JP2015138869A - semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor element which enables manufacturing of a large area semiconductor film in a low temperature process and which can achieve low cost.SOLUTION: A semiconductor element comprises a semiconductor film containing an inorganic semiconductor particle and a compound having a dielectric constant of 2 and over, or a semiconductor film containing an inorganic semiconductor particle and a compound having reduction power against the inorganic semiconductor particle. The inorganic semiconductor particle is an inorganic semiconductor particle other than a compound semiconductor particle which has an average particle size of 50 nm or less, or a compound semiconductor particle which has an average particle size of 100 nm or less.

Description

  The present invention relates to a semiconductor device.

  Currently, for the purpose of weight reduction, workability improvement, and cost reduction, solar cells using a substrate made of resin, metal foil or the like are being actively developed. As solar cells that are flexible and can withstand a certain degree of deformation, amorphous silicon solar cells and CIGS solar cells are currently mainstream. Note that a vacuum process such as a plasma CVD method, a sputtering method, or a vapor deposition method is used for manufacturing a solar cell.

  In contrast, non-vacuum processes have been extensively studied. For example, Patent Document 1 or 2 describes a method for manufacturing a polycrystalline silicon film using a silicon polymer. In addition, a method for producing a CIGS solar cell by a printing method has been studied. In this method, after a copper and indium precursor is printed and a thin film is formed, a solar cell is manufactured through a reduction process and a selenization process.

Japanese Patent No. 4016419 JP 2012-138565 A

  However, in the vacuum system process, it is difficult to obtain a large-area solar cell because the area is limited by the vacuum apparatus. Furthermore, the material utilization efficiency in the vacuum system process is poor. In addition, the devices used in the vacuum process have a large amount of power consumption, the cost of products tends to increase, and the burden on the global environment is large. Moreover, since a high temperature process is required, the base material which can be used is restricted.

  On the other hand, in the method of Patent Document 1 or 2, a semiconductor film containing inorganic semiconductor particles and a dispersion medium is removed by substantially removing the dispersion medium by a high-temperature process such as heat, plasma, and light (flash lamp). A method of making is disclosed. However, it is not clear whether the film from which the dispersion medium has been removed can be used as a semiconductor element such as a solar cell, and the performance is also unclear.

  In addition, since the printing method requires a reduction step and a selenization step, there are problems similar to those of a vacuum system process in terms of cost and environmental load. Furthermore, in the printing method, since a high temperature is required in the selenization process, usable substrates are limited.

  An object of the present invention is to provide a semiconductor element capable of producing a semiconductor film having a large area by a low temperature process and capable of reducing the cost.

  As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.

(1) The present invention includes a semiconductor film containing inorganic semiconductor particles and a compound having a relative dielectric constant of 2 or more, and the inorganic semiconductor particles are compound semiconductor particles having an average particle size of 50 nm or less or an average particle size of 100 nm or less. Provided is a semiconductor element which is an inorganic semiconductor particle other than a compound semiconductor particle.

(2) Further, the present invention includes an inorganic semiconductor particle and a semiconductor film containing a compound having a reducing power with respect to the inorganic semiconductor particle, and the inorganic semiconductor particle has a compound semiconductor particle having an average particle diameter of 50 nm or less or an average Provided is a semiconductor element which is an inorganic semiconductor particle other than a compound semiconductor having a particle size of 100 nm or less.

(3) In the above (1), the content of the compound having a relative dielectric constant of 2 or more is preferably 0.5 to 80% by mass based on the total mass of the semiconductor film.

(4) In said (2), it is preferable that content of the compound which has a reducing power with respect to an inorganic semiconductor particle is 0.5-80 mass% on the basis of the total mass of a semiconductor film.

(5) In the above (1) or (3), the compound having a relative dielectric constant of 2 or more is at least one selected from the group consisting of glycerin, thioglycerol, a cyano group-containing organic compound, and polyvinylidene fluoride (PVDF) It is preferable that The cyano group-containing organic compound is a compound containing one or more cyano groups.

(6) In the above (2) or (4), it is preferable that the compound having a reducing power with respect to the inorganic semiconductor particles is at least one selected from the group consisting of glycerin and thioglycerol.

(7) In any one of the above (1) to (6), the inorganic semiconductor particles other than the compound semiconductor particles are preferably silicon particles.

(8) In any one of the above (1) to (7), it is preferable to further include another semiconductor film having a charge opposite to that of the semiconductor film or another semiconductor layer having a charge opposite to that of the semiconductor film.

(9) In the above (8), it is preferable that an electrode is further provided on the surface of the semiconductor film opposite to the surface facing the other semiconductor film or the other semiconductor layer. In this case, it is more preferable that at least a part of the inorganic semiconductor particles contained in the semiconductor film is in contact with the electrode.

(10) The present invention further includes a first semiconductor layer, a second semiconductor layer, and a junction interface layer containing a compound having a relative dielectric constant of 2 or more between the first semiconductor layer and the second semiconductor layer. And at least one of the first semiconductor layer and the second semiconductor layer is a layer made of inorganic semiconductor particles, and the inorganic semiconductor particles are compound semiconductor particles having an average particle diameter of 50 nm or less or an average particle diameter Provides a semiconductor element which is an inorganic semiconductor particle other than a compound semiconductor particle of 100 nm or less.

(11) In the above (10), the compound having a relative dielectric constant of 2 or more is preferably at least one selected from the group consisting of glycerin, thioglycerol, a cyano group-containing organic compound, and PVDF.

(12) In the above (10) or (11), it is preferable that an electrode is further provided on the surface of the first semiconductor layer and / or the second semiconductor layer opposite to the surface facing the bonding interface layer.

(13) In the above (1) to (12), the semiconductor element is preferably a flexible semiconductor element.

(14) In said (1)-(13), it is preferable that a semiconductor element is a solar cell.

  According to the present invention, it is possible to provide a semiconductor element that is capable of producing a semiconductor film having a large area by a low-temperature process and that is excellent in power generation efficiency and can be reduced in cost.

It is a figure which shows the specific preparation method of the sample for solar cell evaluation in an Example.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  The semiconductor element of this embodiment includes (1) a semiconductor film containing inorganic semiconductor particles and a compound having a relative dielectric constant of 2 or more, or (2) inorganic semiconductor particles and a compound having a reducing power with respect to the inorganic semiconductor particles. A semiconductor film is provided.

(Inorganic semiconductor particles)
The inorganic semiconductor particles are semiconductor particles made of an inorganic material and allowing current to flow under specific conditions. Inorganic semiconductor particles are roughly classified into p-type semiconductor particles and n-type semiconductor particles. Here, p-type refers to the case where the charge transferer in the semiconductor is holes. The n-type refers to the case where conduction electrons are responsible for charge movement in a semiconductor. These holes and conduction electrons are collectively referred to as carriers. As the inorganic semiconductor particles, silicon particles, compound semiconductor particles, metal oxide particles and the like are preferable. Silicon particles are more preferable from the viewpoint of carrier movement and cost.

  Examples of silicon particles include p-type, n-type, and i-type silicon particles.

  Compounds used for compound semiconductor particles include silicon germanium compounds, CIS compounds, CIGS compounds, CZTS compounds, CGS compounds, CdTe compounds, InP compounds, GaAs compounds, GaSb compounds, GaP compounds, InSb compounds, InAs compounds ZnTe compound, ZnSe compound, FeS compound, CuS compound, tin sulfide, antimony sulfide and the like. The CIS compound is a compound composed of Cu, In, and S, or Cu, In, S, and Se, and includes an aspect in which both compounds are used in combination. The CIGS compound is a compound composed of Cu, In, Ga, and S, or Cu, In, Ga, S, and Se, and includes an aspect in which both compounds are used in combination. The CZTS compound is a compound composed of Cu, Zn, Sn, and S, or Cu, Zn, Sn, S, and Se, and includes an aspect in which both compounds are used in combination. The CGS-based compound is a compound composed of Cu, Ga, and S, or Cu, Ga, S, and Se, and includes an aspect in which both compounds are used in combination. In addition, these compounds used for compound semiconductor particles may use 2 or more types together.

  Examples of the oxide used for the metal oxide particles include copper oxide (I), copper oxide (II), iron oxide, zinc oxide, silver oxide, titanium oxide (rutile, anatase), indium gallium zinc oxide ( Metal oxides such as IGZO). Two or more of these oxides used for the metal oxide particles may be used in combination.

  The inorganic semiconductor particles preferably have high crystallinity and high purity. In the case of compound semiconductor particles and metal oxide particles, the crystallinity of the particles can be determined from the full width at half maximum by X-ray analysis, and in the case of silicon particles, it can be determined from the resistivity. The purity of the inorganic semiconductor particles is preferably 99.99% by mass or more, and more preferably 99.999% by mass or more.

  The average particle diameter of the inorganic semiconductor particles of the present embodiment is 50 nm or less in the case of compound semiconductor particles from the viewpoint of reducing the contact resistance between the particles, and inorganic semiconductor particles other than the compound semiconductor (for example, silicon particles or metals) In the case of (oxide particles), the average particle diameter is 100 nm or less. The former is preferably 30 nm or less, and more preferably 15 nm or less, from the viewpoint of improving conversion efficiency. The latter is preferably 50 nm or less, and more preferably 30 nm or less, from the viewpoint of improving the conversion efficiency. In addition, from the viewpoint of reducing the contact resistance between the particles and the electrode and the diffusion length, the average particle diameter of the inorganic semiconductor particles is preferably 0.5 nm or more, and more preferably 1 nm or more.

  The average particle diameter of inorganic semiconductor particles such as silicon particles, compound semiconductor particles, and metal oxide particles is measured by an image processing method using a microscope.

The silicon particles will be described in detail. The method for producing silicon particles is not particularly limited. For example, a method using a high crystalline semiconductor microparticle production apparatus using a pulse pressure applied orifice injection method, a polycrystalline or single crystal silicon ingot or wafer is pulverized. It can be manufactured by a method or the like. Further, chips at the time of wafer fabrication can be used as silicon particles. As the p-type silicon particles, for example, silicon particles doped with boron, gallium or the like as an additive are used. As the n-type silicon particles, silicon particles doped with phosphorus, nitrogen, arsenic or the like as an additive are used. The concentration of these additives contained in the silicon particles is preferably 10 ¹² atoms / cm ³ or more, and more preferably 10 ¹³ atoms / cm ³ or more. Furthermore, the additive concentration is ^preferably 10 21 atom / cm ³ or ^less, more preferably 10 20 atom / cm ³ or less. The resistivity of the silicon particles is preferably 0.0001 Ωcm or more, and more preferably 0.001 Ωcm or more, from the viewpoint of charge transfer in the semiconductor and the spread of the depletion layer. The resistivity is preferably 1000 Ωcm or less, more preferably 100 Ωcm or less.

  As a method of pulverizing the ingot or wafer, either dry pulverization or wet pulverization may be used, or both methods may be used. For the dry pulverization, a Hammar crusher or the like can be used. For wet grinding, a ball mill, a planetary ball mill, a bead mill, a homogenizer, or the like can be used. Examples of the solvent at the time of wet pulverization include a compound having a relative dielectric constant of 2 or more, a compound having a reducing power with respect to inorganic semiconductor particles, and a dispersant.

  The compound semiconductor particles will be described in detail. The method for producing compound semiconductor particles is not particularly limited, and can be produced, for example, by a vapor phase method, a liquid phase method, or the like. As a method for pulverizing the obtained particles, either or both of dry pulverization and wet pulverization can be used in combination. For the dry pulverization, a Hammar crusher or the like can be used. A ball mill, a bead mill, a homogenizer or the like can be used for wet grinding. As the solvent at the time of wet pulverization, a compound having a relative dielectric constant of 2 or more, a compound having a reducing power with respect to inorganic semiconductor particles, and a dispersant can be used.

  The metal oxide particles will be described in detail. The method for producing the metal oxide particles is not particularly limited, and can be produced, for example, by a sol-gel method.

(Compound with a relative dielectric constant of 2 or more)
The relative dielectric constant is a value measured by an impedance method with a measurement frequency of 1 kHz and a measurement temperature of 23 ° C. The preferable range of the relative dielectric constant of the present compound is 2 or more from the viewpoint of photoelectric conversion efficiency, preferably 5 or more, and more preferably 10 or more.

The photoelectric conversion efficiency η can be obtained from the following formula.
η = (output of solar cell) / 100 × 100
Output of solar cell = short circuit current density × open voltage × FF = Vmax · Imax
(Imax is the current when the output of the solar cell is maximized, and Vmax is the voltage when the output of the solar cell is maximized.)

  As organic compounds, general resins include polyvinylidene chloride (PVDF), acrylic resin, acetyl cellulose, aniline resin, ABS resin, ebonite, vinyl chloride resin, acrylonitrile resin, aniline formaldehyde resin, aminoalkyl resin, urethane. AS resin, epoxy resin, vinyl butyral resin, ethylene trifluoride resin, silicon resin, vinyl acetate resin, styrene butadiene rubber, silicone rubber, cellulose acetate, styrene resin, dextrin, nylon, soft vinyl butyral resin, fluorine resin , Furfural resin, polyamide, polyester resin, polycarbonate resin, phenol resin, furan resin, polyacetal resin, melamine resin, urea resin, polysulfide polymer, polyethylene, etc. That. Also, acetone, methyl alcohol, isobutyl alcohol, ethyl alcohol, aniline, isobutyl methyl ketone, ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, glycerin, cresol glycol, diallyl phthalate, dextrin, pyranol, phenol, bakelite varnish, formalin, Examples thereof include thioglycerol, chloropyrene, succinic acid, succinic nitrile, nitrocellulose, ethyl cellulose, hydroxyethyl cellulose, starch, hydroxypropyl starch, pullulan, glycidol pullulan, polyvinyl alcohol, sucrose, sorbitol, and cyano group-containing organic compounds.

  The cyano group-containing organic compound is a compound containing one or more cyano groups. The cyano group-containing organic compound is more preferably a cyanoethyl group-containing organic compound. Specific examples of the cyano group-containing organic compound include cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl saccharose (cyanoethyl sucrose), cyanoethyl cellulose, cyanoethyl hydroxyethyl cellulose, cyanoethyl starch, cyanoethyl hydroxypropyl starch, cyanoethyl glycidol pullulan, cyanoethyl sorbitol and the like. .

Specific examples of the fluororesin include polymers having a skeleton of C ₂ F _4-n H _n (n is 0 to 3), and specifically, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, and the like. It is done. These may be copolymerized, or may be copolymerized with another resin based on the fluororesin. Further, a part of hydrogen in the chemical formula may be substituted with chlorine. Examples thereof include polychlorotrifluoroethylene.

Furthermore, a specific example of the fluorine-based resin is a fluorine-based ion exchange resin. Specifically, the general formula _{CF 2 = CF-O (CF} 2 CFX) n O- (CF 2) a fluorinated vinyl compound represented by m -W, and fluorinated olefin of the formula _CF 2 = CFZ And those comprising at least a binary copolymer. Here, X is F or a perfluoroalkyl group having 1 to 3 carbon atoms, n is an integer from 0 to 3, m is an integer from 1 to 5, Z is H, Cl, F, or a perfluoroalkyl having 1 to 3 carbon atoms It is a group. W is any one of groups represented by COOH, SO ₃ H, SO ₂ F, SO ₂ Cl, SO ₂ Br, COF, COCl, COBr, CO ₂ CH ₃ , and CO ₂ C ₂ H ₅ .

In particular, in the case of an organic compound, an organic compound containing a highly polar atom or functional group is preferable because of its large dielectric constant. The dipole moment, which is an index of polarity, can be estimated by the sum of the coupling moments. As the organic compound having a relative dielectric constant of 2 or more, a compound having a substituent having a bond moment of 1.4D (D = 3.333564 × 10 ⁻³⁰ Cm) or more is preferable. Examples of the substituent having a bond moment of 1.4D or more include OH, CF, CCl, C═O, N═O, and CN. Examples of organic compounds having these substituents and having a relative dielectric constant of 2 or more include fluorine resins, glycerin, thioglycerol, and cyano group-containing organic compounds.

Examples of inorganic compounds include calcium silicate, glass, alumina, zinc oxide, titanium oxide, selenium, barium titanate, bismuth silicate, lead niobate, titanium dioxide, urea, bakelite, pyrex (registered trademark), petrolatum, mica , Copper chloride, copper oxide, copper sulfate, iron oxide, potassium chlorate, potassium chloride, sodium chloride, silver chloride, potassium bromide, lithium fluoride, silicon oxide, magnesium oxide, calcium fluoride, zinc sulfide, NaI, NaF , NaClO ₃ , NaSO _{4 and the} like.

  In addition to the above, the inorganic compounds include composite oxides such as lead zirconate titanate, strontium titanate, calcium titanate, barium strontium titanate, etc., or these composite oxides as main components, and further Ba sites. Perovskite-type composite oxides in which magnesium is substituted for Ti and tin and / or zirconium are substituted on the Ti site can also be used. Furthermore, what added 1 type, or 2 or more types of trace additive to the perovskite type complex oxide can also be used.

Further, as the organic-inorganic composite perovskite _compounds, CH ₃ NH ₃ PbX ₃ and the like. X is one or two of chlorine, bromine and iodine.

  Trace additives include tungsten, tantalum, niobium, iron, copper, magnesium, bismuth, yttrium, molybdenum, vanadium, sodium, potassium, aluminum, manganese, nickel, zinc, calcium, strontium, silicon, tin, selenium, neodymium, Erbium, thulium, hafnium, praseodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, lithium, scandium, barium, lanthanum, actinium, cerium, ruthenium, osmium, cobalt, palladium, silver, cadmium, boron, gallium, germanium, Examples thereof include phosphorus, arsenic, antimony, fluorine, tellurium, lutetium, ytterbium and the like.

  In addition to the above, examples of the trace additive include ionic liquids using imidazolium, pyridinium, pyrrolidinium, phosphonium, ammonium, sulfonium and the like as cations.

  In the present embodiment, from the viewpoint of improving photoelectric conversion efficiency, the compound having a relative dielectric constant of 2 or more is at least selected from the group consisting of glycerin, thioglycerol, a cyano group-containing organic compound, and polyvinylidene fluoride (PVDF). One type is preferable.

As other materials, a dye used in a dye-sensitized solar cell may be mixed with a compound having a relative dielectric constant of 2 or more. Although it does not specifically limit as a pigment | dye, A ruthenium complex, especially a ruthenium polypyridine type complex are desirable, and the more desirable is a ruthenium complex represented by Ru (L) (L ') (X) ₂ . Here, L is 4,4′-dicarboxy-2,2′-bipyridine, or a polypyridine ligand into which a quaternary ammonium salt and a carboxyl group are introduced, and L ′ is the same as L, or 4, 4'-substituted 2,2'-bipyridine, and the substituents at the 4,4 'position of L' include long chain alkyl groups, alkyl substituted vinyl thienyl groups, alkyl or alkoxy substituted styryl groups, thienyl group derivatives and the like. Can be mentioned. X is SCN, Cl, or CN. Examples thereof include bis (4,4′-dicarboxy-2,2′-bipyridine) diisothiocyanate ruthenium complex. Examples of other dyes include metal complex dyes other than ruthenium, such as iron complexes and copper complexes. Further examples include organic dyes such as cyan dyes, porphyrin dyes, polyene dyes, coumarin dyes, cyanine dyes, squarylium dyes, styryl dyes, eosin dyes, and more specifically, manufactured by Mitsubishi Paper Industries, Ltd. And a dye (trade name: D149 dye).

(Compounds with reducing power against inorganic semiconductor particles)
A compound having a reducing power with respect to inorganic semiconductor particles is a compound that reduces the particle surface when mixed with inorganic semiconductor particles.
Examples of compounds having a reducing power for inorganic semiconductor particles include 3-allyloxy-1,2-propanediol, 1,3-bis (allyloxy) -2-propanol, 2,3-dihydroxybenzaldehyde, catechol, and dipentaerythritol. , Allitol, taritol, iditol, glycerol ethoxylate, 1,4-dithioerythritol, 1,4-disulfanyl-2,3-butanediol, maltotriose, glycolic acid, lactic acid, polycarbonate diol, polyester polyol, glyceraldehyde , Glycol aldehyde, invertose, m-erythritol, alkylene glycol, ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, butanediol, pentanediol , Hexanediol, polyalkylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, ethoxyethanol, butanediol, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, octanediol, dodecanediol, glycerin, Glyceraldehyde, 3-allyloxy-1,2-propanediol, thioglycerol, 1,5-pentanediol, 1,12-dodecanedioic acid, pyrocatechol, 3-methoxycatechol, 1,2,3-butanethiol, etc. Alcohols such as ethanol, methanol, isopropyl alcohol and 2-ethylhexyl alcohol; hexylamine, hebutinamine , Octylamine, undecyl amine, tridecylamine, tetradecylamine, pentadecylamine, cetylamine, dibutylamine, diamylamine, cyclohexylamine, aniline, naphthylamine, amine-based materials such as toluidine, and the like. Among the above compounds, at least one selected from the group consisting of glycerin and thioglycerol is particularly preferable.

(Semiconductor film)
The semiconductor film of the present embodiment includes inorganic semiconductor particles and a compound having a relative dielectric constant of 2 or more, and the inorganic semiconductor particles are compound semiconductor particles having an average particle diameter of 50 nm or less, or an average particle diameter of 100 nm or less. Inorganic semiconductor particles other than the compound semiconductor particles. Further, the semiconductor film of the present embodiment may include inorganic semiconductor particles and a compound having a reducing power with respect to the inorganic semiconductor particles, and the inorganic semiconductor particles have a compound semiconductor having an average particle diameter of 50 nm or less. Inorganic semiconductor particles other than compound semiconductor particles having particles or an average particle size of 100 nm or less.

  Examples of the semiconductor film of this embodiment include a p-type semiconductor film, an n-type semiconductor film, and a semiconductor film having both p-type and n-type characteristics in one film.

  The content of the inorganic semiconductor particles in the semiconductor film is preferably 20 to 99.5% by mass from the viewpoint of photoelectric conversion characteristics when a solar cell is used. On the other hand, the content of the compound having a relative dielectric constant of 2 or more, or the content of the compound having a reducing power with respect to the inorganic semiconductor particles is based on the total mass of the semiconductor film from the viewpoint of improving photoelectric conversion efficiency. It is preferable that it is 0.5-90 mass%, and it is more preferable that it is 10-80 mass%.

  The thickness of the semiconductor film is preferably 0.1 μm or more, more preferably 0.5 μm or more from the viewpoint of photoelectric conversion characteristics. From the same viewpoint, the film thickness is preferably 1000 μm or less, more preferably 500 μm or less. The film thickness of the semiconductor film is measured by cross-sectional SEM or cross-sectional TEM observation.

  A compound having a relative dielectric constant of 2 or more in the semiconductor film or a compound having a reducing power for the inorganic semiconductor particles may function as a binder for the inorganic semiconductor particles. Such a compound is preferably a compound having a relative dielectric constant of 2 or more and a reducing power for the inorganic semiconductor particles.

  As the inorganic semiconductor particles contained in the semiconductor film, two or more of the p-type semiconductor particles listed above may be used in combination, or two or more of the n-type semiconductor particles may be used in combination. And n-type semiconductor particles may be used in combination.

  Here, the content of the compound having a reducing power with respect to the inorganic semiconductor particles in the semiconductor film is such that the compound having the reducing power is oxidized as a result of the compound having the reducing power reducing the inorganic semiconductor particles. The amount of things is also included.

  Specifically, glycerol will be described as an example of a compound having a reducing power with respect to inorganic semiconductor particles. When glycerin represented by the following formula (1) and silicon particles are mixed to produce a thin film, the surface of the silicon particles is reduced and a part thereof becomes Si—H bonds. On the other hand, it is estimated that glycerol is oxidized and the compounds described in the following formulas (2) to (13) are generated.

  This can be confirmed from the IR spectrum of the semiconductor film. In the coating liquid for forming a semiconductor film, the peak of stretching vibration of C═O bond is not seen, but when the semiconductor film is formed through the heating process, the peak of stretching vibration of C═O bond is seen. However, not all glycerin is oxidized, and unoxidized glycerin remains.

The oxidation rate of glycerin can be determined from the following general formula (I).
Glycerin oxidation rate = αCO / (αCO + αOH) (I)
In formula (I), αOH represents the peak intensity derived from OH bond near 3350 cm ⁻¹ of glycerin, and αCO represents the peak intensity derived from CO bond near 2350 cm ⁻¹ of a compound formed by oxidation of glycerin.

  The oxidation rate of glycerin is preferably 0.09 or more and preferably less than 1 from the viewpoint of removing the oxidized layer on the surface of the inorganic semiconductor particles. The range is the same when the silicon particles are compound semiconductor particles. Moreover, the said range is the same also when a silicon particle is a metal oxide.

Further, it can be confirmed from the IR spectrum of the semiconductor film that the surface of the silicon particles is reduced and a part thereof becomes Si—H bonds. The reduction rate of the silicon particles can be obtained from the following (II).
Reduction rate of silicon particles = βSiH / (βSiH + βSiOSi) (II)
Wherein (II), βSiH represents the peak intensity derived from the SiH bond at around 2100cm ^-1, βSiOSi shows a peak intensity derived from the SiOSi bond at around 1100 cm ^-1.

  The reduction rate of the silicon particles is preferably 0.01 or more and preferably 0.5 or less from the viewpoint of removing the oxidized layer on the surface of the silicon particles.

  Therefore, in one embodiment, an oxide of glycerin and glycerin is present in a semiconductor film manufactured using glycerin as a compound having a relative dielectric constant of 2 or more, or a compound having a reducing power for inorganic semiconductor particles. doing. In this case, the content of glycerol in the semiconductor film is the total amount of glycerol and glycerol oxidized.

In general, the oxidation rate of a compound having a reducing power with respect to inorganic semiconductor particles can be determined by the following general formula (III).
Oxidation rate of compound having reducing power with respect to inorganic semiconductor particles = α′Y / (α′X + α′Y) (III)
In formula (III), α′X represents a peak intensity derived from a functional group that reacts in the oxidation reaction of the compound, and α′Y represents a peak intensity derived from a functional group formed by oxidation of the compound.

(Semiconductor film manufacturing method)
The semiconductor film can be manufactured by applying a coating solution for forming a semiconductor film to a substrate on which an electrode is formed to obtain a coating film.

  The coating liquid for forming a semiconductor film contains inorganic semiconductor particles, a compound having a relative dielectric constant of 2 or more, a compound having a reducing power with respect to the inorganic semiconductor particles, and a solvent. In addition, a dispersant, a surfactant and the like may be included as additives. The amount of inorganic semiconductor particles contained in the coating solution for forming a semiconductor film is preferably 0.1 to 90% by mass, and more preferably 0.5 to 80% by mass. The amount of the compound having a relative dielectric constant of 2 or more contained in the coating solution for forming a semiconductor film or a compound having a reducing power with respect to the inorganic semiconductor particles is preferably 0.5 to 90% by mass, more preferably 10 to 80% by mass. preferable. 10-99.4 mass% is preferable, and, as for the quantity of the solvent contained in the coating liquid for semiconductor film formation, 20-95 mass% is more preferable.

  In order to produce a semiconductor film, a substrate on which a semiconductor film forming coating solution is applied is a glass substrate; PET (polyethylene terephthalate), PC (polycarbonate), PEN (polyethylene naphthalate), PES (polyethersulfone), PI. Examples include plastic substrates such as (polyimide), PP (polypropylene), and acrylic resins; metal substrates such as aluminum substrates and stainless steel (SUS) substrates; and all substrates such as paper substrates.

  As a coating method of the coating solution for forming a semiconductor film, a coating method such as a cast method, a spin coating method, an ink jet method, a dipping method, a spray method or the like; a printing method such as flexographic printing, gravure printing, or screen printing can be used. In the present embodiment, the coating solution for forming a semiconductor film may contain a dispersant, a surfactant, and the like.

(Dispersant)
The coating liquid for forming a semiconductor film may contain a dispersant from the viewpoint of adjusting the viscosity.

  Examples of the dispersant include alcohols such as methanol, ethanol, propanol, butanol and hexanol; glycols such as ethylene glycol and propylene glycol; cellosolves such as cellosolve, ethyl cellosolve and butyl cellosolve; ketones such as acetone and methylethylketone; Esters such as ethyl acetate and butyl acetate; ethers such as dioxane and tetrahydrofuran; amides such as N, N-dimethylformamide; benzene, toluene, xylene, trimethylbenzene, hexane, heptane, octane, nonane, decane, cyclohexane, Hydrocarbons such as decahydronaphthalene (decalin) and tetralin; water and the like.

  The content of the dispersant contained in the coating solution for forming a semiconductor film is preferably 1% by mass or more, and 98.5% by mass from the viewpoint of easy handling of the coating solution formed by the semiconductor film by adjusting the viscosity. The following is preferable.

  When a compound having a relative dielectric constant of 2 or more or a compound having a reducing power with respect to inorganic semiconductor particles is a liquid, it itself functions as a dispersant. In this case, it is possible to adjust the viscosity without adding a dispersant.

(Surfactant)
A surfactant may be added to the coating solution for forming a semiconductor film for the purpose of improving dispersion stability. The addition amount of the surfactant is preferably 0.0001% by mass or more and preferably 10% by mass or less from the viewpoint of dispersion stability.

  The surfactant is not particularly limited, and for example, an anionic surfactant, a nonionic surfactant, a cationic surfactant, an amphoteric surfactant, and a polymer surfactant can be used.

  Examples of the surfactant include fatty acid salts such as sodium lauryl sulfate, higher alcohol sulfate esters, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, polyoxyethylene alkyl ether sulfates, and polyoxyethylene polycyclic phenyl. Ether sulfate, polyoxynonyl phenyl ether sulfonate, polyoxyethylene-polyoxypropylene glycol ether sulfate, so-called reactivity having a sulfonic acid group or sulfate group and a polymerizable unsaturated double bond in the molecule Anionic surfactants such as surfactants; polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, sorbitan fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene-polyoxyp Pyrene block copolymer, reactive nonionic surfactant having a polymerizable unsaturated double bond in the molecule of these “polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, sorbitan fatty acid ester or polyoxyethylene fatty acid ester” Nonionic surfactants such as; cationic surfactants such as alkylamine salts and quaternary ammonium salts; (modified) polyvinyl alcohols; linear alkylthiols;

(Semiconductor element)
The semiconductor element of the present embodiment may include the semiconductor film and another semiconductor film having a charge opposite to that of the semiconductor film, or other semiconductor film and other semiconductor film having a charge opposite to that of the semiconductor film. A semiconductor layer may be provided. Specific examples include a light emitting diode, a semiconductor laser, a photodiode, or a solar cell, and a solar cell is preferable. Hereinafter, the present embodiment will be described by taking a solar cell as an example.

(Solar cell)
The solar cell of this embodiment includes a semiconductor film containing p-type or n-type inorganic semiconductor particles and a compound having a relative dielectric constant of 2 or more, another p-type or n-type semiconductor layer or semiconductor film, an electrode, and a substrate. And generating electricity by light. In addition, the solar cell of this embodiment includes a semiconductor film containing p-type or n-type inorganic semiconductor particles and a compound having a reducing power with respect to the inorganic semiconductor particles, and another p-type or n-type semiconductor layer or semiconductor film. And an electrode and a substrate, and generates electricity by light. The semiconductor constituting the solar cell may be a pp junction type or an nn junction type, but is preferably a pn junction type.

  The p-type semiconductor film is formed from the above-described coating liquid for forming a semiconductor film, and preferably contains at least one of silicon particles and compound semiconductor particles. The n-type semiconductor film is formed from the above-described coating liquid for forming a semiconductor film, and preferably contains at least one of silicon particles and metal oxide particles.

  The inorganic semiconductor particles are preferably in contact with the electrode in order to efficiently extract electrons and holes to the electrode. That is, in the semiconductor element further including an electrode on the surface opposite to the surface facing the other semiconductor film or the other semiconductor layer of the semiconductor film, the layer made of the semiconductor film of the present embodiment adjacent to the electrode It is preferable that at least a part of the inorganic semiconductor particles contained in the electrode is in contact with the electrode so that the electrode is covered with the inorganic semiconductor particle. However, the entire surface of the electrode may not be covered with inorganic semiconductor particles. From the viewpoint of power generation efficiency, the inorganic semiconductor particles preferably cover 30% or more of the electrode, and more preferably 50% or more. The degree of contact, that is, the degree of coating can be observed and evaluated by, for example, an optical microscope or an electron microscope.

  The thickness between the electrodes of the solar cell of this embodiment is determined by the semiconductor used. By reducing the thickness between the electrodes to 1000 μm or less, a solar cell that is flexible and can withstand some deformation can be obtained. In particular, when inorganic semiconductor particles are used, the stress can be relaxed between the particles with respect to the stress when bent. Therefore, when producing a flexible solar cell, it is preferable to use inorganic semiconductor particles.

  The solar cell of the present embodiment preferably has flexibility, and is preferably a flexible solar cell (flexible semiconductor element).

  In the present embodiment, the “semiconductor layer” is different from the “semiconductor film”. As described above, the “semiconductor film” is composed of inorganic semiconductor particles and a compound having a relative dielectric constant of 2 or more. Or a semiconductor film consists of a compound which has a reducing power with respect to inorganic semiconductor particles and inorganic semiconductor particles. On the other hand, the “semiconductor layer” is formed of a semiconductor such as a silicon wafer, an inorganic semiconductor layer, or an organic semiconductor layer. That is, the semiconductor layer is obtained by using a silicon wafer obtained by slicing a silicon ingot, a silicon wafer obtained by polishing the silicon wafer, a vacuum apparatus such as a vapor deposition method, a CVD method, or a sputtering method on the substrate. An inorganic semiconductor layer formed from an inorganic semiconductor material or an organic semiconductor layer formed from an organic semiconductor material using a coating method, a vapor deposition method, or the like.

  Specifically, the p-type semiconductor layer is, for example, a monocrystalline or polycrystalline silicon wafer, an amorphous silicon film, a compound semiconductor layer such as CIGS type or CZTS type, a metal oxide layer such as copper (I) oxide, silicon Examples thereof include a layer made of particles, a layer made of metal oxide particles such as copper oxide (I), a layer made of compound semiconductor particles such as CIGS and CZTS, and a layer made of a p-type organic semiconductor. Examples of the p-type organic semiconductor include pentacene derivatives such as pentacene and 6,13-bis (triisopropylsilylethynyl) pentacene, tetracene derivatives such as tetracene and 2-hexyltetracene, and N, N′-diphenyl-N, N′-bis. (1-naphthyl) -1,1′-biphenyl-4,4′-diamine (NPD), N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-biphenyl- Examples include aromatic amine materials such as 4,4′-diamine (TPD) and 1,3,5-tris (3-methyldiphenylamino) benzene (m-MTDATA). In addition, p-type organic semiconductors include phthalocyanine complexes such as copper phthalocyanine (CuPc) and zinc phthalocyanine (ZnPc), porphyrin compounds, perylene derivatives, imidazole derivatives, triazole derivatives, pyrazoline derivatives, oxazole derivatives, An oxadiazole derivative, a stilbene derivative, a polyarylalkane derivative, graphene oxide, and the like can be given. Furthermore, examples of the p-type organic semiconductor include thiophene derivatives, polyphenylvinylene (PPV) derivatives, and the like. Specific examples of thiophene derivatives include P3HT (Poly (3-hexylthiophene-2,5-diyl)), P3OT (Poly (3-octylthiophene-2,5-diyl)), P3DDT (Poly (3-dodecylthiophene- 2,5-diyl)) and PEDOT polymers. The dopant of the PEDOT polymer is not particularly limited, and examples thereof include PSS (Poly (styrene sulfonate)), PVS (polyvinyl sulfonic acid), dodecylbenzene sulfonic acid, or salts thereof. They are used as PEDOT: PSS or PEDOT: PVS. As a product of PEDOT: PSS, clevios (manufactured by Heraeus) can be mentioned. Two or more kinds of the p-type semiconductors may be mixed and used.

The n-type semiconductor layer is, for example, a monocrystalline or polycrystalline silicon wafer, an amorphous silicon film, titanium oxide (rutile, anatase), zinc oxide, indium oxide, tin oxide, indium tin oxide (ITO), indium gallium zinc Layer made of metal oxide such as oxide (IGZO), layer made of silicon particles, titanium oxide (rutile, anatase), zinc oxide, indium oxide, tin oxide, indium tin oxide (ITO), indium gallium zinc Examples include a layer made of metal oxide particles such as an oxide (IGZO) and a layer made of an n-type organic semiconductor. Examples of the n-type organic semiconductor include fluorinated acene compounds, fullerenes, fullerenes such as 60 PCBM ([6,6] -phenylC ₆₁ methyl acid methyl ester), 70 PCBM ([6,6] -phenyl C ₇₁ methyl acid ester). Examples thereof include compounds, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, perylene tetracarboxylic acid diimide derivatives, oxadiazole derivatives, triazole derivatives, triazine derivatives, quinoline derivatives, and the like. The n-type semiconductor layer is preferably a single crystal or polycrystalline silicon wafer, a metal oxide, or a layer made of metal oxide particles from the viewpoint of carrier movement and cost.

  The semiconductor element of this embodiment includes a first semiconductor layer, a second semiconductor layer, and a junction interface layer containing a compound having a relative dielectric constant of 2 or more between the first semiconductor layer and the second semiconductor layer. And at least one of the first semiconductor layer and the second semiconductor layer is a layer made of inorganic semiconductor particles, and the inorganic semiconductor particles are compound semiconductor particles having an average particle diameter of 50 nm or less or an average particle diameter May be a semiconductor element which is an inorganic semiconductor particle other than a compound semiconductor particle of 100 nm or less. Further, a compound having a relative dielectric constant of 2 or more may be added to compound semiconductor particles having an average particle size of 50 nm or less or inorganic semiconductor particles other than the compound semiconductor particles having an average particle size of 100 nm or less.

  Here, examples of the inorganic semiconductor particles include those described above, and a layer composed of the inorganic semiconductor particles can be formed using the particles by a coating method or the like. In addition, when the layer made of inorganic semiconductor particles is not used as the first semiconductor layer or the second semiconductor layer, the above-described “semiconductor film” or “semiconductor layer” is employed as the first semiconductor layer or the second semiconductor layer. can do. Further, the first semiconductor layer and / or the second semiconductor layer may be further provided with an electrode on a surface opposite to the surface facing the bonding interface layer.

(Bonding interface layer)
By providing a bonding interface layer made of a compound having a relative dielectric constant of 2 or more at the bonding interface of the semiconductor layer, a solar cell excellent in power generation efficiency can be easily produced. In particular, the junction interface between the p-type semiconductor layer and the n-type semiconductor layer, the junction interface between the p-type semiconductor film and the n-type semiconductor layer, the junction interface between the p-type semiconductor layer and the n-type semiconductor film, the p-type semiconductor film and the n-type semiconductor film. It is preferable to provide a bonding interface layer made of a compound having a relative dielectric constant of 2 or more at the bonding interface.

  Examples of the compound having a relative dielectric constant of 2 or more include those described above. Further, the bonding interface layer is preferably made of an organic compound from the viewpoints of flexibility, film formability, and the like. The organic compound preferably has OH, CF, CCl, C═O, N═O, CN or the like as a substituent. The specific organic compound is preferably a fluorine-based resin, glycerin, thioglycerol, or a cyano group-containing organic compound. A cyano group-containing organic compound is a compound containing one or more cyano groups. The cyano group-containing organic compound is more preferably a cyanoethyl group-containing organic compound. Specific examples of the cyano group-containing organic compound include cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl saccharose (cyanoethyl sucrose), cyanoethyl cellulose, cyanoethyl hydroxyethyl cellulose, cyanoethyl starch, cyanoethyl hydroxypropyl starch, cyanoethyl glycidol pullulan, cyanoethyl sorbitol and the like. .

Specific examples of the fluororesin include polymers having a skeleton of C ₂ F _4-n H _n (n is 0 to 3), and specifically, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, and the like. It is done. These may be copolymerized, or may be copolymerized with another resin based on the fluororesin. Further, a part of hydrogen in the chemical formula may be substituted with chlorine. Examples thereof include polychlorotrifluoroethylene.

Furthermore, a specific example of the fluorine-based resin is a fluorine-based ion exchange resin. Specifically, the general formula _{CF 2 = CF-O (CF} 2 CFX) n O- (CF 2) a fluorinated vinyl compound represented by m -W, and fluorinated olefin of the formula _CF 2 = CFZ And those comprising at least a binary copolymer. Here, X is F or a perfluoroalkyl group having 1 to 3 carbon atoms, n is an integer from 0 to 3, m is an integer from 1 to 5, Z is H, Cl, F, or a perfluoroalkyl having 1 to 3 carbon atoms It is a group. W is a group represented by COOH, SO ₃ H, SO ₂ F, SO ₂ Cl, SO ₂ Br, COF, COCl, COBr, CO ₂ CH ₃ , and CO ₂ C ₂ H ₅ .

  In the present embodiment, from the viewpoint of improving photoelectric conversion efficiency, the compound having a relative dielectric constant of 2 or more contained in the bonding interface layer is composed of glycerin, thioglycerol, a cyano group-containing organic compound, and polyvinylidene fluoride (PVDF). It is preferably at least one selected from the group.

  A preferable range of the relative dielectric constant of the bonding interface layer is 2 or more from the viewpoint of photoelectric conversion efficiency, preferably 5 or more, and more preferably 10 or more. The relative dielectric constant is preferably 5000 or less, more preferably 1500 or less, and further preferably 200 or less from the same viewpoint.

  The content of the compound having a relative dielectric constant of 2 or more in the bonding interface layer is preferably 50% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and 95% by mass from the viewpoint of photoelectric conversion efficiency. The above is extremely preferable. On the other hand, the upper limit of the content is preferably 100% by mass, that is, the bonding interface layer is composed of a compound having a relative dielectric constant of 2 or more from the viewpoint of improving the solar cell characteristics. The bonding interface layer is preferably filled without containing air from the viewpoint of the performance of the solar cell. The bonding interface layer may contain a general-purpose resin, a surfactant, a dispersant and the like as a binder component as long as the characteristics are not impaired.

  The bonding interface layer may not be introduced to the entire surface of the bonding interface between the p-type semiconductor layer and the n-type semiconductor layer. From the viewpoint of power generation efficiency, it is preferable to cover 30% or more of the entire bonding interface, more preferably 50% or more, and even more preferably 100%.

  The average thickness of the bonding interface layer is preferably 1 nm or more, more preferably 20 nm or more, further preferably 30 nm or more, and extremely preferably 50 nm or more from the viewpoint of power generation efficiency and carrier movement. From the same viewpoint, the thickness is preferably 500 μm or less, more preferably 100 μm or less, further preferably 50 μm or less, extremely preferably 10 μm or less, and most preferably 5 μm or less. This bonding interface layer is characterized in that it has a high photoelectric conversion characteristic even with a thickness of 30 nm or more in which a current due to tunneling is difficult to flow. The film thickness of the bonding interface layer is measured by vertscan 2.0 (manufactured by Ryoka System Co., Ltd.) or cross-sectional TEM observation.

  Note that the bonding interface layer is preferably transparent to some extent from the viewpoint of allowing the semiconductor layer to absorb light. The transmittance of the bonding interface layer is preferably 35% or more with respect to light having a wavelength of 550 nm, preferably 50% or more, and more preferably 70% or more. The transmittance can be measured with a spectrophotometer. The upper limit of the transmittance is not particularly limited, but is 100% or less. The transmittance can be measured using a spectrophotometer. As the measurement substrate, quartz glass or a resin substrate can be used.

A higher resistivity of the bonding interface layer is preferable. Thereby, it is estimated that it can contribute to prevention of leakage current. From this point of view, the resistivity is preferably 10 Ωcm or more, more preferably 100 Ωcm or more, further preferably 1000 Ωcm or more, extremely preferably 10,000 Ωcm or more, and most preferably 1000000 Ωcm or more. The upper limit of the resistivity is not particularly limited, but is preferably 1 × 10 ¹⁹ Ωcm or less.

The resistivity in the present embodiment is a measure of the ease of conducting electricity and is a resistivity per unit volume. This value is a value unique to the substance, and is obtained by passing a constant current I through the cross-sectional area W of the substance and measuring the potential difference V between the electrodes separated by a distance L.
Resistivity = (V / I) × (W / L)

  Since the bonding interface layer can be reduced in cost, it is effective to produce it using a printing method. At this time, the flexible electrode substrate having flexibility is preferable. Thereby, since the electrode substrate provided with the joining interface layer can be wound up in a roll shape, the manufacturing speed can be improved.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  Hereinafter, the present invention will be described in more detail with reference to specific examples.

[Evaluation method]
Hereinafter, unless otherwise specified, evaluation was performed under conditions of 25 ° C. and humidity 45%.
(1) Average particle diameter 100 particles were randomly selected by a microscope, and an arithmetic average value of particle diameters evaluated by equivalent circle diameter using image analysis was defined as an average particle diameter. A digital microscope manufactured by Keyence Corporation was used as a microscope.

(2) Evaluation of IV characteristics DC voltage / current source (6241A, manufactured by ADMT) controlled by a computer (Solar cell IV measurement software manufactured by System House Sunrise Co.) and a simple solar simulator (manufactured by Mitsunaga Electric Manufacturing Co., Ltd.) Photovoltaic characteristics were measured using XES-40S1), and IV characteristics were evaluated. A BS-500Si photodiode detector (for crystalline Si solar cell, manufactured by Spectrometer Co., Ltd., secondary reference solar cell) was used for the test of the light quantity (AM1.5G, 100 mW / cm ² ).

  The measurement was performed with the solar cell fixed. A specific method for preparing a measurement sample will be described with reference to FIG. First, the solar cell 4 is placed on a metal jig 5 coated with an insulating material. On top of that, a 2 mm thick silicone rubber sheet 3, a 3 mm thick quartz plate 2, and a metal jig 1 coated with an insulating treatment material (a light transmitting hole for transmitting light 10 at the center is provided. The metal jigs 1 and 5 are fixed with screws 9 at the four corners.

  In this evaluation, IV characteristics, Imax and Vmax were obtained. Note that Imax is a current when the output of the solar cell is maximized, and Vmax is a voltage when the output of the solar cell is maximized.

  And the short circuit current density, the open circuit voltage, FF, and the photoelectric conversion efficiency were computed from the graph of IV characteristic. The short-circuit current density (Isc) is a current density when the voltage is 0, and the open circuit voltage (Voc) is a voltage when the current is 0.

FF can be obtained from the following equation.
FF = (Vmax · Imax) / (Voc · Isc)
The photoelectric conversion efficiency η can be obtained from the following formula.
η = (output of solar cell) / 100 × 100
Output of solar cell = short circuit current density × open voltage × FF = Vmax · Imax

(3) Relative permittivity The relative permittivity is a value measured by an impedance method with a measurement frequency of 1 kHz and a measurement temperature of 23 ° C. Specifically, it can be determined from the following formula using an LCR meter (Agilent 4284A PRESIONION LCR meter).
Dielectric constant of sample = (distance between electrodes × capacitance) / (area of electrode × dielectric constant of vacuum)
(However, the dielectric constant of vacuum is 8.854 × 10 ⁻¹² (F / m).)
When the sample is a liquid, the dielectric constant is measured by inserting an electrode into the liquid using a liquid measuring jig (16452 ALIQUID TEST FIXTURE manufactured by Agilent).
When the sample is a solid, the dielectric constant is measured by forming a film on an electrode plate using a film measurement jig (manufactured by Agilent, 16451B DIEECTRIC TEST FIXTURE) and sandwiching the film with one electrode.

(4) Resistivity Resistivity is a measure of the ease of conducting electricity and is the resistivity per unit volume. This value is a value unique to the substance, and is obtained by passing a constant current I through the cross-sectional area W of the substance and measuring the potential difference V between the electrodes separated by a distance L.
Resistivity = (V / I) × (W / L)
The resistivity was measured using Loresta (Mitsubishi Chemical Analytech).

(5) Film thickness The film thickness of the semiconductor layer and the bonding interface layer was measured by vertscan 2.0 (manufactured by Ryoka System Co., Ltd.). A semiconductor layer or a bonding interface layer for measurement was produced by coating on a substrate under the same conditions as those for producing the element. About these layers, the film thickness of five places was measured arbitrarily, the average was calculated, and it was set as the average film thickness.

  The film thickness of the semiconductor film was measured with a cross-sectional SEM using a tabletop scanning microscope CarryScope JCM5100 (manufactured by JEOL). The film thickness of the semiconductor film was measured by measuring the cross section of the semiconductor element. The cross-sectional SEM measurement was performed at two locations, and the film thickness at five points was measured at equal intervals per location. A total of 10 film thicknesses were measured, and the average value was defined as the average film thickness.

  The thickness after producing the solar cell was measured by cross-sectional TEM observation. The measurement was performed after cutting the cross section of the solar cell by the FIB method.

  In the FIB method, Ga ions accelerated at 30 to 40 kV were focused to 0.01 to 0.1 μm and sputtered while scanning the cross section of the solar cell. A carbon film or a tungsten film was deposited as the protective film on the outermost surface of the sputtering. Moreover, cross-sectional TEM observation was performed at two places, and the film thickness at five points was measured at equal intervals per place. The average value of the film thicknesses of a total of 10 points was calculated and taken as the average film thickness. It was confirmed that the average film thickness obtained by the cross-sectional TEM observation was a value almost equivalent to the result of the film thickness measurement.

[Example 1]
(1) Preparation CIGS particles of CIGS particles containing semiconductor film-forming coating solution _{(composition: Cu (In 0.8 Ga 0.2)} S 2) , and 1-thioglycerol / ethanol mixed solvent (mass ratio 1/4 To prepare a 5% by mass solution. Zirconia balls were added to this solution and subjected to ultrasonic treatment, followed by stirring and shaking for 10 hours. After stirring and shaking, the zirconia balls were taken out. The average particle diameter of the CIGS particles was 48 nm. The composition of the coating solution for forming a semiconductor film was 5 mass% for CIGS particles, 19 mass% for 1-thioglycerol, and 76 mass% for ethanol.

(2) Film formation The above coating solution for forming a semiconductor film is drop-cast on a glass substrate with a transparent electrode of fluorine-doped tin oxide (FTO), and this is heated on a hot plate at 120 ° C. Removed. After removing ethanol, the substrate was further heated at 150 ° C. for 3 minutes to produce a substrate with a p-type semiconductor film. The composition of the semiconductor film was 90% by mass of CIGS particles and 10% by mass of the total of the compounds in which 1-thioglycerol and 1-thioglycerol were oxidized. The film thickness of the semiconductor film was 20 μm. The relative dielectric constant of 1-thioglycerol was 132.

(3) Production of Solar Cell A solar cell was produced using a substrate with a p-type semiconductor film, an n-type semiconductor layer composed of titanium oxide particles, and a substrate provided with IZO as a transparent electrode. The n-type semiconductor layer was prepared by spin coating on a transparent electrode using a water / 2-butoxyethanol mixed solvent containing titanium oxide particles having an average particle diameter of 20 nm (anatase type, solid content 5 mass%). The thickness of the n-type semiconductor layer obtained after spin coating and drying at 120 ° C. for 60 minutes was 500 nm. A substrate with a p-type semiconductor film and a substrate with an n-type semiconductor layer were bonded to form a solar cell.

[Comparative Example 1]
(1) Preparation of CIGS particle-containing semiconductor film-forming coating solution CIGS particles were obtained under the same conditions as in Example 1 except that ethanol was used as the 1-thioglycerol / ethanol mixed solvent (mass ratio 1/4). The average particle diameter of the CIGS particles was 48 nm. The composition of the coating solution for forming a semiconductor film was 5% by mass for CIGS particles and 95% by mass for ethanol.

(2) Film Formation A substrate with a p-type semiconductor layer was produced under the same conditions as in Example 1. The composition of the semiconductor layer was 100% by mass of CIGS particles. The film thickness of the semiconductor layer was 20 μm.

(3) Production of Solar Cell A solar cell was produced using a substrate with a p-type semiconductor layer, an n-type semiconductor layer composed of titanium oxide particles, and a substrate provided with IZO as a transparent electrode. The n-type semiconductor layer was prepared by spin coating on a transparent electrode using a water / 2-butoxyethanol mixed solvent containing titanium oxide particles having an average particle diameter of 20 nm (anatase type, solid content 5 mass%). The thickness of the n-type semiconductor layer obtained after spin coating and drying at 120 ° C. for 60 minutes was 500 nm. A substrate with a p-type semiconductor layer and a substrate with an n-type semiconductor layer were bonded to form a solar cell.

[Solar cell characteristic evaluation 1]
The solar cells of Example 1 and Comparative Example 1 were evaluated. The evaluation of the IV characteristics of the solar cell was performed by adjusting the solar cell so that the amount of light was 1 sun. Moreover, the said electrode and the electrically conductive tape were joined using the silver paste. The terminal at the time of IV measurement was taken from the conductive tape.

  The solar cell having the semiconductor film of Example 1 containing CIGS particles and 1-thioglycerol had a photoelectric conversion efficiency of 0.001%. The solar cell having the semiconductor layer of Comparative Example 2 consisting only of CIGS particles did not generate electricity.

[Example 2]
(1) Production of solar cell using compound semiconductor particles A PET film with ITO (manufactured by Aldrich, sheet resistance 60 Ω / □) is coated with a CIGS particle dispersion (rutile type, solid content 12% by mass) having an average particle diameter of 48 nm. A CIGS layer made of CIGS particles was prepared by spin coating. In addition, the thickness of the CIGS layer after drying for 10 minutes at 120 degreeC after spin coating was 300 nm. Further, cyanoethyl saccharose was diluted with 2-methoxyethanol on the CIGS layer, and a solution adjusted to 20% by mass was applied by blade coating, and dried at 120 ° C. for 1 minute. The thickness of the cyanoethyl saccharose layer was 600 nm. An n-type silicon crystal wafer having a thickness of 500 μm and a resistivity of 3 Ωcm was bonded onto the cyanoethyl saccharose layer to produce a solar cell. The relative dielectric constant of cyanoethyl saccharose was 25.

[Comparative Example 2]
(1) Preparation of CIGS particle-containing semiconductor film-forming coating solution A PET film with ITO (manufactured by Aldrich, sheet resistance 60Ω / □) is composed of CIGS particles (rutile type, solid content 12% by mass) with an average particle diameter of 48 nm. A CIGS layer was produced by spin coating. In addition, the thickness of the CIGS layer after drying for 10 minutes at 120 degreeC after spin coating was 300 nm. This was dried at 120 ° C. for 1 minute. An n-type silicon crystal wafer having a thickness of 500 μm and a resistivity of 3 Ωcm was bonded onto the CIGS layer to produce a solar cell.

[Solar cell characteristic evaluation 2]
The solar cells of Example 2 and Comparative Example 2 were evaluated. The evaluation of the IV characteristics of the solar cell was performed by adjusting the solar cell so that the amount of light was 1 sun. The conductive tape and silicon were bonded to the silicon-side electrode using indium and gallium alloy paste. On the CIGS side, an ITO electrode and a conductive tape were joined using a silver paste. The terminal at the time of IV measurement was taken from the conductive tape. In Example 2, the photoelectric conversion efficiency was 0.01%. Comparative Example 2 did not generate electricity.

DESCRIPTION OF SYMBOLS 1,5 ... Metal jig | tool; 2 ... Quartz plate; 3 ... Silicone rubber sheet; 4 ... Solar cell; 9 ... Screw;

Claims (14)

Comprising a semiconductor film containing inorganic semiconductor particles and a compound having a relative dielectric constant of 2 or more,
The said inorganic semiconductor particle is a semiconductor element which is inorganic semiconductor particles other than the compound semiconductor particle whose average particle diameter is 50 nm or less or the compound semiconductor particle whose average particle diameter is 100 nm or less. Comprising a semiconductor film containing inorganic semiconductor particles and a compound having a reducing power with respect to the inorganic semiconductor particles;
The said inorganic semiconductor particle is a semiconductor element which is inorganic semiconductor particles other than the compound semiconductor particle whose average particle diameter is 50 nm or less, or compound semiconductor whose average particle diameter is 100 nm or less.   2. The semiconductor element according to claim 1, wherein the content of the compound having a relative dielectric constant of 2 or more is 0.5 to 80% by mass based on the total mass of the semiconductor film.   The semiconductor element according to claim 2, wherein the content of the compound having a reducing power with respect to the inorganic semiconductor particles is 0.5 to 80% by mass based on the total mass of the semiconductor film.   4. The semiconductor device according to claim 1, wherein the compound having a relative dielectric constant of 2 or more is at least one selected from the group consisting of glycerin, thioglycerol, a cyano group-containing organic compound, and PVDF.   5. The semiconductor device according to claim 2, wherein the compound having a reducing power with respect to the inorganic semiconductor particles is at least one selected from the group consisting of glycerin and thioglycerol.   The semiconductor element according to claim 1, wherein the inorganic semiconductor particles other than the compound semiconductor particles are silicon particles.   The semiconductor element according to claim 1, further comprising another semiconductor film having a charge opposite to that of the semiconductor film or another semiconductor layer having a charge opposite to that of the semiconductor film.   The semiconductor element according to claim 8, further comprising an electrode on a surface of the semiconductor film opposite to a surface facing the other semiconductor film or the other semiconductor layer. A first semiconductor layer, a second semiconductor layer, and a bonding interface layer containing a compound having a relative dielectric constant of 2 or more between the first semiconductor layer and the second semiconductor layer,
At least one of the first semiconductor layer and the second semiconductor layer is a layer made of inorganic semiconductor particles,
The said inorganic semiconductor particle is a semiconductor element which is inorganic semiconductor particles other than the compound semiconductor particle whose average particle diameter is 50 nm or less or the compound semiconductor particle whose average particle diameter is 100 nm or less.   The semiconductor element according to claim 10, wherein the compound having a relative dielectric constant of 2 or more is at least one selected from the group consisting of glycerin, thioglycerol, a cyano group-containing organic compound, and PVDF.   12. The semiconductor device according to claim 10, further comprising an electrode on a surface of the first semiconductor layer and / or the second semiconductor layer opposite to a surface facing the bonding interface layer.   The semiconductor element according to claim 1, which is a flexible semiconductor element. The semiconductor element of any one of Claims 1-13 which is a solar cell.

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