electron donor. Specifically, it is preferable that 50% by weight or more, particularly 70% by weight or more, more preferably 90% by weight or more of the electron donor is the benzoporphyrin compound according to the present invention, and the benzoporphyrin compound according to the present invention. It is particularly preferable to use only. This is because the advantage of using the benzoporphyrin compound according to the present invention is effectively exhibited.

  The thickness of the electron donor layer 5 is not limited. However, it is usually preferably 5 nm or more, especially 10 nm or more, and usually 500 nm or less, especially 200 nm or less. If the electron donor layer 5 is too thick, the series resistance may increase, and if it is too thin, the light absorption necessary for photoelectric conversion may not be sufficiently obtained.

(Electron acceptor layer)
On the other hand, among the layers constituting the active layer 9, the electron acceptor layer 6 is a layer formed including an electron acceptor, and is provided on the electron donor layer 5. The electron acceptor contained in the electron acceptor layer 6 has a function of efficiently separating the electrons generated at the bonding interface with the electron donor and transporting them to the n-type semiconductor layer 7.

  In order to efficiently transfer electrons from the electron donor layer 5 to the electron acceptor layer 6, the relative relationship between the minimum empty orbit (LUMO) of the materials used for each electron donor layer 5 and the electron acceptor layer 6 is is important. Specifically, the LUMO of the electron donor that is the material of the electron donor layer 5 is higher than the LUMO of the electron acceptor that is the material of the electron acceptor layer 6 by a predetermined energy, in other words, the electron acceptor. It is preferable that the electron affinity of the body is larger than the electron affinity of the electron donor by a predetermined energy. The value of the predetermined energy varies depending on the application, but is usually 0.1 eV or more, preferably 0.2 eV or more, more preferably 0.3 eV or more, and usually 0.6 eV or less, preferably 0.4 eV or less. It is.

Examples of the electron acceptor that satisfies such conditions include a fullerene compound. Among these, specific examples of preferable fullerene compounds include the following.

  When the fullerene compound as described above is used as an electron acceptor, the organic photoelectric conversion element 1 includes the electron donor layer 5 containing the benzoporphyrin compound according to the present invention and the electron acceptor layer 6 containing the fullerene compound. become. In this case, the photoelectric conversion characteristics are improved, which is particularly preferable.

  Moreover, as an electron acceptor, things other than a fullerene compound may be used together with a fullerene compound, or may be used in place of a fullerene compound. However, when the electron acceptor layer 6 contains a fullerene compound, it is preferable to use a lot of fullerene compounds as the electron acceptor. Specifically, among the electron acceptors, usually 50% by weight or more, particularly 70% by weight or more, more preferably 90% by weight or more is preferably a fullerene compound, and it is particularly preferable to use only a fullerene compound. This is because the advantage of using the fullerene compound is effectively exhibited.

In addition, an electron acceptor may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio.
There is no limitation on the thickness of the electron acceptor layer 6. However, it is usually preferably 5 nm or more, especially 10 nm or more, and usually 500 nm or less, especially 200 nm or less. If the electron acceptor layer 6 is too thick, the series resistance may be increased, and if it is too thin, the coverage may be deteriorated.

[N-type semiconductor layer]
An n-type semiconductor layer 7 is usually provided on the electron acceptor layer 6. The role required for the n-type semiconductor layer 7 is that the exciton (exciton) generated by absorbing light in the active layer 9 (that is, the electron donor layer 5 and the electron acceptor layer 6) is quenched by the negative electrode 8. It is to prevent. For that purpose, it is preferable that the material of the n-type semiconductor layer 7 (n-type semiconductor material) has an optical gap larger than that of the electron donor and the electron acceptor.

From this point of view, preferable examples of n-type semiconductor materials include organic compounds exhibiting electron transport properties such as phenanthroline derivatives and silole derivatives; inorganic semiconductors such as TiO ₂ . In addition, n type semiconductor material may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no limitation on the thickness of the n-type semiconductor layer 7. However, it is preferably 2 nm or more, particularly 5 nm or more, and usually 200 nm or less, particularly 100 nm or less. By forming the n-type semiconductor layer 7 in such a thickness range, when light incident from the positive electrode 3 is transmitted without being absorbed by the active layer 9, it is reflected by the negative electrode 8 and returns to the active layer 9 again. It is possible to utilize the optical interference effect by

[Negative electrode]
A negative electrode 8 is formed on the n-type semiconductor layer 7. The negative electrode 8 is an electrode that plays a role of receiving electrons separated in the active layer 9 through the n-type semiconductor layer 7.
The material of the negative electrode 8 (negative electrode material) is arbitrary as long as it has conductivity, as long as the effects of the present invention are not significantly impaired. However, in order to collect electrons efficiently, it is preferable to use a metal having good contact with the n-type semiconductor layer 7.

From this point of view, a suitable example of the negative electrode material is an appropriate metal such as magnesium, indium, calcium, aluminum, silver, or an alloy thereof.
Furthermore, inserting an ultra-thin insulating film (0.1-5 nm) such as LiF, MgF ₂ , Li ₂ O, for example, at the interface between the negative electrode 8 and the n-type semiconductor layer 7 also increases the efficiency of the organic photoelectric conversion element 1. It is an effective way to improve.

  There is no limitation on the thickness of the negative electrode 8. However, it is usually preferably 10 nm or more, especially 50 nm or more, and usually 1000 nm or less, especially 500 nm or less. If the negative electrode 8 is too thick, the process takes time and costs may increase, which may be undesirable in practice, and if it is too thin, the series resistance may increase and efficiency may decrease.

〔Production method〕
The organic photoelectric conversion element 1 of this embodiment is manufactured through a step of converting the soluble precursor according to the present invention into the benzoporphyrin compound according to the present invention by thermal conversion in the step of forming the electron donor layer 5. be able to. A specific manufacturing method is as follows, for example.

  First, the substrate 2 is prepared, and the positive electrode 3 is formed thereon (positive electrode forming step). Although there is no restriction | limiting in the formation method of the positive electrode 3, For example, it can form by sputtering method, a vacuum evaporation method, etc.

  Next, the p-type semiconductor layer 4 is formed on the positive electrode 3 (p-type semiconductor layer forming step). Although there is no restriction | limiting in the formation method of the p-type semiconductor layer 4, For example, when using the p-type semiconductor material which has sublimation property, it can form by a vacuum evaporation method etc. In addition, for example, when a p-type semiconductor material soluble in a solvent is used, it can be formed by a wet coating method such as spin coating or ink jet.

  Then, the electron donor layer 5 is formed on the p-type semiconductor layer 4 (electron donor layer forming step). When forming the electron donor layer 5, first, the soluble precursor according to the present invention is dissolved in a solvent to prepare a precursor solution. At this time, a soluble precursor corresponding to the benzoporphyrin compound contained in the electron donor layer 5 is used. In addition, only 1 type may be used for a soluble precursor and it may use 2 or more types together by arbitrary combinations and a ratio.

  The type of the solvent used in the precursor solution is arbitrary as long as the electron donor layer 5 is obtained. For example, aromatic hydrocarbons such as toluene, benzene, xylene, chlorobenzene; methanol, ethanol, propanol, butanol Lower alcohols such as acetone; ketones such as acetone, methyl ethyl ketone, cyclopentanone and cyclohexanone; esters such as ethyl acetate, butyl acetate and methyl lactate; nitrogen-containing organic solvents such as pyridine and quinoline; chloroform, methylene chloride and dichloroethane , Halogenated hydrocarbons such as trichloroethane and trichloroethylene; ethers such as ethyl ether, tetrahydrofuran and dioxane; amides such as dimethylformamide and dimethylacetamide; In addition, only 1 type may be used for a solvent and it may use 2 or more types together by arbitrary combinations and a ratio.

  The concentration of the soluble precursor in the precursor solution is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1 g / L or more, preferably 0.5 g / L or more, more preferably 1 g / L or more, Moreover, it is 1000 g / L or less normally, Preferably it is 500 g / L or less, More preferably, it is 200 g / L or less.

  Then, the prepared precursor solution is apply | coated to the p-type semiconductor layer 4, and a coating film (application layer, precursor layer) is formed. There is no restriction | limiting in the method at the time of application | coating, For example, a spin coat method, a dip coat method, a spray coat method, an inkjet method etc. can be used.

And this application layer is heat-processed. Thereby, since the soluble precursor which concerns on this invention is converted into the benzoporphyrin compound which concerns on this invention by heat conversion, the said coating layer can be converted into the electron donor layer 5. FIG. Conditions such as temperature, pressure, time, and atmosphere during heat conversion are described in [2. As described above in the section of soluble precursor of benzoporphyrin compound]. In addition, before performing heat conversion, you may dry and remove a solvent from an application layer. In that case, the coating layer is amorphous or a good layer close to amorphous.
In addition, when using things other than the benzoporphyrin compound concerning this invention as an electron donor together, what is necessary is just to dissolve or disperse | distribute the electron donor used together in the said solution.

  As described above, the soluble precursor according to the present invention is thermally converted to form a layer of a benzoporphyrin compound having a highly planar molecular structure, whereby crystallization and a thin film shape can be controlled. For this reason, the hole mobility in the electron donor layer 5 can be increased, and the contact between the electron donor layer 5 and the electron acceptor layer 6 can be maximized. And it is guessed by this that the photoelectric conversion characteristic of the manufactured organic photoelectric conversion element 1 can be improved compared with the past.

  After the formation of the electron donor layer 5, the electron acceptor layer 6 is formed (electron acceptor layer forming step). Although there is no restriction | limiting in the formation method of the electron acceptor layer 6, For example, it is preferable to form an electron acceptor by laminating | stacking on the electron donor layer 5 with a wet coating method or a vacuum evaporation method.

  The wet coating method is a method that can be adopted when the electron acceptor is soluble. When this method is used, it is preferable to form the electron acceptor layer 6 from the liquid phase by a coating method as follows. That is, first, an electron acceptor solution containing an electron acceptor is prepared. The type of the solvent used for the electron acceptor solution is arbitrary as long as the electron acceptor layer 6 is obtained. For example, the same solvent as the solvent used for the precursor solution can be used. In addition, only 1 type may be used for a solvent and it may use 2 or more types together by arbitrary combinations and a ratio.

  The concentration of the electron acceptor in the electron acceptor solution is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1 g / L or more, preferably 1 g / L or more, more preferably 5 g / L or more, Usually, it is 1000 g / L or less, preferably 500 g / L or less, more preferably 200 g / L or less.

  Thereafter, the prepared electron acceptor solution is applied to the electron donor layer 5 made of a benzoporphyrin compound thermally converted from a soluble precursor to form a coating layer. Then, the electron acceptor layer 6 is formed by drying and removing the solvent from the coating layer.

  Since the thin-film shape of the benzoporphyrin compound crystallized by heat conversion is composed of very small crystallites, the electron acceptor is formed into each crystal of the electron donor layer 5 by forming the electron acceptor layer 6 by the above coating method. It is possible to intrude between the children. Accordingly, as a result, the contact area between the electron donor and the electron acceptor is increased, conversion efficiency and photocurrent can be increased, and good photoelectric conversion characteristics can be exhibited.

  On the other hand, when the vacuum deposition method is used, the electron acceptor may be stacked by vacuum deposition after the formation of the electron donor layer 5, but the electron acceptor layer 5 and the electron acceptor layer 5 are formed by the method described below. 6 is preferably formed in a series of steps. That is, in the same manner as described in the electron donor layer forming step, a step of forming a layer of the soluble precursor according to the present invention is performed by a coating method. In addition, this layer may remove the solvent, and may contain the solvent. Next, a step of forming an electron acceptor layer 6 is performed by depositing an electron acceptor on the soluble precursor layer by vacuum deposition. Thereafter, a heat treatment is performed to convert the soluble precursor into a benzoporphyrin compound by heat conversion, and the electron donor layer 5 is formed.

  According to this method, crystallization proceeds by converting the soluble precursor into a benzoporphyrin compound, and molecular rearrangement including the electron acceptor layer 6 occurs during the crystallization. Therefore, finally, the boundary between the electron donor layer 5 and the electron acceptor layer 6 has a structure in which both layers diffuse and penetrate each other, the contact area between the electron donor and the electron acceptor increases, Conversion characteristics will be improved.

  After the electron acceptor layer 6 is formed, an n-type semiconductor layer 7 is formed (n-type semiconductor layer forming step). Although there is no restriction | limiting in the formation method of the n-type semiconductor layer 7, For example, similarly to the p-type semiconductor layer 4, it can form by the vacuum evaporation method or the wet apply | coating method.

Thereafter, the negative electrode 8 is formed on the n-type semiconductor layer 7 (negative electrode forming step). Although there is no restriction | limiting in the formation method of the negative electrode 8, For example, similarly to the positive electrode 3, it can form by sputtering method, a vacuum evaporation method, etc.
The organic photoelectric conversion element 1 of this embodiment can be manufactured by the above process.

[Main advantages of the organic photoelectric conversion element of this embodiment]
Since the organic photoelectric conversion element 1 of the present embodiment is configured as described above, it can take in light, generate holes and electrons in the active layer 9, and extract them to the positive electrode 3 and the negative electrode 8. It has become. In this case, the organic photoelectric conversion element 1 of the present embodiment increases the contact area between the electron donor and the electron acceptor and improves the mobility as compared with the conventional organic photoelectric conversion element. Excellent photoelectric conversion characteristics.

  The specific value of the photoelectric conversion characteristic exhibited by the organic photoelectric conversion element 1 of the present embodiment is arbitrary. However, as specific indexes, it is preferable to satisfy at least one of the following indexes, and all of them.

  That is, in the organic photoelectric conversion element 1 of the present embodiment, the open circuit voltage (Voc) is usually 0.3 V or higher, preferably 0.4 V or higher, more preferably 0.5 V or higher. There is no limit on the upper limit.

In the organic photoelectric conversion element 1 of the present embodiment, the short circuit current (Jsc) is usually 1 mA / cm ² or more, preferably 3 mA / cm ² or more, more preferably 5 mA / cm ² or more. There is no limit on the upper limit.

  In the organic photoelectric conversion element 1 of the present embodiment, the energy conversion efficiency (ηp) is usually 0.5% or more, preferably 1.0% or more, and more preferably 1.5% or more. There is no limit on the upper limit.

  In the organic photoelectric conversion element 1 of the present embodiment, the form factor (FF) is usually 0.3 or more, preferably 0.4 or more, more preferably 0.5 or more. There is no limit on the upper limit.

The open-circuit voltage (Voc), short-circuit current (Jsc), energy conversion efficiency (ηp), and form factor (FF) were measured using organic simulators with a solar simulator (AM1.5G) light intensity of 100 mW / cm ^2. It is a value measured by irradiating the conversion element 1 and measuring voltage-current characteristics.

[Others]
The organic photoelectric conversion element 1 of the present embodiment can be implemented by further changing the configuration described above.
For example, the substrate 2 may be formed on the negative electrode 8 side, or may be formed on both the positive electrode 3 and the negative electrode 8 sides.
For example, the p-type or n-type semiconductor layers 4 and 7 may not be provided. In that case, the positive electrode 3 and the negative electrode 8 play a role of receiving holes and electrons generated from the active layer 9 without passing through the p-type or n-type semiconductor layers 4 and 7.

Furthermore, for example, in the first embodiment, light is taken in from the positive electrode 3 side, but may be from the negative electrode 8 side. In that case, in order to make at least one of the positive electrode 3 and the negative electrode 8 and at least one of the p-type semiconductor 4 and the n-type semiconductor layer 7 transparent, the n-type semiconductor 7 and the negative electrode 8 are formed transparently.
For example, each layer constituting the organic photoelectric conversion element 1 may contain one or more components other than the above-described constituent materials as long as the effects of the present invention are not significantly impaired.

  Further, for example, the organic photoelectric conversion element 1 has the above-described substrate 2, positive electrode 3, p-type semiconductor layer 4, electron donor layer 5, electron acceptor layer 6, and n-type semiconductor unless the effects of the present invention are significantly impaired. Layers and components other than the layer 7 and the negative electrode 8 may be provided. As a specific example, a protective layer (not shown) may be formed so as to cover the negative electrode 8.

  Further, for example, in the method for producing the organic photoelectric conversion element 1, the heat treatment for causing the soluble precursor to undergo thermal conversion may be performed any time after the formation of the soluble precursor layer. As a specific example, a soluble precursor layer is formed on the p-type semiconductor layer 4, and then the electron acceptor layer 6, the n-type semiconductor layer 7 and the negative electrode 8 are formed thereon without performing thermal conversion. And finally, you may make it heat-process.

[3-3. Second Embodiment]
In FIG. 2, typical sectional drawing of the organic photoelectric conversion element as 2nd Embodiment of this invention is shown. As shown in FIG. 2, the organic photoelectric conversion element 10 of this embodiment includes a substrate 2, a positive electrode 3, a p-type semiconductor layer 4, an electron donor layer 5, an active layer 11, and an n-type semiconductor layer. 7 and a negative electrode 8. That is, the configuration is the same as that of the organic photoelectric conversion element 1 of the first embodiment except that the active layer 11 is provided instead of the electron acceptor layer 6.

[Substrate, positive electrode and p-type semiconductor layer]
The substrate 2, the positive electrode 3, and the p-type semiconductor layer 4 are the same as in the first embodiment.

(Electron donor layer)
The configuration of the electron donor layer 5 is the same as that of the first embodiment. However, the electron donor layer 5 is formed as a layer different from the active layer 11.

  In the electron donor layer 5 formed separately from the active layer 11 as described above, the benzoporphyrin compound according to the present invention is used as the electron donor, as in the first embodiment. Thereby, the electron donor layer 5 functions as a benzoporphyrin compound layer containing the benzoporphyrin compound according to the present invention. That is, the organic photoelectric conversion element 10 includes an active layer 11 and a benzoporphyrin compound layer formed between the active layer 11 and the positive electrode 3 (or the p-type semiconductor layer 4 when the p-type semiconductor layer 4 is provided). Will be provided.

[Active layer]
The active layer 11 of this embodiment is a mixed active layer containing an electron donor and an electron acceptor in the same layer. Accordingly, the active layer 11 functions as an electron donor layer and also functions as an electron acceptor layer.
The electron acceptor used for the active layer 11 is the same as the electron acceptor used for the electron acceptor layer 6 of the first embodiment.

  On the other hand, the electron donor used for the active layer 11 is not limited and any electron donor can be used. At this time, the electron donor may be used alone or in combination of two or more in any combination and ratio. Therefore, the benzoporphyrin compound according to the present invention can be used as the electron donor of the active layer 11 as in the first embodiment.

  However, in this embodiment, it is preferable to use an electron donor other than the benzoporphyrin compound according to the present invention. In this embodiment, the active layer 11 is formed as a mixed layer of an electron donor and an electron acceptor. However, when the active layer 11 is formed by forming the electron donor layer 5, the active layer 11 is formed. The electron acceptor can effectively contact not only the electron donor in the active layer 11 but also partly the benzoporphyrin compound in the electron donor layer 5. For this reason, if different types of electron donors are used in the electron donor layer 5 and the active layer 11, two types of electron donors having different absorption wavelength regions come into contact with the electron acceptor, thereby increasing the photocurrent. This is because it is possible to improve the photoelectric conversion characteristics.

Even if the active layer 11 does not contain the benzoporphyrin compound according to the present invention as an electron donor, in the present embodiment, the electron donor layer 5 contains a benzoporphyrin compound. The organic photoelectric conversion element 11 of the form contains the benzoporphyrin compound according to the present invention in at least one layer.
Therefore, in the present embodiment, the active layer 11 will be described on the assumption that an electron donor other than a benzoporphyrin compound (for example, copper phthalocyanine) is used.

  In the active layer 11, the ratio of the mixed electron donor and electron acceptor is arbitrary as long as the effect of the present invention is not significantly impaired, but the ratio of the electron donor to the total weight of the electron donor and the electron acceptor, Usually, it is preferably 5% or more, particularly 10% or more, particularly 15% or more, and usually 95% or less, especially 90% or less, particularly 85% or less. When there are too few or too many electron donors, there exists a possibility that a photoelectric conversion characteristic may fall.

  There is no limitation on the thickness of the active layer 11. However, it is usually preferably 5 nm or more, especially 10 nm or more, and usually 1000 nm or less, especially 500 nm or less. If the active layer 11 is too thick, the series resistance may increase, and if it is too thin, light absorption may be insufficient.

[N-type semiconductor layer and negative electrode]
In the organic photoelectric conversion element 10, the n-type semiconductor layer 7 and the negative electrode 8 are formed on the active layer 11. The n-type semiconductor layer 7 and the negative electrode 8 are the same as in the first embodiment.

〔Production method〕
In the step of forming the electron donor layer 5 which is a benzoporphyrin compound layer, the organic photoelectric conversion element 10 of the present embodiment converts the soluble precursor according to the present invention into the benzoporphyrin compound according to the present invention by thermal conversion. It can manufacture through the process to do. A specific manufacturing method is as follows, for example.

First, the substrate 2 is prepared, and the positive electrode 3 and the p-type semiconductor layer 4 are formed thereon in the same manner as described in the first embodiment.
Next, an electron donor layer 5 that is a benzoporphyrin compound layer is formed on the p-type semiconductor layer 4. Also in the present embodiment, as in the first embodiment, a soluble precursor according to the present invention is dissolved in a solvent to prepare a precursor solution, and the prepared precursor solution is applied to the p-type semiconductor layer 4 to obtain What is necessary is just to form the electron donor layer 5 by heat-processing the obtained coating layer, converting a soluble precursor into a benzoporphyrin compound by heat conversion.

  Then, the active layer 11 is formed on the electron donor layer 5. The active layer 11 may be formed by any method. For example, an electron donor and an electron acceptor may be laminated on the electron donor layer 5 by a wet coating method or a vacuum deposition method. Specifically, the electron acceptor layer forming step in the first embodiment may be performed except that an electron donor contained in the active layer 11 is used in addition to the electron acceptor. By adopting such a method, the same advantage as the electron acceptor layer forming step can be obtained at the boundary between the active layer 11 and the electron donor layer 5. That is, according to the wet coating method, the contact area between the electron donor and the electron acceptor is increased, conversion efficiency and photocurrent can be increased, and good photoelectric conversion characteristics can be exhibited. Moreover, if the electron donor layer 5 and the active layer 11 are formed in a series of steps by a vacuum deposition method, the boundary between the electron donor layer 5 and the active layer 11 has a structure in which both layers diffuse and penetrate each other. The contact area between the electron donor and the electron acceptor can be increased to improve the photoelectric conversion characteristics.

Thereafter, the n-type semiconductor layer 7 and the negative electrode 8 are formed in the same manner as described in the first embodiment.
The organic photoelectric conversion element 10 of this embodiment can be manufactured by the above process.

[Main advantages of the organic photoelectric conversion element of this embodiment]
Since the organic photoelectric conversion element 10 of the present embodiment is configured as described above, it can take in light, generate holes and electrons in the active layer 11, and extract them to the positive electrode 3 and the negative electrode 8. It has become. In this case, in the organic photoelectric conversion element 10 of the present embodiment, the electron acceptor and the benzoporphyrin compound can effectively contact not only inside the active layer 11 but also between the active layer 11 and the electron donor layer 5. For this reason, an increase in photocurrent is caused, so that the photoelectric conversion characteristics are excellent.

  The specific value of the photoelectric conversion characteristic exhibited by the organic photoelectric conversion element 10 of the present embodiment is arbitrary. However, the organic photoelectric conversion element 10 of the present embodiment also has the same open circuit voltage (Voc), short-circuit current (Jsc), energy conversion efficiency (ηp), and form factor (FF) as the organic photoelectric conversion element 1 of the first embodiment. And the maximum value of the external quantum efficiency can be realized.

[Others]
The organic photoelectric conversion element 10 of the present embodiment can be implemented by further changing the configuration described above. For example, the same change as described in the first embodiment may be performed.

For example, the benzoporphyrin compound according to the present invention can be used as the electron donor of the active layer 11. However, even in this case, it is preferable that the benzoporphyrin compound of the electron donor layer 5 and the benzoporphyrin compound of the active layer 11 contain different types. This is to increase the photocurrent and improve the photoelectric conversion characteristics. In addition, the manufacturing method of the active layer 11 in this case can be performed similarly to the electron donor layer formation process in 1st Embodiment except making an electron acceptor coexist in a precursor solution.
Furthermore, for example, an electron acceptor layer 6 may be provided between the active layer 11 and the n-type semiconductor layer 7 as in the third embodiment described later.

[3-4. Third Embodiment]
In FIG. 3, typical sectional drawing of the organic photoelectric conversion element as 3rd Embodiment of this invention is shown. As shown in FIG. 3, the organic photoelectric conversion element 12 of this embodiment includes a substrate 2, a positive electrode 3, a p-type semiconductor layer 4, an active layer 13, an electron acceptor layer 6, and an n-type semiconductor layer. 7 and a negative electrode 8. That is, the configuration is the same as that of the organic photoelectric conversion element 1 of the first embodiment except that the active layer 13 is provided instead of the electron donor layer 5.

[Substrate, positive electrode and p-type semiconductor layer]
The substrate 2, the positive electrode 3, and the p-type semiconductor layer 4 are the same as in the first embodiment.

[Active layer]
The active layer 13 of this embodiment is the same as the active layer 11 described in the second embodiment, except that it must contain the benzoporphyrin compound of the present invention as an electron donor. Under the present circumstances, only 1 type may be used for a benzoporphyrin compound and it may use 2 or more types together by arbitrary combinations and a ratio. In this case, the active layer 13 functions as an electron donor layer and also functions as an electron acceptor layer.

  By using the benzoporphyrin compound according to the present invention as the electron donor of the active layer 13, an advantage that high photoelectric conversion efficiency can be realized can be obtained.

(Electron acceptor layer)
The configuration of the electron acceptor layer 6 is the same as that of the first embodiment. However, the electron acceptor layer 6 is formed as a layer different from the active layer 13.

The electron acceptor layer 6 formed separately from the active layer 13 can be formed in the same manner as described in the first embodiment. However, even in that case, it is preferable that the electron acceptor of the electron acceptor layer 6 contains a different type from the electron acceptor of the active layer 13. In this embodiment, the active layer 13 is formed as a mixed layer of an electron donor and an electron acceptor. However, by forming the electron acceptor layer 6 between the n-type semiconductor layer 7, the active layer 13 in the active layer 13 is formed. The benzoporphyrin compound can effectively contact not only the electron acceptor in the active layer 13 but also partly the electron acceptor constituting the electron acceptor layer 6. For this reason, if different types of electron acceptors are used in the active layer 13 and the electron acceptor layer 6, two types of electron acceptors having different absorption wavelength regions come into contact with the benzoporphyrin compound, thereby increasing the photocurrent. This is because it is possible to improve the photoelectric conversion characteristics.
Therefore, in the present embodiment, the electron acceptor layer 6 will be described on the assumption that a different type of electron acceptor from that of the active layer 13 is used as the electron acceptor.

[N-type semiconductor layer and negative electrode]
In the organic photoelectric conversion element 12, an n-type semiconductor layer 7 and a negative electrode 8 are formed on the electron acceptor layer 6. The n-type semiconductor layer 7 and the negative electrode 8 are the same as in the first embodiment.

〔Production method〕
In the step of forming the active layer 13 that is an electron donor layer, the organic photoelectric conversion element 12 of the present embodiment is a step of converting the soluble precursor according to the present invention into the benzoporphyrin compound according to the present invention by thermal conversion. Can be manufactured. A specific manufacturing method is as follows, for example.

  First, the substrate 2 is prepared, and the positive electrode 3 and the p-type semiconductor layer 4 are formed thereon in the same manner as described in the first embodiment.

  Next, the active layer 13 is formed on the p-type semiconductor layer 4. The active layer 13 can be formed in the same manner as the electron donor layer forming step in the first embodiment except that an electron acceptor is allowed to coexist in the precursor solution.

Thereafter, the electron acceptor layer 6, the n-type semiconductor layer 7, and the negative electrode 8 are formed in the same manner as described in the first embodiment.
The organic photoelectric conversion element 10 of this embodiment can be manufactured by the above process.

[Main advantages of the organic photoelectric conversion element of this embodiment]
Since the organic photoelectric conversion element 12 of the present embodiment is configured as described above, it can take in light, generate holes and electrons in the active layer 13, and extract them to the positive electrode 3 and the negative electrode 8. It has become. In this case, the organic photoelectric conversion element 12 of the present embodiment can effectively contact the electron acceptor and the benzoporphyrin compound not only inside the active layer 13 but also between the active layer 13 and the electron acceptor layer 6. For this reason, an increase in photocurrent is caused, so that the photoelectric conversion characteristics are excellent.

  The specific value of the photoelectric conversion characteristic exhibited by the organic photoelectric conversion element 12 of the present embodiment is arbitrary. However, the organic photoelectric conversion element 12 of this embodiment also has the same open circuit voltage (Voc), short circuit current (Jsc), energy conversion efficiency (ηp), and form factor (FF) as those of the organic photoelectric conversion element 1 of the first embodiment. And the maximum value of the external quantum efficiency can be realized.

[Others]
The organic photoelectric conversion element 12 of the present embodiment can be implemented by further changing the configuration described above. For example, the same change as described in the first embodiment may be performed.

  For example, an electron donor layer (not shown) may be provided between the active layer 13 and the p-type semiconductor layer 4. This electron donor layer may contain the benzoporphyrin compound based on this invention, and does not need to contain it. At this time, when the benzoporphyrin compound is not contained as the electron donor or when a benzoporphyrin compound different from that used in the active layer 13 is used, the photocurrent is obtained in the same manner as in the second embodiment. This is preferable.

  Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples, and can be implemented with arbitrary modifications within the scope not departing from the gist of the present invention. In the following description of the embodiments, reference numerals shown in parentheses [] correspond to reference numerals displayed in the referenced drawings.

[Example 1]
An organic photoelectric light emitting device having the structure shown in FIG. 1 was produced by the following method.
That is, an indium tin oxide (ITO) transparent conductive film deposited at 145 nm (sheet resistance: 8.4Ω) on a glass substrate [2] is 2 mm wide using ordinary photolithography technology and hydrochloric acid etching. A transparent electrode [3] was formed by patterning into a stripe. The patterned transparent electrode [3] is cleaned in the order of ultrasonic cleaning with a surfactant, water cleaning with ultra pure water, and ultrasonic cleaning with ultra pure water, followed by drying with nitrogen blow, and finally UV ozone cleaning. It was.

  On this transparent substrate [3], poly (ethylenedioxythiophene): poly (styrenesulfonic acid) (PEDOT: PSS, manufactured by Starck Vitec Co., Ltd., product name Baytron PH), which is a conductive polymer, has a thickness of 40 nm. After spin coating, the substrate was heat-dried at 120 ° C. for 10 minutes in the air, and then heat-treated at 180 ° C. for 3 minutes in nitrogen to form a p-type organic semiconductor layer [4].

  Next, the BP-1 precursor, which is a precursor of the benzoporphyrin compound BP-1, is spin-coated on the p-type organic semiconductor layer [4] using a solution obtained by dissolving 0.25 wt% in chloroform. did. After the application, heat treatment was performed at 210 ° C. for 30 minutes on a hot plate. By this heat treatment, the brown precursor film was thermally converted to a green BP-1 film, and a crystalline electron donor layer [5] having an average film thickness of 45 nm was obtained.

  Subsequently, spin coating was performed on the electron donor layer [5] made of benzoporphyrin using a solution of fullerene compound F-4 (commonly known as PCBM) dissolved in 1.2% by weight of chlorobenzene. After coating, heat treatment was performed at 150 ° C. for 10 minutes, and an electron acceptor layer [6] having an average film thickness of 40 nm was laminated.

Next, the substrate [2] on which the series of organic layers [4], [5] and [6] were formed was placed in a vacuum deposition apparatus. After roughly exhausting the vacuum deposition apparatus using an oil rotary pump, the vacuum deposition apparatus was evacuated using a cryopump until the degree of vacuum in the vacuum deposition apparatus reached 1.9 × 10 ⁻⁴ Pa. And the phenanthroline derivative (common name BCP) shown below was put into the metal boat arrange | positioned in a vacuum evaporation system, it heated, and the phenanthroline derivative was vapor-deposited. The degree of vacuum at the time of vapor deposition was 1.7 × 10 ⁻⁴ Pa, and the vapor deposition rate was 1.0 nm / second. As a result, a film having a thickness of 6 nm was laminated on the electron acceptor layer [6] to complete the n-type semiconductor layer [7].

Subsequently, a 2 mm wide stripe-shaped shadow mask as a mask for forming the upper electrode was placed in close contact with the element so as to be orthogonal to the ITO stripe of the transparent electrode [3] and placed in another vacuum deposition apparatus. Then, in the same manner as when the n-type semiconductor layer [7] was formed, evacuation was performed until the degree of vacuum in the vacuum deposition apparatus reached 7.6 × 10 ⁻⁵ Pa. Then, aluminum was vapor-deposited with a film thickness of 80 nm on the n-type semiconductor layer [7] at a vapor deposition rate of 3 nm / second to form the upper electrode [8]. The degree of vacuum during vapor deposition was 1.2 × 10 ⁻⁴ Pa.
As described above, an organic thin-film solar cell composed of the organic photoelectric conversion element [1] having a light receiving area portion having a size of 2 mm × 2 mm was obtained.

The organic photoelectric conversion element was irradiated with light from a solar simulator (AM1.5G) at an irradiation intensity of 100 mW / cm ² and measured for voltage-current characteristics. As a result, an open circuit voltage (Voc) of 0.55 V, a short-circuit current ( Jsc) 5.5 mA / cm ² , energy conversion efficiency (ηp) 1.45%, and form factor (FF) 0.48 were obtained.
Moreover, from the measurement of the spectral sensitivity of this organic photoelectric conversion element, the maximum value of the external quantum efficiency was 52% at a wavelength of 460 nm. In addition, the said spectral sensitivity irradiated the monochromatic light, measured the electric current intensity | strength photoelectrically converted, and represented the said electric current amount in the ratio with respect to per photon. Absorption correction was not performed. The same applies to the following examples and comparative examples.

[Comparative Example 1]
As the electron donor layer [5], an organic photoelectric conversion element was produced in the same manner as in Example 1 except that copper phthalocyanine was formed by a vacuum deposition method with a film thickness of 25 nm.
The organic photoelectric conversion element was irradiated with light from a solar simulator (AM1.5G) at an irradiation intensity of 100 mW / cm ² and measured for voltage-current characteristics. As a result, an open circuit voltage (Voc) of 0.57 V, a short circuit current ( The photoelectric conversion characteristics of Jsc) 3.3 mA / cm ² , energy conversion efficiency (ηp) 0.72%, and form factor (FF) 0.38 were obtained.
Moreover, from the measurement of the spectral sensitivity of this organic photoelectric conversion element, the maximum value of the external quantum efficiency was 19% at a wavelength of 620 nm.

[Example 2]
As a coating solution for the benzoporphyrin compound BP-1, a solution obtained by dissolving the precursor in a mixed solvent of chloroform-chlorobenzene (mixed at a weight ratio of 1: 1) at 1.0% by weight is used on the p-type organic semiconductor layer. After spin coating, an organic photoelectric conversion device was produced in the same manner as in Example 1 except that the electron donor layer [5] having a film thickness of 85 nm was obtained by heating at 210 ° C. for 30 minutes.

The organic photoelectric conversion element was irradiated with light from a solar simulator (AM1.5G) at an irradiation intensity of 100 mW / cm ² and measured for voltage-current characteristics. As a result, an open circuit voltage (Voc) of 0.52 V, a short-circuit current ( The photoelectric conversion characteristics of Jsc) 6.3 mA / cm ² , energy conversion efficiency (ηp) 1.64%, and form factor (FF) 0.50 were obtained.
Moreover, from the measurement of the spectral sensitivity of this organic photoelectric conversion element, the maximum value of the external quantum efficiency was 54% at a wavelength of 620 nm.

[Example 3]
As a PCBM coating solution, a solution dissolved in toluene at 1.2% by weight was used, except for spin coating and heating at 65 ° C. for 10 minutes to form an electron acceptor layer [6] having a thickness of 40 nm. In the same manner as in Example 2, an organic photoelectric conversion element was produced.

The organic photoelectric conversion element was irradiated with light from a solar simulator (AM1.5G) at an irradiation intensity of 100 mW / cm ² and measured for voltage-current characteristics. As a result, an open circuit voltage (Voc) of 0.55 V, a short-circuit current ( The photoelectric conversion characteristics of Jsc) 5.6 mA / cm ² , energy conversion efficiency (ηp) 1.74%, and form factor (FF) 0.56 were obtained.
Moreover, from the measurement of the spectral sensitivity of this organic photoelectric conversion element, the maximum value of the external quantum efficiency was 50% at a wavelength of 460 nm.

[Example 4]
An organic photoelectric conversion device was produced in the same manner as in Example 3 except that the heat treatment after spin cording performed at the time of forming the electron acceptor layer [6] was set at 90 ° C. for 10 minutes.
When this organic photoelectric conversion element was irradiated with light from a solar simulator (AM1.5G) at an irradiation intensity of 100 mW / cm ² and measured for voltage-current characteristics, an open circuit voltage (Voc) of 0.56 V, a short circuit current ( The photoelectric conversion characteristics of Jsc) 6.5 mA / cm ² , energy conversion efficiency (ηp) 1.85%, and form factor (FF) 0.51 were obtained.
From the measurement of the spectral sensitivity of this organic photoelectric conversion element, the maximum value of the external quantum efficiency was 46% at a wavelength of 460 nm.

[Example 5]
An organic photoelectric conversion device was produced in the same manner as in Example 3 except that the fullerene compound F-5 was used in place of PCBM.
When this organic photoelectric conversion element was irradiated with light from a solar simulator (AM1.5G) at an irradiation intensity of 100 mW / cm ² and the voltage-current characteristics were measured, the open circuit voltage (Voc) was 0.54 V, the short-circuit current ( The photoelectric conversion characteristics of Jsc) 6.2 mA / cm ² , energy conversion efficiency (ηp) 1.20%, and form factor (FF) 0.36 were obtained.
From the measurement of the spectral sensitivity of the organic photoelectric conversion element, the maximum value of the external quantum efficiency was 54% at a wavelength of 460 nm.

[Example 6]
An organic photoelectric conversion element [10] having a structure shown in FIG. 2 in which the benzoporphyrin compound BP-1 was provided between the p-type organic semiconductor layer [4] and the active layer [11] was produced by the following method.
That is, a p-type organic semiconductor layer [4] was formed in the same manner as in Example 1 on a glass substrate [2] on which a transparent electrode [3] was formed by ITO. Then, using the solution which melt | dissolved the said BP-1 precursor which is a precursor of the benzoporphyrin compound BP-1 in the mixed solvent (weight ratio 1: 1) of chloroform and chlorobenzene at 0.25 weight%, p The organic semiconductor layer [4] was spin coated. After the application, heat treatment was performed at 210 ° C. for 30 minutes on a hot plate to form a crystalline benzoporphyrin compound layer [5] having an average film thickness of 20 nm.

Next, a film in which copper phthalocyanine and C ₆₀ were mixed at a weight ratio of 1: 1 was formed to a film thickness of 15 nm by a vacuum deposition method, thereby forming a mixed active layer [11]. Furthermore, C ₆₀ was deposited to 30 nm and BCP was deposited to 6 nm by a vacuum deposition method to form an n-type semiconductor layer [7] on the mixed active layer [11]. Finally, aluminum was formed as the upper electrode [8] in the same manner as in Example 1 to complete the organic photoelectric conversion element [10].

When this organic photoelectric conversion element [10] was irradiated with light from a solar simulator (AM1.5G) at an irradiation intensity of 100 mW / cm ² and measured for voltage-current characteristics, the open circuit voltage (Voc) was 0.40 V, The photoelectric conversion characteristics of a short-circuit current (Jsc) of 8.9 mA / cm ² , an energy conversion efficiency (ηp) of 1.74%, and a form factor (FF) of 0.49 were obtained.
Further, from the measurement of the spectral sensitivity of the organic photoelectric conversion element, a maximum value of 50% of the external quantum efficiency was obtained at wavelengths of 440 nm and 690 nm.

[Summary]
It can be seen from Examples 1 to 6 and Comparative Example 1 that a highly efficient solar cell can be produced by using a benzoporphyrin compound.

  The method for producing an organic photoelectric conversion element and the organic photoelectric conversion element of the present invention can be used in any industrial field, and are particularly suitable for use in a photovoltaic power generation element, an image sensor, and the like.

It is a typical sectional view of the organic photoelectric conversion element as a 1st embodiment of the present invention. It is typical sectional drawing of the organic photoelectric conversion element as 2nd Embodiment of this invention. It is typical sectional drawing of the organic photoelectric conversion element as 3rd Embodiment of this invention.

Explanation of symbols

1, 10, 12 Organic photoelectric conversion element 2 Substrate 3 Positive electrode 4 P-type semiconductor layer 5 Electron donor layer 6 Electron acceptor layer 7 N-type semiconductor layer 8 Negative electrode 9, 11, 13 Active layer

Claims (5)

A substrate, a pair of electrodes formed on the substrate, at least one of which is transparent; an electron donor layer including an electron donor formed between the electrodes; and an electrode including an electron acceptor. A method for producing an organic photoelectric conversion device comprising an electron acceptor layer formed,
Converting the soluble precursor of a benzoporphyrin compound represented by the following formula (I) or (II) having a bicyclo ring into the benzoporphyrin compound as the electron donor by thermal conversion, and the electron donor layer Forming a step ;
After the step of forming the electron donor layer by the thermal conversion, the step of forming the electron acceptor layer by a coating method,
The method for producing an organic photoelectric conversion element, wherein the electron acceptor layer contains a fullerene compound .

(In the formulas (I) and (II), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represents a monovalent atom or atomic group, provided that Z ^ia and Z good .R ¹ to R ⁴ to form a ring and ^ib are bonded to each independently, .M representing a monovalent atom or atomic group, a divalent metal atom, or a trivalent or higher Represents an atomic group in which other metals are bonded to other atoms.) The method for producing an organic photoelectric conversion device according to claim 1, wherein the soluble precursor is a compound represented by the following formula (III) or (IV).

(In the formulas (III) and (IV), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represents a monovalent atom or atomic group, provided that Z ^ia and Z ^ib may be bonded to form a ring, R ^{1 to} R ⁴ each independently represents a monovalent atom or atomic group, and Y ¹ to Y ⁴ each independently represents a monovalent atom. M represents an atomic group in which a divalent metal atom or a trivalent or higher metal is bonded to another atom. A substrate, a pair of electrodes formed on the substrate, at least one of which is transparent; an electron donor layer including an electron donor formed between the electrodes; and an electrode including an electron acceptor. A method for producing an organic photoelectric conversion device comprising an electron acceptor layer formed,
Forming a layer of a soluble precursor of a benzoporphyrin compound represented by the following formula (I) or (II) having a bicyclo ring by a coating method;
Performing the step of forming the electron acceptor layer on the soluble precursor layer by vacuum deposition,
Thereafter, the soluble precursor by thermal transformation, the converted into the benzoporphyrin compound is an electron donor, an organic photoelectric characterized <br/> performing the step of forming the electron donor layer conversion Device manufacturing method.

(In the formulas (I) and (II), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represents a monovalent atom or atomic group, provided that Z ^ia and Z good .R ¹ to R ⁴ to form a ring and ^ib are bonded to each independently, .M representing a monovalent atom or atomic group, a divalent metal atom, or a trivalent or higher Represents an atomic group in which other metals are bonded to other atoms.)   The electron acceptor layer contains a fullerene compound
The manufacturing method of the organic photoelectric conversion element of Claim 3 characterized by the above-mentioned.   The soluble precursor is a compound represented by the following formula (III) or (IV)
The manufacturing method of the organic photoelectric conversion element of Claim 3 or Claim 4 characterized by the above-mentioned.

(In the above formulas (III) and (IV), Z ^ia And Z ^ib (I represents an integer of 1 to 4) each independently represents a monovalent atom or atomic group. However, Z ^ia And Z ^ib May combine with each other to form a ring. R ¹ ~ R ^Four Each independently represents a monovalent atom or atomic group. Y ¹ ~ Y ^Four Each independently represents a monovalent atom or atomic group. M represents a divalent metal atom or an atomic group in which a trivalent or higher metal and another atom are bonded. )

Images