WO2018168004A1 - Metal fine particle dispersion, conductive ink and electronic device - Google Patents

Abstract

The present invention provides: metal fine particles which exhibit sufficient electrical conductivity and transistor characteristics with a firing temperature around 120°C; a metal fine particle dispersion which contains the metal fine particles; a metal fine particle ink which uses the metal fine particle dispersion; and a thin film transistor electrode, a thin film transistor and an electronic device, each of which uses the metal fine particle ink that uses the metal fine particle dispersion. According to the present invention, metal fine particles which are able to be stably dispersed in a polar solvent or a solvent with low polarity without using a dispersant that has a high molecular weight are produced by using, as a protective agent, a primary amine that contains at least one hetero element other than an amino group. It is found that a metal fine particle dispersion according to the present invention exhibits excellent electrical conductivity by means of firing at a low temperature around 120°C, while exhibiting excellent transistor characteristics by means of firing at a low temperature around 120°C. It is also found that the fine particle dispersion is able to be stably dispersed at 23°C, while exhibiting the above-described characteristics.

Description

Metal fine particle dispersion, conductive ink, and electronic device

The present invention relates to an organic electroluminescent element, an organic thin film transistor, an organic thin film solar cell, etc., in an organic electronic device, a conductive material used for wiring, electrode, etc. formed by printing, in particular, metal fine particles used for an electrode in contact with an organic semiconductor, and TECHNICAL FIELD The present invention relates to a metal fine particle dispersion in which it is dispersed, a conductive ink prepared from the metal fine particle dispersion, a thin film transistor electrode formed by applying the conductive ink to form a conductive film, a thin film transistor having the electrode, and an electronic device It is an invention.

In recent years, in addition to reducing the weight and thinning of electronic devices, in order to form circuits on flexible and stretchable substrates, printable electronics technology has been developed to produce electronic devices by printing semiconductor materials, conductive materials, and insulating materials. Attention has been paid.

Nano-sized and micro-sized fine metal particles are used for the formation of wiring parts and electrode parts by printed electronics technology. By forming these metal fine particles into ink, wiring parts and electrode parts can be easily formed by printing. Is possible. The source electrode and the drain electrode of the thin film transistor electrode greatly affect the charge mobility, which is one of the transistor characteristics, of the smoothness of the electrode surface. Therefore, it is necessary that the metal fine particles are nano-sized or a mixture of nano-sized particles.

Nano-sized metal fine particles cannot exist stably as a dispersion unless they are protected with organic matter because of their high surface activity. However, the organic matter remaining on the surface after forming the electrode serves as an insulator, which obstructs the electron path at the interface between the electrode and the organic semiconductor, and deteriorates the transistor characteristics. It is difficult to develop high conductivity and high transistor characteristics while ensuring this dispersion stability.

As a method for producing high-definition wiring portions and electrode portions by printing, a letterpress reverse printing method is known. In the letterpress reverse printing method, printing is generally performed via a transfer member having a releasability made of silicone rubber. Therefore, when the metal fine particle dispersion, which is a nonpolar solvent, is used as an ink, the nonpolar solvent, which is a dispersion medium, swells the silicone rubber that is a transfer member having releasability, so that it can be reproduced continuously. An electrode image cannot be produced with good properties. In order to produce an electrode image by the letterpress reverse printing method, the metal fine particle dispersion must be dispersed in a low polarity or high polarity solvent.

In order to develop high conductivity and transistor characteristics, as a method of reducing the amount of organic matter remaining on the surface after electrode formation, a metal fine particle dispersion using a low molecular weight substance as an organic matter (protective agent) for protecting metal fine particles is used. A method to be used is disclosed (Patent Document 1, Patent Document 2). This is because the low molecular weight protective agent is detached from the electrode surface during coating film sintering, and thus organic substances remaining on the electrode surface can be reduced. However, any of these publications is a dispersion of metal fine particles using a low molecular weight protective agent in a nonpolar solvent, and cannot be suitably used as an ink for letterpress reverse printing.

In order to impart high dispersion stability to a metal fine particle dispersion, a method of dispersing metal fine particles in a polar solvent by using a high molecular weight dispersant in combination with metal fine particles using a low molecular weight substance as a protective agent is disclosed. (Patent Document 3 and Patent Document 4). Since the high molecular weight dispersant adheres firmly to the surface of the metal fine particles, a stable metal fine particle dispersion can be obtained even in a polar solvent. However, the dispersant that adheres firmly to the metal surface does not desorb during low-temperature firing at 120 ° C., and prevents fusion between the metal fine particles, making it difficult to develop high conductivity. This high sintering temperature makes it difficult to adapt to the transistor electrode corresponding to the flexible base material and its peripheral circuit. In addition, when the dispersion containing a high molecular weight dispersant is used, the dispersant remaining on the electrode surface becomes an insulator at the interface with the semiconductor, and the transistor characteristics are remarkably deteriorated. Therefore, a metal fine particle dispersion consisting only of a low molecular weight protective agent that does not use a high molecular weight dispersant is required.

WO 2007/120756 JP 2008-270245 A WO2016 / 084312 JP 2010-177084 A

The problems to be solved by the present invention include metal fine particles that exhibit sufficient conductivity and transistor characteristics at a firing temperature of about 120 ° C., metal fine particle dispersions containing the metal fine particles, and metal fine particles using the metal fine particle dispersions It is an object of the present invention to provide a thin film transistor electrode, a thin film transistor, and an electronic device using an ink and a metal fine particle ink using the metal fine particle dispersion.

As a result of intensive studies to solve the above problems, the present inventors use a high molecular weight dispersant by using a primary amine compound containing at least one hetero element in addition to an amino group as a protective agent. Thus, the inventors have completed the invention of fine metal particles that can be stably dispersed in a polar solvent or a low-polar solvent. It has been found that the metal fine particle dispersion according to the present invention exhibits excellent conductivity when fired at a low temperature of about 120 ° C. and excellent transistor characteristics when fired at a low temperature of about 120 ° C. Further, it was found that the fine particle dispersion can be stably dispersed even at 23 ° C. in addition to exhibiting the above properties.

(1) A metal fine particle dispersion in which metal fine particles containing a primary amine compound having an amino group and at least one hetero element are dispersed in a polar solvent.

(2) The fine metal particle dispersion according to (1), wherein the heteroelement described in (1) is a heteroelement selected from at least one of nitrogen, oxygen, sulfur, and phosphorus.

(3) The metal fine particle dispersion described in (1), wherein the polar solvent described in (1) contains an alkanol having 2 to 7 carbon atoms.

(4) A metal fine particle dispersion wherein the metal fine particles according to any one of (1) to (3) are silver.

(5) An ink containing the metal fine particle dispersion described in any one of (1) to (4).

(6) The ink according to (5), comprising a surface energy adjusting agent.

(7) The ink according to (5) or (6), which comprises a printing aid.

(8) The ink for ink jet or letterpress reverse printing according to any one of (5) to (7).

(9) A conductive film or a conductive pattern formed using the ink according to any one of (5) to (8).

(10) An electrode for a semiconductor device formed using the ink according to any one of (5) to (8).

(11) An electronic device comprising the semiconductor device electrode according to (10) in its configuration

(12) An electronic circuit including a conductive film or a conductive pattern according to (9) or an electronic device according to (11) in its configuration.

The present invention uses metal fine particles that exhibit sufficient conductivity and transistor characteristics at a baking temperature of about 120 ° C., metal fine particle ink using the metal fine particle dispersion, and metal fine particle ink using the metal fine particle dispersion. Thin film transistor electrodes, thin film transistors, and electronic devices.

3 is a TG-DTA measurement result of a silver fine particle dispersion produced based on Example 1. FIG. 4 is a TG-DTA measurement result of a silver fine particle dispersion produced based on Example 2. FIG. 4 is a transmission electron microscope image of a silver fine particle dispersion produced based on Example 1. FIG. 7 is a transmission electron microscope image of a silver fine particle dispersion produced based on Example 2. FIG.

Hereinafter, the present invention will be described in detail.

(Synthesis of metal fine particle)
The method for producing fine metal particles according to the present embodiment produces a complex compound by mixing an amine mixed solution containing a primary amine compound having a hetero element other than nitrogen of a primary amino group and a metal compound. Step (first step), step of heating and decomposing the complex compound to produce metal fine particles (second step), and purification step of removing unnecessary substances from the reaction product containing metal fine particles (third step) ) And. In this specification, “boiling point” means a boiling point at 1 atm.

In the step of generating the complex compound (first step), it is preferable to use an amine compound that can completely complex the metal compound. If it is a compound containing a primary amino group selected from one or more primary amine compounds containing 3 or more carbon atoms containing a hetero element in addition to nitrogen of the primary amino group, two or more types may be used alone. These compounds may be used as a mixture. From the viewpoint of reactivity, an amine compound having a high amine concentration per volume is preferable, and an amine compound having 8 or less carbon atoms is preferably included.

In the step of forming metal fine particles by heating and decomposing the complex compound (second step), the surface of the generated metal fine particles is effectively coated from the viewpoint of stabilizing the dispersion by preventing collisions between the metal colloid particles. It is preferable to use an amine compound that can be used. If it is a compound containing a primary amino group selected from one or more primary amine compounds containing 4 or more carbon atoms containing a hetero element in addition to nitrogen of the primary amino group, it may be used alone or in combination of two or more. These compounds may be used as a mixture. In order to reduce the formation of aggregates due to contact between particles, an amine compound having a long chain structure or a branched structure having 6 or more carbon atoms is preferably contained.

Since the step of generating the complex compound (first step) and the step of heating and decomposing the complex compound to form metal fine particles (second step) are performed continuously, before performing the second step, The complex compound produced in the first step needs to have a useful amine compound in the second step. Even when the first step is started with only the useful amine compound in the first step, the useful amine compound in the second step can be added before the second step is started. Moreover, when starting a 1st process, the amine compound useful in a 1st process and the amine compound useful in a 2nd process can also be used together. When the same kind of compound can be used as the amine compound useful in the first step and the amine compound useful in the second step, only one kind may be used as the amine compound.

Although the amine compound which can be utilized for the 1st process and the 2nd process is illustrated below, it is not limited to this. In the case where the molecular structure contains an element capable of a covalent bond having a valence of 3 or more, a branched structure may exist, and the element at the branched portion is a hetero element such as nitrogen or phosphorus other than carbon. There may be.

As the amine compound containing oxygen as a hetero element other than nitrogen of the primary amino group, alkoxyalkylamines having 3 or more carbon atoms having an alkoxy group in addition to the primary amino group can be used. Specifically, 2-methoxyethylamine, 2-ethoxyethylamine, 2-n-propoxyethylamine, 2-isopropoxyethylamine, 2-n-butoxyethylamine, 2-isobutoxyethylamine, 2-tert-butoxyethylamine, 2-n -Pentyloxyethylamine, 2-n-hexyloxyethylamine, 2-n-heptyloxyethylamine, 2-n-octyloxyethylamine, 2- (2-ethylhexyloxy) ethylamine, 2- (2-butylhexyloxy) ethylamine, 2-decyloxyethylamine, 2-dodecyloxyethylamine, 2-tetradecyloxyethylamine, 2-stearyloxyethylamine, 2-oleyloxyethylamine, 3-methoxypropylamine, 3-ethoxypro Ruamine, 3-n-propoxypropylamine, 3-isopropoxypropylamine, 3-n-butoxypropylamine, 3-isobutoxypropylamine, 3-tert-butoxypropylamine, 3-n-pentyloxypropylamine, 3 -N-hexyloxypropylamine, 3-n-heptyloxypropylamine, 3-n-octyloxypropylamine, 3- (2-ethylhexyloxy) propylamine, 3- (2-butylhexyloxy) propylamine, 3 -Decyloxypropylamine, 3-dodecyloxypropylamine, 3-tetradecyloxypropylamine, 3-stearyloxypropylamine, 3-oleyloxypropylamine, bis (2-aminoethyl) ether, bis (3-aminopropyl) D Ether, 1,2-bis (3-amino-ethoxy) ethane, can be exemplified 1,2-bis (3-amino-propoxy) ethane.

As the amine compound containing oxygen as a hetero element other than nitrogen of the primary amino group, an alkanolamine having 4 or more carbon atoms having a hydroxyl group in addition to the primary amino group can be used. Specifically, 2- (aminoethylamino) ethanol, 2- (aminoethoxy) ethanol, 3- (2-hydroxyethylamino) propylamine, N- (2-hydroxypropyl) ethylenediamine, N- (3-amino Propyl) diethanolamine and the like.

As the amine compound containing nitrogen as a hetero element other than nitrogen of the primary amino group, a diamine having 4 or more carbon atoms having a secondary or tertiary amino group or the like in addition to the primary amine can be used. . Specifically, N-methylethylenediamine, N-ethylethylenediamine, Nn-propyltylethylenediamine, N-isopropyltylethylenediamine, Nn-butylethylenediamine, N-isobutylethylenediamine, N-tert-butylethylenediamine, N- Methyl-1,3-propanediamine, N-ethyl-1,3-propanediamine, 3-n-propylaminopropylamine, 3-isopropylaminopropylamine, 3-n-butylaminopropylamine, 3-isobutylaminopropyl Amine, 3-tert-butylaminopropylamine, 3-dodecylaminopropylamine, N, N-dimethylethylenediamine, N, N-diethylethylenediamine, N, N-di-n-propylethylenediamine, N, N-di Sopropylethylenediamine, N, N-di-n-butylethylenediamine, N, N-diisobutylethylenediamine, N, N-di-tert-butylethylenediamine, N, N-dimethyl-1,3-propanediamine, N, N- Diethyl-1,3-propanediamine, 3- (di-n-propylamino) propylamine, 3- (diisopropylamino) propylamine, 3- (1,3-pudi-n-butylamino) propylamine, 3 -(Diisobutylamino) propylamine, 3- (di-tert-butylamino) propylamine, N, N-dimethyl-1,4-butanediamine, N, N-diethyl-1,4-butanediamine, N, N -Dibutyl-1,4-butanediamine, N, N-dimethyl-1,6-hexanediamine, N, N-diethyl- , 6-hexanediamine, N, N-dibutyl-1,6-hexanediamine, N, N-dimethylaminoethoxypropylamine, N- (3-aminopropyl) morpholine, N- (2-aminoethyl) piperidine, N -(2-aminoethyl) -4-pipecoline, N- (2-aminoethyl) -3-pipecoline, N- (2-aminoethyl) -2-pipecoline, N- (3-aminopropyl) -4-pipecoline N- (3-aminopropyl) -3-pipecoline, N- (3-aminopropyl) -2-pipecoline, N- (tert-butoxycarbonyl) -1,4-diaminobutane, N- (tert-butoxycarbonyl) ) -1,5-diaminopentane, N- (tert-butoxycarbonyl) -1,6-diaminohexane, and the like.

As the amine compound containing nitrogen as a hetero element other than nitrogen of the primary amino group, a polyamine having 4 or more carbon atoms having a secondary or tertiary amino group or the like in addition to the primary amine can also be used. . Specifically, iminobisethylamine, methyliminobisethylamine, iminobispropyldiamine, methyliminobispropylamine, 1- (3-aminoethyl) piperazine, 1- (3-aminopropyl) piperazine, 1,4-bis ( Examples thereof include 3-aminoethyl) piperazine, 1,4-bis (3-aminopropyl) piperazine, triethylenetetramine, tetraethylenepentamine and the like.

As the amine compound containing sulfur as a hetero element in addition to nitrogen of the primary amino group, alkylthioalkylamines having 3 or more carbon atoms having an alkylthio group in addition to the primary amino group can be used. Specifically, 2-methylthioethylamine, 2-ethylthioethylamine, 2-n-propylthioethylamine, 2-isopropylthioethylamine, 2-n-butylthioethylamine, 2-isobutylthioethylamine, 2-tert-butylthioethylamine 2-n-pentylthioethylamine, 2-n-hexylthioethylamine, 2-n-heptylthioethylamine, 2-n-octylthioethylamine, 2- (2-ethylhexylthio) ethylamine, 2- (2-butylhexyl) Thio) ethylamine, 2-decylthioethylamine, 2-dodecylthioethylamine, 2-tetradecylthioethylamine, 2-stearylthioethylamine, 2-oleylthioethylamine, 3-methylthiopropylamine, 3-ethylthiopropyl Min, 3-n-propylthioamine, 3-isopropylthiopropylamine, 3-n-butylthiopropylamine, 3-isobutylthiopropylamine, 3-tert-butylthiopropylamine, 3-n-pentylthiopropylamine 3-n-hexylthiopropylamine, 3-n-heptylthiopropylamine, 3-n-octylthiopropylamine, 3- (2-ethylhexylthio) propylamine, 3- (2-butylhexylthio) propylamine , 3-decylthiopropylamine, 3-dodecylthiopropylamine, 3-tetradecylthiopropylamine, 3-stearylthioamine, 3-oleylthiopropylamine and the like.

In addition, as long as the effects of the present invention are not impaired, an amine compound containing no hetero element other than nitrogen of the primary amino group can be used in combination as amines. For example, an alkylamine can be used as the primary amine, specifically, 1-octylamine, 2-ethylhexylamine, 1-nonylamine, 1-decylamine, isodecylamine, 1-undecylamine, Examples include 1-dodecylamine, 1-tridecylamine, 1-tetradecylamine, 1-pentadecylamine, 1-hexadecylamine, 1-heptadecylamine, stearylamine, oleylamine and the like.

In addition, secondary amine compounds can be used in combination as amines as long as the effects of the present invention are not impaired. For example, dialkylamine can be used, and specifically, di-n-ethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, di-n-hexylamine, di-1-octylamine Bis (2-ethylhexyl) amine, di-1-nonylamine, di-1-decylamine, diisodecylamine, di-1-undecylamine, di-1-dodecylamine, dioleylamine and the like.

In addition, a tertiary amine compound can be used in combination as amines as long as the effects of the present invention are not impaired. For example, a trialkylamine can be used, and specifically, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, heptacosafluorotributylamine, tri-n-amylamine, perfluorotria Myramine, tri-n-hexylamine, N, Nn-octylamine, tri-n-octylamine, tri-n-octylamine, tris (2-ethylhexyl) amine, tri-n-nonylamine, tri-n -Decylamine, triisodecylamine, tri-n-undecylamine, tri-n-dodecylamine, trioleylamine, 1- [N, N-bis (2-ethylhexyl) aminomethyl] benzotriazole, 1- [N, N-bis (2-ethylhexyl) aminomethyl] methylbenzo Riazor can quinuclidine, diazabicyclo [2.2.2] octane, tetramethylethylenediamine, tetramethyl propanediamine, pentamethyldiethylenetriamine, pentamethyldipropylenetriamine propane triamine, be exemplified hexamethyl triethylenetetramine.

In addition, as long as the effects of the present invention are not impaired, alkanolamines having 4 or more carbon atoms having a hydroxyl group can be used as the tertiary amine compound. Specifically, N, N-dimethylaminoethanol, N, N-diethylaminoethanol, N, N-di-n-propylaminoethanol, N, N-diisopropylaminoethanol, N, N-di-n-butylamino Ethanol, N, N-diisobutylaminoethanol, N, N-di-tert-butylaminoethanol, N, N-bis (2-hydroxyethyl) -1,3-propanediamine, N, N-dimethylaminoisopropanol, N , N-diethylaminoisopropanol, N, N-di-n-propylaminoisopropanol, N, N-diisopropylaminoisopropanol, N, N-di-n-butylaminoisopropanol, N, N-diisobutylaminoisopropanol, N, N- Di-tert-butylaminoisopropanol, -(2-dimethylaminoethoxy) ethanol, 2- (2-diethylaminoethoxy) ethanol, diethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, Nn-propyldiethanolamine, N-isopropyldiethanolamine, Nn-butyldiethanolamine N-isobutyldiethanolamine, N-tert-butyldiethanolamine, Nn-hexyldiethanolamine, Nn-octyldiethanolamine, N- (2-ethylhexyl) diethanolamine, Nn-decyldiethanolamine, N-isodecyldiethanolamine, N -Dodecyldiethanolamine, N-tetradecyldiethanolamine, N-hexadecyldiethanolamine, N-stearyldiethanol Amine, N-oleyldiethanolamine, 2,2 ′-[[(methyl-1H-benzotriazol-1-yl) methyl] imino] bisethanol, diisopropanolamine, N-methyldiisopropanolamine, N-ethyldiisopropanolamine Nn-propyldiisopropanolamine, N-isopropyldiisopropanolamine, Nn-butyldiisopropanolamine, N-isobutyldiisopropanolamine, N-tert-butyldiisopropanolamine, Nn-hexyldiisopropanolamine Nn-octyldiisopropanolamine, N- (2-ethylhexyl) diisopropanolamine, Nn-decyldiisopropanolamine, N-isodecyldiisopropanolamine, N-dodecy Ludiisopropanolamine, N-tetradecyldiisopropanolamine, N-hexadecyldiisopropanolamine, N-stearyldiisopropanolamine, N-oleyldiisopropanolamine, triethanolamine, triisopropanolamine, 3- (dimethylamino) -1 2, 2-propanediol, 3- (diethylamino) -1,2-propanediol, and the like.

In addition, amidines can be used in combination as long as the effects of the present invention are not impaired. For example, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0] -7-undecene and the like can be exemplified.

In addition, carboxylic acids can be added as long as the effects of the present invention are not impaired. Carboxylic acids include fatty acids having 1 to 22 carbon atoms, oleic acid, linoleic acid, linolenic acid, ricinoleic acid, 15-hydroxypentadecanoic acid, 12-hydroxystearic acid, cholic acid, deoxycholic acid, dehydrocol Acid, chenooxycholic acid, 12-oxochenodeoxycholic acid, glycocholic acid, colanic acid, lithocholic acid, hyodeoxycholic acid, ursodeoxycholic acid, apocholic acid, taurocholic acid, abietic acid, dehydroabietic acid, glycyrrhizic acid, glycyrrhizin Acid, lauroyl sarcosine, stearoyl sarcosine, oleoyl sarcosine acid, 6-aminohexanoic acid, N- (tert-butoxycarbonyl) -6-aminohexanoic acid, cinnamic acid, 2- (2- (2-methoxyethoxy) ethoxy) Acetic acid, - it can be exemplified benzoyl benzoate.

In addition, thiols can be added as long as the effects of the present invention are not impaired. As thiols, octanethiol, decanethiol, dodecanethiol, perfluorooctanethiol, perfluorodecanethiol, perfluorododecanethiol, benzenethiol, 3-methylbenzenethiol, 4-methylbenzenethiol, 3-fluorobenzenethiol, 4 -Fluorobenzenethiol, 3-chlorobenzenethiol, 4-chlorobenzenethiol, pentachlorobenzenethiol, 3-bromobenzenethiol, 4-bromobenzenethiol, 3-methoxybenzenethiol, 4-methoxybenzenethiol, 3-methylthiobenzenethiol, 4 -Methylthiobenzenethiol, 3-trifluoromethoxybenzenethiol, 4-trifluoromethoxybenzenethiol, 3-trifluoromethylthiol Benzenethiol, 4-trifluoromethylthiobenzenethiol, pentafluorobenzenethiol, 3-trifluoromethylbenzenethiol, 4-trifluoromethylbenzenethiol, 4-trifluoromethyl-2,3,5,6-tetrafluorobenzenethiol 3-nitrobenzenethiol, 4-nitrobenzenethiol, fluorenethiol, 3-cyanobenzenethiol, 4-cyanobenzenethiol, biphenylthiol, 2-mercapto-5-nitrobenzimidazole, 5-chloro-2-mercaptobenzimidazole, etc. It can be illustrated.

In addition, phosphines can be added as long as the effects of the present invention are not impaired. Examples thereof include tri-1-butylphosphine, tri-1-octylphosphine, tricyclohexylphosphine, and triphenylphosphine.

The metal species of the metal fine particles of the present invention are limited as long as the metal can be chemically bonded to a nitrogen-containing functional group selected from a primary amino group, a secondary amino group, a tertiary amino group, and an amidino group. For example, gold, silver, copper, nickel, zinc, aluminum, platinum, palladium, tin, chromium, lead, tungsten, or the like can be used. Further, the metal species may be one type, a mixture of two or more types, or an alloy.

Moreover, as a metal compound which can react with an amine compound and can form a complex compound, carboxylate, a chloride, an oxide, carbonate, nitrate etc. are mentioned, for example. Among these, oxalate and formate are particularly preferable. Oxalates and formates are because the carboxylate ions are decomposed by heating to reduce silver ions and volatilize as carbon dioxide at the same time, so that impurities hardly remain.

(First step)
In the first step of producing a complex compound, an amine compound and a silver compound are mixed to produce a complex compound therebetween. The total amount of amine contained in the amine mixture is preferably equal to or greater than the stoichiometric amount of the metal in the metal compound. This is because if a metal compound that does not become a complex compound remains, uniform and stable dispersion of metal nanoparticles may be hindered.

The formation reaction of the complex compound between the amine mixture and the metal compound needs to be adjusted because the reactivity changes depending on the amine compound and the metal compound to be used, but the mixture containing the amine mixture and the metal compound can be adjusted from 30 ° C. It can be carried out by stirring at about 50 ° C. for about 5 minutes to 3 hours. Although the reaction time can be shortened by increasing the reaction temperature, the reaction temperature is preferably 50 ° C. or less from the viewpoint of avoiding an unexpected decomposition reaction by providing a sufficient temperature difference from the thermal decomposition start temperature in the second step. . In order to avoid chemical changes and ignition of the reaction system, particularly amine compounds, it is preferable to avoid mixing of carbon dioxide and moisture, and the reaction can be performed in an inert gas such as nitrogen or argon, or in a dry air atmosphere.

(Second step)
In the next step (second step), metal complexes are formed by heating and decomposing the complex compound produced in the previous step. The temperature at which the complex compound is decomposed by heating varies depending on the amine compound and the metal compound to be used, so adjustment is necessary, but the metal compound is decomposed to generate a metal, and the amine compound from the generated metal fine particles From the viewpoint of preventing desorption, it is preferable to react in the range of 70 ° C. to 150 ° C. for about 5 minutes to 2 hours. In particular, when a low-boiling amine compound is used to form an electrode at a low temperature, the reaction temperature in this step should not exceed the boiling point of the amine compound due to the heat generated by the progress of the thermal decomposition reaction. It is preferable from the viewpoint of avoiding bumping. Moreover, in order to prevent ignition of the vaporized amine compound, it is preferable to make it react on low oxygen concentration conditions.

In the second step, heat generation due to thermal decomposition of the metal oxalate metal salt amine complex occurs, and therefore it is possible that the reaction heat cannot be controlled when the reaction scale is expanded. Therefore, when the ratio of the molar amount m2 of the amine to the molar amount m1 of the metal (m2 / m1) is, for example, in the range of 5-20, the amine solution is added excessively to generate oxalate during thermal decomposition. The reaction heat to be absorbed can be absorbed by the amine solution, and bumping can be prevented.

The reaction liquid after the thermal decomposition of the complex compound becomes, for example, a brown suspension when the metal species is silver. From this suspension, target metal fine particles can be obtained by a separation operation such as decantation.

(Third process)
When performing decantation or washing, it is preferable to use an organic solvent such as hexane or alcohol in which the target metal fine particles do not exhibit sufficient dispersibility. According to the manufacturing method according to this embodiment described above, metal fine particles having an average particle diameter of 100 nm or less can be obtained. Further, in the third step, it is sufficient if unnecessary substances can be removed from the reaction product containing metal fine particles, and a method other than decantation can also be adopted.

(Metal fine particle dispersion)
It is considered that the metal fine particles whose surface is coated with a protective agent by decantation reflects the chemical properties of the protective agent and is well dispersed in a solvent that gives an interaction within a specific range. By selecting and using an amine compound containing a hetero element in addition to nitrogen of the primary amino group, the polarity of the surface of the fine particles coated with the amine compound can be increased and uniformly and stably in a polar solvent. Metal fine particles that can be dispersed are obtained.

The polar solvent in the present invention has at least one hydroxyl group, carboxyl group, amino group, ether group, carbonyl group, amide group, nitrile group, or ester group as a polar functional group, and has a solubility parameter (SP value). It refers to a solvent of 20 [MPa ^1/2 ] or more. In addition, the polar solvent used here may be used independently, but can also be mixed and used. If the SP value as a mixture is 20 [MPa ^1/2 ] or more, a low polarity solvent having an SP value of less than 20 [MPa ^1/2 ] can be used in combination. Note that the selection criterion is not limited to the SP value, and another parameter may be used as long as the polarity of the solvent can be evaluated based on an appropriate criterion.

The solubility parameter is a parameter related to mutual solubility of substances proposed by Hildebrand et al., And is determined by measuring the energy required for vaporization of a single component per average molar volume, as shown in Equation (1).
δ = (E / V _m ) ^1/2 = (ΔH _evap −RT) / V _m ) ^1/2 equation (1)
Where δ: solubility parameter [MPa ^1/2 ]
E; heat of vaporization T; Temperature R; gas constant V _m; molar volume [Delta] H; vaporization enthalpy Delta] E; vaporization energy

The organic fine particle dispersion of the present invention is selected by selecting an organic solvent having a solubility parameter (SP value) of 20 [MPa ^1/2 ] or more as a polar solvent, adding the metal nanoparticles obtained in the second step, and stirring. Can be obtained. Organic solvents having an SP value of 20 [MPa ^1/2 ] or more are described in, for example, Polymer Handbook 4th Edition, John Wiley & Sons, Inc. And can be selected based on the value.

Examples of the organic solvent having an SP value of 20 [MPa ^1/2 ] or more include the following hydroxyl group-containing solvents. The value in () is the SP value of the solvent. Methanol (29.7), ethanol (26.0), 1-propanol (24.3), isopropanol (23.5), 1-butanol (23.3), isobutanol (21.5), sec-butanol (22.1), tert-butanol (21.7), amyl alcohol (22.3), tert-amyl alcohol (22.3), 1-hexanol (21.9), cyclohexanol (23.3), Benzyl alcohol (24.8), 2-ethyl-1-butanol (21.5), 1-heptanol (21.7), 1-octanol (21.1), 4-methyl-2-pentanol (20. 5), neopentyl glycol (22.5), propionitrile (22.1), ethylene glycol (29.9), propylene glycol (25.8) 1,3-butanediol (23.7), 1,4-butanediol (24.8), 2,3-butanediol (22.7), isobutylene glycol (22.9), 2,2-dimethyl- 1,3-butanediol (20.5), 2-methyl-1,3-pentanediol (21.1), 2-methyl-2,4-pentanediol (19.8), diethylene glycol (24.8) , Triethylene glycol (21.9), tetraethylene glycol (20.3), 1,5-pentanediol (23.5), 2,4-pentanediol (22.1), dipropylene glycol (20.7) ), 2,5-hexanediol (21.2), glycerin (33.8), diethylene glycol monobutyl ether (20.9), ethylene glycol monobenzyl ether Ter (22.3), ethylene glycol monoethyl ether (21.5), ethylene glycol monomethyl ether (23.3), ethylene glycol monophenyl ether (23.5), propylene glycol dimethyl ether (20.7), etc. be able to.

Other organic solvents having an SP value of 20 [MPa ^1/2 ] or more include acetone (20.3), cyclopentanone (21.3), cyclohexanone (20.3), acetophenone (21.7), acrylonitrile. (24.3), propionitrile (22.1), n-butyronitrile (21.5), isobutyronitrile (20.1), γ-butyrolactone (25.8), ε-caprolactone (20.7) ), Propiolactone (27.2), 2,3-butylene carbonate (24.8), ethylene carbonate (30.1), 1,2-ethylene carbonate (27.2), dimethyl carbonate (20.3) ), Ethylene carbonate (30.1), dimethyl malonate (22.5), ethyl lactate (20.5), methyl benzoate (21.5), methyl salicylate (21.7), ethylene glycol diacetate Cole (20.5), ε-caprolactam (26.0), dimethyl sulfoxide (29.7), N, N-dimethylformamide (24.8), N, N-dimethylacetamide (22.1), N— Methylformamide (32.9), N-methylacetamide (29.9), N-ethylacetamide (25.2), N, N-diethylformamide (21.7), formamide (39.3), pyrrolidine (30 .1), 1-methyl-2-pyrrolidinone (23.1), hexamethylphosphoric triamide (21.5), and naphthalene (20.3).

Specific examples of solvents that can be used in combination include water, isoamyl alcohol, 3-methoxy-1-butanol, 2-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 1- Hexanol, 2-hexanol, 2-ethylhexanol, 1-octanol, isooctyl alcohol, 2-butyl-1-octanol, 1-nonanol, 1-decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, Alcohols such as 2- (2-ethoxyethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, furfuryl alcohol, terpineol, phenol, 2-phenoxyethanol, 1-phenoxy-2-propanol, ethylene glycol , Propylene glycol, diethylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, octanediol, diols such as triethylene glycol, and polyols such as glycerin , Pentane, hexane, octane, nonane, decane, undecane, dodecane, octadecane, cyclohexane, methylcyclohexane, p-menthane, toluene, xylene and other aliphatic hydrocarbons, limonene, cymene, terpinene, α-ferrandylene, etc. Hydrocarbon, ethyl acetate, propyl acetate, isopropyl acetate, 1-methoxy-2-propyl acetate, 3-methoxybutyl acetate, ethylene glycol monomethyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate Cetates, 2- (2-butoxyethoxy) ethyl acetate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, γ-butyrolactone, esters such as ethyl lactate, methyl ethyl ketone, methyl isobutyl ketone, 2 -Ketones such as pentanone, 2-heptanone, cyclohexanone, ethers such as diethyl ether, 1,2-dimethoxyethane, ethylene glycol diethyl ether, diethylene glycol diethyl ether, tetrahydrofuran, N, N-dimethylformamide, N-methylpyrrolidone, Examples thereof include amides such as N, N-dimethylacetamide. The dispersion solvent may be used alone or in combination of two or more.

In order to impart dispersion stability to the metal fine particle dispersion of the present invention, amines, alkanolamines, amidines, carboxylic acids, thiols, and phosphines exemplified above may be added. In particular, by adding a fatty acid and a hydroxy fatty acid, dispersibility in a nonpolar solvent is improved, and dispersion at a metal concentration of 50% or more becomes possible. Also, the dispersion stability at room temperature is improved.

The average particle diameter of the metal fine particles can be calculated by the following method, for example. First, metal fine particles are observed with an electron microscope (TEM). The square root of the area S of specific metal fine particles in the obtained image is defined as the particle size a of the metal fine particles (a = S ^1/2 ). The particle diameter a of 50 arbitrary metal fine particles is calculated. The average value of the calculated particle diameter a is defined as the average particle diameter of the primary particles of the metal fine particles. Alternatively, the average particle diameter of the metal fine particles can also be obtained by a dynamic light scattering method or minimal angle X-ray scattering.

(Metal fine particle ink)
The metal fine particle dispersion of the present invention is converted into an ink by pad printing, screen printing, screen offset printing, ink jet printing, flexographic printing, letterpress printing, planographic offset printing, waterless planographic offset printing, gravure printing, gravure offset printing, The image can be formed using a printing method selected from the group consisting of letterpress reversal printing, laser printing, xerographic printing, pad printing, and combinations thereof.

When forming the metal fine particle dispersion of the present invention into an ink, a low viscosity solvent of 50 mPa · s or less at 20 ° C. can be further added. Examples of such a solvent include water, methanol, ethanol, 1-propanol, isopropanol, 1-butanol, sec-butanol, tert-butanol, isoamyl alcohol, 3-methoxy-1-butanol, 1-pentanol, 2 -Pentanol, 4-methyl-2-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 1-hexanol, 2-hexanol, 2-ethylhexanol, 1-octanol, isooctyl Alcohol, 2-butyl-1-octanol, 1-nonanol, 1-decanol, oleyl alcohol, 2- (2-ethoxyethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, furfuryl alcohol, terpineol, 2-phenoxyethanol , 1-Fe Alcohols such as xyl-2-propanol, pentane, hexane, octane, nonane, decane, undecane, dodecane, octadecane, cyclohexane, methylcyclohexane, p-menthane, aliphatic hydrocarbons such as limonene, cymene, terpinene , Unsaturated hydrocarbons such as α-ferrandrene, ethyl acetate, propyl acetate, isopropyl acetate, 1-methoxy-2-propyl acetate, 3-methoxybutyl acetate, ethylene glycol monomethyl acetate, 2- (2-ethoxyethoxy) ethyl Acetates, 2- (2-butoxyethoxy) ethyl acetate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, γ-butyrolactone, esters such as ethyl lactate, methyl ethyl ketone, Ketones such as butyl isobutyl ketone, 2-pentanone, 2-heptanone, cyclohexanone, ethers such as diethyl ether, 1,2-dimethoxyethane, ethylene glycol diethyl ether, diethylene glycol diethyl ether, tetrahydrofuran, N, N-dimethylformamide, Examples thereof include amides such as 1-methyl-2-pyrrolidinone and N, N-dimethylacetamide. The dispersion solvent may be used alone or in combination of two or more. When two or more of the dispersion solvents are used in combination, the viscosity of the mixed solution is preferably 50 mPa · s or less at 20 ° C.

In addition to the above solvent (dispersion medium), the metal fine particle ink includes a binder component such as a resin, an antifoaming agent, an adhesion imparting agent to the base material, an antioxidant, and various catalysts for promoting film formation. Various surfactants such as silicone surfactants and fluorine surfactants, leveling agents, mold release accelerators, and the like can be added as printing aids.

Since the metal fine particle ink of the present invention is excellent in dispersion stability, it can be suitably used for forming an image such as a thin film electrode. Furthermore, since firing at a low temperature is possible, the metal fine particle ink of this embodiment can be applied or printed on a substrate having low heat resistance such as a resin substrate or a paper substrate to form a wiring.

(Image formation by letterpress reverse printing)
When producing an electrode for a semiconductor device using the metal fine particle ink of the present invention, letterpress reversal printing which can form a thin film having a narrower line width and a smoother shape can be suitably used. Further, in the letterpress reverse printing method, the employed electrode width in the cross section of the thin film transistor is not different in the thickness direction, and a device electrode without transfer abnormality can be obtained. A thin film transistor having such a source electrode and a drain electrode is a thin film transistor with less variation in mobility and threshold voltage when driven.

Specifically, the electrodes have the same thickness, both of which are made of extremely uniform conductors of 50 nm or more, preferably 100 to 200 nm, and can be easily formed into electrodes having an appropriate electrode shape with no abnormalities such as concave and convex shapes. Is obtained. As a result, such an electrode is optimal for obtaining a transistor array including a thin film transistor, an integrated circuit, and the like. In addition, since a stable channel shape can be obtained in the thin film transistor electrode, the thin film transistor has less variation in mobility and threshold voltage when driven. Such excellent features are the features of transfer printing described above, which cannot be achieved by conventional printing methods such as screen printing and ink jet printing.

In the letterpress reverse printing method, a letterpress on which a convex portion corresponding to an image reversal pattern is formed and a transferred member (blanket) having releasability are used. Applying metal fine particle ink to the entire surface of the member to be transferred and pressing the relief plate onto the coated surface on the member to be transferred, and transferring and removing the portion corresponding to the reversal pattern of the image on the relief plate And a step of transferring and printing an image on a support such as a substrate using a member to be transferred on which an image portion corresponding to the image pattern is formed by removing the reverse pattern pressed by the relief printing plate. The printing method provided with.

In letterpress reversal printing, the viscosity of the ink is excessive because the high-boiling solvent remains in the ink coating until the image formed on the transferred member by the letterpress is transferred to the printing substrate. Can be prevented, and can maintain appropriate adhesiveness and cohesive force necessary for transfer, and printing becomes possible.

As the high boiling point solvent solvent added to the fine metal particle ink used for letterpress reverse printing, one or more of ester solvents, alcohol solvents, ether solvents and hydrocarbon solvents are used. The total ink composition contains 5 to 90% by mass, preferably 30 to 70% by mass, and more preferably 40 to 60% by mass. The blending amount is adjusted in the range of 5 to 90% by mass depending on the printing speed and printing order of the letterpress reverse printing method. When a sufficient amount of the high boiling point solvent is not used, the ink coating film on the blanket is dried too much, so that the ink coating film does not transfer to the relief plate and a good image is not formed on the blanket. Moreover, since it will not dry and the ink coating film on a blanket will not transfer to a letterpress if it becomes excess, it is not preferable.

The high boiling point solvent used in the ink is selected in consideration of the dispersion stability of the metal fine particles, and the following can be used, but is not limited thereto. For example, n-nonane (boiling point 150 ° C.), n-decane (boiling point 174 ° C.), n-undecane (boiling point 195 ° C.), n-dodecane (boiling point 216 ° C.), n-tridecane (boiling point 235 ° C.), n-tetradecane (Boiling point 253 ° C), n-hexanol (boiling point 157 ° C), n-heptanol (boiling point 177 ° C), n-octanol (boiling point 194 ° C), n-nonanol (boiling point 214 ° C), n-decanol (boiling point 233 ° C) N-undecanol (boiling point 243 ° C.), tridecanol, pentadecanol, ester solvents such as butyl acetate (boiling point 126 ° C.), isobutyl acetate (boiling point 118 ° C.), ethyl lactate (boiling point 155 ° C.), 3-methoxy-3 -Methyl-1-butyl acetate (boiling point 188 ° C), propylene glycol monomethyl acetate (PGMAc), propylene Glycol monoethyl acetate (PGMEA), ethoxyethyl propionate (EEP) and the like, may be used as a mixture thereof.

(Sintering method of metal fine particles)
The metal fine particles of the present invention are excellent in low-temperature sinterability, and can exhibit excellent conductivity by sintering at a temperature of 120 ° C. or lower. Therefore, the metal fine particles of the present invention can be used for materials having low heat resistance such as resin films.

Here, the firing method for sintering the metal fine particles is not limited to sintering by heat, and the metal fine particles may be fused. For example, the metal fine particles can be sintered by using visible light, infrared light or laser light irradiation, or plasma treatment including hydrogen gas. For example, when visible light is used for sintering of the metal fine particles, it can be performed by light irradiation using a flash lamp.

If the metal fine particles of this embodiment are used, wiring, electrodes, etc. having sufficiently low resistivity (6 × 10E-6 Ω · cm or less by baking at 120 ° C. when silver is used for the metal). A conductive structure can be formed. Therefore, the metal fine particles of the present embodiment can be suitably used for manufacturing various electronic components such as a thin film transistor, an integrated circuit including a thin film transistor, a touch panel, an RFID, a flexible display, an organic EL, a circuit board, and a sensor device.

(Thin film organic transistor)
In the present invention, a thin film transistor is a transistor in which at least a gate electrode, an insulator layer, a source electrode and a drain electrode, and a semiconductor layer are stacked over a substrate. The thin film transistor usually has a thickness of 0.1 to 3 μm excluding the substrate serving as a support.

A thin film transistor is formed by laminating a source electrode, a drain electrode, a gate electrode, a semiconductor layer, and an insulator layer made of a conductor in any order on a substrate so that the function of the transistor is exhibited. It can be manufactured easily.

The thin film transistor of the present invention can have horizontal and vertical transistor structures. As the lateral transistor, for example, a bottom-gate (BG) or top-gate (TG) transistor defined by the positional relationship of the gate electrode with the transistor component can be used. Further, depending on the positional relationship between the source / drain electrodes and the organic semiconductor layer in each of the BG type and the TG type, a transistor structure such as a bottom contact type, a top contact type, and a bottom top contact type can be adopted.

(Electrode for thin film organic transistor)
The thin film transistor of the present invention is characterized in that at least one electrode is formed using the metal fine particles of the present invention. In addition, the electrode for the thin film organic transistor includes the metal fine particles of the present invention and other conductive materials (for example, gold, silver, copper, nickel, zinc, aluminum, calcium, magnesium, iron, platinum, palladium, tin, chromium). Metal particles such as silver, palladium, and alloys of these metals such as silver / palladium; thermally decomposable metal compounds that give a conductive metal by thermal differentiation at a relatively low temperature, such as silver oxide, organic silver, and organic gold; zinc oxide (ZnO), conductive metal oxide particles such as indium tin oxide (ITO), etc.) can also be used as a mixture.

The electrode for a thin film organic transistor of the present invention is an ink jet printing method, a screen printing method, a screen offset printing method, a spin coating method, a bar coating method, a pad printing method, a slit coating method, a dip coating method, a spray coating method, a gravure printing method. Forming an image using a printing method selected from the group consisting of a flexographic printing method, a lithographic offset printing method, a gravure offset printing method, a relief printing method, a relief printing method, a relief printing method, and combinations thereof. it can. Among these, it is preferable to use a letterpress reverse printing method because an electrode image portion can be formed with a finer and smoother thin film.

In the letterpress reverse printing method, the electrode width in the laminated section of the thin film transistor is not different in the thickness direction, and an electrode having no transfer abnormality is obtained. A thin film transistor having such an electrode is a thin film transistor with less variation in mobility and threshold voltage when driven.

The method of forming transistor electrodes by letterpress reversal printing does not require an expensive vacuum device and can drastically reduce production costs including capital investment, compared to methods for obtaining the electrodes by vapor deposition or other dry methods. It becomes. In addition, the process can be reduced in temperature, and a resin film can be used as the substrate, which is preferable for realizing flexibility and low cost.

By subjecting the source and drain electrodes of the thin film transistor of the present invention to surface treatment as necessary, the charge injection efficiency into the semiconductor layer can be improved. The surface treatment material of the electrode for the thin film organic transistor can be arbitrarily selected according to the energy level of the semiconductor. For example, octanethiol, decanethiol, dodecanethiol, perfluorooctanethiol, perfluorodecanethiol, perfluoro Dodecanethiol, benzenethiol, 3-methylbenzenethiol, 4-methylbenzenethiol, 3-fluorobenzenethiol, 4-fluorobenzenethiol, 3-chlorobenzenethiol, 4-chlorobenzenethiol, pentachlorobenzenethiol, 3-bromobenzenethiol, 4-bromobenzenethiol, 3-methoxybenzenethiol, 4-methoxybenzenethiol, 3-methylthiobenzenethiol, 4-methylthiobenzenethiol, 3-trifluoro Romethoxybenzenethiol, 4-trifluoromethoxybenzenethiol, 3-trifluoromethylthiobenzenethiol, 4-trifluoromethylthiobenzenethiol, pentafluorobenzenethiol, 3-trifluoromethylbenzenethiol, 4-trifluoromethylbenzenethiol, 4-trifluoromethyl-2,3,5,6-tetrafluorobenzenethiol, 3-nitrobenzenethiol, 4-nitrobenzenethiol, fluorenethiol, 3-cyanobenzenethiol, 4-cyanobenzenethiol, biphenylthiol, 2-mercapto Thiol compounds such as -5-nitrobenzimidazole and 5-chloro-2-mercaptobenzimidazole; disulfide compounds such as diphenyl disulfide; Sulfide compounds such as I de; silane coupling agents such as long chain fluoroalkyl silane; molybdenum oxide, vanadium oxide, tungsten oxide, etc. can be used metal oxides such as rhenium oxide. Among them, those having a functional group that can be chemically bonded to the electrode surface are preferable.

As a surface treatment method of the electrode for a thin film organic transistor, it can be formed by any known and commonly used dry or wet process. Specific examples of the wet method include spin coating, bar coating, slit coating, dip coating, spray coating, dispenser, and ink jet.

The surface treatment amount of the thin film organic transistor electrode can be determined by measuring the work function of the electrode before and after the surface treatment using an atmospheric photoelectron spectrometer.

(Substrate for thin film organic transistor)
There are no limitations on the substrate applicable to the thin film transistor of the present invention. For example, silicon, a thermal oxide film silicon whose surface is oxidized to be an insulating layer, glass, a thin metal plate such as stainless steel on which an insulating layer is formed; polycarbonate (PC) Plastic films such as polyethylene terephthalate (PET), polyimide (PI), polyethersulfone (PES), polyethylene naphthalate (PEN), liquid crystal polymer (LCP), polyparaxylylene, polyphenylene sulfide (PPS), cellulose; A composite film obtained by adding a gas barrier layer, a hard coat layer, etc. to a plastic film can be used. Among these, from the viewpoint of making the transistor flexible, a resin film can be suitably used as the substrate.

(Insulating layer for thin film organic transistor)
The insulator material used for the insulator layer of the thin film transistor of the present invention is not limited as long as it includes an insulating material, and a publicly known material can be used. For example, polyparaxylylene resin, polystyrene resin, polycarbonate resin, polyvinyl alcohol resin, polyvinyl acetate resin, polysulfone resin, polyacrylonitrile resin, methacrylic resin, polyvinylidene chloride resin, fluorine resin, epoxy resin, polyimide resin , Polyamide resins, polyamideimide resins, polyvinylpyrrolidone resins, polycyanate resins, polyolefin resins, polyterpene resins, polyvinylidene fluoride, polytetrafluoroethylene and other fluorine resins, (meth) acrylic resins, diallyl phthalate resins, melamine resins, Resins that form organic films such as urethane resins, polyester resins, alkyd resins, benzocyclobutene resins, and silanes that form inorganic films by hydrolysis and heat treatment if necessary Compound, silazane compound, a magnesium alkoxide compound, an aluminum alkoxide compound, a tantalum alkoxide compounds, ionic liquids, ionic gels can be used. These may be used alone or in combination of two or more. If necessary, oxides such as zirconia, silicon dioxide, aluminum oxide, titanium oxide, and tantalum oxide, ferroelectric oxides such as SrTiO ₃ and BaTiO ₃ , Dielectric fine particles such as nitrides such as silicon nitride and aluminum nitride, sulfides and fluorides can be dispersed.

The insulator layer and the gate electrode layer can be formed by any known and commonly used dry or wet processes.

In order to improve the transistor characteristics, the surface of the insulator layer may be formed by, for example, hexamethyldisilazane (HMDS), octyltrichlorosilane (OTS-8), octadecyltrichlorosilane, (OTS-18), dodecyltrichlorosilane (DTS), SAM (self-assembled film) treatment can be performed with various silane coupling agents such as fluorine-substituted octatrichlorosilane (PFOTS) and β-phenethyltrichlorosilane.

In addition, when the affinity of the interface between the insulator layer and the semiconductor layer subjected to the SAM treatment is insufficient, if necessary, in order to improve it and improve the transistor characteristics, a fluorine-based material is used. A surfactant or the like can be used.

The thickness of the insulating layer and the gate electrode of the thin film transistor of the present invention is not particularly limited, but the thickness of the insulating layer is preferably 5 to 1000 nm from the viewpoint of suppressing variations in ON / OFF values. The thickness of the gate electrode is preferably 20 to 1000 nm from the viewpoint of good followability to a flexible substrate.

(Semiconductor layer for thin film organic transistor)
As a semiconductor material used for the semiconductor layer of the thin film transistor, an organic or inorganic semiconductor material can be applied. Examples of organic semiconductor materials include low-molecular organic semiconductors such as phthalocyanine derivatives, porphyrin derivatives, naphthalene tetracarboxylic acid diimide derivatives, fullerene derivatives, pentacene and pentacentriisopropylsilyl (TIPS) pentacene, and various pentacene precursors. Body, anthracene, perylene, pyrene, phenanthrene, coronene and other polycyclic aromatic compounds and derivatives thereof, oligothiophene and derivatives thereof, thiazole derivatives, fullerene derivatives, dinaphthothiophene compounds, carbon nanotubes and other carbon compounds, etc. One or more kinds of various low-molecular semiconductors combined with thiophene such as benzothienobenzothiophene, phenylene, vinylene, and the like, and copolymers thereof can be suitably used.

In addition, as a polymer compound, polythiophene, poly (3-hexylthiophene) (P3HT), polythiophene polymers such as PQT-12, thiophene-thienothiophene copolymers such as B10TTT, PB12TTT, PB14TTT, and fluorenes such as F8T2 Polymers, phenylene vinylene polymers such as paraphenylene vinylene, arylamine polymers such as polytriarylamine, and the like can be suitably used. In addition to these organic semiconductor materials, solution-soluble Si semiconductor precursors that can be modified into inorganic semiconductors by energy treatment such as heat treatment, EB, and Xe flash lamps, and oxide semiconductors such as IGZO, YGZO, and ZnO A precursor of the above can be applied.

As a semiconductor material used for the semiconductor layer of the thin film transistor, an organic semiconductor is preferable to an inorganic semiconductor because the semiconductor layer can be easily formed at a lower temperature and is easy to handle. Among organic semiconductors, those having a high self-aggregation property and easy to take a crystal structure are preferable because more excellent transistor characteristics can be exhibited.

Solvents that can be applied to inks of organic and inorganic semiconductor materials only need to be able to dissolve the semiconductor materials at room temperature or slightly heated, have appropriate volatility, and form an organic semiconductor thin film after volatilization of the solvent. , Xylene, chloroform, chlorobenzenes, cyclohexylbenzene, tetralin, 1-methyl-2-pyrrolidinone, dimethyl sulfoxide, isophorone, sulfolane, tetrahydrofuran, mesitylene, anisole, naphthalene derivatives, benzonitrile, amylbenzene, γ-butyrolactone, acetone, methyl ethyl ketone An organic solvent such as can be used.

The method for forming the semiconductor layer of the thin film transistor is not particularly limited, and the thin film transistor can be formed by any known and commonly used dry or wet process.

In the thin film transistor of the present invention, a protective film layer can be formed on the uppermost layer if necessary. By providing the protective film layer, the influence of outside air can be minimized, and the electrical characteristics of the thin film transistor can be stabilized.

The thin film transistor of the present invention can be manufactured by any of the manufacturing methods exemplified above. Further, the thin film transistor thus obtained can be a transistor array or an integrated circuit by integrating a plurality of elements.

Hereinafter, the present invention will be specifically described with reference to examples. Here, “%” is “% by mass” unless otherwise specified.

[Measurement of average primary particle size by small-angle X-ray measurement]
The metal fine particle dispersion was subjected to minimal angle X-ray scattering (USAXS) measurement with a small angle X-ray measuring device (SmartLab manufactured by Rigaku), and the average primary particle size was calculated from the obtained scattering curve.

[Measurement of particle size distribution by heterodyne method]
The metal fine particle dispersion is subjected to dynamic light scattering measurement using a particle size distribution measuring device (UPA-EX manufactured by MicrotracBEL), the particle size distribution is calculated from the frequency of the obtained scattered light, and the volume average particle size value is a reference value. Used as.

[Measurement of weight loss rate by thermogravimetric analysis]
2-25 mg of fine metal particle dispersion is precisely weighed on an aluminum pan for thermogravimetric analysis and placed on an EXSTAR TG / DTA6300 differential thermogravimetric analyzer (made by SII NanoTechnology Co., Ltd.). The temperature was increased at a rate of 10 ° C. per minute until a weight reduction rate of 100 ° C. to 600 ° C. was measured.

[Production method of sintered film and measurement of volume resistivity]
A coating film was prepared by spin-coating a metal fine particle dispersion on a non-alkali glass substrate (40 mm × 50 mm) having a thickness of 0.7 mm. The obtained coating film was sintered at 120 ° C. for 30 minutes with a constant temperature / dryer (clean oven DE411 made by Yamato Kagaku) to obtain a sintered film. The number of rotations during spin coating was adjusted so that the thickness of the sintered film was 100 nm. The volume resistivity was measured with a low resistivity meter Lorester EP (manufactured by Mitsubishi Chemical Corporation) using a four-terminal measurement method. The volume resistivity was determined from the film thickness of the conductive film (sintered film) of the test piece. For example, the volume resistivity is shown by a method in which 8.8 × 10 ⁻⁶ Ω · cm is described as “8.8E-6 Ω · cm”.

[Production of electrodes by letterpress reverse printing method]
A silver fine particle ink in which silver fine particles having an average particle size of nanometer order are uniformly dispersed in a liquid medium is uniformly applied to a silicone rubber surface of a transparent blanket in which a silicone rubber layer is formed on a film by a slit coater. It was dried to such an extent that the tack remained. A glass relief plate on which a negative pattern of a desired source and drain electrode pattern was formed was pressed against the silver fine particle ink uniform coating surface to remove unnecessary portions. The glass relief printing plate is obtained by wet etching of glass excellent in accuracy of convex acute angle portions (edges). After the pattern remaining on the blanket was further dried and the solvent in the silver fine particle ink was sufficiently volatilized, it was pressed onto the substrate at a pressure of 150 kPa to transfer the desired source and drain electrode patterns onto the substrate. . In addition, when the 10 × 1 μm square range was arbitrarily provided over the entire silicone rubber surface of the transparent blanket and the arithmetic average roughness thereof was measured, the average value was 0.8 nm. The electrode pattern produced by letterpress reverse printing was produced with a channel length (L) of 20 μm and a channel width (W) of 100 μm. The electrode film thickness was made to be 100 nm after sintering.

[Characteristic evaluation of thin-film organic transistors]
The fabricated device was subjected to a heat treatment in the atmosphere at 50 ° C. for about 10 minutes, and the Id-Vg and Id-Vd characteristics were measured with a semiconductor parameter measuring device (Keithley 4200CSC). The / OFF ratio was determined by a known method. The unit of field effect mobility is cm ² / Vs.

Example 1
(Synthesis of silver fine particle dispersion)
In a 1 L flask equipped with a condenser, thermometer, and stirrer under an argon gas atmosphere, 153.2 g (1.738 mmol) of N, N-dimethylethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 3- (2-ethylhexyloxy) propyl After adding 325.6 g (1.738 mmol) of amine (manufactured by Tokyo Chemical Industry Co., Ltd.), the mixture was heated and stirred with an oil bath until the internal temperature of the amine solution reached 30 ° C. Under heat and stirring, 35.2 g (0.116 mmol) of silver oxalate (manufactured by Matsuda Sangyo Co., Ltd.) was added, and the mixture was heated and stirred until the internal temperature reached 40 ° C. After maintaining heating and stirring for 1 hour while maintaining the temperature, the upper part of the flask was opened, and the oil bath was heated to 94 ° C. After the reaction solution rose to 94-100 ° C due to the heat of reaction due to thermal decomposition of the silver oxalate-amine complex, it was confirmed that the temperature of the reaction solution had dropped, and then the flask was removed from the oil bath and reacted in an argon gas atmosphere. It cooled until the internal temperature of a liquid became 40 degrees C or less. After adding 167.0 g of N-hexane (manufactured by Kanto Chemical Co., Inc.) to the flask, stirring was maintained for 10 minutes. After the stirring was stopped, the mixture was allowed to stand for about 30 minutes, and then 630.9 g of the supernatant was removed by decantation. The same operation was repeated once with 167.0 g of N-hexane and twice with 83 g of N-hexane to wash the silver fine particles. After drying until the weight of the silver fine particles is about 30.1 g, 61.2 g of 1-butanol (manufactured by Kanto Chemical Co., Inc.) is added so that the silver concentration in the dispersion is 20 wt%, and the mixture is stirred for about 30 minutes to 1 hour. As a result, 91.2 g of a brown transparent silver fine particle dispersion was obtained.

(Evaluation of silver fine particle dispersion)
[Measurement of average primary particle size by small-angle X-ray measurement]
The average primary particle size calculated by USAXS measurement was estimated to be 17 nm.

[Measurement of particle size distribution by heterodyne method]
From the particle size distribution calculated by dynamic light scattering measurement, the volume average particle size value was estimated to be 14.8 nm.

[Measurement of weight loss rate by thermogravimetric analysis]
About 1 g of the produced silver fine particle dispersion was placed in a tin petri dish, and an organic solvent having a low boiling point was dried at room temperature to obtain a nonvolatile material. The non-volatile content of 12.74 mg was precisely weighed on an aluminum pan for thermogravimetric analysis, and the temperature was increased from room temperature to 600 ° C. at a rate of 10 ° C. per minute under an air stream, and the weight reduction rate was measured. At this time, the weight reduction rate at 120 ° C. was −1.2%, the weight reduction rate at 200 ° C. was −3.7%, the weight reduction rate at 300 ° C. was −4.9%, and 553 At 0 ° C., the weight loss rate was −5.0%.

[Measurement of volume resistivity of sintered film]
The prepared metal fine particle dispersion was spin coated on a glass substrate to prepare a coating film. The obtained coating film was sintered at 120 ° C. for 30 minutes with a constant temperature dryer to obtain a sintered film. The volume resistivity estimated from the resistance value obtained by measurement and the sintered film thickness was 8.1E-6 Ω · cm.

(Production of thin-film organic transistors)
A thin film transistor having a bottom gate bottom contact (BGBC) structure having a source electrode or a drain electrode formed by patterning a silver fine particle ink produced using the silver fine particle dispersion of the present invention by a letterpress reverse printing method was produced and evaluated by the following procedure. .

(1) Fabrication of gate electrode A Cr film having a film thickness of 100 nm is formed on a non-alkali glass having a thickness of 0.7 mm by sputtering, then a photoresist is applied, exposed and developed, and the Cr film is formed by wet etching. A gate electrode was formed by patterning.

(2) Production of insulating layer Polyparaxylylene resin (trade name Parylene-C, manufactured by Japan Parylene Co., Ltd.) is chemically deposited on the support on which the gate electrode is formed by the CVD method to form an insulating layer having a thickness of 1000 nm. did.

(3) Preparation of source electrode and drain electrode by letterpress reverse printing method Silver fine particle ink comprising the silver fine particle dispersion of the present invention containing 1-butanol or 1-propanol (manufactured by Kanto Chemical Co., Inc.) as a solvent on the insulating layer. A source electrode and a drain electrode were produced by using a letterpress reverse printing method. The channel length of the transistor was 20 μm and the channel width was 100 μm. After pattern formation, sintering was performed at 120 ° C. for 30 minutes in a clean oven. The electrode thickness after sintering was 100 nm.

(5) Surface treatment of electrode After immersing the above-mentioned source and drain electrode substrates in a 30 mmol / L solution of pentafluorobenzenethiol (manufactured by Tokyo Chemical Industry Co., Ltd.) in isopropyl alcohol (manufactured by Kanto Chemical Co., Inc.) for 20 minutes, isopropyl alcohol And dried with an air gun.

(6) Formation of Semiconductor Layer A para-xylene 0.4 wt% solution of organic semiconductor 2,7-dioctyl [1] benzothieno [3,2-b] [1] benzothiophene (C8-BTBT) (Aldrich) The semiconductor layer was formed on the channel of the source electrode and the drain electrode previously formed by the drop casting method, and dried on a hot plate at 50 ° C. for 10 minutes.

(Characteristic evaluation of thin-film organic transistors)
The fabricated device had a field effect mobility of 0.6 and an ON / OFF ratio of 3.8E + 6.

(Example 2)
(Synthesis of silver fine particle dispersion)
Instead of 153.2 g (1.738 mmol) of N, N-dimethylethylenediamine described in Example 1 and 325.6 g (1.738 mmol) of 3- (2-ethylhexyloxy) propylamine, 3-methoxypropylamine (Tokyo Kasei) Kogyo Co., Ltd.) 93.0 g (1.042 mmol) and 3- (2-ethylhexyloxy) propylamine 195.4 g (1.042 mmol) were used in the same manner, except that brown transparent silver fine particle dispersion 93 0.7 g was obtained.

(Evaluation of silver fine particle dispersion)
[Measurement of average primary particle size by small-angle X-ray measurement]
The average primary particle size calculated by USAXS measurement was estimated to be 15 nm.

[Measurement of particle size distribution by heterodyne method]
From the particle size distribution calculated by dynamic light scattering measurement, the volume average particle size value was estimated to be 18.9 nm.

[Measurement of weight loss rate by thermogravimetric analysis]
About 1 g of the produced silver fine particle dispersion was placed in a tin petri dish, and an organic solvent having a low boiling point was dried at room temperature to obtain a nonvolatile material. The non-volatile content of 12.74 mg was precisely weighed on an aluminum pan for thermogravimetric analysis, and the temperature was increased from room temperature to 600 ° C. at a rate of 10 ° C. per minute under an air stream, and the weight reduction rate was measured. At this time, the weight reduction rate at 120 ° C. was −1.7%, the weight reduction rate at 200 ° C. was −3.7%, the weight reduction rate at 300 ° C. was −4.4%, and 575 The decrease in weight was -4.5% at ° C.

[Measurement of volume resistivity of sintered film]
The prepared metal fine particle dispersion was spin coated on a glass substrate to prepare a coating film. The obtained coating film was sintered at 120 ° C. for 30 minutes with a constant temperature / dryer to obtain a sintered film. The volume resistivity estimated from the resistance value obtained by measurement and the sintered film thickness was 6.2E-6 Ω · cm.

(Production of thin film transistor)
A source electrode and a drain electrode were prepared by a letterpress reverse printing method using a silver fine particle ink produced using the silver fine particle dispersion of the present invention. Otherwise, a thin film transistor having a bottom gate bottom contact (BGBC) structure was produced in the same manner as in the method described in Example 1.

(Characteristic evaluation of thin-film organic transistors)
The fabricated device had a field effect mobility of 0.8 and an ON / OFF ratio of 1.2E + 5.

(Comparative Example 1)
(Synthesis of silver fine particle dispersion)
The silver fine particle dispersion used in Comparative Example 1 was prepared by the method described in [Sample 1] of the examples described in WO2015 / 075929.

Specifically, 11.4 mmol of n-octylamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 7.6 mmol of N, N-dibutylethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 1 mmol of oleylamine (manufactured by Tokyo Chemical Industry Co., Ltd.), Oleic acid (47.7 μL) was mixed to prepare an amine mixture.

Meanwhile, an aqueous solution of oxalic acid (manufactured by Kanto Chemical Co., Inc.) and an aqueous solution of silver nitrate (manufactured by Kanto Chemical Co., Ltd.) were mixed to synthesize silver oxalate.

When 1.5 g of silver oxalate was added to the amine mixture and the resulting reaction solution was stirred at 30 ° C. for about 15 minutes, a white silver complex compound was formed. Furthermore, when the reaction solution was stirred at 110 ° C. for about 10 minutes, a suspension in which blue-brown silver nanoparticles were dispersed after foaming of carbon dioxide for several minutes was obtained. 10 mL of methanol (manufactured by Kanto Chemical Co., Inc.) was added to the suspension and centrifuged, the supernatant was removed, and the silver fine particle precipitate was collected. To this silver fine particle, a mixed solution prepared by adjusting the volume ratio of n-dodecane (manufactured by Tokyo Chemical Industry Co., Ltd.) and n-nonanol (manufactured by Tokyo Chemical Industry Co., Ltd.) to a volume ratio of 3: 1 was added, and the silver concentration was 50 wt%. The silver fine particle dispersion was diluted so that

[Measurement of particle size distribution by heterodyne method]
From the particle size distribution calculated by dynamic light scattering measurement, the volume average particle size value was estimated to be 4.9 nm.

[Measurement of weight loss rate by thermogravimetric analysis]
About 1 g of the produced silver fine particle dispersion was placed in an aluminum petri dish, and an organic solvent having a low boiling point was dried at room temperature to obtain a nonvolatile material. 9.56 mg of this non-volatile content was precisely weighed on an aluminum pan for thermogravimetric analysis, and the temperature was increased from room temperature to 600 ° C. at a rate of 10 ° C. per minute under an air stream, and the weight reduction rate was measured. At this time, the weight reduction rate at 120 ° C. was −1.1%, the weight reduction rate at 200 ° C. was −4.0%, the weight reduction rate at 300 ° C. was −7.5%, and at 581 ° C. The weight loss rate was -8.4%.

[Measurement of volume resistivity of sintered film]
The prepared metal fine particle dispersion was spin coated on a glass substrate to prepare a coating film. The obtained coating film was sintered at 120 ° C. for 30 minutes with a constant temperature / dryer to obtain a sintered film. The volume resistivity estimated from the resistance value obtained by measurement and the sintered film thickness was 6.0E + 1 Ω · cm.

(Production of thin film transistor)
Instead of the silver fine particle dispersion of the present invention, a source electrode and a drain electrode were prepared by a letterpress reverse printing method using a silver fine particle ink prepared by adjusting the silver fine particle dispersion prepared in this Comparative Example. Otherwise, a thin film transistor having a bottom gate bottom contact (BGBC) structure was produced in the same manner as in the method described in Example 1.

(Characteristic evaluation of thin-film organic transistors)
The fabricated device had a field effect mobility of 0.9 and an ON / OFF ratio of 5.7E + 5.

(Comparative Example 2)
(Synthesis of silver fine particles)
The conductive paste used in Comparative Example 2 was produced by the method described in Example 1 described in WO2007 / 120756.

Specifically, 3.34 g of silver acetate and 37.1 g of dodecylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in 400 ml of toluene (manufactured by Kanto Chemical Co., Inc.). 1.51 g of sodium borohydride (NaBH ₄ ) (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 150 ml of water. The NaBH ₄ aqueous solution was added dropwise to the reaction flask with stirring using a dropping funnel over 5 minutes, followed by stirring for 2.5 hours. The solution was allowed to stand for two phases, and then the aqueous phase was removed with a separatory funnel. Toluene was removed from the solution using a rotor evaporator to obtain a highly viscous silver fine particle dispersion. To the resulting silver fine particle dispersion, 125 ml of methanol and 125 ml of acetone were added to precipitate silver fine particles. The solution containing silver particulates was filtered through a fine sintered glass funnel and the solid product was collected and dried in vacuo at room temperature. 2.3 g of a dark blue solid product as silver fine particles was obtained.

Cyclohexane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the dark blue solid product obtained by synthesis so that the silver concentration was 50 wt%, and the mixture was stirred overnight to obtain a silver fine particle dispersion.

[Measurement of particle size distribution by heterodyne method]
From the particle size distribution calculated by dynamic light scattering measurement, the volume average particle size value was estimated to be 27.0 nm.

[Measurement of weight loss rate by thermogravimetric analysis]
About 1 g of the produced silver fine particle dispersion was placed in a tin petri dish, and an organic solvent having a low boiling point was dried at room temperature to obtain a nonvolatile material. 9.56 mg of this non-volatile content was precisely weighed on an aluminum pan for thermogravimetric analysis, and the temperature was increased from room temperature to 600 ° C. at a rate of 10 ° C. per minute under an air stream, and the weight reduction rate was measured. At this time, the weight loss rate at 120 ° C was -0.8%, the weight loss rate at 200 ° C was -7.7%, and the weight loss rate at 300 ° C was -11.7%. The weight loss rate was -13.7%.

[Measurement of volume resistivity of sintered film]
The prepared metal fine particle dispersion was spin coated on a glass substrate to prepare a coating film. The obtained coating film was sintered at 120 ° C. for 30 minutes with a constant temperature / dryer to obtain a sintered film. The volume resistivity estimated from the resistance value obtained by measurement and the sintered film thickness was 6.7E-6 Ω · cm.

(Production of thin film transistor)
In place of the silver fine particle dispersion of the present invention, an attempt was made to produce a source electrode and a drain electrode by a letterpress reverse printing method using a silver fine particle ink produced by adjusting the silver fine particle dispersion produced in this Comparative Example. However, in the silver fine particle dispersion, aggregation was generated between the silver fine particles on the blanket in the step of applying ink on the blanket and drying. As a result, an electrode for a thin film organic transistor could not be produced by the letterpress reverse printing method.

(Comparative Example 3)
<Synthesis of Silver Fine Particle Dispersion> 5.39 g (2.5 mmol) of a methoxypolyethylene glycol compound having a p-toluenesulfonyloxy group at the terminal, 20.0 g of branched polyethyleneimine (manufactured by Aldrich, molecular weight 25,000) 0.8 mmol), 0.07 g of potassium carbonate and 100 ml of N, N-dimethylacetamide were stirred at 100 ° C. for 6 hours under a nitrogen atmosphere. To the resulting reaction mixture, 300 ml of a mixed solution of ethyl acetate and hexane (V / V = 1/2) was added, and after vigorous stirring at room temperature, the solid product was filtered. The solid was washed twice with 100 ml of a mixed solution of ethyl acetate and hexane (V / V = 1/2), dried under reduced pressure, and a polymer compound in which polyethylene glycol was bonded to branched polyethyleneimine. 24.4 g of solid was obtained.

10.0 g of silver oxide was added to 138.8 g of an aqueous solution using 0.592 g of the obtained polymer compound, and the mixture was stirred at 25 ° C. for 30 minutes. Subsequently, when 46.0 g of dimethylethanolamine was gradually added with stirring, the reaction solution turned brown and slightly exothermic, but was left as it was and stirred at 25 ° C. for 30 minutes. Thereafter, 15.2 g of a 10% ascorbic acid aqueous solution was gradually added with stirring. While maintaining the temperature, stirring was continued for another 20 hours to obtain a brown dispersion.

A mixed solvent of 200 ml of isopropyl alcohol and 200 ml of hexane was added to the dispersion obtained after completion of the reaction and stirred for 2 minutes, followed by centrifugal concentration at 3000 rpm for 5 minutes. After removing the supernatant, 20 g of water was further added to the precipitate, followed by stirring for 2 minutes, and the organic solvent was removed under reduced pressure to obtain a silver fine particle dispersion.

(Evaluation of silver fine particle dispersion)
[Measurement of average primary particle size by small-angle X-ray measurement]
The average primary particle size calculated by USAXS measurement was estimated to be 22 nm.

[Measurement of particle size distribution by heterodyne method]
From the particle size distribution calculated by the dynamic light scattering measurement, the volume average particle size value was estimated to be 45.9 nm.

[Measurement of weight loss rate by thermogravimetric analysis]
About 1 g of the produced silver fine particle dispersion was placed in a tin petri dish, and an organic solvent having a low boiling point was dried at room temperature to obtain a nonvolatile material. This non-volatile content (5.14 mg) was precisely weighed on an aluminum pan for thermogravimetric analysis, and the temperature was increased from room temperature to 600 ° C. at a rate of 10 ° C. per minute under an air stream, and the weight reduction rate was measured. At this time, the weight reduction rate at 200 ° C. was −0.9%, the weight reduction rate at 300 ° C. was −2.4%, and the weight reduction rate at −443 ° C. was −2.9%. .

[Measurement of volume resistivity of sintered film]
The prepared metal fine particle dispersion was spin coated on a glass substrate to prepare a coating film. The obtained coating film was sintered at 120 ° C. for 30 minutes with a constant temperature / dryer to obtain a sintered film. The volume resistivity estimated from the resistance value obtained by the measurement and the sintered film thickness was 2.5E + 1 Ω · cm.

(Production of thin film transistor)
A source electrode and a drain electrode were prepared by a letterpress reverse printing method using a silver fine particle ink produced using the silver fine particle dispersion of the present invention. Otherwise, a thin film transistor having a bottom gate bottom contact (BGBC) structure was produced in the same manner as in the method described in Example 1.

(Characteristic evaluation of thin-film organic transistors)
The fabricated device had a field effect mobility of 0.07 and an ON / OFF ratio of 6.5E + 5.

The results obtained in Examples 1 and 2 and Comparative Examples 1 to 3 are summarized in Table 1.

In Table 1, “Loss of letterpress reversal printing”, “◯” indicates that the obtained silver fine particle dispersion was converted into an ink so that an image could be formed by the printing method. . “△” indicates that it was possible to form an image by the printing method by converting the silver fine particle dispersion into an ink, but continuous printing was impossible due to swelling of the blanket. ing. “X” indicates that even if the silver fine particle dispersion was converted to ink, it was impossible to produce a printed image due to aggregation between fine particles on the releasable substrate.

Claims (12)

A metal fine particle dispersion in which metal fine particles containing a primary amine compound having an amino group and at least one hetero element are dispersed in a polar solvent. The metal fine particle dispersion according to claim 1, wherein the hetero element according to claim 1 is a hetero element selected from at least one of nitrogen, oxygen, sulfur and phosphorus. The metal fine particle dispersion according to claim 1, wherein the polar solvent according to claim 1 contains an alkanol having 2 to 7 carbon atoms. A metal fine particle dispersion wherein the metal fine particles according to any one of claims 1 to 3 are silver. An ink containing the metal fine particle dispersion according to any one of claims 1 to 4. 6. The ink according to claim 5, further comprising a surface energy adjusting agent. The ink according to claim 5 or 6, further comprising a printing aid. The ink for ink jet or letterpress reverse printing according to any one of claims 5 to 7. A conductive film or pattern formed using the ink according to any one of claims 5 to 8. An electrode for a semiconductor device formed using the ink according to any one of claims 5 to 8. An electronic device comprising the semiconductor device electrode according to claim 10 in its configuration. An electronic circuit comprising the conductive film or conductive pattern according to claim 9 or the electronic device according to claim 11 in its configuration.

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