JP2778092B2 - Sol-gel film forming liquid and film forming method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sol-gel film forming solution suitable for forming transparent conductive tin oxide and a method for forming a transparent conductive tin oxide sol-gel film.

(Conventional technologies and problems) In recent years, with the remarkable development of the electro-optical element field,
The development of transparent electrodes for various optical devices such as electroluminescence, liquid crystal, and image storage, heating elements and resistors, solar cells, and permselective membranes for solar thermal power generation has been active.
Attention has been focused on transparent conductive films such as O ₂ and In ₂ O ₃ .

As a method for forming these transparent conductive films, a so-called sol-gel method in which a substrate is coated with a (sol) containing oxide precursor molecules and then gelled and fired, which is a spray method, a vapor deposition method, a CVD method, a sputtering method, or the like. Is known.

The above-mentioned spray method, vapor deposition method, CVD method, and sputtering method are all complicated equipments and inferior in productivity, usually require an etching step to form a pattern, a large area.
There are drawbacks such as difficulty in forming a uniform and dense film.

The sol-gel method includes a method of spraying a sol to coat a substrate, a spinner method of dropping on a rotating substrate, and a method of dipping the substrate in the sol. It has the advantage that it can be coated in a shape, but it is easily affected by physical stains on the coating surface, chemically functional groups, it takes time from the sol film to the cured oxide film, the film thickness is uneven However, such drawbacks as pinhole-like unevenness tend to occur, and these drawbacks have resulted in a decrease in visible light transmittance and an increase in electric resistance of the transparent conductive film.

(Problem to be Solved by the Invention) An object of the present invention is to provide industrially advantageous properties such as transparency, uniformity, denseness, and conductivity of a finally formed coating film. An object of the present invention is to provide a sol-gel film forming liquid and a sol-gel film forming method.

(Means for Solving the Problems) A sol-gel film-forming liquid that can achieve the above-mentioned object of the present invention is a transparent conductive oxide obtained by reacting a tin carboxylate and hydrogen peroxide in an aqueous medium. A fluorinated alkyloxybenzenesulfonate is added as a surfactant to a transparent aqueous solution for forming tin, and a sol-gel film forming method is to apply ultrasonic vibration to a substrate to give a carboxylic acid to the substrate. The reaction can be performed by coating with a transparent aqueous solution for forming a transparent conductive tin oxide obtained by reacting a tin salt and hydrogen peroxide in an aqueous medium or the above-mentioned solution for forming a sol-gel film.

 Hereinafter, the present invention will be described in detail.

Examples of the tin carboxylate used in the present invention include, for example, stannous formate, stannous acetate, stannous oxalate, stannous tartrate, and the like. preferable.

The amount of hydrogen peroxide is desirably set to 1.5 moles or more, preferably 1.6 to 2.2 moles, per mole of the tin salt. Tin density and conductivity are reduced, and the effect of improving performance is not recognized when used more than necessary.

Also, to form a uniform reaction product transparent aqueous solution, it is desirable to coexist a dopant in the reaction system, in order to finally provide tin oxide having excellent conductivity, as such a dopant, for example, Cu, Ag, Ib group such as Au, Cd
Group IIb group, IIIa group such as Ce, Eu, etc., Va such as V, Nb, Ta, etc.
Group, Vb group such as As, Sb, Bi, VIa group such as Cr, Mo, W, Re
Group VIIa, such as Ru, Rh, Pd, Os, Ir, Pt and other elements of Group VIII and fluorine-containing compounds, among which I
b, Va, Vb, VIa, a compound containing an element selected from the group VIII and fluorine, particularly Sb ₂ O ₃ , Sb ₂ O ₄ , Sb
Antimony oxide such as ₆ O ₁₃ is preferably used, and the used amount is 0.01 to 0.35 mol per mol of tin carboxylate,
It is desirable to set it within the range of preferably 0.03 to 0.25 mol.

Here, when the above-mentioned dopant coexists with the tin carboxylate, the amount of hydrogen peroxide is 1.5 mol or more, preferably 1.6 to 2.2 mol, per mol of the total mol of the tin salt and the dopant. It is desirable to set within the range.

Water is usually used as the aqueous medium, but a water-miscible organic solvent such as alcohol or acetone may be used in combination as long as the viscosity of the reaction product solution does not increase and gelation does not occur.

As a means for producing a transparent aqueous solution for forming a transparent conductive tin oxide, a tin carboxylate and a dopant as needed are added to an aqueous medium, stirred, and a desired amount of hydrogen peroxide is added.

Means for producing such an aqueous solution is described in, for example, JP-A-62-1871.
No. 13 is described.

Next, as the sol-gel film-forming solution of the present invention, it is necessary to use a fluorinated alkyloxybenzene sulfonate as a surfactant in the aqueous solution described above. The alkyl chain is linear or branched, and the fluorination includes partially fluorinated or fully fluorinated ones. Examples of the sulfonic acid salt include a sodium salt, a potassium salt, and an ammonium salt of sulfonic acid. Any of these can be used, and examples thereof include partially fluorinated potassium heptyloxybenzenesulfonate and fully fluorinated sodium nonenyloxybenzenesulfonate.

The amount of the fluorinated alkyloxybenzene sulfonate added depends on the type of the aqueous medium, but it is preferably used in an amount of 10 ppm or more based on the aqueous solution. The heating may be performed if necessary.

Means for forming a film using the above-described aqueous solution or the sol-gel film-forming solution according to the present invention requires applying ultrasonic vibration to the substrate to be coated, and the uniformity and uniformity of film formation can be achieved by such a means. Denseness is imparted.

As long as ultrasonic vibration is applied to the substrate, any method such as a spray method, a spinner method, and an immersion method may be adopted as a film forming method.

Here, as the ultrasonic vibration, a commercially available centralized type, surface oscillation type ultrasonic oscillator, or the like can be used as appropriate, and can be brought into direct contact with the substrate or vibrated through a medium.

The frequency and oscillation output of the ultrasonic oscillator can be appropriately set according to the film formation method, the size of the substrate, and the like.

(Effect) The sol-gel film-forming liquid of the present invention has a great effect on forming a uniform film, and can show excellent effects on transparency, denseness, and conductivity. The sol-gel film forming method promotes close contact between the substrate and the film forming liquid by applying ultrasonic vibration, and at the same time, removes dust in the substrate and the film forming liquid, In addition, the effect of desorbing dissolved gas can be combined to form a uniform and highly physical film.

The effect of the sol-gel film forming method of the present invention is more remarkable when the sol-gel film forming liquid of the present invention is used.

The above-mentioned sol-gel film forming solution and film forming method provide a film having excellent uniformity, denseness, transparency, conductivity, and high physical properties, and have a transparent electrode, an antistatic film, an antistatic film, and an electric current. It can be used widely in fields that require performance.

Examples Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited by the descriptions of these Examples. Parts and percentages shown in the examples are on a weight basis unless otherwise specified.

In addition, the visible light transmittance and the surface resistivity were measured as follows.

1. Visible light transmittance Hitachi, Ltd., using a spectrophotometer U-3400 type,
The reference side is air, and the sample side is measured using a quartz glass substrate (13 mm x 60 mm, 1 mm thick) coated on both sides with the test sample, and the visible light range is used to avoid the influence of the interference waveform due to the film thickness. The integrated average transmittance from 350 to 700 nm was determined and defined as visible light transmittance (T%).

2. Electric conductivity An aluminum electrode having a width of 10.0 mm and an interval of 10.0 mm was deposited on the film, and the surface resistivity ρ _s (Ω / □) was obtained by a DC four-terminal method.

Example 1 467.4 g of stannous oxalate (SnC ₂ O ₄ ) and 17.35 g of diantimony trioxide were added to 2006 g of water at room temperature, and 31% of the mixture was stirred.
509.2 g of H ₂ O ₂ water was added and reacted for 50 minutes to obtain a clear aqueous solution.

Sn / Sb (atomic molar ratio) of the solution is 95/5, and H ₂ O
₂ is twice as much as the total number of moles of stannous oxalate and diantimony trioxide.

To this solution was added FUTAJIENT 100 (manufactured by Neos Co., Ltd. (sodium perfluorononenyloxybenzenesulfonate)).
Was added to the solution and stirred and dissolved.
A liquid for gel film formation was obtained.

Dilute 40 parts of the sol-gel film forming solution with 60 parts of water to prepare a film forming stock solution (A), and immerse a quartz glass plate in the stock solution for 1 minute (a descent speed of 13.2 cm / min., A rising speed of 58 cm / min.) and then 1
Air-dried at room temperature for an hour, and 800 in an electric furnace (Denken Co., Ltd.)
The firing was performed at a temperature of 2 ° C. × 2 hours.

This immersion-firing was performed for 4 cycles to obtain a film (1).

Comparative Example 1 Instead of using the stock solution (A) of Example 1, Example 1 was used.
Diluent (B) of 40 parts of the transparent aqueous solution diluted with 60 parts of water
A film (2) was obtained in the same manner as in Example 1 except for the above.

Examples 2 and 3 Ultrasonic vibration is applied at the time of immersion using the stock solutions (A) and (B) (using B-220 manufactured by Bransonic Corporation).
Except for the above, films (3) and (4) were obtained in the same manner as in Example 1.

Table 1 shows the results of the film forming characteristics of Examples 1, 2 and 3 and Comparative Example 1.

As is clear from Table 1, 1 using the sol-gel film-forming liquid of the present invention is superior in both transmittance and surface resistivity as compared with 2, and the transmittance is increased by applying ultrasonic vibration. In addition, it is understood that both the surface resistivity and the surface resistivity show excellent values, and the effect 3 is particularly remarkable when the sol-gel film forming solution of the present invention and the film forming method are used in combination.

Claims (2)

(57) [Claims] 1. A fluorinated alkyloxybenzenesulfonate as a surfactant is added to a transparent aqueous solution for forming a transparent conductive tin oxide obtained by reacting a tin carboxylate and hydrogen peroxide in an aqueous medium. A sol-gel film forming liquid. 2. A transparent aqueous solution for forming a transparent conductive tin oxide obtained by applying ultrasonic vibration to a substrate and reacting the substrate with a tin carboxylate and hydrogen peroxide in an aqueous medium. A method for forming a sol-gel film, characterized by coating with a sol-gel film-forming liquid.