JPWO2010038721A1 - Organic photoelectric conversion element and manufacturing method thereof - Google Patents

Abstract

It is an object to provide a flexible organic photoelectric conversion element having excellent energy conversion efficiency, high durability against repeated bending, and excellent light durability, and a method for producing the same. In the organic photoelectric conversion element in which at least the charge transporting portion and the photoelectric conversion portion are stacked between the first electrode and the second electrode, the photoelectric conversion portion is a bulk hetero of the p-type semiconductor material and the n-type semiconductor material. It has a junction structure and is characterized in that a continuous concentration gradient due to the mass conversion ratio between the p-type semiconductor material and the n-type semiconductor material exists at least in a region from the first electrode side to the second electrode side. To do.

Description

  The present invention relates to an organic photoelectric conversion element. In particular, the present invention relates to a flexible organic photoelectric conversion element having excellent energy conversion efficiency, improved durability against bending, and improved durability against light irradiation, and a method for producing the same.

  Since organic solar cells can be formed by a coating method, they have attracted attention as solar cells suitable for mass production and are actively studied by many research institutions. In organic solar cells, the so-called bulk heterojunction structure in which an organic donor material and an organic acceptor material are mixed improves charge separation efficiency, which has been a problem (see, for example, Patent Document 1). As a result, the energy conversion efficiency has been improved to the 5% level, and it can be said that this field has been developed to a practical level at once.

  The above-described bulk heterojunction type organic solar cell is characterized by efficient charge separation before quenching excitons formed by light absorption, but the generated free carriers are generated by the organic donor material or the organic acceptor material, respectively. Since it moves by diffusion through the percolation structure existing in a phase-separated form, there has been a problem that bipolar free carriers are recombined on the electrode and the energy conversion efficiency is liable to decrease.

  On the other hand, a technique for suppressing carrier recombination on the electrode by providing an exciton blocking layer between the power generation layer and the electrode has been introduced (see, for example, Patent Document 2), which is important for high efficiency. It can be said that it is knowledge.

  However, if a bulk heterojunction type power generation layer and an exciton blocking layer are stacked, an electrical barrier is formed in the vicinity of the interface, which becomes a recombination site, and the effect of high efficiency cannot be sufficiently obtained. There was a thing.

  Similarly, an electrical barrier formed in the vicinity of the interface may cause a reduction in efficiency under light irradiation, which has been a practical problem.

  In addition, an attempt to achieve both charge separation and carrier extraction by providing a continuous mixed region between pn layers has been introduced (see, for example, Patent Document 3). The bulk heterojunction structure region was extremely narrow, and sufficient conversion efficiency could not be obtained.

  When forming a mixed region by a coating method with excellent productivity, controlling the concentration gradient with respect to the film thickness direction cannot be easily formed by a coating process as introduced in the conventional literature. The desired performance and productivity by coating could not be achieved.

  Furthermore, when these structures are applied to a flexible organic solar battery formed by a coating method, a behavior in which the conversion efficiency decreases due to repeated bending is a practical problem.

US Pat. No. 5,331,183 US Pat. No. 7,026,041 JP-A-2005-244159

  The present invention is to solve the conventional problems as described above, and its purpose is to provide a flexible organic photoelectric sensor having excellent energy conversion efficiency, high durability against repeated bending, and excellent light durability. It is providing the conversion element and its manufacturing method.

  The above object of the present invention is achieved by the following configurations.

  1. In an organic photoelectric conversion element in which at least a charge transport portion and a photoelectric conversion portion are stacked between a first electrode and a second electrode, the photoelectric conversion portion is a bulk hetero of a p-type semiconductor material and an n-type semiconductor material. It has a junction structure, and a region having a continuous concentration gradient due to a mass conversion ratio between the p-type semiconductor material and the n-type semiconductor material exists at least between the first electrode and the second electrode. Organic photoelectric conversion element.

  2. 2. The organic photoelectric conversion element according to 1 above, wherein the continuous concentration gradient region is in the vicinity of an interface between the photoelectric conversion unit and the charge transport unit.

  3. 3. The organic photoelectric conversion element as described in 1 or 2 above, wherein the charge transporting part is a hole transporting part that mainly transports holes.

  4). 3. The organic photoelectric conversion element as described in 1 or 2 above, wherein the charge transporting part is an electron transporting part that mainly transports electrons.

  5. The charge transport part includes at least a hole transport part that mainly transports holes and an electron transport part that mainly transports electrons, and the photoelectric conversion part is sandwiched between the hole transport part and the electron transport part 5. The organic photoelectric conversion element according to any one of 1 to 4, which has a structure.

  6). 6. The organic photoelectric conversion element according to any one of 1 to 5, wherein the continuous concentration gradient region is formed by a coating method or a printing method.

  7). It is a manufacturing method of the organic photoelectric conversion element of any one of said 1-6, Comprising: The precursor which apply | coats the solution which has at least any one among a p-type semiconductor material precursor and an n-type semiconductor material precursor Inducing a chemical structure change of at least one of the p-type semiconductor material precursor and the n-type semiconductor material precursor by an application process, a patterning process for removing unnecessary portions of the applied film, and an external stimulus process, And an insolubilizing step of insolubilizing the precursor induced by the chemical structure change.

  8). At least one of the p-type semiconductor material precursor and the n-type semiconductor material precursor is a precursor having a crosslinkable substituent, and at least a part of the precursor is crosslinked and insolubilized in the insolubilization step. 8. The method for producing an organic photoelectric conversion element as described in 7 above, wherein

  9. At least one of the p-type semiconductor material precursor and the n-type semiconductor material precursor is a precursor that undergoes a chemical structure change by an external stimulus process, and the precursor is changed in chemical structure in the insolubilization step to be insolubilized. 8. The method for producing an organic photoelectric conversion element as described in 7 above.

  10. The organic photoelectric conversion according to any one of 7 to 9, wherein the external stimulation treatment is any one of heat treatment, UV light irradiation treatment, or combined use of heat treatment and UV light irradiation treatment. Device manufacturing method.

  11. Any one of 7 to 10 above, wherein a power generation region that is sequentially stacked is formed by repeatedly performing a process group including at least the precursor application process, the patterning process, and the insolubilization process. The manufacturing method of the organic photoelectric conversion element as described in a term.

  12 A sequential power generation region having at least a continuous concentration gradient is formed by sequentially laminating coating solutions having different mixing ratios of the p-type semiconductor material precursor and the n-type semiconductor material precursor. The manufacturing method of the organic photoelectric conversion element as described in 11 above.

  13. 13. The method of manufacturing an organic photoelectric conversion element according to 11 or 12, wherein the sequentially stacked power generation regions each include a region having a continuous concentration gradient and a region having a constant concentration.

  According to the present invention, a flexible organic photoelectric conversion element having excellent energy conversion efficiency, high durability against repeated bending, and excellent light durability, and a method for producing the same can be provided.

It is the schematic of the manufacturing method of the organic photoelectric conversion element of this invention. It is sectional drawing which shows a bulk heterojunction type organic photoelectric conversion element. It is a figure which shows typically the density | concentration gradient in this invention. It is sectional drawing which shows the solar cell which consists of an organic photoelectric conversion element provided with a tandem-type bulk heterojunction layer.

  Hereinafter, the present invention will be described in detail.

  The organic photoelectric conversion element of the present invention is an organic photoelectric conversion element in which at least a charge transport part and a photoelectric conversion part are stacked between a first electrode and a second electrode, wherein the photoelectric conversion part is a p-type semiconductor material. A region of continuous concentration gradient due to the mass conversion ratio of the p-type semiconductor material and the n-type semiconductor material is at least between the first electrode and the second electrode. It is characterized by the existence.

  The manufacturing method of the organic photoelectric conversion element of this invention is demonstrated using figures. FIG. 1A shows a precursor coating step of coating a solution having at least one of a p-type semiconductor material precursor and an n-type semiconductor material precursor on a conductive substrate 1, and a coating film. A photoelectric conversion portion (bulk heterojunction layer) 2 is formed by performing a patterning step for removing unnecessary portions and an insolubilization step for inducing a chemical structure change of the precursor by external stimulation treatment to insolubilize the precursor. In FIG. 1B, the same precursor coating process, patterning process, and insolubilization process are performed on the photoelectric conversion unit 2 to form 3. Thereafter, the photoelectric conversion units 4 and 5 are formed in the same manner. If necessary, a photoelectric conversion unit is further formed. At this time, the p-type semiconductor material precursor and the n-type semiconductor material precursor mixing ratio of the photoelectric conversion units 2 to 5 may be changed to form a sequentially stacked photoelectric conversion unit having a continuous concentration gradient, Alternatively, a region having a continuous concentration gradient and a region having a constant concentration can be formed.

  It is preferable that at least one of the above-described p-type semiconductor material precursor or n-type semiconductor material precursor is a precursor having a crosslinkable substituent. In particular, an embodiment in which a by-product that affects carrier traps and device lifetime is not generated by the external stimulus treatment described later, and precursors are networked together to form a semiconductor material. Specific examples of the substituent include a vinyl group and An epoxy group is exemplified, and a compound that is a vinyl group is particularly preferable.

  As the external stimulus to be processed into the semiconductor material precursor, any external stimulus can be preferably used as long as a part of the above-mentioned crosslinkable substituents are crosslinked to form a network. For example, it is preferable to perform a heat treatment and a UV light irradiation treatment, or a combination of both, and the treatment conditions can be appropriately selected from the performance of photoelectric conversion and the element lifetime.

  In the manufacturing method of the organic photoelectric conversion element of this invention, it has the patterning process. Preferably, it has a patterning process before the insolubilization process by the external stimulation process mentioned above, and it is still more preferable to perform a precursor application | coating process, a patterning process, and an insolubilization process in this order. The patterning step can be applied by any known method as long as the effect of the present invention is not impaired. Examples of the patterning step include a physical scrub method, an optical scrub method, and a laser scrub method.

  In addition, various printing methods such as letterpress printing, ink jet printing, and screen printing, patterning methods such as photo-etching, and methods of patterning by applying after masking in advance and removing the mask are included. A bank may be formed in advance, and the coating process and the patterning process may be performed by a method of pouring a coating solution into the bank.

  More preferable examples include a method of forming a pattern by coating and drying a precursor coating solution and then wiping with a solvent having the same solvent as the coating solution or a solvent having a solubility parameter close to that of the coating solution.

  The organic photoelectric conversion element of this invention is demonstrated in detail using FIG. FIG. 2 is a schematic cross-sectional view showing the basic structure of a bulk heterojunction photoelectric conversion element.

  In FIG. 2, a bulk heterojunction organic photoelectric conversion element 10 includes a transparent electrode 12 (first electrode), charge transporting portions 15 and 16, a photoelectric conversion portion 14 having a bulk heterojunction structure, and a pair on one surface of a substrate 11. The electrode 13 (second electrode) has a structure in which the electrodes are sequentially stacked as shown in FIG. Furthermore, in the organic photoelectric conversion element of the present invention, the photoelectric conversion portion 14 has a bulk heterojunction structure of at least a p-type semiconductor material and an n-type semiconductor material, and is continuous by a mass conversion ratio of the p-type semiconductor material and the n-type semiconductor material. A region having a high concentration gradient exists at least between the first electrode and the second electrode.

  The bulk heterojunction structure constituting the photoelectric conversion unit 14 of the present application is composed of at least a mixture of a p-type semiconductor material and an n-type semiconductor material, and has a domain structure by phase separation of each material, A structure that is three-dimensionally connected for extraction. The photoelectric conversion portion is a region having a function of generating free charges by excitons generated by light absorption at the interface between the p-type semiconductor material and the n-type semiconductor material.

  Further, the charge transporting portion 15 (or 16) of the present application refers to a region made of a single material or a region that is in a uniform phase without phase separation even when a plurality of types of semiconductor materials are mixed. The charge transport portion has a function of transporting free charges, and refers to a region where new charges are not generated due to charge separation even when light is absorbed.

  The mass conversion ratio between the p-type semiconductor material and the n-type semiconductor material of the present application can be defined as the p / n ratio from the mass ratio of the respective materials.

  In FIG. 3, in order to schematically illustrate the concentration gradient in the present invention, the relationship between the p / n ratio and the depth in the element thickness direction is shown. FIG. 3A is an example showing a conventional layer structure, and shows a generally used layered concentration distribution. FIG. 3B also exemplifies a conventional layer structure. For example, a p-type semiconductor layer and an n-type semiconductor such as those introduced in Japanese Patent Application Laid-Open No. 2005-244159 and International Publication No. 05 / 4252A3 pamphlet are shown. This has a concentration distribution at the interface with the type semiconductor layer. When the structure of FIG. 3A is applied to a flexible organic solar cell formed by a coating method, a behavior in which conversion efficiency decreases due to repeated bending is a practical problem. In addition, the structure shown in FIG. 3B has an extremely narrow bulk heterojunction structure region that is excellent in charge separation capability, and sufficient conversion efficiency could not be obtained. FIG. 3B shows the result that the concentration distribution of the p / n ratio has changed abruptly as a result of the application of the p-type semiconductor layer and the n-type semiconductor layer, and the bulk heterojunction structure region has become extremely narrow. Yes, outside the present invention.

  FIG. 3C illustrates a layer structure that can be preferably used in the present invention. The cross-sectional view of FIG. 2 illustrates the charge transport portion 15 formed on the first electrode side, for example. When mainly made of a hole transporting material, the charge transporting part 16 formed on the second electrode side is preferably made of an electron transporting material, and further, the p / of the photoelectric conversion part 14 in contact with the charge transporting part 15. The n ratio is high, the p / n ratio of the photoelectric conversion unit 14 in contact with the charge transport unit 16 is low, and the p / n ratio of the photoelectric conversion unit 14 is continuously increased from the charge transport unit 15 side to the charge transport unit 16 side. The structure which becomes low can be mentioned and is a preferable aspect in this invention. The p / n ratio is a mass conversion ratio between the p-type semiconductor material and the n-type semiconductor material, but the mass conversion ratio is not particularly limited in the present invention, and the p-type ratio may be larger than the n-type. At least, the effects of the present application can be obtained.

  FIG. 3D illustrates a layer structure that can be preferably used in the present invention. When described with reference to the cross-sectional view of FIG. 2, at least from the charge transporting portion 15 (or 16) to the photoelectric conversion portion 14, A configuration having a region having a continuous concentration gradient and a region having no concentration gradient can also be mentioned, which is a more preferable aspect in the present invention.

  FIG. 3E illustrates a layer structure that can be preferably used in the present invention. When described with reference to the cross-sectional view of FIG. 2, at least the charge transporting portion 15 (or 16) and the photoelectric conversion portion 14 are arranged. A configuration in which a region having a continuous concentration gradient and a region having no concentration gradient are formed and a uniform layer of the charge transport layer 15 (or 16) is formed can be given. It is.

  The region having a continuous concentration gradient in the present invention is preferably present at least in the photoelectric conversion unit 14 and distributed in the vicinity of the interface from the photoelectric conversion unit 14 to the charge transport unit 15 (or 16). Furthermore, it is preferable that a region having a continuous concentration gradient and a region having no concentration gradient exist in the photoelectric conversion unit 14, and more preferably, a region having a continuous concentration gradient and a region having no concentration gradient. More preferably, a region having a continuous concentration gradient is distributed in the vicinity of the interface from the photoelectric conversion unit 14 to the charge transporting unit 15 (or 16).

  In the present invention, the charge transport part is a hole transport part or an electron transport part, and a structure in which the photoelectric conversion part is sandwiched between the hole transport part and the electron transport part is preferable.

  The region having a continuous concentration gradient in the present invention is characterized by having a bulk heterojunction structure. Here, “continuous” means a structure in which a plurality of regions having different p / n ratios are stacked, and the p / n ratio gradually changes, or the p / n ratio changes stepwise but over a plurality of layers. This means a structure in which the concentration continuously changes. As a configuration of a region having a continuous concentration gradient, for example, a region having a continuous concentration gradient of the present application can be formed by stacking several to several hundred layers having different p / n ratios. Preferably, three or more layers having different p / n ratios are stacked, more preferably 10 or more layers, and most preferably, a layer having a substantially continuous concentration gradient is preferable. .

  As a method for forming a region having a continuous concentration gradient in the present invention, any method can be used as long as it can realize the configuration of the present application, and a vapor deposition method or a coating method is preferable, and a coating method is particularly preferable. The method is preferred.

  In the coating method, a general casting method, a spin coating method, various printing methods, and the like can be used, and it is preferable to form a film by stacking coating solutions having different p / n ratios. Specifically, a method in which a coating solution in which a semiconductor material is dissolved is applied to the front surface and then patterned into a desired shape in a wiping process or is applied in a pattern in advance.

  The region having a continuous concentration gradient is formed by, for example, applying a curable semiconductor material solution adjusted to a desired p / n ratio, insolubilizing the semiconductor film by heat treatment or light irradiation, and subsequently forming p in the lower layer. By repeating the step of laminating and applying a semiconductor material solution having a concentration different from the / n ratio, a region having a desired continuous concentration gradient can be formed.

  For the insolubilization of the semiconductor film, it is preferable to use a polymer compound having low solubility, and more preferably, after coating and film formation, a polymer film having a network structure is formed and insolubilized by some external stimulus such as heat treatment or light irradiation. The structure which does is preferable.

  As for the molecular weight of the above-described polymer semiconductor material, a compound having a molecular weight of preferably 1000 or more, more preferably 2000 or more, and further preferably 5000 or more is classified as a polymer compound. The molecular weight can be measured by gel permeation chromatography (GPC). However, in the case of a polymer having a network structure as described later, it is difficult to specify the molecular weight accurately.

  Examples of a method for evaluating a region having a continuous concentration gradient in the present invention include a method for analytically evaluating a concentration distribution in the depth direction by dynamic secondary ion mass spectrometry (Dynamic-SIMS), and a surface / interface. By using a physical property evaluation apparatus (SAICAS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) in combination, a continuous concentration gradient can be evaluated analytically. In the latter method, a surface cutting sample with an expanded fault is created using SAICAS, and mass analysis of secondary ions is performed by TOF-SIMS, so that the mass distribution in the cross-sectional direction can be obtained without destroying the molecular structure of organic matter. Can be evaluated.

  Hereinafter, an n-type semiconductor material and a p-type semiconductor material that can be preferably used in the present invention will be described in detail. Here, n-type and p-type indicate whether a semiconductor material contributes to electric conduction is an electron or a hole.

[N-type semiconductor materials]
The organic photoelectric conversion element of the present invention includes a precursor coating step for applying a solution having at least one of a p-type semiconductor material precursor and an n-type semiconductor material precursor, and patterning for removing unnecessary portions of the applied film. And an insolubilization step in which the chemical structure of the precursor is induced by an external stimulus treatment to insolubilize the precursor.

  Preferred n-type semiconductors of the present invention include precursors having a crosslinkable substituent, and the precursors are cross-linked in the insolubilization step and can be insolubilized in the solution applied to the upper layer. Is preferred.

  Examples of n-type semiconductor materials include fullerene, octaazaporphyrin, p-type semiconductor perfluoro compounds (perfluoropentacene, perfluorophthalocyanine, etc.), naphthalenetetracarboxylic anhydride, naphthalenetetracarboxylic diimide, perylenetetracarboxylic acid Examples thereof include polymer compounds containing an anhydride, an aromatic carboxylic acid anhydride such as perylenetetracarboxylic acid diimide, or an imidized product thereof as a skeleton.

  Among these, fullerene-containing polymer compounds are preferable. Fullerene-containing polymer compounds include fullerene C60, fullerene C70, fullerene C76, fullerene C78, fullerene C84, fullerene C240, fullerene C540, mixed fullerene, fullerene nanotubes, multi-walled nanotubes, single-walled nanotubes, nanohorns (conical), etc. Examples thereof include a polymer compound having a skeleton. As the fullerene-containing polymer compound, a polymer compound (derivative) having fullerene C60 as a skeleton is preferable.

  The fullerene-containing polymers are roughly classified into polymers in which fullerene is pendant from a polymer main chain and polymers in which fullerene is contained in the polymer main chain. Fullerene is contained in the polymer main chain. Are preferred. This is because a polymer in which fullerene is contained in the polymer main chain does not have a branched structure, so that when it is solidified, a high-density packing can be formed, resulting in high mobility. It is estimated that.

  Specifically, a compound represented by the following general formula (1) can be suitably used.

In the general formula (1), R ₁ and R ₂ represent a substituent selected from a substituted or unsubstituted alkyl group, cycloalkyl group, aralkyl group, aryl group, heteroaryl group, and silyl group, and L ₁ , L ₂ Is a substituted or unsubstituted alkylene group, alkenediyl group, alkynediyl group, cycloalkylene group, arylene group, heteroarylene group, silylene group, ether group, thioether group, carbonyl group, carboxyl group, amino group, amide group, or these Represents a structure of multiple connections. n represents an integer of 2 or more.

Specific examples of the substituted or unsubstituted alkyl group, cycloalkyl group, aralkyl group, aryl group, heteroaryl group, and silyl group represented by R ₁ and R ₂ include an alkyl group (for example, methyl group, ethyl group). Group, propyl group, isopropyl group, t-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group etc.), Aralkyl groups (for example, benzyl group, 2-phenethyl group, etc.), aryl groups (for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group) Group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group ), Heteroaryl group (for example, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, phthalazinyl group, etc.), silyl group (for example, , Trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, triisopropylsilyl group, t-butyldiphenylsilyl group, etc.), and these substituents include alkyl groups, halogenated alkyl groups, alkenyl groups, As for the alkynyl group, aryl group, heteroaryl group, and alkylsilyl group, specifically, an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, pentyl group, hexyl group, octyl group) , Dodecyl group, tridecyl group, teto Decyl group, pentadecyl group etc.), halogenated alkyl group (eg trifluoromethyl group, 1,1,1-trifluoropropyl group etc.), alkenyl group (eg vinyl group, allyl group etc.), alkynyl group (eg , Ethynyl group, propargyl group, etc.), cycloalkyl group (eg, cyclopentyl group, cyclohexyl group, etc.), aryl group (eg, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, xylyl group, naphthyl group, anthryl group) , Azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc., halogenated aryl group (pentafluorophenyl group, pentachlorophenyl group etc.), heteroaryl group (for example, furyl group, thienyl, etc.) Group, pyridyl group, pyridazinyl group, Pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, phthalazinyl group, etc.), alkylsilyl group (for example, trimethylsilyl group, triethylsilyl group, tripropyl (i or n) silyl group, tributyl (I, t, or n) a silyl group, etc.), and these substituents may be further substituted with the above substituents, or a plurality thereof may be bonded to each other to form a ring.

A substituted or unsubstituted alkylene group, alkenediyl group, alkynediyl group, cycloalkylene group, arylene group, heteroarylene group, silylene group, ether group, thioether group, carbonyl group, carboxyl group, amino group represented by L ₁ or L ₂ Groups and amide groups include alkylene groups having 1 to 22 carbon atoms, alkene-1,2-diyl groups, alkyne-1,2-diyl groups, and cycloalkylene groups. Arylene groups include phenylene groups and naphthylene groups. Group, and a phenylene group is preferable. Examples of the heteroarylene group include a furylene group, a thienylene group, a pyridinylene group, a pyridazinylene group, a pyrimidinylene group, a pyrazinylene group, a triazinylene group, an imidazolinylene group, a pyrazolinylene group, a thiazolinylene group, a quinazolinylene group, and a phthalazinylene group. Examples of the silylene group include a dimethylsilylene group and a diphenylsilylene group.

  More preferably, the n-type semiconductor forms a crosslinked network structure. By forming such a network structure, when forming a stack of bulk heterojunction layers and a hole transport layer, an electron transport layer, a hole block layer, an electron block layer, etc. thereon by a solution process, Since the layers do not dissolve, the materials do not mix with each other, the effects of the present invention can be exhibited, and a highly rigid n-type carrier path structure can be formed. It is possible to prevent the phase separation structure of the p-type layer and the n-type layer from changing over time, and as a result, an organic photoelectric conversion element having high durability can be obtained.

  As a further secondary effect, when forming a hole transport layer, an electron transport layer, a hole block layer, an electron block layer, etc. on the bulk hetero junction layer by a solution process, the bulk hetero junction layer is formed. Therefore, the material constituting the layer and the material forming the bulk heterojunction layer are not mixed with each other, so that further efficiency improvement and lifetime improvement can be achieved.

  The fullerene-containing monomer capable of forming a three-dimensional network structure is represented by the following general formula (2).

In the formula, R ₃ and R ₄ represent a substituent selected from a substituted or unsubstituted alkyl group, cycloalkyl group, aralkyl group, aryl group, heteroaryl group, and silyl group, and L ₃ and L ₄ are substituted or unsubstituted. Substituted alkylene group, alkenediyl group, alkynediyl group, cycloalkylene group, arylene group, heteroarylene group, silylene group, ether group, thioether group, carbonyl group, carboxyl group, amino group, amide group, or a structure in which a plurality of these are linked Represents. G ₁ and G ₂ are polymerized groups that become a bond chain of the network structure. In the formula, only one hemispherical portion of the spherical fullerene structure is shown, the other hemispherical portion is omitted, and a first substituent containing G ₁ , R ₃ , and L ₃ substituted for the fullerene structure; positional relationship between the second substituent comprising G _{2, R 4, L} 4 is optional. R ₃ and R ₄ correspond to R ₁ and R ₂ in the general formula (1), and L ₃ and L ₄ correspond to L ₁ and L ₂ .

  Examples thereof include the following compounds.

  These compounds are described in J. Org. Mater. Chem. , Vol. 15 (2005), p5158, Adv. Mater. , Vol. 20 (2008), p2116, Angewedte Chemie, International Edition, vol. 41 (2002), p838, etc., can be used to synthesize monomers.

Among these compounds, compounds that are vinyl groups are preferred as the polymerizable groups (G ₁ and G ₂ in the general formula (2)) that do not generate a functional group that becomes a carrier trap after the polymerization crosslinking reaction.

  In addition, since the polymer compound that forms these networks is insoluble in the solvent, after forming the bulk heterojunction layer in the monomer state, it is exposed to a compound vapor that causes heat, light, radiation, and a polymerization initiation reaction. The method can cause a polymerization cross-linking reaction to form a network structure. A polymerization initiator that causes a polymerization initiation reaction by heat, light, radiation, or the like may be mixed in advance. Among these methods, it is preferable to cause a polymerization crosslinking reaction by heat or light, and among them, a compound capable of polymerization crosslinking without using a polymerization initiator is preferable.

[P-type semiconductor materials]
Examples of the p-type semiconductor material used in the present invention include various condensed polycyclic aromatic compounds and conjugated compounds.

  Examples of the condensed polycyclic aromatic compound include anthracene, tetracene, pentacene, hexacene, heptacene, chrysene, picene, fluorene, pyrene, peropyrene, perylene, terylene, quaterylene, coronene, ovalene, thacumanthracene, bisanthene, zesulene, heptazelene. , Pyranthrene, violanthene, isoviolanthene, cacobiphenyl, anthradithiophene, and the like, and derivatives and precursors thereof.

  Examples of the conjugated compound include polythiophene and its oligomer, polypyrrole and its oligomer, polyaniline, polyphenylene and its oligomer, polyphenylene vinylene and its oligomer, polythienylene vinylene and its oligomer, polyacetylene, polydiacetylene, tetrathiafulvalene compound, quinone Compounds, cyano compounds such as tetracyanoquinodimethane, fullerenes and derivatives or mixtures thereof.

  In particular, among polythiophene and oligomers thereof, thiophene hexamer α-seccithiophene α, ω-dihexyl-α-sexualthiophene, α, ω-dihexyl-α-kinkethiophene, α, ω-bis (3- An oligomer such as butoxypropyl) -α-sexithiophene can be preferably used.

  Other examples of the polymer p-type semiconductor include polyacetylene, polyparaphenylene, polypyrrole, polyparaphenylene sulfide, polythiophene, polyphenylene vinylene, polycarbazole, polyisothianaphthene, polyheptadiyne, polyquinoline, polyaniline, and the like. Substituted-unsubstituted alternating copolymer polythiophenes such as JP-A-2006-36755, JP-A-2007-51289, JP-A-2005-76030, J. Org. Amer. Chem. Soc. , 2007, p4112, J.A. Amer. Chem. Soc. , 2007, p7246, etc., polymers having a condensed thiophene structure, WO08 / 664 pamphlet, Adv. Mater. , 2007, p4160, Macromolecules, 2007, Vol. Examples thereof include thiophene copolymers such as 40 and p1981.

  In the present invention, the above-described polymer semiconductor material is preferably formed in such a manner that after the precursor layer is formed, the chemical structure of the precursor is changed by an external stimulus treatment to form the polymer semiconductor material. A compound having a vinyl group is more preferable as a polymerizable group that does not generate a functional group that becomes a carrier trap after the polymerization crosslinking reaction.

  Since the polymer compound that forms these networks is insoluble in the solvent, it is polymerized by methods such as exposure to heat, light, radiation, and a compound vapor that causes a polymerization initiation reaction after forming the bulk heterojunction layer in the monomer state. It can cause a crosslinking reaction and form a network structure. A polymerization initiator that causes a polymerization initiation reaction by heat, light, radiation, or the like may be mixed in advance. Among these methods, it is preferable to cause a polymerization crosslinking reaction by heat or light, and among them, a compound capable of polymerization crosslinking without using a polymerization initiator is preferable.

  Further organic compounds such as porphyrin, copper phthalocyanine, tetrathiafulvalene (TTF) -tetracyanoquinodimethane (TCNQ) complex, bisethylenetetrathiafulvalene (BEDTTTTF) -perchloric acid complex, BEDTTTTF-iodine complex, TCNQ-iodine complex, etc. Molecular complexes, fullerenes such as C60, C70, C76, C78, and C84, carbon nanotubes such as SWNT, dyes such as merocyanine dyes and hemicyanine dyes, σ-conjugated polymers such as polysilane and polygerman, and JP 2000 Organic / inorganic hybrid materials described in Japanese Patent No. -260999 can also be used.

  Among these π-conjugated materials, at least one selected from the group consisting of condensed polycyclic aromatic compounds such as pentacene, fullerenes, condensed ring tetracarboxylic acid diimides, metal phthalocyanines, and metal porphyrins is preferable.

  Examples of pentacenes include substituents described in International Publication No. 03/16599, International Publication No. 03/28125, US Pat. No. 6,690,029, Japanese Patent Application Laid-Open No. 2004-107216, and the like. A pentacene derivative described in U.S. Patent Application Publication No. 2003/136964 and the like; Amer. Chem. Soc. , Vol. 127. Examples thereof include substituted acenes described in No. 14.4986 and the like and derivatives thereof.

  Among these compounds, compounds that are highly soluble in an organic solvent to the extent that a solution process can be performed, can form a crystalline thin film after drying, and can achieve high mobility are preferable. Such compounds include those described in J. Org. Amer. Chem. Soc. , Vol. 123, p9482; Amer. Chem. Soc. , Vol. 130 (2008), no. No. 9, 2706 and the like, acene-based compounds substituted with a trialkylsilylethynyl group, a pentacene precursor described in U.S. Patent Application Publication No. 2003/136964, etc., and Japanese Patent Application Laid-Open No. 2007-224019 Examples include precursor type compounds (precursors) such as porphyrin precursors. Among these, the latter precursor type can be preferably used.

  This is because the precursor type is insolubilized after conversion, so a bulk heterojunction layer is further laminated on the bulk heterojunction layer, or a hole transport layer, electron transport layer, hole block layer, electron block layer, etc. When it is formed in the process, the bulk heterojunction layer will not dissolve, so the material constituting the layer and the material forming the bulk heterojunction layer will not be mixed, further improving efficiency, This is because the lifetime can be improved.

  As the p-type semiconductor material of the organic photoelectric conversion element of the present invention, a chemical structure change is caused by a method such as exposing a p-type semiconductor material precursor to heat, light, radiation, or a vapor of a compound that causes a chemical reaction. A compound converted into a semiconductor material is preferred. Among these, compounds that cause a chemical structural change by heat or light are preferable.

  The bulk heterojunction layer is preferably a layer formed from a solution in which a p-type semiconductor material precursor and an n-type semiconductor material are dissolved, and the bulk heterojunction layer is heated or irradiated with light after this layer is formed. It is preferable that it is the layer formed by this.

  The p-type semiconductor material precursor is converted into a p-type semiconductor material by heating or light irradiation. However, the chemical structure changes before and after the heating or light irradiation, and the organic photoelectric conversion element constituting layer is applied (solution application). A compound that greatly changes the solubility in a solvent used for forming a constituent layer is preferable. Specifically, it is preferable that the p-type semiconductor material precursor that was solvent soluble is changed to solvent insoluble by heating or light irradiation.

  The p-type semiconductor material precursor in the p-type semiconductor material precursor-containing layer from the viewpoint of adjusting the solubility in the solvent used for coating (solution preparation) of the organic photoelectric conversion element constituent layer before and after heating or light irradiation as described above. It is preferable that the molecular weight A of the body and the molecular weight B of the p-type semiconductor material formed by the conversion process of the precursor satisfy the following inequality (1).

Inequality (1) Molecular weight A> Molecular weight B
Here, the inequality (1) indicates that when the chemical structure changes from the p-type semiconductor material precursor to the p-type semiconductor material, a change in the partial structure of the precursor, for example, elimination of substituents, chemical bonding As a preferable embodiment, the molecular weight A of the precursor is changed by the occurrence of the cleavage of the.

  In addition, when elimination of a substituent or cleavage of a chemical bond occurs, the eliminated substituent or a molecule generated by the cleavage of a chemical bond significantly impairs the characteristics of the p-type semiconductor material and the organic photoelectric conversion element. Any structure may be used as long as it is not present, and it is preferable that the structure be easily removed out of the organic photoelectric conversion element.

  Among these p-type semiconductor materials, tetrabenzoporphyrin derivatives are particularly preferably used.

  Examples of tetrabenzoporphyrin derivatives include the following compounds, but the present invention is not limited to these.

  Examples of the tetrabenzoporphyrin derivative precursor include compounds represented by the following general formulas (3) and (4), but the present invention is not limited thereto.

In General Formulas (3) and (4), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represent a monovalent atom or atomic group. However, Z ^ia and Z ^ib 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 atomic group. M represents an atomic group in which a divalent metal atom or a trivalent or higher metal and another atom are bonded.

As examples of Z ^ia and Z ^ib , examples of the atom include a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, and a halogen atom such as an iodine atom. On the other hand, as an atomic group, a hydroxyl group, an amino group, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an acyl group, an alkoxy group, an alkoxycarbonyl group, an aryloxy group, a dialkylamino group, a diaralkylamino group, a haloalkyl group, Examples thereof include organic groups such as aromatic hydrocarbon ring groups and aromatic heterocyclic groups.

  Among the organic groups, the alkyl group may have any carbon number as long as the effects of the present invention are not significantly impaired, but is usually 12 or less, preferably 8 or less. It is preferable that the number of carbon atoms in the alkyl group is 12 or less because not only high semiconductor characteristics can be obtained, but also resolubilization at the time of lamination is reduced by optimum solubility, and further, heat resistance becomes higher. 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. It is preferable that the number of carbon atoms in the aralkyl group is 12 or less because not only high semiconductor characteristics can be obtained, but also the resolubility at the time of lamination is reduced by optimum solubility, and further the heat resistance becomes higher. Examples of the aralkyl group include a benzyl group.

  Among the 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. It is preferable that the number of carbon atoms of the alkenyl group is 12 or less because not only high semiconductor characteristics can be obtained, but also the resolubility at the time of lamination is reduced by the optimum solubility, and further the heat resistance is further improved. 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. When the number of carbon atoms in the acyl group is 12 or less, not only high semiconductor characteristics can be obtained, but also resolubilization at the time of lamination is reduced by optimum solubility, and further, heat resistance is further improved, which is preferable. 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. It is preferable that the number of carbon atoms of the alkoxy group is 12 or less because not only high semiconductor characteristics can be obtained, but also resolubilization at the time of lamination is reduced by optimum solubility, and further, heat resistance becomes higher. Examples of the alkoxy group include a methoxy group and an ethoxy group.

  Among the organic groups, the number of carbon atoms of the alkoxycarbonyl group is arbitrary as long as the effects of the present invention are not significantly impaired, but it is usually 12 or less, preferably 8 or less. By setting the number of carbon atoms of the alkoxycarbonyl group to 12 or less, not only high semiconductor characteristics can be obtained, but also resolubilization at the time of lamination is reduced by optimum solubility, and further, heat resistance is further improved, which is preferable. 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. It is preferable that the number of carbon atoms of the aryloxy group is 12 or less because not only high semiconductor characteristics can be obtained, but also resolubilization at the time of lamination is reduced by optimum solubility, and further, heat resistance becomes higher. 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. Setting the number of carbon atoms in the dialkylamino group to 12 or less is preferable because not only high semiconductor properties can be obtained, but also the resolubility during lamination is reduced by optimum solubility, and further, the heat resistance becomes higher. Examples of the dialkylamino group include a diethylamino group and a diisopropylamino group.

  Among the organic groups, the carbon number of the diaralkylamino 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. It is preferable that the number of carbon atoms of the diaralkylamino group is 12 or less because not only high semiconductor characteristics can be obtained, but also resolubilization at the time of lamination is reduced by optimum solubility, and further, the heat resistance becomes higher. 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. Setting the number of carbon atoms of the haloalkyl group to 12 or less is preferable because not only high semiconductor characteristics can be obtained, but also resolubilization at the time of lamination is reduced by optimum solubility, and further, heat resistance becomes higher. Examples of the 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 effect of the present invention is not significantly impaired, but is usually 6 or more and 30 or less, preferably 10 or more and 20 or less. By setting the number of carbon atoms of the aromatic hydrocarbon ring group to 6 or more and 30 or less, not only high semiconductor properties can be obtained, but also the optimum solubility reduces re-dissolution during lamination and further increases heat resistance. Therefore, it is preferable. Examples of the aromatic hydrocarbon ring group include a phenyl group and a naphthyl group.

  Among the organic groups, the number of carbon atoms of the aromatic heterocyclic group is arbitrary as long as the effects of the present invention are not significantly impaired, but are usually 2 or more and 30 or less, preferably 5 or more and 20 or less. By setting the number of carbon atoms in the aromatic heterocyclic group to 2 or more and 30 or less, not only high semiconductor characteristics can be obtained, but also optimal dissolution can reduce remelting at the time of lamination and further increase heat resistance. Therefore, it is preferable. Examples of the aromatic heterocyclic group include a thienyl group and a pyridyl group.

  Further, 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, a methoxycarbonyl group, and an ethoxycarbonyl group having 1 carbon atom. 1 to 6 alkoxycarbonyl groups 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 And a haloalkyl group such as a trifluoromethyl group, a cyano group, and the like. In addition, as for this substituent, 1 type 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 combine 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 ) Aromatic hydrocarbon rings optionally having substituents such as benzene ring, naphthalene ring and anthracene ring; aromatics optionally having substituents such as pyridine ring, quinoline ring, furan ring and thiophene ring Non-aromatic cyclic hydrocarbons such as cyclohexane ring; and the like.

The above-mentioned substituents included 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 type 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 the general formulas (3) and (4), 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. As an example of this substituent, the same thing as the substituent of said Z ^ia and Z ^ib is mentioned. In addition, as for this substituent, 1 type 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 enhance the planarity of the molecule.

In the general formula (4), 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 an atomic group in which a trivalent or higher-valent metal and other atoms are bonded, examples thereof include Fe—B ¹ , Al—B ² , Ti═O, Si—B ³ B ^{4, and the} like. Can be mentioned. Here, B ¹ , B ² , B ³ and B ⁴ represent a monovalent group such as a halogen atom, an alkyl group, or an alkoxy group.

In the general formulas (3) and (4), Y ^{1 to} Y ⁴ each independently represent a monovalent atom or atomic group. In the general formulas (3) and (4), 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 atoms and the like 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.

Also, if Y ¹ to Y ⁴ each are an atomic group, the atomic groups, unless significantly impairing the effects of the present invention may have an arbitrary substituent. As an example of this substituent, the same thing as the substituent of said Z ^ia and Z ^ib is mentioned. In addition, as for this substituent, 1 type 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 group having 10 or less carbon atoms. It is particularly preferred that This is because the solubility is increased and the film-forming property is improved.

  The precursor which can be preferably used in the present invention is converted into a benzoporphyrin derivative by heat treatment. There is no limitation on what kind of reaction occurs during the heat treatment. For example, in the case of the precursors represented by the general formulas (3) and (4), the following general formula (5) can be obtained by applying heat. The compound is eliminated. This elimination reaction proceeds quantitatively. The precursor is converted into a benzoporphyrin derivative by this elimination reaction.

The heat treatment will be specifically described by taking the benzoporphyrin derivative BP-1 exemplified above as an example. As a precursor of the benzoporphyrin derivative BP-1, for example, in the general formulas (3) and (4), Z ^ia , Z ^ib , R ^{1 to} R ⁴ and Y ^{1 to} Y ⁴ are all hydrogen atoms ( Hereinafter, it is referred to as “BP-1 precursor”. However, the precursor of the benzoporphyrin derivative 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. The benzoporphyrin derivative BP-1 is obtained by this deethyleneation reaction. This conversion is represented by the following reaction formula.

  When the precursor according to the present invention is converted into the benzoporphyrin derivative according to the present invention by heat treatment, 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. The upper limit is arbitrary, but it may be heated at any temperature as long as it does not damage other functional layers, substrates, etc., and is usually 400 ° C. or lower, preferably 300 ° C. or lower.

  When the precursor according to the present invention is converted into the benzoporphyrin derivative according to the present invention by heat treatment, the heating time is not limited as long as the above reaction proceeds, but usually 10 seconds or more, preferably 30 seconds or more, and usually 10 hours or less, preferably 1 hour or less. This is because if the heating time is too short, conversion may be insufficient, and if it is too long, decomposition may occur.

  When the precursor according to the present invention is converted into the benzoporphyrin derivative according to the present invention by heat treatment, 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, only 1 type may be used for an inert gas and it may use 2 or more types together by arbitrary combinations and a ratio.

  The 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 precursor according to the present invention has high solubility in a solvent, the benzoporphyrin derivative 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 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 derivative according to the present invention has a planar structure. Inferred. Therefore, if the difference in solubility in such a solvent is utilized, a layer containing the benzoporphyrin derivative can be easily formed by a coating method. For example, it can be produced by the following method.

That is, the 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 an amorphous layer. And the layer of a benzoporphyrin derivative with high planarity can be obtained by heat-treating this layer and converting the precursor according to the present invention by thermal conversion. At this time, as in the example described above, among the compounds represented by the general formulas (3) and (4), those in which Y ^{1 to} Y ⁴ are all hydrogen atoms are used as precursors, and the compounds are eliminated. Since it is an ethylene molecule, it is difficult to remain in the system, which is preferable in terms of toxicity and safety.

  There is no restriction | limiting in the manufacturing method of the precursor based on this invention, A well-known method can be employ | adopted arbitrarily. For example, when the BP-1 precursor is mentioned 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.

  Furthermore, the tetrabenzoporphyrin derivative 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.

  Note that when an n-type semiconductor forming the above-described network structure is used, both the p-type semiconductor material and the n-type semiconductor material forming the bulk heterojunction layer have a very high solvent resistance against the solvent, and the bulk hetero When a bulk heterojunction layer is further stacked on the junction layer, or a hole transport layer, an electron transport layer, a hole block layer, an electron block layer, or the like is formed by a solution process, the bulk hetero junction layer dissolves. Will not be lost. Furthermore, it is preferable that the polymerization cross-linking reaction of the n-type semiconductor layer is caused by heat because conversion of the p-type semiconductor material and the n-type semiconductor material can be achieved simultaneously.

  Furthermore, in the present invention, a continuous concentration gradient region based on a mass conversion ratio between the p-type semiconductor material and the n-type semiconductor material exists at least between the first electrode and the second electrode. To do. A method for manufacturing a region having a concentration gradient is not particularly limited in the present application. However, as described above, it is used that at least one of a p-type semiconductor material and an n-type semiconductor material has a very high solvent resistance to a solvent. By doing so, it can be said that this is a preferred embodiment as a method for forming a region having a concentration gradient because the concentration ratio of the p-type semiconductor material precursor and the n-type semiconductor material precursor can be changed and applied and laminated.

[Solar cell]
In FIG. 2, the substrate 11 is a member that holds the transparent electrode 12, the photoelectric conversion unit 14, the charge transport unit 15 (or 16), and the counter electrode 13 that are sequentially stacked. In the present embodiment, since light that is photoelectrically converted enters from the substrate 11 side, the substrate 11 can transmit the light that is photoelectrically converted, that is, is transparent to the wavelength of the light to be photoelectrically converted. It is a member. As the substrate 11, for example, a glass substrate or a resin substrate is used. The substrate 11 is not essential. For example, the bulk heterojunction type organic photoelectric conversion element 10 is configured by forming the transparent electrode 12 and the counter electrode 13 on both surfaces of the photoelectric conversion unit 14 and the charge transport unit 15 (or 16). The

The transparent electrode 12 is an electrode that can transmit light that is photoelectrically converted in the photoelectric conversion unit 14, and is preferably an electrode that transmits light having a wavelength of 300 to 800 nm. Examples of materials include transparent conductive metal oxides such as indium tin oxide (ITO), SnO ₂ and ZnO, metal thin films such as gold, silver and platinum, conductive fibers such as metal nanofibers and carbon nanotubes, and high conductivity Molecules can be used.

  The counter electrode 13 can be made of metal (for example, gold, silver, copper, platinum, rhodium, ruthenium, aluminum, magnesium, indium, etc.), carbon, or the material of the transparent electrode 12, but is not limited thereto.

  The photoelectric conversion unit 14 is a layer that converts light energy into electric energy, and includes a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are mixed. The p-type semiconductor material relatively functions as an electron donor (donor), and the n-type semiconductor material relatively functions as an electron acceptor (acceptor). Here, the electron donor and the electron acceptor are “an electron donor in which, when light is absorbed, electrons move from the electron donor to the electron acceptor to form a hole-electron pair (charge separation state)”. And an electron acceptor ”, which does not simply donate or accept electrons like an electrode, but donates or accepts electrons by a photoreaction.

  Examples of a method for forming a bulk heterojunction layer in which an electron acceptor and an electron donor are mixed include a vapor deposition method and a coating method (including a casting method and a spin coating method). Among these, a coating method is particularly preferable.

  The bulk heterojunction layer of the photoelectric conversion unit 14 is annealed at a predetermined temperature during the manufacturing process to be partially crystallized in order to improve the photoelectric conversion rate.

  In FIG. 2, light incident from the transparent electrode 12 through the substrate 11 is absorbed by the electron acceptor or electron donor in the bulk heterojunction layer of the photoelectric conversion unit 14, and electrons move from the electron donor to the electron acceptor. Thus, a hole-electron pair (charge separation state) is formed. The generated electric charge is caused by an internal electric field, for example, when the work functions of the transparent electrode 12 and the counter electrode 13 are different, the electrons pass between the electron acceptors due to the potential difference between the transparent electrode 12 and the counter electrode 13, and the holes are Passing between the electron donors and being carried to different electrodes, photocurrent is detected. For example, when the work function of the transparent electrode 12 is larger than the work function of the counter electrode 13, electrons are transported to the transparent electrode 12 and holes are transported to the counter electrode 13. If the work function is reversed, electrons and holes are transported in the opposite direction. In addition, by applying a potential between the transparent electrode 12 and the counter electrode 13, the transport direction of electrons and holes can be controlled.

  In addition, it is preferable to form a coating film in the lower layer before forming the bulk heterojunction layer at the same time because it has the effect of leveling the coating surface and reduces the influence of leakage and the like.

  Examples of the material constituting these layers include H.P. as a hole transport portion as a charge transport portion. C. Product made by Starck, PEDOT-PSS such as trade name BaytronP, polyaniline and its doping material, triarylamine compounds described in JP-A-5-271166, cyan compounds described in WO 06/19270, etc., In addition, metal oxides such as molybdenum oxide, nickel oxide, and tungsten oxide can be used. Moreover, the layer which consists of a p-type semiconductor material single-piece | unit used for the bulk heterojunction layer can also be used. The means for forming these layers may be either a vacuum deposition method or a solution coating method, but is preferably a solution coating method.

  In addition, as an electron transporting portion as a charge transporting portion, octaazaporphyrin, a p-type semiconductor perfluoro product (perfluoropentacene, perfluorophthalocyanine, etc.), naphthalene tetracarboxylic acid anhydride, naphthalene tetracarboxylic acid diimide, perylene tetra N-type semiconductor materials such as carboxylic acid anhydrides and perylenetetracarboxylic acid diimides, and n-type inorganic oxides such as titanium oxide, zinc oxide and gallium oxide, and alkali metal compounds such as lithium fluoride, sodium fluoride and cesium fluoride Etc. can be used. A layer made of a single n-type semiconductor material used for the bulk heterojunction layer can also be used. The means for forming these layers may be either a vacuum deposition method or a solution coating method, but is preferably a solution coating method.

The first electrode (transparent electrode) of the organic photoelectric conversion element of the present invention is not particularly limited to a cathode and an anode, and can be selected according to the element configuration, but preferably a transparent electrode is used as an anode. For example, when used as an anode, it is preferably an electrode that transmits light of 380 to 800 nm. As the material, for example, transparent conductive metal oxides such as indium tin oxide (ITO), SnO ₂ and ZnO, metal thin films such as gold, silver and platinum, metal nanowires and carbon nanotubes can be used.

  Also, a conductive material selected from the group consisting of polypyrrole, polyaniline, polythiophene, polythienylene vinylene, polyazulene, polyisothianaphthene, polycarbazole, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, polyphenylacetylene, polydiacetylene and polynaphthalene. A functional polymer can also be used. A plurality of these conductive compounds can be combined to form a transparent electrode.

The second electrode (counter electrode) of the organic photoelectric conversion element of the present invention may be a single layer of a conductive material, but in addition to a conductive material, a resin that holds these may be used in combination. As the conductive material of the counter electrode, a material having a small work function (4 eV or less) metal, alloy, electrically conductive compound and a mixture thereof is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the viewpoint of electron extraction performance and durability against oxidation, etc., a mixture of these metals and a second metal which is a stable metal having a larger work function value than this, for example, a magnesium / silver mixture, magnesium / Aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The counter electrode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm.

  Furthermore, it is good also as a tandem-type structure which laminated | stacked such a photoelectric conversion element for the purpose of the improvement of sunlight utilization factor (photoelectric conversion efficiency). FIG. 4 is a cross-sectional view showing a solar cell composed of a bulk heterojunction organic photoelectric conversion element including a tandem bulk heterojunction layer.

  In the case of the tandem configuration, the transparent electrode 12, the first photoelectric conversion unit 14, and the charge transport unit 15 (or 16) are sequentially stacked on the substrate 11, and then the charge recombination layer 17 is stacked. By stacking the photoelectric conversion unit 14 ′, the charge transport unit 15 ′ (or 16 ′), and then the counter electrode 13, a tandem configuration can be obtained. The second photoelectric conversion unit 14 ′ may be a layer that absorbs the same spectrum as the absorption spectrum of the first photoelectric conversion unit 14, or may be a layer that absorbs a different spectrum, but is preferably a layer that absorbs a different spectrum. is there. The material of the charge recombination layer 17 is preferably a layer using a compound having both transparency and conductivity, such as transparent metal oxides such as ITO, AZO, FTO, and titanium oxide, Ag, Al, and Au. A very thin metal layer such as PEDOT: PSS or a conductive polymer material such as polyaniline is preferable. Moreover, as a preferable configuration of the present invention, a configuration substantially free of the charge recombination layer 17 may be used.

  Moreover, it is preferable to seal by the well-known method so that the produced organic photoelectric conversion element 10 does not deteriorate with oxygen, moisture, etc. in the environment. For example, a method of sealing a cap made of aluminum or glass by bonding with an adhesive, a plastic film on which a gas barrier layer such as aluminum, silicon oxide, or aluminum oxide is formed and the organic photoelectric conversion element top 10 with an adhesive Method of pasting, method of coating organic polymer material with high gas barrier property (polyvinyl alcohol, etc.), method of directly depositing inorganic thin film with high gas barrier property (silicon oxide, aluminum oxide, etc.), and composite lamination of these And the like. Moreover, it is good also as a structure which has getters, such as oxygen and a water | moisture content, in sealing as needed.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1
(Preparation of semiconductor materials)
<BP-1 precursor>
Chemical Communications, vol. 22 (1999), p2275, a BP-1 precursor of a p-type semiconductor material was obtained.

<Exemplary Compound n-1>
In the following scheme, monomer 1 and vinyl alcohol were subjected to a polycondensation reaction in the presence of a base and purified by silica gel column chromatography to obtain n-1. Similarly, n-3 was synthesized.

[Production of organic photoelectric conversion element]
(Preparation of organic photoelectric conversion element SC-101)
An indium tin oxide (ITO) transparent conductive film deposited to a thickness of 110 nm on a 30 mm square white glass substrate (sheet resistance 13 Ω / □) is patterned to a width of 2 mm using ordinary photolithography and hydrochloric acid etching. A transparent electrode was formed.

  The patterned transparent electrode was washed in the order of ultrasonic cleaning with a surfactant and ultrapure water, followed by ultrasonic cleaning with ultrapure water, dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning.

On this transparent substrate, Baytron P4083 (manufactured by HC Starck), which is a conductive polymer, was spin-coated with a film thickness of 30 nm, and then dried by heating at 140 ° C. in the air for 10 minutes. After this, the work was performed in a nitrogen atmosphere glove box having an O ₂ and H ₂ O concentration of 1 ppm or less.

  First, the substrate was heat-treated at 150 ° C. for 5 minutes in a nitrogen atmosphere. Next, a coating solution in which 1.2% by mass of the above-described BP-1 precursor is dissolved in chlorobenzene is prepared, coated and dried using a coater, and heat-treated on a hot plate at 150 ° C. for 30 minutes. The film was formed to 20 to 30 nm. Subsequently, a coating solution in which 1.2% by mass of the BP-1 precursor and 1.0% by mass of the above-described n-1 (monomer of the crosslinked polymer n-type semiconductor material) was dissolved in chlorobenzene was prepared. The coating was used, dried at room temperature for 30 minutes, and heat-treated on a hot plate at 150 ° C. for 30 minutes to form a film having a thickness of 80 to 100 nm.

  Then, the coating liquid which dissolved 1.0 mass% of n-1 in chlorobenzene was prepared, and it apply | coated similarly and formed into a film so that a film thickness might be set to 40-50 nm. The BP-1 precursor is converted to BP-1 during the heat treatment (Mw511, low-molecular p-type semiconductor material, molecular weight is reduced to about 5/6 before and after conversion), and n-1 is 150 in the same manner. Polymerization was carried out at 30 ° C. for 30 minutes to modify the polymer into a crosslinked polymer n-type semiconductor.

Next, the substrate on which the series of organic layers is formed is moved into the vacuum deposition apparatus chamber, the shadow mask having a width of 2 mm is set so as to be orthogonal to the transparent electrode, and the vacuum deposition apparatus is up to 10 ⁻⁴ Pa or less. After depressurizing the inside, 0.6 nm of lithium fluoride was deposited at a deposition rate of 0.01 nm / second, and then 80 nm of Al metal was deposited at a deposition rate of 0.2 nm / second, thereby forming a 2 mm square size organic. A photoelectric conversion element SC-101 was obtained. The obtained organic photoelectric conversion element SC-101 was moved to a nitrogen atmosphere glove box, and sealed using an aluminum sealing can and a UV curable resin.

  For the organic layer laminated sample prepared separately, the surface / interface physical property evaluation apparatus (SAICAS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) were used in combination, and the concentration distribution in the film thickness direction of the semiconductor material was evaluated. FIG. 3A shows a stepwise concentration distribution as exemplified in FIG.

(Preparation of organic photoelectric conversion element SC-102)
A solution prepared by dissolving 0.12% by mass of a BP-1 precursor (a precursor of a low-molecular p-type semiconductor) in chlorobenzene on a substrate prepared in the same manner as in the preparation of SC-101, and n-1 ( A solution B in which 0.10% by mass of the monomer of the cross-linked polymer n-type semiconductor material) is prepared, and after the solution A is applied and dried, heat treatment is performed at 150 ° C. for 30 minutes, and the BP-1 precursor is converted into BP- A layer composed of a p-type semiconductor converted to 1 (Mw511, low-molecular p-type semiconductor material, molecular weight reduced to about 5/6 before and after conversion) is formed, and then exposed to chlorobenzene vapor for about 10 seconds. Then, the solution B was laminated and applied, and similarly heat treated at 150 ° C. for 30 minutes to form a layer made of a crosslinked polymer n-type semiconductor.

  In the subsequent step, SC-102 was produced in the same manner as SC-101 and sealed in the same manner.

  Further, when the concentration distribution in the film thickness direction of the semiconductor material was evaluated in the same manner as SC-101 for the separately prepared organic layer stacked sample, the concentration was extremely narrow at the pn interface as illustrated in FIG. Distribution was shown.

(Preparation of organic photoelectric conversion element SC-103)
A coating solution in which 1.2% by mass of the BP-1 precursor was dissolved in chlorobenzene was prepared on a substrate prepared in the same manner as in the preparation of SC-101, applied and dried using a coater, and 150 ° C. 30 on a hot plate. It heat-processed for minutes and formed into a film so that a film thickness might be set to 20-30 nm. Subsequently, BP-1 and n-1 were dissolved in chlorobenzene so as to have the concentration shown in the first layer of Table 1, and coated so as to have a film thickness of 16 to 18 nm in the same manner as SC-101. A first layer was formed by heat treatment at 150 ° C. for 10 minutes.

  Subsequently, the second and subsequent layers shown in Table 1 were sequentially applied and laminated to heat treatment, and the sixth layer was similarly laminated to form a film. After forming to the 6th layer, the coating liquid which dissolved 1.0 mass% of n-1 in chlorobenzene was prepared, and it apply | coated similarly, and formed into a film so that a film thickness might be set to 40-50 nm.

  In the subsequent step, SC-103 was produced in the same manner as SC-101 and sealed in the same manner.

  Further, when the concentration distribution in the film thickness direction of the semiconductor material was evaluated in the same manner as SC-101 for the separately prepared organic layer laminated sample, it has a continuous concentration gradient as illustrated in FIG. Distribution was shown.

(Preparation of organic photoelectric conversion element SC-104)
In the preparation of SC-103, instead of the BP-1 precursor, the p-type semiconductor material is changed to a reke regular made of Reike Metal with a number average molecular weight of 45000, poly (3-hexylthiophene (P3HT, polymer p-type semiconductor material)) SC-104 was prepared in the same manner as SC-103 except that.

  A separately prepared organic layer laminated sample showed the same semiconductor material concentration distribution as SC-103.

(Preparation of organic photoelectric conversion element SC-105)
SC-105 was produced in the same manner as SC-103, except that in the production of SC-103, instead of the configuration shown in Table 1, a laminated film was formed so as to have the configuration shown in Table 2.

  Further, regarding the organic layer laminated material prepared separately, when the concentration distribution in the film thickness direction of the semiconductor material was evaluated in the same manner as SC-101, it has a continuous concentration gradient as illustrated in FIG. A distribution composed of a region and a region having a constant density is shown.

(Preparation of organic photoelectric conversion element SC-106)
In the production of SC-105, as a p-type semiconductor material, instead of the BP-1 precursor, Reikemetal regioregular poly (3-hexylthiophene) (P3HT, polymer p-type semiconductor material) having a number average molecular weight of 45,000 is used. SC-106 was produced in the same manner as SC-105 except that the changes were made.

  The separately prepared organic layer laminated sample showed the same semiconductor material concentration distribution as SC-105.

(Preparation of organic photoelectric conversion element SC-107)
SC-107 was produced in the same manner as SC-105 except that n-3 was used instead of n-1 as the n-type semiconductor material in the production of SC-105.

  The separately prepared organic layer laminated sample showed the same semiconductor material concentration distribution as SC-105.

[Evaluation of energy conversion characteristics of photoelectric conversion elements]
About the organic photoelectric conversion element produced by the above method, an AM1.5G filter using a solar simulator, light having an intensity of 100 mW / cm ² is irradiated, and a mask having an effective area of 4.0 mm ² is overlaid on the light receiving unit. For each of the four light receiving portions formed on the element, energy conversion efficiency η (%) is obtained using Equation 1 from the short circuit current density Jsc (mA / cm ² ), the open circuit voltage Voc (V), and the fill factor ff. The average value was obtained, and the relative values are shown in Table 3 when the energy conversion efficiency of SC-101 was taken as 100.

[Formula 1] Jsc (mA / cm ² ) × Voc (V) × ff = η (%)

  From Table 3, it can be seen that the organic photoelectric conversion element of the present invention is clearly superior in energy conversion efficiency to the comparative organic photoelectric conversion element.

Example 2
[Production of organic photoelectric conversion element]
(Preparation of organic photoelectric conversion element SC-201)
In the SC-101 fabrication method, an indium tin oxide (ITO) transparent conductive film was deposited to a thickness of 150 nm on a 200 μm-thick biaxially oriented polyethylene naphthalate (PEN) substrate having a size of 20 mm × 110 mm square instead of a glass substrate. SC-201 was prepared in the same manner as SC-101, except that an effective light receiving area that contributed to photoelectric conversion was made to be about 1000 mm ² of about 10 mm × 100 mm square using a sheet (sheet resistance 13Ω / □).

(Production of organic photoelectric conversion elements SC-202 to SC-206)
In SC-202 to SC-206, SC-202 to SC-206 were produced in the same manner as the production method of SC-201, respectively.

[Bending resistance evaluation]
About the organic photoelectric conversion element produced by the above method, a 1-inch φ plastic cylindrical rod is prepared, the front and back are set as one set, and the retention rate of energy conversion efficiency η before and after winding 50 sets is obtained according to Equation 2, It is shown in Table 4.

  [Formula 2] Retention rate (%) = η after winding / η × 100 before winding

  From Table 4, it can be seen that the organic photoelectric conversion device of the present invention is clearly superior in bending resistance to the comparative organic photoelectric conversion device.

Example 3
[Production of organic photoelectric conversion element]
[Production of Organic Photoelectric Conversion Element SC-301]
A PEN film substrate with a barrier layer on which an indium tin oxide (ITO) transparent conductive film is deposited to a thickness of 150 nm (sheet resistance 13Ω / □) is 10 × 100 mm square using normal photolithography technology and hydrochloric acid etching. The light receiving part and the extraction electrode part were patterned to form a transparent electrode. The patterned transparent electrode was washed in the order of ultrasonic cleaning with a surfactant and ultrapure water, followed by ultrasonic cleaning with ultrapure water, dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning.

  After applying Baytron P4083 (made by Starck Vitec), which is a conductive polymer, on this transparent substrate so that the film thickness is 50 nm, the electrode part is cleaned with a wiping roller soaked with ultrapure water. Then, it was dried at 140 ° C. for 10 minutes, and a hole transport layer patterned to 10 × 100 mm square was formed.

  After this, the substrate was brought into the glove box and worked under a nitrogen atmosphere.

First, the substrate was heat-treated at 140 ° C. for 10 minutes in a nitrogen atmosphere. Next, P3HT (manufactured by Prectronics: regioregular poly-3-hexylthiophene) (Mw = 52000, polymer p-type semiconductor material) and PCBM (frontier carbon: 6,6-phenyl-C ₆₁ -butyric acid) were added to chlorobenzene. Methyl ester) (Mw = 911, low molecular weight n-type semiconductor material) prepared at a ratio of 1: 1 so as to be 3.0% by mass, and applied to a film thickness of 200 nm while filtering through a filter. And left to dry at room temperature. Subsequently, the electrode part was taken out with a wiping roller soaked with chlorobenzene, patterned to 10 × 100 mm square, and subjected to heat treatment at 140 ° C. for 15 minutes to form a photoelectric conversion layer. Next, a solution in which Ti-isopropoxide is dissolved in dehydrated ethanol so as to have a concentration of 0.05 mol / L is prepared, and after taking out the electrode portion, coating is performed so that the film thickness becomes 20 nm. Allowed to dry. Subsequently, the masking was removed, the electrode portion was washed with a wiping roller soaked in ethanol, transported in nitrogen with the water vapor amount adjusted, and left to form an electron transport layer.

Next, the substrate on which the series of functional layers is formed is moved into a vacuum deposition apparatus chamber, the pressure inside the vacuum deposition apparatus is reduced to 10 ⁻⁴ Pa or less, and then the deposition rate is 0.01 nm / The electrode layer was formed by laminating 0.6 nm of lithium fluoride in a second, and then laminating 80 nm of Al metal at a deposition rate of 0.2 nm / second, thereby forming an organic photoelectric conversion element SC-301 having a size of 10 × 100 mm. Got. The obtained organic photoelectric conversion element SC-301 was moved to a nitrogen atmosphere glove box and sealed with a PEN film with a barrier and a UV curable resin.

[Production of Organic Photoelectric Conversion Element SC-302]
After film formation up to the hole transport layer in the same manner as in the preparation of SC-301, the substrate was moved to a nitrogen atmosphere and the substrate was heat-treated at 140 ° C. for 10 minutes. Next, P3HT (manufactured by Prectronics: regioregular poly-3-hexylthiophene) (Mw = 52000, high-molecular p-type semiconductor material) and n-1 in chlorobenzene at 1: 1 so as to be 3.0% by mass. A mixed solution was prepared, applied to a film thickness of 200 nm while being filtered with a filter, and allowed to dry at room temperature. Subsequently, the electrode portion was taken out with a wiping roller soaked with chlorobenzene, patterned to 10 × 100 mm square, and heat-treated at 140 ° C. for 15 minutes. Furthermore, UV light was irradiated using a UV lamp to react n-1 to insolubilize it, thereby forming a photoelectric conversion layer. Thereafter, an electron transport layer and an electrode layer were formed in the same manner as in the preparation of SC-301 to obtain SC-302. The obtained element was sealed in the same manner as SC-301.

[Production of Organic Photoelectric Conversion Element SC-303]
SC-303 was obtained in the same manner as SC-302 except that p-1 was used instead of P3HT as the p-type semiconductor material in the preparation of SC-302.

[Production of Organic Photoelectric Conversion Element SC-304]
In the production of SC-302, except that BP-1 was used as the p-type semiconductor material instead of P3HT, and the insolubilization treatment was performed at 140 ° C. for 20 minutes, followed by UV light irradiation during the insolubilization treatment. Obtained SC-304 in the same manner as SC-302.

[Production of Organic Photoelectric Conversion Element SC-305]
After film formation up to the hole transport layer in the same manner as in the preparation of SC-301, the substrate was moved to a nitrogen atmosphere and the substrate was heat-treated at 140 ° C. for 10 minutes. Next, prepare a solution in which p-1 and n-1 are mixed at a ratio of 1: 1 to 3.0% by mass in chlorobenzene, and the first layer is adjusted so that the film thickness becomes 150 nm while filtering through a filter. It was applied and allowed to dry at room temperature. Subsequently, the electrode portion was taken out with a wiping roller soaked with chlorobenzene, patterned to 10 × 100 mm square, and heat-treated at 140 ° C. for 15 minutes. Subsequently, insolubilization treatment was performed by irradiating with UV light using a UV lamp. Furthermore, on the insolubilized layer, the liquid obtained by mixing the above p-1 and n-1 was applied in a second layer so that the film thickness was similarly 150 nm, and chlorobenzene was soaked. The electrode portion was taken out with a wiping roller and heated at 140 ° C. for 15 minutes. Subsequently, insolubilization treatment was performed by irradiating with UV light using a UV lamp. Thereafter, an electron transport layer and an electrode layer were formed in the same manner as in the preparation of SC-301 to obtain SC-305. The obtained element was sealed in the same manner as SC-301.

[Production of Organic Photoelectric Conversion Element SC-306]
In the production of SC-305, SC except that the mixing ratio of the first layer of p-1 and n-1 was 1.2: 0.8 and the mixing ratio of the second layer was 0.8: 1.2. SC-306 was obtained in the same manner as -305.

[Production of Organic Photoelectric Conversion Element SC-307]
In the preparation of SC-305, the mixing ratio of p-1 and n-1 and the heat treatment were performed under the conditions shown in Table 5, except that the layers were laminated in the same manner from the first layer to the sixth layer. SC-307 was obtained.

[Production of Organic Photoelectric Conversion Element SC-308]
After film formation up to the hole transport layer in the same manner as in the preparation of SC-301, the substrate was moved to a nitrogen atmosphere and the substrate was heat-treated at 140 ° C. for 10 minutes. Next, liquids prepared by dissolving p-1 and chlorobenzene separately are prepared, and UV light is introduced through a fiber and irradiated onto the coated surface, using inkjet (IJ), and p-1 and n-1 While changing the mixing ratio continuously from 4: 1 to 1: 1, the coating is applied to a film thickness of 30 nm, the electrode part is washed with a wiping roller soaked with chlorobenzene, and heated at 140 ° C. for 5 minutes. Processed. Further, on the insolubilized layer, a liquid in which p-1 and n-1 are mixed at a ratio of 1: 1 is applied so as to have a film thickness of 150 nm, and is taken out by a wiping roller soaked with chlorobenzene. Was washed and heat-treated at 140 ° C. for 15 minutes. Subsequently, insolubilization treatment was performed by irradiating with UV light using a UV lamp. Furthermore, the film thickness is 30 nm while continuously changing the mixing ratio of p-1 and n-1 from 1: 1 to 1: 4 using an ink jet while introducing UV light through a fiber and irradiating the coated surface. The electrode part was washed with a wiping roller soaked with chlorobenzene and heat-treated at 140 ° C. for 5 minutes. Thereafter, an electron transport layer and an electrode layer were formed in the same manner as in the preparation of SC-301 to obtain SC-308.

[Dark spot evaluation]
The fabricated device was exposed to light from a 100 W halogen lamp for 1000 hours. Subsequently, with respect to the exposed element, a region where the amount of power generation was reduced in the element plane was measured by an LBIC (Laser Beam Electromotive Current) measurement method, and the deterioration rate was obtained according to Equation 2, and shown in Table 6.

  (Equation 2) Degradation rate = area of the area where the amount of power generation is reduced / effective area of the element × 100 (%)

  Table 6 clearly shows that the organic photoelectric conversion element of the present invention is superior in energy conversion efficiency and durability during light irradiation to the comparative organic photoelectric conversion element.

1 Conductive substrate 2, 3, 4, 5 Photoelectric conversion part (bulk heterojunction layer)
10 organic photoelectric conversion element 11 substrate 12 transparent electrode (first electrode)
13 Counter electrode (second electrode)
14, 14 'photoelectric conversion part 15, 16, 15', 16 'charge transport part 17 charge recombination layer

Claims (13)

In an organic photoelectric conversion element in which at least a charge transport portion and a photoelectric conversion portion are stacked between a first electrode and a second electrode, the photoelectric conversion portion is a bulk hetero of a p-type semiconductor material and an n-type semiconductor material. It has a junction structure, and a region having a continuous concentration gradient due to a mass conversion ratio between the p-type semiconductor material and the n-type semiconductor material exists at least between the first electrode side and the second electrode. An organic photoelectric conversion element. The organic photoelectric conversion element according to claim 1, wherein the continuous concentration gradient region is in the vicinity of an interface between the photoelectric conversion unit and the charge transport unit. The organic photoelectric conversion element according to claim 1, wherein the charge transporting part is a hole transporting part that mainly transports holes. The organic photoelectric conversion element according to claim 1, wherein the charge transporting part is an electron transporting part that mainly transports electrons. The charge transport part includes at least a hole transport part that mainly transports holes and an electron transport part that mainly transports electrons, and the photoelectric conversion part is sandwiched between the hole transport part and the electron transport part It has a structure, The organic photoelectric conversion element of any one of Claims 1-4 characterized by the above-mentioned. The organic photoelectric conversion element according to claim 1, wherein the continuous concentration gradient region is formed by a coating method or a printing method. It is a manufacturing method of the organic photoelectric conversion element of any one of Claims 1-6, Comprising: The precursor which apply | coats the solution which has at least any one among a p-type semiconductor material precursor and an n-type semiconductor material precursor A body coating step, a patterning step for removing unnecessary portions of the applied film, and an external stimulus treatment to induce a chemical structure change of at least one of the p-type semiconductor material precursor and the n-type semiconductor material precursor. And an insolubilization step of insolubilizing the precursor induced by the chemical structure change. At least one of the p-type semiconductor material precursor and the n-type semiconductor material precursor is a precursor having a crosslinkable substituent, and at least a part of the precursor is crosslinked and insolubilized in the insolubilization step. The manufacturing method of the organic photoelectric conversion element of Claim 7 characterized by the above-mentioned. At least one of the p-type semiconductor material precursor and the n-type semiconductor material precursor is a precursor that undergoes a chemical structure change by an external stimulus process, and the precursor is changed in chemical structure in the insolubilization step to be insolubilized. The manufacturing method of the organic photoelectric conversion element of Claim 7 characterized by the above-mentioned. 10. The organic photoelectric device according to claim 7, wherein the external stimulation process is a heat process, a UV light irradiation process, or a combination of a heat process and a UV light irradiation process. A method for manufacturing a conversion element. The power generation region that is sequentially stacked is formed by repeatedly performing a process group including at least the precursor application process, the patterning process, and the insolubilization process. The manufacturing method of the organic photoelectric conversion element of item 1. A sequential power generation region having at least a continuous concentration gradient is formed by sequentially laminating coating solutions having different mixing ratios of the p-type semiconductor material precursor and the n-type semiconductor material precursor. The manufacturing method of the organic photoelectric conversion element of Claim 11. The method of manufacturing an organic photoelectric conversion element according to claim 11, wherein the power generation regions sequentially stacked include a region having a continuous concentration gradient and a region having a constant concentration.