JP2011108722A - Organic solar cell device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic solar cell device having superior efficiency of energy conversion and high-temperature/high-humidity durability, and to provide a method of manufacturing the organic solar cell device. <P>SOLUTION: The organic solar cell device 10 includes laminated layers consisting of a second electrode 15, a first light-transmitting electrode 12, and an organic layer 13 which contains a power-generating layer and is interposed between the second electrode and the first light-transmitting electrode. An interface 14 between the organic layer and the second electrode has a fine irregular structure. The organic solar cell device also includes a fluorine-containing compound located near the interface. The method of manufacturing the organic solar cell device is also provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an organic solar cell element and a method for manufacturing the organic solar cell element. More specifically, the electrode on the side facing the transparent electrode on which light is incident is made of a light reflecting member, and the functional layer for generating power and the electrode on the opposite side The present invention relates to an organic solar cell element having an uneven structure at the interface between and an organic solar cell element manufacturing method.

  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.

  Many of the coating-type organic thin-film solar cells that have been developed recently have so-called bulk heterojunction structures in which the organic donor material and the organic acceptor material are phase-separated to increase the contact area. It is characterized in that it can efficiently move to the contact interface and charge separation before the child is deactivated. The electric charges generated here diffuse in the percolation structure where each domain is connected to the electrode, and generate electricity by reaching the electrode.

However, the device made of such an organic thin film is designed to reduce the thickness of the power generation layer in order to pass a current using the principle of space charge limited current (SCLC). In this case, the optical path length necessary for light absorption is limited. Here, SCLC is a current that flows by injecting and moving a space charge from the outside, and the current density is represented by Child's law, that is, the following formula (1). J is current density, ε is relative permittivity, ε ₀ is vacuum permittivity, μ is carrier mobility, V is voltage, and d is a distance between electrodes to which V is applied (hereinafter referred to as “film thickness”). It is. As can be seen from equation (1), SCLC is inversely proportional to the cube of the thickness d, and therefore can only flow with a structure in which electrodes are sandwiched between both sides of a very thin film. More specifically, considering the general carrier mobility of organic materials, the thin film should be about 200 nm.

  As a means for overcoming the optical path length restriction described above, a transparent electrode having a concavo-convex structure is used, and a power generation element is formed on the transparent electrode. A so-called optical confinement technique for earning a long length is generally performed (for example, see Patent Document 1). Similarly, in the organic solar cell element, an element having a light confinement function inside the element using a concavo-convex structure has been introduced (for example, see Patent Documents 2 and 3), and the power generation efficiency of the solar cell element is improved. Has been shown to be effective.

JP 2000-340815 A JP 2007-5620 A Special table 2005-538556 gazette

  However, according to the study by the inventors, it has become clear that in an organic solar cell element having an uneven structure as described above, flowing SCLC itself becomes the biggest problem. In other words, in the examples introduced in the prior art, since the shape of the concavo-convex structure is not highly controlled, a power generation failure region shorted from the concavo-convex convex portion is generated, and the yield of the organic solar cell element is increased. Has been found to be extremely bad.

  In the prior art disclosed in Patent Document 2 described above, a buffer layer is provided to prevent a short circuit, and in particular in the embodiment, the uneven structure is smoothed by using a thick film of several hundred nm, and a power generation layer is provided thereon. Although it shows that power is generated even after coating film formation, in this configuration, the distance from the concavo-convex structure to the power generation layer is far away, so the light confinement effect due to light scattering is insufficient, and at the same time, refraction at the interface Since the rate difference has become apparently small, the light confinement effect has decreased, leading to a decrease in power generation efficiency. Furthermore, the diffusion layer from the PEDOT: PSS buffer layer causes the opposing electrode layers to be easily oxidized and corroded, and the durability of the device under high temperature and high humidity and the durability against light irradiation are extremely low. It was.

  In view of the above problems, there has been a demand for a technique that achieves both the formation of a light-scattering structure whose shape is highly controlled and the associated element durability.

  Therefore, the objective of this invention is providing the manufacturing method of the organic solar cell element excellent in energy conversion efficiency and excellent in high temperature, high humidity durability, and an organic solar cell element.

  The above object is achieved by the following configurations and methods.

  1. In an organic solar cell element in which an organic layer including a power generation layer is laminated between a second electrode and a light transmissive first electrode, the unevenness of the interface between the organic layer and the second electrode is fine. An organic solar cell element having a structure and containing a fluorine-containing compound in the vicinity of the interface.

  2. 2. The organic solar cell element according to 1, wherein the fine concavo-convex structure has a maximum process difference Rpv between a concave portion and a convex portion of 50 nm to 150 nm.

  3. 3. The organic solar cell element according to 1 or 2, wherein the second electrode has a light scattering reflection structure and is a porous body made of conductive fine particles.

  4). 4. The organic solar cell element as described in 3 above, wherein the conductive fine particles contain nanowires.

  5. In the manufacturing method of the organic solar cell element according to any one of 1 to 4, after laminating an organic layer including a power generation layer between the second electrode and the light transmissive first electrode, An organic material comprising at least a step of preparing a mold having an uneven structure coated with a fluorine-containing compound, embossing the organic layer while applying temperature, and transferring the uneven structure to the surface of the organic layer Manufacturing method of solar cell element.

  6). The material of the organic layer has at least a compound that exhibits a crosslinking reaction by UV light irradiation or heat treatment, and has at least a step of crosslinking the compound by UV light irradiation or heat treatment while keeping the mold pressed. 6. The method for producing an organic solar cell element according to 5 above.

  According to the present invention, an organic solar cell element excellent in energy conversion efficiency and excellent in high temperature and high humidity durability and a method for producing the organic solar cell element can be provided.

It is sectional drawing of the solar cell element which concerns on this invention. It is sectional drawing of the solar cell element of another structure which concerns on this invention. It is process drawing which shows the manufacturing method of the solar cell element which concerns on this invention. It is a figure which shows the flow of the manufacturing process of a metal mold | die. This is a process for producing a mold by forming a groove in a silicon substrate. An apparatus for processing a silicon substrate.

  Although the form for implementing this invention is described in detail below, this invention is not limited to this at all.

  The solar cell element of the present invention has an organic layer including a power generation layer between a light-transmitting first electrode and a second electrode, and an uneven structure in which the interface between the organic layer and the second electrode is fine. And having an agent containing a fluorine atom in the vicinity of the interface.

  Hereinafter, the structure of the organic solar cell element that can be preferably used in the present invention will be described in detail with reference to FIGS. 1 and 2.

  In FIG. 1, which is one preferred configuration, the organic solar cell element 10 of the present invention includes a light transmissive first electrode 12, an organic layer 13 including a power generation layer, a first layer stacked sequentially on a transparent substrate 11. 2, the interface between the organic layer 13 and the second electrode 15 has a fine concavo-convex structure 14, and has an agent containing fluorine atoms in the vicinity of the interface.

  Further, in FIG. 2, which is a more preferable configuration, the organic solar cell element 20 includes a light-transmitting first electrode 22 sequentially laminated on a transparent substrate 21, an organic layer 23 including a power generation layer, and conductive fine particles. The interface between the organic layer 23 and the second electrode 25 has a fine concavo-convex structure 24 and an agent containing fluorine atoms in the vicinity of the interface.

  Here, the second electrode 25 in FIG. 2 is preferably a porous body made of conductive fine particles in the present invention, but further includes a nanowire made of a conductive material as the conductive fine particles. More preferably.

  In the above FIG. 1 or FIG. 2, the organic layer of the present invention is characterized in that it includes at least a power generation layer. More preferably, in addition to the power generation layer, a charge transport layer such as a hole transport layer, an electron transport layer, It is more preferable to have a hole injection (extraction) layer, an electron injection (extraction) layer, or the like. Moreover, as long as the effect of the present invention is obtained, any layer may be provided between the first electrode and the second electrode, but an organic layer made of an organic compound is preferable.

(Fine uneven structure)
As described above, the following effects are expected by having a fine concavo-convex structure at the interface between the organic layer and the second electrode.
(1) Light incident on the surface of the second electrode is diffusely reflected and the optical path length is extended, thereby improving the short-circuit current density Jsc and improving the conversion efficiency.
(2) The interface surface area between the organic layer and the second electrode is increased, and the interface resistance is reduced, whereby the fill factor FF is improved and the conversion efficiency is improved. Furthermore, the durability at the time of light irradiation is improved by optimizing the carrier balance when extracting holes and electrons.
(3) Since the second electrode has a concavo-convex structure in the thickness direction of the organic layer, the region where the electric field enhancement effect by plasmon resonance is obtained on the surface of the metal electrode is expanded, and the conversion efficiency is improved by improving the short-circuit current density Jsc. To do.

(Shape of fine uneven structure)
The fine concavo-convex structure is not a concavo-convex structure large enough to penetrate the organic layer, but the maximum process difference Rpv between the concave and convex portions is preferably 50 nm to 150 nm, more preferably 50 nm to 120 nm, and 60 nm to 100 nm is most preferred. At this time, Rpv smaller than at least the thickness of the organic layer is preferable from the viewpoint of suppressing leakage current. Here, Rpv represents the height difference between the convex and concave portions of the concavo-convex structure. When the width of the concave and convex portions in the lateral direction is one pitch, the pitch width is preferably about 100 nm to 1000 nm from the viewpoint of light scattering light image formation, more preferably 150 nm to 600 nm, and most preferably about 180 nm to 500 nm.

  As the concavo-convex structure preferable in the present invention, any structure having a comb shape, a lattice shape, a triangular prism shape, a dot shape, a pyramid shape, a spherical shape, a regular shape, and an irregular shape can be preferably used. From the viewpoint of ease of embossing, a triangular prism shape with a sharp tip, a dot shape, a pyramid shape and the like are preferable.

  Such a fine concavo-convex structure can be confirmed by observing with a scanning transmission electron microscope (TEM) or the like, but for example, an atomic force microscope (AFM) or the like can be used to easily and highly accurately evaluate. Can do.

(Formation method of fine uneven structure)
The organic solar cell element of the present invention is an organic solar cell element in which an organic layer including a power generation layer is laminated between a light-transmitting first electrode and a second electrode, At least a step of laminating an organic layer and a mold having a concavo-convex structure coated with a fluorine-containing compound, embossing the organic layer while applying temperature, and transferring the concavo-convex structure to the surface of the organic layer .

  More preferably, the organic layer material described above preferably uses a compound that exhibits a crosslinking reaction by UV light irradiation or heat treatment, and the step of crosslinking the compound by UV light irradiation or heat treatment while keeping the mold pressed. It is more preferable to have at least.

  A preferred method for producing the organic solar cell element of the present invention will be described with reference to FIG.

  In FIG. 3A, a first electrode 32 is provided on a transparent substrate 31, and a mold 36 is pressed onto the organic layer 33 formed thereon while heating as necessary. (FIG. 3B), the mold is released to transfer a fine uneven structure to the surface of the organic layer (FIG. 3C). Furthermore, an organic solar cell element is obtained by laminating the second electrode layer 35 on the produced concavo-convex structure.

  Here, by preliminarily attaching a fluorine-containing compound to the surface of the mold 36, the transferability at the time of pressing the mold is excellent, and further, the structural collapse at the time of mold release can be suppressed.

  When a compound that exhibits a crosslinking reaction by UV light irradiation or heat treatment is used for the organic layer, networking by the crosslinking reaction is promoted by irradiating light from the substrate side or applying heat while pressing the above-described mold. It is preferable. By forming the network polymer and proceeding with the curing, it becomes possible to easily remove the mold without cooling. This causes a specific effect that the network polymer is cured and contracted by proceeding with the polymerization by the cross-linking reaction, and can be easily released without cooling.

  Furthermore, when the network polymer is generated, it is insolubilized in the upper layer coating solution, and thus, for example, a solvent-based metal particle dispersion is applied onto the organic layer having a fine uneven structure formed by removing the mold, A process of stacking the second electrode is also possible.

(Fluorine-containing compounds)
As the fluorine-containing compound that can be used in the present invention, both organic and inorganic compounds are useful, but from the viewpoint of applicability by a solution, it is organic and more preferably a soluble organic compound.

  The effects obtained by containing the fluorine-containing compound in the vicinity of the interface between the organic layer and the second electrode are presumed to be the following three points. In the present invention, the vicinity of the interface between the organic layer and the second electrode means within 20 nm from the interface or the interface surface.

  (1) Due to the influence of the polarization of fluorine, a negative charge is formed on the surface of the organic layer, and an electrical bonding state preferable for power generation is formed at the organic layer-second electrode (metal) interface. As a result, improvement in power generation efficiency and improvement in light irradiation durability due to maintaining carrier balance can be expected.

  (2) Since the fluorine-containing compound is localized between the organic layer and the second electrode, the corrosive substance moving in the organic layer is blocked, and the second electrode is prevented from being corroded. In particular, improvement in heat and humidity durability is expected.

  (3) When forming a fine concavo-convex structure, the releasability after transferring to an organic layer improves because a fluorine-containing compound adheres to a metal mold | die. As a result, a desired concavo-convex structure can be formed uniformly and an improvement in power generation efficiency can be expected. At the same time, since the fluorine-containing compound can be transferred to the surface of the organic layer, it can be expected that the effects (1) and (2) described above can be obtained together.

  The fluorine-containing compound used in the present invention may be any compound as long as it is a compound containing a fluorine atom, and preferably includes the following compounds.

Compound 1; F ₃ CCF ₂ CF ₂ (OCF ₂ CF ₂ CF ₂ ) ₁₁ OCF ₂ CF ₂ CH ₂ OCH ₂ CH ₂ CH ₂ Me ₂ SiOMe ₂ SiC ₂ H ₄ Si (OMe) ₃
Compound 2; F ₃ CCF ₂ CF ₂ (OCF ₂ CF ₂ CF ₂ ) ₁₁ OCF ₂ CF ₂ CH ₂ OCH ₂ CH ₂ CH ₂ Me ₂ SiOMe ₂ SiC ₂ H ₄ Si (OMe) ₃
Compound 3; F ₃ CCF ₂ CF ₂ (OCF ₂ CF ₂ CF ₂ ) ₁₁ OCF ₂ CF ₂ CONHCH ₂ CH ₂ CH ₂ Me ₂ SiOMe ₂ SiC ₂ H ₄ Si (OMe) ₃
Compound _{4; F 3 CCF 2 CF 2} O [CF (CF 3) CF 2 O] 3 CF (CF 3) CH 2 OCH 2 CH 2 CH 2 Me 2 SiOMe 2 SiC 2 H 4 Si (OMe) 3
Compound 5; F ₃ CCF ₂ CF ₂ O [CF (CF ₃ ) CF ₂ O] ₃ CF (CF ₃ ) CONHCH ₂ CH ₂ CH ₂ Me ₂ SiOMe ₂ SiC ₂ H ₄ Si (OMe) ₃
Compound _{6; F 3 CCF 2 CF 2} O [CF (CF 3) CF 2 O] 4 CF (CF 3) CH 2 OCH 2 CH 2 CH 2 Me 2 SiOMe 2 SiC 2 H 4 Si (OMe) 3
Compound _7; etc. _{F 3 CCF 2 CF 2 O [} CF (CF 3) CF 2 O] 5 CF (CF 3) CH 2 OCH 2 CH 2 CH 2 Me 2 SiOMe 2 SiC 2 H 4 Si (OMe) 3 In addition, Commercially available fluorine agents include Zonyl TC coat (manufactured by DuPont), OPTOOL DSX (manufactured by Daikin), Durasurf HD-2101Z (manufactured by Daikin), Cytop CTL-107M (manufactured by Asahi Glass), Novec EGC-1720 (Manufactured by 3M) can be used.

  As a method for detecting a fluorine-containing compound, various analytical methods can be used. In the present invention, at least for evaluating the presence or absence of a fluorine atom, the fluorine atom is detected by X-ray electron spectroscopy (XPS method). The wavelength range of the resulting binding energy can be measured and confirmed from the peak intensity.

(Mold making method)
The material of the mold may be a metal, an inorganic substance, or an organic substance. For example, there are nickel, quartz, silicon and the like, but silicon is preferable from the viewpoint of workability for forming the mold having the above shape. In the present invention, when a photopolymerization type network polymer is used as the semiconductor material, light irradiation can be performed from the mold side, and in that case, it is also preferable to select quartz or the like.

  As a method of forming a mold using silicon, Japanese Patent Application Laid-Open No. 2006-216630 provides a mold having a good mold releasability by reducing the roughness of the side wall by repeatedly performing a plasma etching process and a deposition process on a silicon substrate. It is described that Japanese Patent Application Laid-Open No. 2003-23101 discloses that a good releasability can be obtained when the boundary line between a finely processed region and a non-microstructured region is a sawtooth shape. Are listed.

  In the present invention, it is preferable to use a mold in which a fine structure is formed on a silicon substrate by a method of repeatedly performing plasma etching and deposition. In the present invention, it is further preferable to use a mold in which the boundary line between the processed region of the fine shape and the unprocessed region of the fine structure has a sawtooth shape.

  A method for manufacturing such a mold will be described with reference to FIGS. FIG. 4 is a flowchart showing the steps of a processing method for forming fine irregularities with a high aspect ratio on a silicon substrate. FIG. 5 is a view schematically showing a process of forming fine irregularities on a silicon substrate by the processing method of FIG.

  The silicon substrate processing method of FIG. 4 includes an alternate deposition / plasma etching process for a silicon substrate 210 having an etching mask 42 on which a predetermined fine pattern is formed by electron beam drawing / development as shown in FIG. By doing so, a high aspect ratio groove having a depth H and a width W as shown in FIG. 5B is processed.

  First, a resist (photosensitive resin) is uniformly applied to the silicon substrate 210 (S01), a predetermined fine pattern is drawn on the resist surface by an electron beam (S02), and development is performed with a predetermined developing material. Thus (S03), an etching mask 42 having a fine pattern is formed on the surface 210a of the silicon substrate 210 as shown in FIG.

  The electron beam drawing in step S02 is performed by the present inventors together with the other inventors using, for example, the electron beam drawing apparatus proposed in Japanese Patent Application Laid-Open Nos. 2004-107793, 2004-54218, and the like. Can do. As a result, a desired drawing pattern can be formed on the resist film with high accuracy on the order of several tens of nanometers by three-dimensional drawing using an electron beam.

  Next, the silicon substrate 210 on which the above-described etching mask 42 is formed is held by the substrate holder 215 in the vacuum plasma chamber 211 of FIG. 6 and set in the ICP etching apparatus 200 (S04). Then, optimization conditions such as bias power and RF power are input and set in the ICP etching apparatus 200 (S05).

  Next, the ICP etching apparatus 200 is operated under the above conditions, and the vacuum plasma chamber 211 is evacuated. Then, a deposition gas is introduced into the vacuum plasma chamber 211 from the deposition gas source 225 by the control valve 226, A high frequency voltage is applied to the electrodes 213 and 214 to generate plasma, and deposition is performed on the silicon substrate 210 (S06).

Next, the supply of the deposition gas is stopped by the control valve 226, and the deposition gas is exhausted by the vacuum device 221 until the internal pressure of the vacuum plasma chamber 211 becomes 10 ⁻² Pa or less (S07).

  Next, an etching gas is introduced from the etching gas source 223 into the vacuum plasma chamber 211 by the control valve 224, a high frequency voltage is applied to the electrodes 213 and 214 to generate plasma, and a bias voltage is applied to the silicon substrate 210, Etching is performed on the silicon substrate 210 (S08).

If the etching continues (S09), the supply of the etching gas is stopped by the control valve 224, and the etching gas is exhausted by the vacuum device 221 until the internal pressure of the vacuum plasma chamber 211 becomes 10 ⁻² Pa or less (S10). .

  Next, returning to the above-described step S06, deposition is performed, and then exhaust (S07) and etching (S08) are performed in the same manner. In this way, the silicon substrate 210 is etched by alternately repeating the deposition process and the etching process.

  Next, when the above etching is completed (S09), the ICP etching apparatus is stopped (S11), and the silicon substrate 210 is moved from the vacuum plasma chamber (S12).

  As described above, by alternately repeating the plasma etching process and the deposition process on the silicon substrate 210 on which the mask 42 is formed with the resist, the surface 210a of the silicon substrate 210 has a depth H as shown in FIG. A plurality of grooves 41 having a width W and a high aspect ratio (H / W) can be formed.

  As described above, it is possible to obtain a periodic groove structure having the grooves 41 having the pitch size P of 10 nm to 200 nm and the aspect ratio (H / W) of 2 to 30 in the silicon substrate 210.

  In FIG. 4, when the deposition (S06) and the etching (S08) are alternately repeated, the next process (deposition) is performed after performing the exhausting process (S07, S10) for exhausting the immediately preceding process gas sufficiently. In the next process, there is no mixed state of the etching gas and the deposition gas, each process can be executed stably, and the periodic groove structure having the above-mentioned desired groove shape is formed in the silicon substrate 210. Can be processed with high accuracy.

  The pitch size and aspect ratio as described above can be evaluated by observing a tomographic sample prepared with a focused ion beam (FIB) or the like with an electron microscope or the like, and more easily by using an atomic force microscope (AFM) or the like. Can be evaluated.

(Semiconductor material precursor)
In the present invention, since the power generation efficiency is higher as the area of the interface between the p-type semiconductor material and the n-type semiconductor material is larger, it is desirable to increase the aspect ratio of the unevenness.

  In order to form irregularities with a large aspect ratio, it is necessary to push deeply into the mold having a fine structure. Therefore, it is desirable that the semiconductor material is soft. However, when the mold is released, it is desirable that the semiconductor material is hard and strong so that the shape of the molded semiconductor material is not broken. In the present invention, the semiconductor material precursor to be nanoimprinted (p-type semiconductor material and n-type semiconductor material precursor) is preferably a compound having such properties.

  Further, when the semiconductor material precursor is polymerized, it undergoes curing shrinkage, stress is generated at the interface with the mold, and it becomes easy to peel off from the mold. Therefore, the semiconductor material precursor is preferably a compound having a large cure shrinkage rate.

  The semiconductor material precursor is a compound having a group capable of forming a network structure by polymerization or cross-linking, and has a function of a p-type semiconductor or an n-type semiconductor when the network structure is formed. Examples of groups capable of forming a network structure by polymerization or cross-linking include epoxy groups, vinyl groups, acryloyl groups, isocyanate groups, methylol groups, etc., among which acryloyl groups and vinyl groups have radical polymerization. A possible group is preferred because of its high cure shrinkage.

  In the present invention, networking refers to a structure in which low-molecular monomers are polymerized, or polymer chains are linked by a covalent bond through a crosslinking reaction.

(N-type semiconductor material)
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.

  Of these, fullerene-containing compounds are preferred. Fullerene-containing 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. The compound which has is mentioned. As the fullerene-containing compound, a compound (derivative) having fullerene C60 as a skeleton is preferable.

  When a fullerene derivative is used as a precursor, a semiconductor material that is networked by an external stimulus treatment and has a polymer (polymer) structure is more preferable. Such 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 included in the polymer main chain. The compound contained is preferred. This is not because fullerene is contained in the main chain because the polymer does not have a branched structure, so that it can be packed with high density when solidified, resulting in high mobility. It is estimated.

  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, tert-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, biphenyl ), Heteroaryl groups (eg, furyl, thienyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, imidazolyl, pyrazolyl, thiazolyl, quinazolinyl, phthalazinyl, etc.), silyl Groups (for example, a trimethylsilyl group, a triethylsilyl group, a tert-butyldimethylsilyl group, a triisopropylsilyl group, a tert-butyldiphenylsilyl group, etc.), and these substituents include an alkyl group, a halogenated alkyl group, As for the alkenyl group, alkynyl group, aryl group, heteroaryl group, and alkylsilyl group, specifically, an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group) , Octyl group, dodecy Group, tridecyl group, tetradecyl 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 groups (eg, ethynyl group, propargyl group, etc.), cycloalkyl groups (eg, cyclopentyl group, cyclohexyl group, etc.), aryl groups (eg, phenyl group, p-chlorophenyl group, mesityl group, tolyl 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 group, pyri Zyl 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) silyl group, etc.), and these substituents may be further substituted by the above substituents, but a plurality of them may be bonded to each other to form a ring. Also good.

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 three-dimensionally crosslinked network structure. By forming such a three-dimensional network structure, when stacking a bulk heterojunction layer and forming a hole transport layer, an electron transport layer, a hole block layer, an electron block layer, etc. on the solution process, Since the lower layer is not dissolved, the materials are not mixed with each other, and the effects of the present invention can be exhibited. As a further secondary effect, a highly rigid n-type carrier path structure can be formed, preventing the phase separation structure of the p-type layer and the n-type layer from changing over time, resulting in high durability. Since the organic photoelectric conversion element which has it can be obtained, the further efficiency improvement and lifetime improvement can be achieved.

  The n-type semiconductor material precursor is a compound having a group capable of forming a network structure by polymerization or crosslinking, and has a function of an n-type semiconductor when the network structure is formed. Examples of groups capable of forming a network structure by polymerization or cross-linking include epoxy groups, vinyl groups, acryloyl groups, isocyanate groups, methylol groups, etc., among which acryloyl groups and vinyl groups have radical polymerization. A possible group is preferred because of its high cure shrinkage.

  Preferable examples of the n-type semiconductor material precursor include the following compounds.

(P-type semiconductor material)
Examples of the p-type semiconductor material include a condensed polycyclic aromatic compound precursor. Examples of the condensed polycyclic aromatic compound precursor include anthracene, tetracene, pentacene, hexacene, heptacene, chrysene, picene, fluorene, pyrene, peropyrene, perylene, terylene, quaterylene, coronene, ovalene, circumanthracene, bisanthene, zeslen, Precursors such as heptazethrene, pyranthrene, violanthene, isoviolanthene, sacobiphenyl, anthradithiophene and the like can be mentioned.

  Furthermore, examples of the p-type semiconductor material used in the present invention include various condensed polycyclic aromatic compounds and conjugated compounds.

  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 ring thiophene structure, WO2008 / 000664, Adv. Mater. , 2007, p4160, Macromolecules, 2007, Vol. Examples thereof include thiophene copolymers such as 40 and p1981.

  The p-type semiconductor material precursor is a compound having a group capable of forming a network structure by polymerization or crosslinking, and preferably has a function of a p-type semiconductor when the network structure is formed. Examples of groups capable of forming a network structure by polymerization or cross-linking include epoxy groups, vinyl groups, acryloyl groups, isocyanate groups, methylol groups, etc., among which acryloyl groups and vinyl groups have radical polymerization. A possible group is preferred because of its high cure shrinkage.

  Examples of preferred specific compounds are listed below.

(Networked)
In the present invention, networking refers to a structure in which low-molecular monomers are polymerized, or polymer chains are linked by a covalent bond through a crosslinking reaction.

  At least one of the p-type semiconductor material precursor and the n-type semiconductor material precursor of the present invention is exposed to heat, light, radiation, a vapor of a compound that causes a polymerization reaction or a cross-linking reaction, etc., when it is uneven by a mold. As a result, a polymerization reaction or a crosslinking reaction is caused to form a network structure.

  In general, a polymer is often used for the p-type semiconductor material, whereas an n-type semiconductor material is generally composed of a low-molecular material. In the present invention, it is more preferable that the n-type semiconductor material made of a low-molecular material, which has a large insolubilizing effect on the formation of the upper layer, is networked as described above. More preferably, both the p-type semiconductor material and the n-type semiconductor material are networked as described above from the viewpoint of insolubilization with respect to the upper layer formation and releasability when peeling from the mold.

  As a trigger for these reactions, heat or light is preferred. The p-type semiconductor material precursor or the n-type semiconductor material precursor may be combined with a polymerization initiator, but the p-type semiconductor material precursor or the n-type semiconductor material precursor is a compound that can be polymerized without using a polymerization initiator. Preferably there is.

(Hole transport layer)
As a material preferably used as the hole transport layer (hole injection layer, electron block layer), H.P. C. Made by Starck Co., Ltd., PEDOT such as trade name BaytronP, polyaniline and its doping material, triarylamine compounds described in JP-A No. 5-271166, cyanogen compounds described in WO2006 / 019270, etc., molybdenum oxide, Metal oxides such as nickel oxide and tungsten oxide can be used. A layer made of a single p-type semiconductor material used for the bulk heterojunction layer can also be used. The means for forming these layers is preferably formed by a solution coating method.

  In the present invention, a hole injection layer and a hole transport layer may be laminated according to the purpose, and an optimum material may be selected for the hole transport property and the bonding between the electrodes.

  In the present invention, a material that has a function of blocking electrons as reverse carriers and improves the selectivity of charges may be selected.

  A preferable film thickness range of each layer is preferably 0.1 nm to 100 nm, more preferably 5 nm to 70 nm, and most preferably 10 nm to 50 nm.

(Electron transport layer)
As the electron transport layer (electron injection layer, hole blocking layer) material, various n-type materials can be used. Examples of materials that can be preferably used in the organic electronic device of the present invention include metal complex compounds such as 8-hydroxyquinolinate lithium and bis (8-hydroxyquinolinato) zinc, or the following nitrogen-containing five-membered rings. There are derivatives. That is, oxazole, thiazole, oxadiazole, thiadiazole or triazole derivatives are preferred. Specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole, 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5-bis (1 -Phenyl) -1,3,4-oxadiazole, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) 1,3,4-oxadiazole, 2,5-bis ( 1-naphthyl) -1,3,4-oxadiazole, 1,4-bis [2- (5-phenyloxadiazolyl)] benzene, 1,4-bis [2- (5-phenyloxadiazolyl) -4-tert-butylbenzene], 2- (4'-tert-butylphenyl) -5- (4 "-biphenyl) -1,3,4-thiadiazole, 2,5-bis (1-naphthyl) -1 , 3,4-thiadiazole, 1,4-bis [2- (5-phenyl) Asiazolyl)] benzene, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-triazole, 2,5-bis (1-naphthyl) -1,3,4 -Triazole, 1,4-bis [2- (5-phenyltriazolyl)] benzene and the like.

  In addition to the above-mentioned compounds, fullerenes, carbon nanotubes, p-type semiconductor perfluoro compounds (perfluoropentacene, perfluorophthalocyanine, etc.), and n-type inorganic oxides such as titanium oxide, zinc oxide, gallium oxide, etc. It is also preferable in the present invention to use.

  In the present invention, an electron injection layer and an electron transport layer may be laminated according to the purpose, and an optimal material may be selected in connection with electron transport properties and electrodes.

  In the present invention, a material that has a function of blocking electrons as reverse carriers and improves the selectivity of charges may be selected.

  The preferred film thickness range of each layer is preferably from 0.1 nm to 100 nm, more preferably from 5 nm to 80 nm, and most preferably from 10 nm to 60 nm.

  The electron injection layer (buffer layer) is selected from halides containing lithium, potassium, sodium, cesium and other ions, acetates, phosphates, etc., for example, lithium fluoride, potassium fluoride, etc. A structure that improves the bonding with the electrode is particularly preferred in the present invention.

(First electrode)
The cathode and anode of the first electrode of the present invention are not particularly limited, and can be selected depending on the element configuration. For example, when used as an anode, the first electrode 12 is preferably an electrode that transmits light of 300 to 800 nm. A material having a work function larger (deep) than 4 eV is suitable as the material, for example, a transparent conductive metal oxide such as indium tin oxide (ITO), SnO ₂ , or ZnO, or a metal such as gold, silver, or platinum. Thin films, metal nanowires, carbon nanotubes, and conductive polymers can be used.

  In the present invention, when UV light is used as an external stimulus and light is irradiated from the opposite side of the mold after pressing the mold, the material used for the first electrode is a material that transmits most of the UV light. The structure consisting of is more preferable.

(Second electrode)
The second electrode of the present invention is not particularly limited to a cathode and an anode, and can be selected depending on the element structure, but a transparent electrode is preferably used as the anode. For example, when used as a cathode, it is preferable to use a metal, an alloy, an electrically conductive compound having a work function of 4 eV or less (shallow), and a mixture thereof as an electrode material. 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 electrical bonding with the organic layer and durability against oxidation, etc., a mixture of these metals and a second metal which is a stable metal having a larger (deeper) work function than this metal. For example, a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum alone and the like are suitable.

  The second 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.

  If a highly reflective metal material is used as the second electrode, for example, in an organic EL element, a part of the emitted light can be reflected and extracted to the outside. In the organic solar cell element, a photoelectric conversion layer The effect of increasing the optical path length is obtained by reflecting the light that has passed through and returning again to the photoelectric conversion layer, and in any case, an improvement in external quantum efficiency can be expected.

  Furthermore, it may be a nanoparticle, nanowire, or nanostructure made of metal (eg, gold, silver, copper, platinum, rhodium, ruthenium, aluminum, magnesium, indium, etc.) or carbon, and highly dispersed nanoparticle or nanowire. A transparent paste is preferable because a transparent and highly conductive counter electrode can be formed by a coating method or a printing method.

  In the present invention, the second electrode is preferably conductive fine particles, more preferably at least nanowire-like conductive fine particles.

  Moreover, when making the counter electrode side light-transmitting, for example, after forming a conductive material suitable for the counter electrode such as aluminum and aluminum alloy, silver and silver compound in a thin film thickness of about 1 to 20 nm, By providing a film of the conductive light transmissive material mentioned in the description of the transparent electrode, a light transmissive electrode can be obtained.

(Base material)
The base material used in the organic electronics element of the present invention is preferably a member that can transmit emitted light or light for generating electromotive force, that is, a member transparent to the wavelength of these lights. . Examples of the substrate that can be used in the present invention include a glass substrate and a resin substrate, but it is desirable to use a transparent resin film from the viewpoint of lightness and flexibility.

  There is no restriction | limiting in particular in the transparent resin film which can be preferably used as a transparent base material by this invention, About the material, a shape, a structure, thickness, etc., it can select suitably from well-known things. For example, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) modified polyester, polyethylene (PE) resin film, polypropylene (PP) resin film, polystyrene resin film, polyolefin resins such as cyclic olefin resin Film, vinyl resin film such as polyvinyl chloride, polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysulfone (PSF) resin film, polyether sulfone (PES) resin film, polycarbonate (PC) resin film, A polyamide resin film, a polyimide resin film, an acrylic resin film, a triacetyl cellulose (TAC) resin film, and the like can be given. If the resin film transmittance of 80% or more at ~800nm), can be preferably applied to a transparent resin film according to the present invention. Among these, from the viewpoint of transparency, heat resistance, ease of handling, strength and cost, it is preferably a biaxially stretched polyethylene terephthalate film, a biaxially stretched polyethylene naphthalate film, a polyethersulfone film, or a polycarbonate film, and biaxially stretched. More preferred are polyethylene terephthalate films and biaxially stretched polyethylene naphthalate films.

  The transparent substrate used in the present invention can be subjected to a surface treatment or an easy-adhesion layer in order to ensure the wettability and adhesion of the coating solution. A conventionally well-known technique can be used about a surface treatment or an easily bonding layer. For example, the surface treatment includes surface activation treatment such as corona discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, and laser treatment. Examples of the easy adhesion layer include polyester, polyamide, polyurethane, vinyl copolymer, butadiene copolymer, acrylic copolymer, vinylidene copolymer, and epoxy copolymer.

  Further, for the purpose of suppressing the permeation of oxygen and water vapor, a barrier coat layer may be formed in advance on the transparent material, or a hard coat layer is formed in advance on the side where the transparent conductive layer is formed or on the opposite side. It may be.

(Sealing)
In order to prevent the produced organic photoelectric conversion element from being deteriorated by oxygen, moisture, etc. in the atmosphere, it is preferable to seal the organic electroluminescence element and the organic solar cell element by a known method. For example, a method of sealing and bonding a plastic film on which a gas barrier layer such as a thin film of aluminum, silicon oxide, or aluminum oxide is formed and an organic electronics element with an adhesive or UV curable / thermosetting resin, etc. Spin coating of high organic polymer materials (polyvinyl alcohol, etc.), inorganic thin films (silicon oxide, aluminum oxide, etc.) or organic films (parylene, etc.) with high gas barrier properties under vacuum or air, sputtering, CVD, etc. And a method of laminating them in a composite manner.

  Furthermore, in the present invention, from the viewpoint of improving the life of the element, the entire element including the base material may be laminated and sealed with two base materials with a barrier, and preferably a structure in which a moisture getter or the like is enclosed. More preferred in the present invention.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to this.

(Preparation of organic solar cell element SC-101)
(Formation of the first electrode)
An indium tin oxide (ITO) transparent conductive film deposited with a thickness of 150 nm on a PEN film substrate with a barrier layer (sheet resistance 10 Ω / □) is made 2 mm wide using ordinary photolithography technology and hydrochloric acid etching. Patterning was performed 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.

(Formation of hole transport layer)
On this transparent base material, Clevious P4083 (made by Starck Co., Ltd.), which is a conductive polymer, was applied to a film thickness of 30 nm, and then the electrode part was wiped off with a wiping tool soaked with ultrapure water. Then, the film was dried at 150 ° C. for 15 minutes to form a hole transport layer.

  After this, the base material was brought into the glove box and operated under a nitrogen atmosphere in which the low moisture concentration and low oxygen concentration were controlled.

  Hereinafter, in the examples, a substrate in which a first electrode and a hole transport layer are laminated on a base material is referred to as a substrate.

(Formation of power generation layer)
First, the substrate was heat-treated at 120 ° C. for 15 minutes in a nitrogen atmosphere. Next, p-1 shown as the exemplary compound of the p-type semiconductor material precursor and n-1 shown as the exemplary compound of the n-type semiconductor material precursor were mixed at a mass ratio of 1: 0.8, 3 A solution dissolved in chlorobenzene was prepared so as to be 0.0% by mass, and coating was performed so that the film thickness when dried by filtration through a filter was 150 nm, followed by heat treatment at 150 ° C. for 10 minutes. The removal electrode portion of the substrate is removed and cleaned with a wiping member soaked with acetone, and then heated at 120 ° C. using a 170 W high-pressure mercury lamp until the accumulated energy reaches 200 mJ / cm ^2. Intermittent exposure was performed, and a p-type semiconductor material precursor and an n-type semiconductor material precursor were subjected to a crosslinking reaction to form a power generation layer.

Next, the sample on which the series of organic layers has been formed is moved into the vacuum deposition apparatus chamber, the pressure inside the vacuum deposition apparatus is reduced to 10 ⁻⁴ Pa or less, and then arranged so as to be orthogonal to the patterned ITO. Through the 2 mm wide shadow mask, 0.6 nm of lithium fluoride was stacked at a deposition rate of 0.01 nm / second to form an electron injection layer.

(Formation of second electrode)
Subsequently, an electrode layer was formed by laminating 100 nm of Al metal at a deposition rate of 0.2 nm / second, and the light receiving portion was a 2 × 2 mm size power generation area. The obtained element was moved to a nitrogen atmosphere glove box and sealed with a PEN film with a barrier and a thermosetting resin, to produce an organic solar cell element SC-101.

(Preparation of organic solar cell element SC-102)
In the same manner as in the preparation of SC-101, the sample formed up to the power generation layer is moved into the vacuum deposition apparatus chamber, the pressure inside the vacuum deposition apparatus is reduced to 10 ⁻⁴ Pa or less, and then directly applied to the patterned ITO. Through a 2 mm wide shadow mask arranged in a shape, 20 nm of Cu metal is stacked at a deposition rate of 0.1 nm / second, and then 100 nm of Al metal is stacked at a deposition rate of 0.2 nm / second to form an electrode layer. Except for the formation, an organic solar cell element SC-102 having a light receiving portion of 2 × 2 mm was obtained in the same manner as in the preparation of SC-101 described above.

(Preparation of organic solar cell element SC-103)
In the same manner as in the preparation of SC-101, a sample formed up to the hole transport layer was prepared, this base material was brought into a glove box, and the following was continued under a nitrogen atmosphere in which low moisture concentration and low oxygen concentration were controlled. Worked.

(Formation of power generation layer)
First, the substrate was heat-treated at 120 ° C. for 15 minutes in a nitrogen atmosphere. Next, p-1 shown as the exemplary compound of the p-type semiconductor material precursor and n-1 shown as the exemplary compound of the n-type semiconductor material precursor were mixed at a mass ratio of 1: 0.8, 3 A solution dissolved in chlorobenzene was prepared so as to be 0.0% by mass, and coating was performed so that the film thickness when dried by filtration through a filter was 150 nm, followed by heat treatment at 150 ° C. for 10 minutes. The removal electrode portion of the substrate was removed and cleaned with a wiping member soaked with acetone, and then the mold 1 produced as described below was embossed at a pressure of 2.5 MPa while being heated at 140 ° C. Further, with the embossing, using a 170 W high-pressure mercury lamp from the transparent substrate side, heating at 120 ° C. and intermittent exposure until the accumulated energy reaches 800 mJ / cm ² , the p-type semiconductor material precursor and n The type semiconductor material precursor was subjected to a crosslinking reaction.

  Subsequently, before cooling to room temperature, the entire substrate was peeled from the mold, and a fine concavo-convex structure was formed on the power generation layer in which the p-type semiconductor material and the n-type semiconductor material were mixed.

  From the observation by the scanning electron microscope (SEM), the produced concavo-convex structure was confirmed that the organic layer material was slightly adhered to the mold side, and the dot shape disorder on the organic layer side was partially confirmed. The dot size itself is released in a shape almost identical to the mold, the dot-shaped groove width is 40 nm (corresponding to the convex part of the mold), the dot pitch is about 110 nm, and the average depth of the dot-shaped grooves is about 80 nm. Rpv estimated by AFM in the region of 5 μm × 5 μm was about 130 nm.

  An organic solar cell element SC-103 was produced in the same manner as in the production of SC-101 except that the fine uneven structure described above was formed.

(Production of mold 1)
A dot-like periodic shape having the following dimensions was formed on a silicon substrate by an alternate deposition / etching process. An uneven structure having a dot-to-dot pitch of 110 nm, a recess width of 70 nm, a protrusion width of 40 nm, and a height of 200 nm could be formed.

  The above process conditions were set as follows.

Device: ULVAC, Inc. Model CE300I Device name ICP etching device Gas (1) (deposition gas): SF ₆ / O ₂
Deposition gas pressure: 1.33Pa
Gas (2) (etching gas): C ₄ F ₈
Etching gas pressure: 0.3 Pa
High frequency output for plasma excitation during deposition: 300W
High frequency output for plasma excitation during etching: 150W
Bias output: 3W.

(Preparation of organic solar cell element SC-104)
In the preparation of SC-102, after forming a fine concavo-convex structure on the organic layer, the sample was moved into a vacuum deposition apparatus chamber, the inside of the vacuum deposition apparatus was depressurized to 10 ⁻⁴ Pa or less, and then patterned. Through a 2 mm wide shadow mask placed perpendicular to ITO, 20 nm of Cu metal was deposited at a deposition rate of 0.1 nm / second, followed by 100 nm of Al metal at a deposition rate of 0.2 nm / second. Thus, an organic solar cell element SC-104 having a light receiving part size of 2 × 2 mm was obtained in the same manner as in the preparation of SC-102 described above except that the electrode layer was formed.

(Preparation of organic solar cell element SC-105)
In producing SC-103, SC-105 was obtained in the same manner as in producing SC-103, except that a fine uneven structure was produced on the organic layer by the method described below.

(Formation of power generation layer)
First, the substrate was heat-treated at 120 ° C. for 15 minutes in a nitrogen atmosphere. Next, p-1 shown as the exemplary compound of the p-type semiconductor material precursor and n-1 shown as the exemplary compound of the n-type semiconductor material precursor were mixed at a mass ratio of 1: 0.8, 3 A solution dissolved in chlorobenzene was prepared so as to be 0.0% by mass, and coating was performed so that the film thickness when dried by filtration through a filter was 150 nm, followed by heat treatment at 150 ° C. for 10 minutes.

  The removal electrode portion of the substrate is removed and cleaned with a wiping member soaked in acetone, and then the fluorine-containing compound 1 is diluted with HFE-7200 (manufactured by 3M) on the mold 1 described above. Then, the excess fluorine-containing compound was washed and removed with tetrafluoropropyl alcohol (TFPO), and then the organic layer was embossed at a pressure of 1.25 MPa while being heated at 140 ° C.

Further, with the embossing, using a 170 W high-pressure mercury lamp from the transparent substrate side, heating at 120 ° C. and intermittent exposure until the accumulated energy reaches 800 mJ / cm ² , the p-type semiconductor material precursor and n The type semiconductor material precursor was subjected to a crosslinking reaction.

  Subsequently, before cooling to room temperature, the entire substrate was peeled from the mold, and a fine concavo-convex structure was formed on the power generation layer in which the p-type semiconductor material and the n-type semiconductor material were mixed.

  The prepared concavo-convex structure is a periodic dot shape with no disorder without the organic layer material adhering to the mold side, as observed by a scanning electron microscope (SEM), and the dot size itself is almost the mold. In a 5 μm × 5 μm area, the dot-shaped groove width is 40 nm (corresponding to the convex part of the mold), the inter-dot pitch is about 110 nm, and the average depth of the dot-shaped grooves is about 50 nm. Rpv estimated by AFM was about 70 nm.

  When the surface of the organic layer after peeling was analyzed by X-ray photoelectron spectroscopy (XPS method), the presence of fluorine atoms attributable to the fluorine-containing compound could be confirmed.

(Formation of second electrode)
Subsequently, SC-105 was prepared in the same manner as SC-101 except that the second electrode layer was formed by laminating 100 nm of Al metal at a deposition rate of 0.2 nm / sec.

(Preparation of organic solar cell element SC-106)
SC-106 was prepared in the same manner as SC-105 except that Compound 1 of the fluorine-containing compound was changed to OPTOOL DSX (manufactured by Daikin Industries) in the preparation of SC-105.

  When the surface of the organic layer after peeling was analyzed by X-ray photoelectron spectroscopy (XPS method) in the same manner as SC-105, the presence of fluorine atoms attributable to the fluorine-containing compound could be confirmed.

(Preparation of organic solar cell element SC-107)
SC-107 was produced in the same manner as SC-105, except that in the production of SC-105, the mold was pressed at a pressure of 5 MPa while being heated at 180 ° C.

  The prepared concavo-convex structure is a periodic dot shape with no disorder without the organic layer material adhering to the mold side, as observed by a scanning electron microscope (SEM), and the dot size itself is almost the mold. In the shape of 5μm × 5μm, the dot-shaped groove width is 40nm (corresponding to the convex part of the mold), the inter-dot pitch is about 110nm, the average depth of the dot-shaped groove is about 100nm. Rpv estimated by AFM was about 160 nm.

  When the surface of the organic layer after peeling was analyzed by X-ray photoelectron spectroscopy (XPS method), the presence of fluorine atoms attributable to the fluorine-containing compound could be confirmed.

  Except for the above, SC-107 was prepared in the same manner as SC-105.

(Production of organic solar cell element SC-108)
SC-108 was produced in the same manner as in SC-105 except that in the production of SC-105, the mold was pressed at a pressure of 0.5 MPa while being heated at 130 ° C.

  The prepared concavo-convex structure is a periodic dot shape with no disorder without the organic layer material adhering to the mold side, as observed by a scanning electron microscope (SEM), and the dot size itself is almost the mold. In the area of 5μm × 5μm, the dot-shaped groove width is 40nm (corresponding to the convex part of the mold), the inter-dot pitch is about 110nm, the average depth of the dot-shaped groove is about 30nm. Rpv estimated by AFM was about 40 nm.

  When the surface of the organic layer after peeling was analyzed by X-ray photoelectron spectroscopy (XPS method), the presence of fluorine atoms attributable to the fluorine-containing compound could be confirmed.

  Except for the above, SC-108 was prepared in the same manner as SC-105.

(Production of organic solar cell element SC-109)
In the production of SC-105, after forming a fine concavo-convex structure on the power generation layer, a silver paste (RA-FL-011 manufactured by Toyo Ink Co., Ltd.) is directly applied to the patterned ITO by screen printing. Printing was performed to a width of 2 mm and a drying process was performed at 85 ° C. for 30 minutes to form a second electrode having a thickness of about 2 μm.

  SC-109 was prepared in the same manner as SC-105 except that the second electrode was changed to the method described above.

(Preparation of organic solar cell element SC-110)
In the production of SC-105, after forming a fine uneven structure on the power generation layer, a silver nanowire dispersion prepared by the method described later is applied so that the basis weight of the silver nanowire is 80 mg / m ² , After silver nanowires were sprayed, a silver paste (RA-FL-011 manufactured by Toyo Ink Co., Ltd.) was printed in a 2 mm width by screen printing on the patterned ITO, and was printed at 85 ° C. for 30 minutes. A drying process was performed to form a second electrode having a thickness of about 2 μm.

  Silver nanowires are described in Adv. Mater. , 2002, 14, 833 to 837, silver nanowires having an average diameter of 75 nm and an average length of 35 μm were prepared, and the silver nanowires were filtered and washed with an ultrafiltration membrane, followed by ethanol. It was re-dispersed in a silver nanowire (AgNW) dispersion (silver nanowire content 5 mass%).

  SC-110 was produced in the same manner as SC-105 except that the second electrode was changed to the method described above.

(Preparation of organic solar cell element SC-111)
(Formation of the first electrode)
On the PEN film substrate with a barrier layer, a 150 nm thick zinc oxide (ZnO) transparent conductive film deposited (sheet resistance 10Ω / □) was formed by sputtering. The produced transparent conductive film was formed to have a concavo-convex structure with a height of 100 to 300 nm and a pitch of 200 to 400 nm, and was patterned to a width of 2 mm using a normal photolithography technique and hydrochloric acid etching to form a transparent electrode.

  The patterned transparent electrode was sequentially subjected to ultrasonic cleaning with a surfactant and ultrapure water, ultrasonic cleaning with acetone, and ultrasonic cleaning with IPA, followed by drying with nitrogen blowing, and finally ultraviolet ozone cleaning.

(Formation of hole transport layer)
On this transparent base material, Clevious P4083 (manufactured by Starck Co., Ltd.), which is a conductive polymer, is applied so that the film thickness becomes 600 nm, and then the electrode part is wiped off with a wiping tool soaked with ultrapure water. Then, the film was dried at 150 ° C. for 60 minutes to form a hole transport layer.

  After this, the base material was brought into the glove box and operated under a nitrogen atmosphere in which the low moisture concentration and low oxygen concentration were controlled.

(Formation of power generation layer)
Regioregular P3HT (poly-3-hexylthiophene-2,5-idyl, Plexcore manufactured by Plextronics) as p-type semiconductor material, PCBM ([6,6] -phenyl-C61 butyric acid methyl ester, n-type semiconductor material, E100H manufactured by Frontier Carbon Co., Ltd.) and a solution obtained by dissolving polyfluorene in chloroform so as to be 0.1% by mass with a mass ratio of 1: 1: 1, and having a film thickness when dried while filtering through a filter. Coating was performed to 50 nm, followed by heat treatment at 150 ° C. for 60 minutes.

  The extraction electrode portion of the substrate was removed and cleaned with a wiping member soaked in toluene to form a power generation layer.

(Formation of second electrode)
Subsequently, the sample formed up to the power generation layer is moved into the vacuum deposition apparatus chamber, the pressure inside the vacuum deposition apparatus is reduced to 10 ⁻⁴ Pa or less, and then arranged in a shape perpendicular to the patterned ZnO. Except that the electrode layer was formed by laminating 100 nm of Cu metal at a deposition rate of 0.1 nm / second through the shadow mask, and then laminating 200 nm of Al metal at a deposition rate of 0.2 nm / second. In the same manner as in the preparation of SC-101, an organic solar cell element SC-111 with a light receiving portion of 2 × 2 mm size was obtained.

(Preparation of organic solar cell element SC-112)
In the production of SC-105, instead of p-1, re-regular P3HT (poly-3-hexylthiophene-2,5-idyl, Plexcore manufactured by Plextronics) is used as a p-type semiconductor material. SC-112 was produced in the same manner as SC-105 except that PCBM ([6,6] -phenyl-C61 butyric acid methyl ester, E100H manufactured by Frontier Carbon Co.) was used as the semiconductor material.

<< Evaluation of energy conversion efficiency PCE >>
The organic solar cell element produced above is irradiated with light of 100 mW / cm ² of solar simulator (AM1.5G filter), and a mask with an effective area of 4.0 mm ² is overlaid on the light receiving part, and the short circuit current density Jsc Four light receiving portions formed on the same element were measured for (mA / cm ² ), open circuit voltage Voc (V), and fill factor (fill factor) FF, and average values were obtained. Further, the energy conversion efficiency PCE (%) was obtained from Jsc, Voc, and FF according to the equation (2), and the results are shown in Table 1.

Formula (2)
PCE (%) = Jsc (mA / cm ² ) × Voc (V) × FF
The PCE is preferably 4.0% or more, and if it is 3.2% or more, it is practical. If it is less than 3.2%, it is not practical, and if it is less than 2.8%, it cannot be used.

<Evaluation of light irradiation durability retention>
The device prepared above was exposed to light from a 100 W halogen lamp for 1000 hours while being heated to 65 ° C. Subsequently, for the exposed element, the short-circuit current density Jsc was estimated in the same manner as described above, and the retention rate was determined according to Equation (3), and is shown in Table 1.

  It is most preferable that the light irradiation durability retention rate exceeds 95%, preferably 85% or more and 95% or less, and practical if it is 75% or more and less than 85%. If it is less than 75%, the practicality is poor, and if it is less than 50%, it cannot be used.

Formula (3)
Light irradiation durability retention rate (%) = short-circuit current density after exposure / short-circuit current density before exposure × 100
<Evaluation of heat and humidity durability retention>
The fabricated device was left to stand for 1000 hours in an environment of a temperature of 65 ° C. and a relative humidity of 85%. Subsequently, for the element after being left in the environment, the short-circuit current density Jsc was estimated in the same manner as described above, and the retention rate was obtained according to the equation (4), and is shown in Table 1.

Formula (4)
Thermal humidity durability retention rate (%) = short-circuit current density after leaving the environment / short-circuit current density before leaving the environment × 100
It is most preferable that the heat and humidity durability retention ratio exceeds 90%, preferably 80% or more and 90% or less, and practical if it is 70% or more and less than 80%. If it is less than 70%, it is not practical, and if it is less than 50%, it cannot be used.

  As is apparent from Table 1, according to the present invention, the organic solar cell not only has excellent energy conversion efficiency but also has excellent light irradiation durability and heat and humidity durability as compared with organic solar cell elements according to the prior art. It turns out that it is an element.

10, 20 Organic solar cell element 11, 21 Base material 12, 22 First electrode 13, 23 Organic layer 14, 24 Interface between organic layer and second electrode 15, 25 Second electrode 31 Base material 32 First Electrode 33 Organic layer 34 Surface of organic layer 35 Second electrode layer 36 Mold 41 Multiple grooves 42 Etching mask 210 Silicon substrate 211 Vacuum plasma chamber 212 High frequency power source for plasma generation 216 Bias high frequency power source for machining shape control P Pitch of groove H Groove depth W Groove width

Claims (6)

  In an organic solar cell element in which an organic layer including a power generation layer is laminated between a second electrode and a light transmissive first electrode, the unevenness of the interface between the organic layer and the second electrode is fine. An organic solar cell element having a structure and containing a fluorine-containing compound in the vicinity of the interface.   2. The organic solar cell element according to claim 1, wherein the fine uneven structure has a maximum process difference Rpv between a concave portion and a convex portion of 50 nm to 150 nm.   The organic solar cell element according to claim 1 or 2, wherein the second electrode has a light scattering reflection structure and is a porous body made of conductive fine particles.   The organic solar cell element according to claim 3, wherein the conductive fine particles include nanowires.   In the manufacturing method of the organic solar cell element of any one of Claims 1-4, after laminating | stacking the organic layer containing an electric power generation layer between a 2nd electrode and a 1st electrode of light transmittance. A mold having a concavo-convex structure coated with a fluorine-containing compound, having at least a step of embossing the organic layer while applying temperature, and transferring the concavo-convex structure to the surface of the organic layer. A method for producing an organic solar cell element.   The material of the organic layer has at least a compound that exhibits a crosslinking reaction by UV light irradiation or heat treatment, and has at least a step of crosslinking the compound by UV light irradiation or heat treatment while keeping the mold pressed. The manufacturing method of the organic solar cell element of Claim 5.

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