KR101765361B1 - Method for preparing solution comprising antimony tin oxide nanoparticles - Google Patents

Abstract

The present invention relates to a method of producing a dispersion containing ATO nanoparticles, and a method of manufacturing a dispersion containing ATO nanoparticles by using an organic solvent, It is excellent in dispersibility without dispersant and can be used as a transparent conductive thin film material.

Description

TECHNICAL FIELD The present invention relates to a method for preparing a dispersion containing antimony tin oxide (ATO) nanoparticles,

The present invention relates to a method for producing a dispersion containing antimony tin oxide (ATO) nanoparticles, a dispersion containing the ATO nanoparticles, and uses thereof.

To date, a method of sputtering mainly ITO (indium doped tin oxide) to form a flexible transparent conductive thin film and a method of thinning a conductive filler such as ITO particles, metal nanoparticles and conductive polymer particles by dispersing them in a matrix have been mainly studied. However, although the thin film sputtered with ITO has excellent conductivity and transparency, cracks are generated due to repetitive mechanical stimulation and the resistance rapidly increases. Especially, even when the ITO electrode film is folded once, cracks are generated in the folded surface, . In addition, there is a problem that indium is exhausted, and it is difficult to form a pattern by a roll-to-roll method which must be applied to a flexible large-area device in the future. Methods of dispersing conductive particles such as ITO nanoparticles or metal nanoparticles have various drawbacks depending on the characteristics of the particles. Particularly, in order to preserve the transparency, it is required to be made into particles of 100 nm or less and the dispersion characteristics should be excellent. However, in order to secure the crystallinity of the particles, it is required to undergo a process such as heat treatment, so that it is difficult to form a dispersion substantially after the heat treatment. In order to solve this problem, there is a method of finely pulverizing and dispersing using a metal chelating agent. However, impurities tend to flow in the process of crushing, and the productivity also drops. In particular, since the use of a metal chelating agent causes an increase in resistance, its use is very limited.

Therefore, ATO (antimony doped tin oxide) nanodispersions have been developed to improve the price, transparency, fairness and flexibility shown in the previous studies and to apply them to flexible transparent conductive thin film materials.

Korean Patent No. 10-1089566 (November 29, 2011) Korean Patent No. 10-0348702 (Jul. 31, 2002)

 D.E. Dyshel et al., Powder Metallurgy and Metal Ceramics, vol.34 (3,4), pp.219-220 (1995)

It is an object of the present invention to provide a method for producing a dispersion containing antimony tin oxide (ATO) nanoparticles, a dispersion containing the ATO nanoparticles and a use thereof.

In order to accomplish the above object, the present invention provides a method for producing an antimony tin oxide precursor, comprising: reacting a tin compound and an antimony compound in a first organic solvent to prepare an antimony tin oxide precursor; And reacting the precursor in a second organic solvent having a boiling point of 150 ° C to 350 ° C.

[Chemical Formula 1]

Sb _x Sn _(1-x) O ₂

In the above formula (1), x is a number within the range of 0.02 to 0.3.

The present invention also provides a dispersion prepared by the method of the present invention and comprising 0.1 to 50 parts by weight of the particles of the formula 1 having an average diameter of 1 nm to 30 nm.

The present invention also provides a conductive film made using the dispersion of the present invention.

The present invention also provides an electronic device comprising the conductive film.

The present invention can provide a dispersion of antimony tin oxide (ATO) nanoparticles having excellent dispersibility at a size of 30 nm or less without heat treatment or pulverization, and which can be used, for example, as a flexible transparent conductive thin film material.

In addition, ATO nanoparticles that can be used as a conductive film material having excellent physical properties in terms of transparency, printability, cost, and flexibility can be provided.

1 is a TEM photograph of antimony tin oxide (ATO) nanoparticles according to one embodiment of the present invention.
FIG. 2 shows an X-ray diffraction (XRD) pattern of antimony tin oxide (ATO) nanoparticles according to an embodiment of the present invention.
Figure 3 shows the X- ray diffraction (XRD) pattern of the tin oxide (SnO ₂₎ according to Comparative Example 1.

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

The present invention relates to a process for preparing an antimony tin oxide precursor by reacting a tin compound and an antimony compound in a first organic solvent to produce an antimony tin oxide precursor; And reacting the precursor in a second organic solvent having a boiling point of 150 ° C to 350 ° C. The present invention relates to a process for preparing a dispersion comprising particles according to the following formula:

[Chemical Formula 1]

Sb _x Sn _(1-x) O ₂

In the above formula (1), x is a number within the range of 0.02 to 0.3.

The present invention is characterized by producing a dispersion in which nanostructured ATO particles having high crystallinity are stably dispersed without heat treatment or a separate dispersant or metal chelating agent. That is, instead of using indium used as an expensive indium tin oxide (ITO), antimony is doped in tin oxide and ATO nanoparticles having excellent crystallinity without heat treatment process for producing ATO dispersion maintaining high dispersion stability And the ATO nanodispersion can maintain excellent dispersibility without using a metal chelating agent.

The dispersion containing the ATO nanoparticles according to the present invention can be prepared by a wet process and a two-step reaction, in which the ATO particles are dispersed in a solvent phase.

The first step is to prepare an ATO precursor, and a step of precipitating a tin compound and an antimony compound in a first organic solvent to prepare an antimony tin oxide (ATO) precursor.

Generally, distilled water is used as a solvent in a precipitation method used for preparing antimony tin oxide. However, the distilled water induces intergranular bonds while forming hydrogen bonds on the surface of the particles determined in the precipitation reaction process. As a result, strong agglomerates are formed as the crystallization progresses, resulting in poor dispersion of particles.

Therefore, by using an organic solvent instead of distilled water, the present invention forms a carbon group on the surface during particle formation and serves as a dispersing agent for preventing aggregation between particles thereof, and slows down the growth process after nucleation, thereby finally solving the above-mentioned problem . In addition, the solvent has a unique dielectric constant value, and the dielectric constant of the solvent influences nucleation and growth by changing the surface energy or surface charge in nucleation and crystal growth during powder synthesis, And shape.

As the first organic solvent, a solvent having a dielectric constant of 10 to 50 and a boiling point of 50 to 300 DEG C may be used. For example, the first organic solvent may be glycol-based or alcohol-based. The glycol system may be a glycol-based solvent having from 1 to 20 carbon atoms, more specifically from 1 to 16 carbon atoms, more specifically from 1 to 12 carbon atoms, most specifically from 1 to 8 carbon atoms. For example, ethylene glycol, 1,4-butanediol, diethylene glycol and the like can be used, but there is no particular limitation. The alcohol system may be a monovalent alcohol having 1 to 20 carbon atoms, more specifically 1 to 16 carbon atoms, more specifically 1 to 12 carbon atoms, and most specifically 1 to 8 carbon atoms. For example, it may be methanol, ethanol, isopropanol, butanol, etc., but is not particularly limited thereto.

The tin compound may be a tin salt, for example, tin chloride, tin sulfate, tin acetate, or tin bromide. The precursor solution can be prepared by directly dissolving the tin salt in an organic solvent.

The tin salt is present in a concentration of 0.05 mol to 2.0 mol, more specifically 0.05 mol to 1.8 mol, 0.05 mol to 1.6 mol, 0.05 mol to 1.4 mol, 0.05 mol to 1.2 mol, and 0.05 mol to 1 mol, per liter of the organic solvent . When the concentration is less than 0.05 mol / L, there is an advantage in terms of uniformity of the morphologically produced particles, but the amount of the precipitated particles is small, which is disadvantageous from the productivity standpoint. When the concentration is more than 2.0 mol / L, it is difficult to control the pH of the solution, so that a large amount of precipitant is additionally required. Even if the concentration is adjusted, the solubility increases during the reaction, There arises a problem of separation in terms of crystal growth or uniformity.

The antimony compound may be an antimony salt, for example, antimony chloride, antimony fluoride, antimony iodide, or antimony acetate. The antimony salt may be directly dissolved in an organic solvent to prepare a precursor solution.

The antimony salt can be determined in consideration of the stoichiometry according to the general formula (1).

When preparing the ATO precursor, a strong mixing system, an ultrasonic system or ball milling may be used in consideration of the solubility between the solvent and the salts.

The ratio between the atoms constituting the particles can be controlled by the concentration between the tin salt and the antimony salt.

[Chemical Formula 1]

Sb _x Sn _(1-x) O ₂

In the above formula (1), x is a number within the range of 0.02 to 0.3.

When x is less than 0.02, insufficient antimony atoms result in insignificant effects on the energy bandgap and can not act as an electrode material. When x is more than 0.3, antimony is added in excess, .

The ATO precursor is prepared by mixing a tin precursor solution and an antimony precursor solution and adding a precipitant to adjust the pH of the solution to 3 to 9 and precipitating the mixture at a reaction temperature of 30 to 250 ° C for 2 to 24 hours to form a precipitate .

The precipitating agent for controlling the pH is not particularly limited as long as it is a compound containing a hydroxyl group. For example, one kind of ammonium hydroxide, potassium hydroxide or sodium hydroxide is used, and the pH of the reaction solution is adjusted to 3.0 to 9.0 . If the pH is less than 3.0, a small amount of precipitate is formed, which is disadvantageous from the viewpoint of productivity. If the pH is more than 9.0, the solubility of the reaction solution is lowered, and uneven crystal grains can be produced.

The precipitation reaction temperature may be 30 ° C or more, more specifically 30 to 250 ° C, 30 to 140 ° C, 30 to 120 ° C, 30 to 100 ° C, 30 to 80 ° C, 40 to 80 ° C, It is preferable that the boiling point of the organic solvent is below the boiling point. For example, when an alcohol-based solvent is used as the first organic solvent, the reaction may be conducted at 90 ° C or less in consideration of boiling point, and a condenser may be used if necessary.

Further, the precipitation reaction time may be 2 hours to 24 hours, more specifically 4 hours to 9 hours, 3 hours to 8 hours, 3 hours to 7 hours, 3 hours to 6 hours. The reaction time is related to the yield of the precipitate. If the reaction time is less than 2 hours, the reaction does not proceed completely and the productivity is not good and the particles may not be uniform. Also, if it exceeds 24 hours, it is disadvantageous in terms of process efficiency.

Meanwhile, since the precipitate formed in the above step is prepared using an organic solvent, a washing step may be further performed to remove organic substances and impurities existing on the surface and inside of the produced particles.

The washing may be carried out in an organic solvent by selecting one of decanter and centrifugation.

As the washing solution used in the washing step, alcohol or ketone may be used. For example, acetone and ethanol may be used. If distilled water is used without using them in the washing step, the hydration reaction by the hydration reaction proceeds, intergranular hydrogen bonding may be formed, and rapid aggregation may occur.

The second step according to the present invention is a process for preparing a dispersion in which nano-sized ATO particles are dispersed by maximizing crystal growth of a precipitate prepared in the above step, that is, an ATO precursor.

To this end, the precipitate (or the ATO precursor) prepared in the step 1 is added in an amount of 2 to 40 parts by weight, more preferably 5 to 30 parts by weight, most preferably 5 to 30 parts by weight based on 100 parts by weight of the second organic solvent having a boiling point of 150 ° C. to 350 ° C. Specifically, 10 to 20 parts by weight are dispersed and mixed. If the above range is less than 2 parts by weight, the process efficiency may be lowered. If the above range is more than 40 parts by weight, intergranular aggregation may occur.

The second organic solvent may be any organic solvent having a boiling point of 150 ° C to 350 ° C. Therefore, if the boiling point is 150 ° C to 350 ° C, the first organic solvent may be used. Examples of the second organic solvent include a glycol having 1 to 8 carbon atoms, an alcohol having 1 to 8 carbon atoms, and an alkane having 8 to 20 carbon atoms. For example, ethylene glycol, 1,4-butanediol, epoxyethanol, diethylene glycol, tetradecane, or the like can be used, but not particularly limited thereto.

A strong mixing system, an ultrasonic system, or ball milling may be used to uniformly mix the precipitate in a solvent.

A strong acid is added to the mixed solution of the ATO precursor and the second organic solvent to lower the pH to 1 or less. The strong acid may be sulfuric acid, nitric acid, hydrochloric acid, acetic acid or the like.

The mixed solution is reacted at a temperature of 150 ° C or higher to a temperature lower than the boiling point of the second organic solvent, preferably 150 ° C to 350 ° C, more preferably 150 ° C to 230 ° C for 30 minutes to 8 hours to induce crystal growth If necessary, a condenser can be used.

The reaction time is 30 minutes to 8 hours, preferably 2 hours to 4 hours. If the reaction time is less than 30 minutes, the reaction does not proceed completely, so that a desired crystal phase can not be obtained. If the reaction time exceeds 8 hours, .

The ATO particles of formula (I) prepared through the above steps may be included in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the dispersion, and the diameter may be 1 nm to 30 nm. The ATO particle represented by Formula 1 may exhibit at least one diffraction peak out of a (110) diffraction peak, a (101) diffraction peak, a (200) diffraction peak and a (211) diffraction peak in the XRD analysis.

The dispersion in which the ATO nanoparticles prepared according to the method of the present invention was dispersed was excellent in dispersibility without using a precision milling process or a metal chelating agent.

Accordingly, the present invention also provides a dispersion prepared by the method of the present invention, comprising 0.1 to 50 parts by weight of the particles of Formula 1 having an average diameter of 1 nm to 30 nm.

The present invention also relates to a conductive film produced using the dispersion according to the present invention.

The dispersion according to the present invention includes ATO nanoparticles and can be used as a flexible transparent conductive thin film material excellent in transparency, printability, price, and flexibility since ATO nanoparticles have crystallinity and dispersibility.

The dispersion containing the ATO nanoparticles is excellent in light transmittance and excellent in electric conductivity, and can be used as a transparent electrode of various flat panel displays such as an antistatic film, a thermal barrier film, an organic solar battery, an organic thin film transistor, a liquid crystal display device and an organic light emitting diode Can be used.

The conductive film may be formed by coating a solution containing ATO particles on a substrate using a dipping method, a spin coating method, a spray method, or the like.

The present invention also relates to an electronic device comprising the conductive film.

The electronic device of the present invention uses a conductive film manufactured using a dispersion containing ATO nanoparticles. A dispersion containing ATO nanoparticles is coated on a substrate, and PEDOT: PSS is spin-coated to assist injection and transport of holes. A polymer to be used as a light emitting layer may be heat-treated by spin coating, and then a barium fluoride (BaF ₂ ), barium (Ba), or aluminum (Al) may be vacuum deposited to form a polymer light emitting diode.

Hereinafter, the present invention will be described in detail with reference to examples. However, the following examples are illustrative of the present invention, and the present invention is not limited to the following examples.

≪ Example 1 >

14.529 g of tin chloride pentahydrate (SnCl ₄ .5H ₂ O) was dissolved in 500 mL of methanol and then charged into a 1000 mL reactor. Further, 0.96 g of antimony trichloride (SbCl ₃ ) was dissolved in 100 mL of methanol, the two solutions were mixed, and the pH was adjusted to 5.2 with ammonia water while stirring with an impeller, followed by reaction at 65 ° C for 18 hours. After the reaction, the precipitate was washed by centrifugation.

5 g of the washed precipitate was added to 50 g of 1,4-butanediol and dispersed well by vigorous stirring. The pH of the precipitate was titrated to 1 or less using nitric acid (HNO ₃ ). The solution was reacted at a temperature of 230 캜 for 4 hours to prepare a nanodispersion in which blue antimony was added.

The nanodispersion was analyzed using an FETEM (JEM ARM200F, JEOL) at an acceleration voltage of 200 kV at a magnification of 1,500,000 and an atomic resolution of 0.17 nm.

The results, as shown in Figures 1 and 2, ATO particles are manufactured to a uniform size of about 4.8 nm, XRD measurement results were analyzed by _{Sn 0 .9 Sb 0 .1 O 2} .

≪ Example 2 >

A nanodispersion was prepared in the same manner as in Example 1 except that ethanol was used to prepare the precursor. The size of the ATO particles was about 4.6 nm, which was similar to that of Example 1.

≪ Example 3 >

A nanodispersion was prepared in the same manner as in Example 1 except that propanol was used to prepare the precursor. The size of the ATO particles was about 4.3 nm, which was similar to that of Example 1.

<Example 4>

A nanodispersion was prepared in the same manner as in Example 1 except that ethylene glycol was used to prepare the precursor. The size of ATO particles was about 4 nm.

&Lt; Example 5 >

A nano dispersion was prepared in the same manner as in Example 1 except that ethylene glycol was used to prepare the dispersion. The size of the ATO particles was about 4.1 nm, which was slightly smaller than that of Example 1.

&Lt; Example 6 >

A nanodispersion was prepared in the same manner as in Example 1 except that diethylene glycol was used to prepare the dispersion. The size of the ATO particles was about 4.1 nm, which was slightly smaller than that of Example 1.

&Lt; Comparative Example 1 &

A nanodispersion was prepared in the same manner as in Example 1 except that distilled water was used to prepare the nanodispersion.

As shown in FIG. 3, the XRD analysis showed that SnO ₂ was formed, and that a further heat treatment process was required.

Claims (21)

Reacting the tin compound and the antimony compound in a first organic solvent having a pH of 3 to 9 and then centrifuging to obtain an antimony tin oxide precursor; And
comprising reacting the precursor at a temperature of 150 DEG C to 350 DEG C for 30 minutes to 8 hours under a second organic solvent having a boiling point of 150 DEG C to 350 DEG C at a pH of 1 or lower, &Lt; RTI ID = 0.0 &gt;
[Chemical Formula 1]
Sb _x Sn _(1-x) O ₂
In the above formula (1), x is a number within the range of 0.02 to 0.3.
The method according to claim 1,
Wherein the tin compound is a tin salt and the antimony compound is an antimony salt.
The method according to claim 1,
Wherein the first organic solvent has a dielectric constant between 10 and 50. &lt; RTI ID = 0.0 &
The method according to claim 1,
Wherein the first organic solvent is a glycol-based or alcohol-based solvent.
5. The method of claim 4,
Wherein the first organic solvent is a glycol having 1 to 8 carbon atoms or a monohydric alcohol having 1 to 8 carbon atoms.
The method according to claim 1,
Wherein the concentration of the tin compound in the first organic solvent is from 0.05 mol / L to 2.0 mol / L.
delete The method according to claim 1,
wherein the pH is controlled by a compound comprising a hydroxyl group.
The method according to claim 1,
Wherein the reaction in the first organic solvent is carried out at 30 ° C to 250 ° C.
The method according to claim 1,
Wherein the reaction in the first organic solvent is conducted for 2 to 24 hours.
delete The method according to claim 1,
Wherein at least one selected from the group consisting of alcohols and ketones is added during centrifugation.
The method according to claim 1,
Wherein the ratio of the precursor in the second organic solvent is 2 to 40 parts by weight based on 100 parts by weight of the second organic solvent.
The method according to claim 1,
The second organic solvent is at least one selected from the group consisting of a glycol having 1 to 8 carbon atoms, an alcohol having 1 to 8 carbon atoms, and an alkane having 8 to 20 carbon atoms.
delete delete delete The method according to claim 1,
Wherein the average diameter of the particles is from 1 nm to 30 nm.
A dispersion prepared by the method of claim 1 and comprising 0.1 to 50 parts by weight of particles of the following formula 1 having an average diameter of 1 nm to 30 nm:
[Chemical Formula 1]
Sb _x Sn _(1-x) O ₂
In the above formula (1), x is a number within the range of 0.02 to 0.3.
A conductive film produced using the dispersion of claim 19.
An electronic device comprising the conductive film of claim 20.

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