Tin oxide particle dispersion and method for producing tin oxide particle laminated film

Abstract

To provide a tin oxide particle dispersion capable of forming a tin oxide particle laminated film having excellent conductivity and low water content and a method for producing a tin oxide particle laminated film.SOLUTION: A tin oxide particle dispersion in which tin oxide particles are dispersed in a solvent is characterized in that the solvent is a non-aqueous solvent containing amines, and the tin oxide particles have a zeta potential of -35 mV or less at pH10 when dispersed in water. The concentration of tin oxide is preferably within the range of 3 mass% to 50 mass%.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a tin oxide particle dispersion liquid applicable, for example, when forming a conductive film or the like, and a method for manufacturing a tin oxide particle laminated film using this tin oxide particle dispersion liquid.

Background Art

[0002] Since tin oxide has relatively good conductivity, a tin oxide particle laminated film having a structure in which tin oxide particles are laminated is used as a conductive material such as a conductive layer in various devices. For example, in the electron transport layer of a perovskite solar cell, a tin oxide particle laminated film formed using a tin oxide particle dispersion liquid is utilized.

[0003] Here, when forming an electron transport layer (tin oxide particle laminated film) so as to be laminated on a perovskite layer, if the tin oxide particle dispersion liquid contains moisture, the perovskite layer may deteriorate. Further, in a perovskite solar cell, since the perovskite layer deteriorates significantly due to water as described above, it is necessary to sufficiently reduce the contained moisture.

[0004] Therefore, in order to improve the durability of the perovskite solar cell, it is preferable to use a non-aqueous solvent not containing water as the tin oxide particle dispersion liquid used when forming the tin oxide particle laminated film. On the other hand, in a non-aqueous solvent, tin oxide particles are difficult to ionize and the dispersion effect due to electrical repulsion cannot be expected. For this reason, it is necessary to add a non-volatile (not volatile at 150 ° C) dispersant. However, when a non-volatile dispersant is used, the electrical resistance between tin oxide particles increases and the conductivity of the tin oxide particle laminated film decreases.

[0005] Here, Patent Document 1 discloses using a dispersion liquid (Nanograde N-21X, manufactured by Avantama) in which aluminum-doped zinc oxide particles (AZO) are dispersed in isopropyl alcohol (IPA).

Prior Art Documents

Patent Document

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] By the way, in the isopropyl alcohol (IPA) dispersion of aluminum-doped zinc oxide particles (AZO) described in Patent Document 1, a large amount of particles cannot be contained, and a conductive film excellent in conductivity cannot be efficiently and stably formed. In addition, it is sold as a reagent and is difficult to use industrially.

[0008] This invention has been made in view of the above-described circumstances, and an object thereof is to provide a tin oxide particle dispersion liquid capable of forming a tin oxide particle laminated film excellent in conductivity and having a small amount of moisture, and a method for manufacturing the tin oxide particle laminated film.

Means for Solving the Problems

[0009] As a result of intensive studies by the present inventors to solve the above problems, it has been found that by using amines as a non-aqueous solvent, it is possible to disperse tin oxide particles without using a dispersant composed of a non-volatile organic material.

[0010] The tin oxide particle dispersion liquid of Aspect 1 of the present invention is a tin oxide particle dispersion liquid in which tin oxide particles are dispersed in a solvent, the solvent is a non-aqueous solvent containing amines, and the tin oxide particles are characterized in that the zeta potential at pH 10 in a state of being dispersed in water is -35 mV or less.

[0011] According to the tin oxide particle dispersion of Embodiment 1 of the present invention, since the solvent is a non-aqueous solvent containing amines, the solvent does not contain water. For example, when used to form the electron transport layer of a perovskite solar cell, the durability of the perovskite solar cell can be improved. In addition, by using a non-aqueous solvent containing amines, tin oxide particles can be sufficiently dispersed without using a non-volatile dispersant. Therefore, it becomes possible to form a tin oxide particle laminated film excellent in conductivity. Furthermore, since the zeta potential of the tin oxide particles at pH 10 in a state of being dispersed in water is -35 mV or less, the dispersibility in a non-aqueous solvent containing amines is improved, and a tin oxide particle laminated film excellent in conductivity can be stably formed.

[0012] The tin oxide particle dispersion of Embodiment 2 of the present invention is characterized in that, in the tin oxide particle dispersion of Embodiment 1, the concentration of tin oxide is in the range of 3 mass% or more and 50 mass% or less. According to the tin oxide particle dispersion of Embodiment 2 of the present invention, since the concentration of tin oxide is 3 mass% or more and 50 mass% or less, the tin oxide particles are appropriately dispersed, and a tin oxide particle laminated film excellent in conductivity can be stably formed.

[0013] The tin oxide particle dispersion of Embodiment 3 of the present invention is characterized in that, in the tin oxide particle dispersion of Embodiment 1 or Embodiment 2, the tin oxide particles are doped with a foreign element. According to the tin oxide particle dispersion of Embodiment 3 of the present invention, since the tin oxide particles are doped with a foreign element, the characteristics of the tin oxide particles can be adjusted, and a tin oxide particle laminated film according to the required characteristics can be formed.

[0014] The tin oxide particle dispersion of Embodiment 4 of the present invention is characterized in that, in the tin oxide particle dispersion of Embodiment 3, the foreign element is one or more selected from antimony, fluorine, and phosphorus. According to the tin oxide particle dispersion of Aspect 4 of the present invention, since the foreign element is one or more selected from antimony, fluorine, and phosphorus, the characteristics of the tin oxide particles can be adjusted, and a tin oxide particle laminated film according to required characteristics can be formed.

[0015] The tin oxide particle dispersion of Aspect 5 of the present invention is characterized in that, in any one of the tin oxide particle dispersions of Aspects 1 to 4, the primary particle diameter of the tin oxide particles is in the range of 1.5 nm or more and 100 nm or less. According to the tin oxide particle dispersion of Aspect 5 of the present invention, since the primary particle diameter of the tin oxide particles is in the range of 1.5 nm or more and 100 nm or less, a tin oxide particle laminated film with a nano-order film thickness can be stably formed.

[0016] The tin oxide particle dispersion of Aspect 6 of the present invention is characterized in that, in any one of the tin oxide particle dispersions of Aspects 1 to 5, it further contains a carboxylic anhydride having a boiling point of 200°C or lower in an amount in the range where the tin oxide concentration is 3 mass% or more. According to the tin oxide particle dispersion of Aspect 6 of the present invention, since it contains a carboxylic anhydride having a boiling point of 200°C or lower in an amount in the range where the tin oxide concentration is 3 mass% or more, the water content can be further reduced by the dehydration action of the carboxylic anhydride having a boiling point of 200°C or lower. For example, when used in forming the electron transport layer of a perovskite solar cell, the durability of the perovskite solar cell can be further improved.

[0017] The tin oxide particle dispersion of Aspect 7 of the present invention is characterized in that, in any one of the tin oxide particle dispersions of Aspects 1 to 6, it further contains one or more selected from carboxylic acids, nitrile compounds, and alcohols having a boiling point of 200°C or lower in an amount in the range where the tin oxide concentration is 3 mass% or more. According to the tin oxide particle dispersion of Aspect 7 of the present invention, since it contains one or more selected from carboxylic acids, nitrile compounds, and alcohols in an amount in the range where the tin oxide concentration is 3 mass% or more, the coatability is improved, and it becomes possible to stably form a tin oxide particle laminated film.

[0018] The method for manufacturing a tin oxide particle laminated film according to Embodiment 8 of the present invention is characterized by including a coating step of coating any one of the tin oxide particle dispersion liquids of Embodiments 1 to 7. According to the method for manufacturing a tin oxide particle laminated film according to Embodiment 8 of the present invention, since it includes a coating step of coating any one of the tin oxide particle dispersion liquids of Embodiments 1 to 7, tin oxide particles can be uniformly arranged, and it becomes possible to form a tin oxide particle laminated film excellent in conductivity.

Effects of the Invention

[0019] According to the present invention, it is possible to provide a tin oxide particle dispersion liquid capable of forming a tin oxide particle laminated film excellent in conductivity and having a small amount of moisture, and a method for manufacturing a tin oxide particle laminated film.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0021] Hereinafter, a tin oxide particle dispersion liquid which is an embodiment of the present invention and a method for manufacturing a tin oxide particle laminated film will be described with reference to the attached drawings. Note that each of the embodiments shown below is specifically described to better understand the gist of the invention, and does not limit the present invention unless otherwise specified.

[0022] The tin oxide particle dispersion liquid which is an embodiment of the present invention is used, for example, when forming a tin oxide particle laminated film used as a conductive layer. And the tin oxide particle laminated film according to an embodiment of the present invention is used, for example, as an electron transport layer of the perovskite solar cell shown in FIG. 1. In this embodiment, the perovskite solar cell 10 has a structure in which an ITO film 12, a hole transport layer 13, a perovskite layer 14, an electron transport layer 15, and a back surface electrode 16 are laminated on the surface of a glass substrate 11, as shown in FIG. 1 for example.

[0023] In the tin oxide particle laminated film constituting the electron transport layer 13, the film thickness is in the range of 10 nm or more and 100 nm or less. Therefore, in the tin oxide particle dispersion according to this embodiment, it is required to form a thin and precise tin oxide particle laminated film. Further, the tin oxide particle laminated film is required to be excellent in conductivity as a conductive material.

[0024] The conductivity of the tin oxide particle laminated film is greatly affected by the number of contact points between the tin oxide particles in the tin oxide particle laminated film. Therefore, in order to improve the conductivity, it is necessary to form the tin oxide particle laminated film so that the tin oxide particles are uniformly arranged. Further, it is necessary to reduce the electrical resistance between the tin oxide particles. In addition, in a perovskite solar cell, since the perovskite layer is significantly deteriorated by water, it is necessary to sufficiently reduce the moisture contained in the tin oxide particle laminated film. In particular, when forming the electron transport layer (tin oxide particle laminated film) so as to be laminated on the perovskite layer, if the tin oxide particle dispersion contains moisture, the perovskite layer may be deteriorated.

[0025] Therefore, in the tin oxide particle dispersion according to this embodiment, a non-aqueous solvent containing amines is used as the solvent in which the tin oxide particles are dispersed. Thereby, it becomes possible to disperse the tin oxide particles without using a dispersant made of a non-volatile organic material. Examples of the amines include diethylamine, triethylamine, ethanolamine, etc. These amines may be mixed with each other or mixed with other organic solvents such as alcohols and diols. In addition, when mixing amines with other organic solvents, the total amount of amines is preferably equal to or greater than the amount of tin oxide to be dispersed, in terms of mass ratio.

[0026] Furthermore, in the present embodiment, as the tin oxide particles, those having a zeta potential of -35 mV or less at pH 10 in a state of being dispersed in water are used. Metal oxides such as tin oxide have a surface potential in a dispersion liquid dispersed in water. In this aqueous dispersion of the metal oxide, the potential of the slip plane where liquid flow begins in the electric double layer composed of the ion-fixed layer and the ion-diffusion layer formed around the metal oxide particles is called the zeta potential. The magnitude of this zeta potential depends on the surface state of the metal oxide and the pH of the solution, and the value of the zeta potential of tin oxide becomes stable at pH 10 or higher.

[0027] Here, in a dispersion liquid in which tin oxide is dispersed in water, usually, the zeta potential at pH 10 is about -35 mV to -25 mV. On the other hand, in the tin oxide particle dispersion liquid of the present embodiment, as described above, the zeta potential at pH 10 is configured to be -35 mV or less, which is relatively low. In this way, by setting the zeta potential at pH 10 to be low, the aggregation of tin oxide particles is suppressed by the electrical repulsion between the tin oxide particles, and they are uniformly dispersed.

[0028] Also, in the tin oxide particle dispersion liquid of the present embodiment, the concentration of tin oxide is preferably in the range of 3 mass% or more and 50 mass% or less. By setting the concentration of tin oxide to 3 mass% or more, the number of tin oxide particles is ensured, and it becomes possible to stably form a tin oxide particle laminated film excellent in conductivity. On the other hand, by setting the concentration of tin oxide to 50 mass% or less, the coatability of the tin oxide particle dispersion liquid is ensured, and it becomes possible to stably form a uniform tin oxide particle laminated film. Incidentally, the concentration of tin oxide in the tin oxide particle dispersion is more preferably 5 mass% or more, and even more preferably 8 mass% or more. On the other hand, the concentration of tin oxide in the tin oxide particle dispersion is more preferably 35 mass% or less, and even more preferably 25 mass% or less.

[0029] Furthermore, in the tin oxide particle dispersion of the present embodiment, it is preferable to contain a carboxylic anhydride having a boiling point of 200 °C or lower in a range where the tin oxide concentration is 3 mass% or more. Since the carboxylic anhydride having a boiling point of 200 °C or lower has a dehydrating action, it is possible to further reduce the water content in the tin oxide particle dispersion and the tin oxide particle laminated film.

[0030] Also, in the tin oxide particle dispersion of the present embodiment, it is preferable to contain one or more selected from carboxylic acids, nitrile compounds, and alcohols having a boiling point of 200 °C or lower in a range where the tin oxide concentration is 3 mass% or more. These carboxylic acids, nitrile compounds, and alcohols having a boiling point of 200 °C or lower can improve the coatability, and thus it is possible to stably form a tin oxide particle laminated film.

[0031] Also, in the tin oxide particle dispersion of the present embodiment, the tin oxide particles may be doped with a foreign element other than Sn and O. The content of the foreign element is preferably in the range of 10000 mass ppm to 100000 mass ppm. As the foreign element to be doped, it is preferable to use one or more selected from antimony, fluorine, and phosphorus.

[0032] Furthermore, in the tin oxide particle dispersion of the present embodiment, the primary particle diameter of the tin oxide particles is preferably in the range of 1.5 nm or more and 100 nm or less. Incidentally, the primary particle diameter of the tin oxide particles is more preferably 1.8 nm or more, and even more preferably 2.0 nm or more. Further, the primary particle diameter of the tin oxide particles is more preferably 50 nm or less, and even more preferably 10 nm or less.

[0033] Next, an example of the method for producing the tin oxide particle dispersion according to the present embodiment will be described with reference to the flowchart of FIG. 2.

[0034] (Raw material suspension generation step S01) Potassium stannate trihydrate, which is a tin raw material, is dissolved in ion-exchanged water to produce a base solution. An acid solution is dropped into this base solution and allowed to stand to produce a raw material suspension. In this raw material suspension generation step S01, the dropping rate is preferably in the range of 0.2 mL / min or more and 5 mL / min or less. Further, the standing time is preferably in the range of 0.5 days or more and 14 days or less.

[0035] (Amine addition step S02) The above-mentioned raw material suspension is centrifuged to remove the supernatant to obtain a tin oxide paste. Then, amines are added to the obtained tin oxide paste to produce a tin oxide particle dispersion in which tin oxide particles are dispersed in a non-aqueous solvent. Incidentally, the water content in the tin oxide particle dispersion may be further reduced by adding a dehydrating agent such as molecular sieves.

[0036] The tin oxide particle dispersion according to the present embodiment is formed by the above-described steps.

[0037] Next, an example of the method for producing a tin oxide particle laminated film using the tin oxide particle dispersion according to the present embodiment will be described with reference to the flowchart of FIG. 3.

[0038] (Solid content concentration adjustment step S11) First, the tin oxide particle dispersion according to the present embodiment is prepared, and the solid content concentration in the tin oxide particle dispersion is adjusted to be in the range of 2 mass% or more and 20 mass% or less. In addition, the solid content concentration in the tin oxide particle dispersion is preferably 5 mass% or more, more preferably 8 mass% or more. Also, the solid content concentration in the tin oxide particle dispersion is preferably 18 mass% or less, more preferably 15 mass% or less.

[0039] (Coating step S12) Next, the tin oxide particle dispersion with adjusted solid content concentration is coated on the substrate by a spin coater. The conditions for spin coating in this coating step S12 are preferably within a range of a rotation speed of 500 rpm or more and 3000 rpm or less, and a coating time of 5 seconds or more and 60 seconds or less. Also, the thickness of the coating film is preferably within a range of 20 nm or more and 100 nm or less.

[0040] (Heating step S13) Next, the coating film (the coated tin oxide particle dispersion) is heated to remove the solvent and form a tin oxide particle laminated film. The heating conditions in this heating step S13 are preferably within a range of a heating temperature of 100°C or more and 400°C or less, and a heating time of 1 minute or more and 10 minutes or less.

[0041] By the above-described respective steps, the tin oxide particle laminated film according to the present embodiment is formed. Here, in the tin oxide particle laminated film according to the present embodiment, the average value of the film thickness is within a range of 10 nm or more and 100 nm or less, the standard deviation of the film thickness is within a range of 3 nm or more and 40 nm or less, and the coefficient of variation CV of the film thickness is 50% or less.

[0042] According to the tin oxide particle dispersion of the present embodiment configured as described above, since a non-aqueous solvent containing amines is used as the solvent in which the tin oxide particles are dispersed, the solvent does not contain water. For example, when used in forming the electron transport layer of a perovskite solar cell, deterioration of the perovskite layer can be suppressed, and the durability of the solar cell can be improved. Moreover, by using a non-aqueous solvent containing amines, tin oxide particles can be sufficiently dispersed without using a non-volatile dispersant. Therefore, it becomes possible to form a tin oxide particle laminated film having excellent conductivity. Furthermore, in the tin oxide particle dispersion of the present embodiment, since tin oxide particles having a zeta potential of -35 mV or less at pH 10 in a state of being dispersed in water are used, the dispersibility in a non-aqueous solvent containing amines is further improved, and it becomes possible to stably form a tin oxide particle laminated film having excellent conductivity.

[0043] Here, in the tin oxide particle dispersion of the present embodiment, when the concentration of tin oxide is in the range of 3 mass% or more and 50 mass% or less, the tin oxide particles are appropriately dispersed, and it becomes possible to stably form a tin oxide particle laminated film having excellent conductivity.

[0044] Moreover, in the tin oxide particle dispersion of the present embodiment, when the tin oxide particles are doped with a foreign element, it becomes possible to form a tin oxide particle laminated film according to the required characteristics depending on the type and content of the foreign element to be doped. Here, when the foreign element is one or more selected from antimony, fluorine, and phosphorus, it becomes possible to form a tin oxide particle laminated film having particularly excellent conductivity.

[0045] Furthermore, in the tin oxide particle dispersion of the present embodiment, when the primary particle diameter of the tin oxide particles is in the range of 1.5 nm or more and 100 nm or less, even when a tin oxide particle laminated film is formed with a film thickness on the nano-order, the tin oxide particles are uniformly dispersed, and it becomes possible to stably form a tin oxide particle laminated film having a uniform film thickness.

[0046] Moreover, in the tin oxide particle dispersion of the present embodiment, when the tin oxide particles are doped with a foreign element, it becomes possible to form a tin oxide particle laminated film according to the required characteristics depending on the type and content of the foreign element to be doped. Here, when the foreign element is one or more selected from antimony, fluorine, and phosphorus, it becomes possible to form a tin oxide particle laminated film particularly excellent in conductivity.

[0047] Furthermore, in the tin oxide particle dispersion of this embodiment, when one or more selected from carboxylic acid anhydrides, carboxylic acids, nitrile compounds, and alcohols having a boiling point of 200 ° C. or lower are contained in a total of 3 mass% or more, due to the dehydration action of these compounds, the water content can be further reduced. For example, when used in forming the electron transport layer of a perovskite solar cell, deterioration of the perovskite layer can be suppressed, and the durability of the perovskite solar cell can be further improved.

[0048] According to the method for producing a tin oxide particle laminated film of this embodiment, since it includes a coating step S12 of coating the tin oxide particle dispersion of this embodiment, tin oxide particles are uniformly arranged, and it becomes possible to form a tin oxide particle laminated film excellent in conductivity.

[0049] As described above, an embodiment of the present invention has been described, but the present invention is not limited thereto, and can be appropriately changed without departing from the technical idea of the invention. In this embodiment, the tin oxide particle laminated film has been described as constituting the electron transport layer of the perovskite solar cell shown in FIG. 1, but it may be used in other applications not limited thereto.

Example

[0050] A confirmation experiment conducted to confirm the effectiveness of the present invention will be described.

[0051] (Example of the present invention) In the example of the present invention, potassium stannate trihydrate was used as the tin raw material (base raw material). 1.99 g of potassium stannate trihydrate was dissolved in 10 g of ion-exchanged water to obtain a base solution. Hydrochloric acid was dropped into this base solution at a rate of 1 mL / min and left standing for 3 days to obtain a raw material suspension. The obtained raw material suspension was centrifuged (18,000 rpm, 60 min), and the supernatant was removed to obtain a tin oxide paste. An amine and an additive shown in Tables 1 and 2 were added to this tin oxide paste to obtain a tin oxide particle dispersion.

[0052] In Examples 5-1 to 5-8 of the present invention, 0.180 g of antimony(III) chloride was added to the base solution, and then an acid solution was dropped into the base solution to dope Sb. In Examples 6-1 to 6-8 of the present invention, 0.108 g of phosphorus trichloride was added to the base solution, and then an acid solution was dropped into the base solution to dope P. Furthermore, in Examples 7-1 to 7-8 of the present invention, 0.025 g of tin(IV) fluoride was added to the base solution, and then an acid solution was dropped into the base solution to dope F.

[0053] (Comparative Example) In the comparative example, tin(IV) chloride pentahydrate was used as a tin raw material (acid raw material). 1.80 g of tin(IV) chloride pentahydrate was dissolved in 5.2 g of ion-exchanged water to obtain an acid solution. A base solution containing a base raw material shown in Table 1 was dropped into this acid solution at a rate of 1 mL / min, and left standing for 3 days to obtain a raw material suspension. The obtained raw material suspension was centrifuged (18,000 rpm, 60 min), and the supernatant was removed to obtain a tin oxide paste. An amine shown in Table 2 was added to this tin oxide paste to obtain a tin oxide particle dispersion.

[0054] (Tin oxide particle laminated film) The solid content concentration of the above tin oxide particle dispersion was adjusted to 8 mass%. The tin oxide particle dispersion with adjusted solid content was spin-coated on a 50 mm × 50 mm glass substrate at 500 rpm for 60 seconds using a spin coater (manufactured by Mikasa Co., Ltd., model name: MS-A150) to form a coated film. The glass substrate with the coated film formed thereon was heated on a hot plate at 100 °C for 3 minutes to form a tin oxide particle laminated film.

[0055] For the tin oxide particle dispersion liquid and the tin oxide particle laminated film obtained as described above, each item was evaluated by the following methods.

[0056] (Zeta potential) After diluting the tin oxide particles with ion-exchanged water up to 1.0 mass%, 0.1 mol / L hydrochloric acid was added to adjust the pH to 10.0. This was used as a specimen, and the zeta potential was measured with a particle size distribution measuring device (Zetasizer nano manufactured by Malvern). The measurement was performed three times, and the average value was taken as the value of the zeta potential at pH 10.

[0057] (Primary particle diameter of tin oxide particles) For the tin oxide particles dispersed in the solvent, photographs were taken at a magnification of 200,000 times using a transmission electron microscope (JEOL Ltd., model name: JEM-2010F). The particle diameters of 100 particles were measured from the photographed image using software (product name: Image J), and the average was calculated.

[0058] (Presence or absence of aggregation of tin oxide particles in the tin oxide particle dispersion liquid) The obtained tin oxide particle dispersion liquid was diluted with the same solvent as the dispersion medium up to 0.5 mass%, and the number distribution of the particle diameters was measured by the dynamic light scattering method using a particle size distribution measuring device (Zetasizer nano manufactured by Malvern). The average value was calculated from the number distribution to obtain the value of the hydrodynamic particle diameter. Those with a value obtained by dividing the above hydrodynamic particle diameter by the primary particle diameter measured with a transmission electron microscope of 2.5 or less were judged that the tin oxide particles were sufficiently dispersed and "no aggregation". Those exceeding 2.5 were judged as "aggregation present".

[0059] (Conductivity of the tin oxide particle laminated film) For the tin oxide particle laminated film obtained as described above, the resistance was measured with a surface resistance measuring device (product number: Loresta AP MCP-T400 probe: ASP probe (four needles), manufactured by Mitsubishi Chemical Corporation).

[0060]

Table 1

[0061]

Table 2

[0062]

Table 3

[0063]

Table 4

[0064] In Comparative Example 1, as the tin oxide particles, those having a zeta potential of -24.4 mV at pH 10 in a state of being dispersed in water were used, and aggregation of the tin oxide particles was observed in the tin oxide particle dispersion. In Comparative Example 2, as the tin oxide particles, those having a zeta potential of -21.1 mV at pH 10 in a state of being dispersed in water were used, and aggregation of the tin oxide particles was observed in the tin oxide particle dispersion.

[0065] On the other hand, in Examples 1-1 to 7-8 of the present invention, as the tin oxide particles, those having a zeta potential of -35 mV or less at pH 10 in a state of being dispersed in water were used, and a non-aqueous solvent containing amines was used as the solvent, and the tin oxide particles were sufficiently dispersed in the tin oxide particle dispersion.

[0066] As described above, it was confirmed that according to the present invention, it is possible to provide a tin oxide particle dispersion capable of forming a tin oxide particle laminate film excellent in conductivity and having a small water content, and a method for producing a tin oxide particle laminate film.

Claims

1. A tin oxide particle dispersion liquid in which tin oxide particles are dispersed in a solvent, The solvent is a non-aqueous solvent containing amines, The tin oxide particle dispersion liquid is characterized in that the tin oxide particles have a zeta potential of −35 mV or less at pH 10 when dispersed in water.

2. 2. The tin oxide particle dispersion liquid according to claim 1, wherein the concentration of tin oxide is within the range of 3 mass % to 50 mass %.

3. 2. The tin oxide particle dispersion according to claim 1, wherein the tin oxide particles are doped with a different element.

4. 4. The tin oxide particle dispersion liquid according to claim 3, wherein the different element is one or more elements selected from the group consisting of antimony, fluorine and phosphorus.

5. 2. The tin oxide particle dispersion liquid according to claim 1, wherein the primary particle diameter of the tin oxide particles is within a range of 1.5 nm to 100 nm.

6. 2. The tin oxide particle dispersion liquid according to claim 1, further comprising a carboxylic acid anhydride having a boiling point of 200° C. or less in an amount such that the tin oxide concentration is 3 mass % or more.

7. The tin oxide particle dispersion liquid according to claim 1, further comprising one or more selected from the group consisting of carboxylic acids, nitrile compounds, and alcohols, each having a boiling point of 200° C. or less, in an amount such that the tin oxide concentration is 3 mass% or more.

8. A method for producing a tin oxide particle laminate film, comprising the steps of: A method for producing a tin oxide particle laminate film, comprising: a coating step of coating the tin oxide particle dispersion liquid according to any one of claims 1 to 7.

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