KR20100056118A - Preparation method of la-sr-mn oxide thin film - Google Patents

Abstract

PURPOSE: A manufacturing method of lanthanum-strontium-manganese oxide thin film is provided, which can control a crystal phase structure in perovskite structure from an amorphous substance. CONSTITUTION: A manufacturing method of lanthanum-strontium-manganese oxide thin film comprises: a step of manufacturing precursor solution by dissolving lanthanum precursor, strontium precursor, and manganese precursor aqueous mixed solvent; a step of injecting precursor solution into a nozzle; a step of forming a water drop by spraying precursor solution under the electric field mood; and a step of drying water drop by adsorbing water drop to the preheated substrate.

Description

Preparation method of lanthanum-strontium-manganese oxide thin film {Preparation method of La-Sr-Mn Oxide thin film}

According to the present invention, the lanthanum-strontium-manganese can be applied as a cathode of a solid oxide fuel cell, by controlling the process conditions to control the oxide thin film from the porous to the dense structure, and from the amorphous to the perovskite structure. It relates to a method for producing an oxide thin film.

Due to the depletion of fossil fuel, the main energy source, and global warming due to environmental pollution, research on environmentally friendly and efficient energy sources is underway.

Fuel cells are attracting attention as next-generation energy sources as environmentally friendly power generation devices that generate electricity from hydrogen. Such fuel cells include alkaline fuel cells (AFC), phosphoric acid fuel cells (PAFC), solid oxide fuel cells (SOFC), polymer electrolyte fuel cells (SPEFC), molten carbonate fuel cells (MCFC), and the like.

Among them, the solid oxide fuel cell (SOFC) is composed of all solid components, so it is simpler in structure than other fuel cells, has high efficiency and low pollution, so it is a new clean energy in the future. It is attracting attention as one of the circles. For example, lanthanum / manganese composite oxide (LSM) doped with strontium is used as a cathode, a nickel-zirconium ceramic alloy is used as a cathode, and yttria stabilized zirconia (YSZ) is mainly used as an electrolyte. .

SOFCs operate at 700 to 1000 ° C, the highest temperature of a fuel cell because the electrolyte and the electrodes exhibit sufficient electrical conductivity only at high temperatures. However, this high temperature operation requires that the interconnector or cell housing of the SOFC also be able to withstand high temperatures, thus limiting the choice of materials to ceramic materials. Therefore, the manufacturing process of the SOFC is difficult and requires a high level of technology, such as a well-controlled powder manufacturing technology and precise molding technology is accompanied by a problem that the manufacturing cost increases.

Therefore, when implementing a low-temperature SOFC by lowering the operating temperature of the SOFC below 700 ℃, the manufacturing process is easier and relatively inexpensive metal material can be used to obtain a significant economic effect.

In order to realize the low-temperature SOFC, a method of reducing the resistance of the electrolyte by using an alternative electrolyte having better ion conductivity than the existing stabilized zirconia and thinning may be considered. However, in the case of such a low-temperature SOFC, as the electrode / electrolyte interfacial polarization resistance rises sharply and another problem occurs that lowers the efficiency of the fuel cell, it is necessary to control the microstructure at the interface between the electrode / electrolyte.

Control of the microstructure may be achieved through various methods such as a method of changing a material, a method of modifying a material, and a method of adjusting a film manufacturing process. Therefore, in the present invention, it is possible to control the microstructure through the control of the membrane manufacturing process.

As is known, a wet coating method of forming a thick film and a dry coating method of forming a thin film are employed to produce a film.

Wet coating methods include dry pressing, slurry coating, printing, tape casting, dip coating, and spin coating.

For example, Korean Patent Application No. 1998-41580 mentions a method for producing a dense membrane using a slurry coating method using a pressure and pressure reduction device, and a special pressure and pressure reduction device is required to perform such a method.

In addition, JH Song et al. Mention a method of manufacturing a porous anode layer for SOFC by tape casting method [JH Song, SI Park, JH Lee, and HS Kim, Fabrication characteristics of an anode-supported thin-film electrolyte fabrication by the tape casting method for IT-SOFC, Journal of Material Processing Technology , 198 414-418 2008. Although it is possible to manufacture porous and porous thin films through these methods, most methods have limitations in controlling the thickness and difficult to manufacture thin films of 10 μm or less.

Dry coating methods also include sputtering, pulse-laser deposition, electrochemical vapor deposition, metal-organic chemical vapor deposition, thermal spraying, and droplet flame deposition.

For example, Korean Patent Application No. 2008-1924 proposes a method for manufacturing an SOFC metal connector using a plasma spray method. Specifically, to prepare a lanthanum strontium manganese oxide layer for SOFC cathode, a precursor compound is prepared by using a solid phase reaction method through wet milling and calcining.

In addition, JH Joo et al. Reported the production and electrical conductivity of yttria stabilized zirconia electrolyte thin film for solid oxide fuel cells by PLD method [JH Joo and GM Choi, “Electrical conductivity of YSZ film grown by pulsed laser. deposition ”, Solid State Ionics, 177 1053-1057 2006]. The PDL method uses a laser and expensive vacuum equipment to manufacture a dense ceramic thin film, which is expensive in manufacturing and complicated in apparatus.

L. Gerardo Jose et al. Describe the preparation of electrolytes and anode materials for solid oxide fuel cells by RF sputtering [L. Gerardo Jose, H. Joshua, and T. Harry, “Microstructural Features of RF-sputtered SOFC Anode and Electrolyte Matrials”, Journal of Electroceramics, 13 691-695 2004]. In order to prepare the electrolyte and cathode layer for the solid oxide fuel cell by the RF sputtering method, a solid phase target is required as a deposition source, and a post heat treatment process must be performed to obtain a porous cathode layer.

This dry coating method is suitable for the production of dense thin film, low deposition rate, there is a limit of the selection of the composition of the starting material, and because the process is required in a vacuum state, there is a disadvantage that the manufacturing cost increases because of the complicated equipment.

Therefore, the demand for technology development on the ceramic thin film manufacturing method as well as the thin film manufacturing method of the solid oxide fuel cell component with easy increase of the rate of increase and the wide selection of starting materials is easy with the simple process equipment. Still remains.

Therefore, the inventors of the present invention conducted a study on a method of forming a thin film through the field spray deposition method, which can be processed at atmospheric pressure, which makes the manufacturing apparatus simpler and cheaper than the vacuum deposition method. In addition to controlling the microstructure of the thin film from amorphous to perovskite structure, the process conditions for the wide choice of starting materials can be established.

An object of the present invention is to provide a method for producing a lanthanum-strontium-manganese oxide thin film which can easily control the microstructure.

In order to achieve the above object, the present invention

Dissolving the lanthanum precursor, the strontium precursor, and the manganese precursor in an aqueous mixed solvent to prepare a precursor solution;

Transferring the precursor solution into an electric field spraying device and injecting it into a nozzle;

Spraying a precursor solution using the nozzle to form droplets; And

Uniformly adsorbing the droplets onto a preheated substrate and drying the droplets

It provides a method for producing a lanthanum-strontium-manganese oxide thin film comprising a.

The manufacturing method according to the present invention can easily control the microstructure of the thin film by changing the process conditions. In addition, the deposition rate and thickness of the thin film can be easily adjusted, and the selection range of raw materials is wide, and the equipment is simple because the process is performed at atmospheric pressure, and thus the cost is competitive in terms of manufacturing cost.

This method is widely applicable to the production of electrolyte, cathode and anode thin films of fuel cells, micro sensors and porous ceramic thin films, and in particular, lanthanum-strontium-manganese oxide thin films can be applied as cathodes of solid oxide fuel cells. It is possible.

The preparation of the lanthanum-strontium-manganese oxide thin film according to the present invention is carried out using an electric field spray method, and the present invention will be described in more detail below.

1 is a series of devices implemented for applying the manufacturing method according to the present invention. Such a device may be inserted into each component by another person having ordinary skill in the art.

Referring to FIG. 1, the electric field spray device includes an electric field spray chamber 10, a precursor solution reservoir 11, a nozzle 12, a syringe pump 13, a potential difference generator 14, a substrate 15, and a substrate support ( 16), temperature controller 17, and step motor 18.

Using this device, a method of manufacturing a lanthanum-strontium-manganese oxide thin film is as follows (see FIG. 2).

First, the lanthanum precursor, the strontium precursor, and the manganese precursor are dissolved in an aqueous mixed solvent to prepare a precursor solution, which is injected into the precursor solution reservoir 11.

The lanthanum precursor, the strontium precursor, and the manganese precursor are one selected from the group consisting of alkoxides, chlorides, hydroxides, oxyhydroxides, nitrates, carbonates, acetates, oxalates, and mixtures thereof, each containing strontium, manganese, or lanthanum. It is possible and it does not specifically limit in this invention.

Preferably, lanthanum nitrate hexahydrate is used as the lanthanum precursor, strontium chloride hexahydrate is used as the strontium precursor, and manganese nitrate hexahydrate is used as the manganese precursor.

At this time, the molar ratio of each of the lanthanum precursor, the strontium precursor, and the manganese precursor is selected in consideration of the molar ratio to be finally obtained.

As the aqueous mixed solvent, a mixed solvent of water and a lower alcohol is mixed in a volume ratio of 1:10 to 10: 1. Wherein the lower alcohol includes methanol, ethanol, propanol, isopropanol, and butanol. This aqueous mixed solvent has a higher vapor pressure and viscosity than water alone, so that vaporization in the droplets is easier, thereby making it possible to produce more dense particles.

The precursor and the aqueous mixed solvent are mixed with each other to prepare a precursor solution, and the concentration thereof is adjusted to 0.01 to 0.1 M in consideration of ease of nozzle injection, droplet size, and the like.

Next, the precursor solution from the precursor solution reservoir 11 is transferred to the nozzle 12 side by pressurization using the syringe pump 13.

At this time, the nozzle 12 preferably has a cylindrical shape to form droplets and has a long thin capillary shape along the inside. At this time, the nozzle 12 uses a diameter of 0.5 to 1.0 mm, preferably 0.31 mm to form micron-level droplets. The diameter of the nozzle 12 can be modified in consideration of the voltage applied, the concentration of the mixed solution, and the like as appropriate.

The nozzle 12 is connected to a potential difference generator 14 for generating an electric field. This potential difference generator 14 allows the precursor solution to be charged with a positive charge when ground flows with a negative charge.

Next, the precursor solution is sprayed using the nozzle 12 to form droplets.

Specifically, the precursor solution is sprayed through the nozzle 12 of the electric field spraying device to form droplets, in which droplets of finer and more uniform size are formed by the electric field.

At this time, it is possible to control the size of the droplet formed by adjusting the electric field formed in the chamber, that is, the voltage. For example, the larger the voltage, the smaller the droplet, and the voltage is applied at 0.1 to 50 kV, preferably 3 to 15 kV, to form a micron level droplet.

Next, the droplets are uniformly adsorbed onto the preheated substrate 15 and dried.

That is, a charged precursor solution is sprayed through the nozzle 12 to form droplets, which are adsorbed onto the preheated substrate 15.

The droplet size is proportional to the flow rate of the precursor solution (AM Ganan-Calvo, J. Aerosol. Sci. 28, 249, 1997). Pores are formed in the thin film. Referring to Experimental Example 2 of the present invention, as a result of changing the flow rate of the precursor solution to 2.0 to 4.5 liters per minute, a denser thin film is formed as the flow rate decreases, and the thin film is formed in a dense structure as the flow rate increases. It can be seen that it is converted to a porous thin film.

In this case, the substrate 15 is disposed to be spaced apart from the nozzle 12 by a predetermined distance, that is, the morphology of the lanthanum-strontium-manganese oxide thin film formed according to the distance between the nozzles 12 and 15 appears. According to Experimental Example 3 of the present invention, the oxide thin film formed when the distance from the nozzle-substrate 12 and 15 is 3 cm exhibits a porous structure, and when the distance is increased to 8 cm to form a thin film, the thin film having a dense structure Is switched to. Therefore, the distance between the nozzles and the substrates 12 and 15 is adjusted to obtain physical properties suitable for the purpose of use of the thin film.

In addition, the substrate support 16 is connected to the step motor 18 so that the droplets transferred through the spray can be evenly distributed on the substrate 15. The step motor 18 is a device that enables reciprocation, vibration, and rotational movement about one axis. The step motor 18 adsorbs droplets on the substrate 15 with a uniform thickness.

The deposition time through the spray affects the physical properties of the finally obtained lanthanum-strontium-manganese oxide, and is performed for 1 to 16 minutes. According to Experimental Example 4 of the present invention, the thin film having a dense structure is converted into a thin film having a porous structure as the deposition time is increased.

Next, the droplets adsorbed onto the substrate 15 are dried to remove the aqueous mixed solvent and by-products contained in the droplets, thereby forming a lanthanum-strontium-manganese oxide represented by the following Chemical Formula 1.

[Formula 1]

La _x Sr _1-x MnO ₃

(Wherein, 0 <x <1)

The drying is preferably performed at 120 to 330 ° C, wherein the density of the lanthanum-strontium-manganese oxide increases as the drying temperature increases. This drying process can be carried out through a separate drying device, in the present invention is performed by heating the substrate 15 to the temperature.

The droplets adsorbed on the substrate 15 are oxidized to oxides by evaporation of the aqueous mixed solvent contained in the droplets by the temperature of the substrate 15. The temperature is controlled via a temperature controller 17 which is separately connected to the substrate support 16 supporting the substrate 15, preferably to be heated to 120 to 330 ℃. According to Experimental Example 1 of the present invention, it can be seen that the thin film showing the porous structure is converted into a thin film having a more dense structure as the temperature of the substrate increases.

Through sufficient deposition, a lanthanum-strontium-manganese oxide thin film is formed on the substrate 15 having a predetermined thickness.

The lanthanum-strontium-manganese oxide exhibits porosity, and the morphology of the thin film can be controlled by adjusting the precursor solution flow rate, distance from the nozzle-substrate, substrate temperature, spray time, and heat treatment temperature.

In addition, the lanthanum-strontium-manganese oxide is capable of converting the crystal state of the oxide from amorphous to crystalline through high temperature heat treatment.

This heat treatment may be performed by controlling the temperature of the temperature controller 16 in the electric field spray chamber 10 or by transferring to a separate heat treatment apparatus.

Preferably, the heat treatment is carried out at 700 to 900 ℃ for 10 minutes to 5 hours, according to a preferred Experimental Example 5 of the present invention, the thin film showing the porous structure is more dense perovskite as the heat treatment temperature ( It can be seen that the conversion to a thin film of the perovskite structure.

In particular, the manufacturing method according to the present invention can control the structure of the thin film by changing the process conditions from porous to dense structure, amorphous to perovskite structure, as well as the process described above does not require a separate pressure application Since the process takes place at atmospheric pressure, there is an advantage in terms of cost compared to expensive equipment for conventional deposition.

This method can be widely applied to all fields for the production of porous thin films of 10 mm or less, for example, the electrolyte, cathode and anode thin films of fuel cells, micro sensors and porous ceramic thin films, etc. This is possible.

In particular, the lanthanum-strontium-manganese oxide thin film can be applied as a cathode of a solid oxide fuel cell, and when the thin film is used as a cathode, the interface resistance between the electrolyte and the electrode is low, so that the lanthanum-strontium-manganese oxide thin film is operated as well as the solid oxide fuel cell which is operated at 700 ° C. or higher. There is an advantage that can be used in the low-temperature battery operating below. In addition, by lowering the operating temperature, not only can the manufacturing cost of the SOFC be lowered, but there is an advantage of improving the reliability, portability, and operating time of the fuel cell.

Experimental Example 1

La _0.8 Sr _0.2 MnO ₃ 0.8 mol LaN ₃ O ₉ .XH ₂ O, 0.2 mol SrCl ₂ .6H ₂ O and 1 mol Mn (NO ₃ ) ₂ .6H ₂ to prepare 0.1 mol of precursor compound solution The O starting material was dissolved in 60 ml of a methanol / distilled water mixed solvent by ultrasonic vibration to prepare a precursor solution.

A syringe pump was used to transfer the precursor solution to a stainless nozzle with an inner diameter of 0.03 mm and an outer diameter of 0.64 mm. Subsequently, 18 kV high voltage was applied from a DC power source connected to the nozzle to form an electric field, and the temperature of the substrate was changed from 127 ° C to 330 ° C. At this time, the substrate-nozzle distance was maintained at 4 cm, the flow rate of the precursor solution was 4.5 l / min to perform deposition for 10 minutes to obtain a porous thin film.

Scanning electron microscope

The surface of the thin film obtained above was measured by the scanning electron microscope, and the obtained result is shown in FIG.

3A to 3F show scanning electron micrographs of a La _0.8 Sr _0.2 MnO ₃ thin film according to substrate temperature.

Referring to FIG. 3, it can be seen that the thin film of the porous structure in (a) is converted into a thin film of dense structure as shown in (f) as the temperature of the substrate increases.

In other words, the lower the temperature of the substrate (127 ° C., a), the more unstable the volatilization of the solvent in the droplets results in the formation of a wet deposit on the substrate. This wet deposit affects the volatilization of solvents and by-products such as NOx and COx that cause pore formation by previous deposition. On the contrary, as the temperature of the substrate increases (330 ° C., f), the precursor is adsorbed and oxidized to the substrate while removing the solvent and by-products in the droplet, thereby forming a thinner film having a more dense structure.

Experimental Example 2

La _0.8 Sr _0.2 MnO ₃ 0.8 mol LaN ₃ O ₉ .XH ₂ O, 0.2 mol SrCl ₂ .6H ₂ O and 1 mol Mn (NO ₃ ) ₂ .6H ₂ to prepare 0.1 mol of precursor compound solution The O starting material was dissolved in 60 ml of a methanol / distilled water mixed solvent by ultrasonic vibration to prepare a precursor solution.

A syringe pump was used to transfer the precursor solution to a stainless steel nozzle with an inner diameter of 0.03 mm and an outer diameter of 0.64 mm. Subsequently, an 18 kV high voltage was applied from a DC power source connected to the nozzle to form an electric field, and the temperature of the substrate was adjusted to 219 ° C. At this time, the substrate-nozzle distance was maintained at 4 cm, the deposition solution was carried out for 10 minutes while changing the flow rate of the precursor solution from 2.0 to 4.5 l / min to obtain a porous thin film.

Scanning electron microscope

The surface of the porous thin film obtained above was measured with a scanning electron microscope, and the obtained result is shown in FIG.

Figure 4 (a) to (f) shows a scanning electron micrograph of the porous La _0.8 Sr _0.2 MnO ₃ thin film according to the flow rate of the precursor solution.

Referring to FIG. 4, it can be seen that the thin film having a dense structure in (a) is converted into a porous thin film as shown in (f) as the flow rate increases. That is, as the precursor flow rate increases, the size of the droplets formed increases, and as the size of the droplets increases, the thin film formed on the substrate exhibits porosity due to unstable volatilization of solvents and impurities in the droplets when adsorbed onto the substrate.

Experimental Example 3

La _0.8 Sr _0.2 MnO ₃ 0.8 mol LaN ₃ O ₉ .XH ₂ O, 0.2 mol SrCl ₂ .6H ₂ O and 1 mol Mn (NO ₃ ) ₂ .6H ₂ to prepare 0.1 mol of precursor compound solution The O starting material was dissolved in 60 ml of a methanol / distilled water mixed solvent by ultrasonic vibration to prepare a precursor solution.

A syringe pump was used to transfer the precursor solution to a stainless nozzle with an inner diameter of 0.03 mm and an outer diameter of 0.64 mm. Subsequently, an 18 kV high voltage was applied from a DC power source connected to the nozzle to form an electric field, and the temperature of the substrate was performed at 219 ° C. At this time, the distance between the substrate and the nozzle was changed from 3cm to 8cm, and the deposition solution was flown at 4.5 l / min for 10 minutes to obtain a La _0.8 Sr _0.2 MnO ₃ thin film.

Scanning electron microscope

The surface of the thin film obtained above was measured by the scanning electron microscope, and the obtained result is shown in FIG.

5 (a) to (f) show a scanning electron micrograph of La _0.8 Sr _0.2 MnO ₃ according to the distance between the nozzle and the substrate.

Referring to (a) to (f) of FIG. 5, it can be seen that as the distance between the substrate and the nozzle increases, the porous structure is converted into a thin film having a dense structure.

That is, the closer the distance to the nozzle-substrate, the more droplets sprayed from the nozzle are deposited on the surface of the substrate, and then new droplets are deposited on top of it, so that the solvent and impurities through drying cannot be sufficiently removed, indicating a porous structure. Therefore, as the distance from the nozzle-substrate increases, the time is sufficient to be converted into a thinner film having a more dense structure.

Experimental Example 4

La _0.8 Sr _0.2 MnO ₃ 0.8 mol LaN ₃ O ₉ .XH ₂ O, 0.2 mol SrCl ₂ .6H ₂ O and 1 mol Mn (NO ₃ ) ₂ .6H ₂ to prepare 0.1 mol of precursor compound solution The O starting material was dissolved in 60 ml of a methanol / distilled water mixed solvent by ultrasonic vibration to prepare a precursor solution.

A syringe pump was used to transfer the precursor solution to a stainless steel nozzle with an inner diameter of 0.03 mm and an outer diameter of 0.64 mm. Subsequently, an electric field was formed by applying an 18 kV high voltage from a DC power source connected to the nozzle, and the temperature of the substrate was performed at 129 ° C. At this time, the distance between the substrate and the nozzle was maintained at 4 cm, the flow rate of the precursor solution was 4.5 l / min, and the deposition was performed while changing the deposition time from 1 minute to 16 minutes to obtain a La _0.8 Sr _0.2 MnO ₃ thin film.

Scanning electron microscope

The surface of the thin film obtained above was measured by the scanning electron microscope, and the obtained result is shown in FIG.

6 (a) to (f) show a scanning electron micrograph of La _0.8 Sr _0.2 MnO ₃ according to the deposition time.

Referring to FIG. 6, it can be seen that the thin film having a dense structure in (a) is converted into a thin film of porous structure as shown in (f) as the deposition time increases.

That is, the faster the deposition time, the denser the thin film is formed, and a crack-free thin film is formed by the complete volatilization of the solvent and impurities in the droplets. However, as the deposition time increases, the thickness of the thin film becomes thicker, and the volatilization of the solvent and impurities in the droplet is incomplete, thereby forming pores in the thin film.

Experimental Example 5

La _0.8 Sr _0.2 MnO ₃ 0.8 mol LaN ₃ O ₉ .XH ₂ O, 0.2 mol SrCl ₂ .6H ₂ O and 1 mol Mn (NO ₃ ) ₂ .6H ₂ to prepare 0.1 mol of precursor compound solution The O starting material was dissolved in 60 ml of a methanol / distilled water mixed solvent by ultrasonic vibration to prepare a precursor compound solution.

The solution obtained using a syringe pump was transferred to a stainless steel nozzle with an inner diameter of 0.03 mm and an outer diameter of 0.64 mm. Then, an 18 kV high voltage was applied from a DC power source connected to the nozzle to form an electric field, and the temperature of the substrate was adjusted to 160 ° C. At this time, the substrate-nozzle distance was maintained at 4 cm, the flow rate of the precursor solution was adjusted to 4.5 l / min to perform deposition for 10 minutes to obtain a porous thin film.

In addition, the porous thin film was heat-treated at 700 ° C., 800 ° C., and 900 ° C. for 3 hours to obtain a perovskite structure thin film.

Scanning electron microscope

The surface of the porous thin film and the perovskite thin film obtained above were measured with a scanning electron microscope, and the obtained result is shown in FIG.

Figure 7 (a) is a scanning electron micrograph of the porous thin film prepared in Example 1, (b) is a scanning electron micrograph of the perovskite thin film heat-treated at 900 ℃.

Referring to FIG. 7, it can be seen that the thin film exhibited about 1.9 times shrinkage (before / after heat treatment) through heat treatment and was deposited at a thickness of 0.3 μm per minute.

X-ray diffraction pattern

The oxide of the perovskite structure obtained through the heat treatment was measured by an X-ray diffractometer, and the results obtained are shown in FIG. 8.

8 is an X-ray diffraction pattern of La _0.8 Sr _0.2 MnO ₃ obtained before heat treatment (As-deposit) of La _0.8 Sr _0.2 MnO ₃ , and after heat treatment at 700 ° C., 800 ° C., and 900 ° C. FIG.

Referring to FIG. 8, it can be seen that La _0.8 Sr _0.2 MnO ₃ thin film is transformed from amorphous to crystalline through heat treatment. Especially, in case of heat treatment at 900 ° C. for 3 hours, La _0.8 Sr _0.2 MnO ₃ having perovskite structure is obtained. It was confirmed that it can be obtained.

It is possible to apply to the manufacture of the electrode of the solid oxide fuel cell produced according to the present invention.

1 is a series of devices implemented for applying the manufacturing method according to the present invention.

FIG. 2 is a flowchart illustrating a method of manufacturing a La _0.8 Sr _0.2 MnO ₃ thin film using the apparatus of FIG. 1.

3 (a) to (f) show a scanning electron micrograph of a La _0.8 Sr _0.2 MnO ₃ thin film according to the substrate temperature.

4 (a) to (f) show a scanning electron micrograph of the La _0.8 Sr _0.2 MnO ₃ thin film according to the precursor flow rate.

5A to 5F show scanning electron micrographs of a La _0.8 Sr _0.2 MnO ₃ thin film according to the distance between the nozzle and the substrate.

6 (a) to 6 (f) show scanning electron micrographs of a La _0.8 Sr _0.2 MnO ₃ thin film according to deposition time.

7 (a) is a scanning electron micrograph of the porous La _0.8 Sr _0.2 MnO ₃ thin film prepared in Example 1, (b) is a scan of the perovskite La _0.8 Sr _0.2 MnO ₃ thin film heat-treated at 900 ℃ Electron micrograph.

8 is La _0.8 Sr _0.2 MnO ₃ before heat treatment of a of 700 ℃, 800 ℃ obtained after heat treatment at, and _{900 ℃ La 0.8 Sr 0.2 MnO 3} X- ray diffraction pattern.

Claims (12)

Dissolving the lanthanum precursor, the strontium precursor, and the manganese precursor in an aqueous mixed solvent to prepare a precursor solution; Transferring the precursor solution into an electric field spraying device and injecting it into a nozzle; Spraying a precursor solution using the nozzle under an electric field atmosphere to form droplets; And Uniformly adsorbing the droplets onto a preheated substrate and drying the droplets Method for producing a lanthanum-strontium-manganese oxide thin film comprising a. The method of claim 1, The lanthanum-strontium-manganese oxide is a method of producing a lanthanum-strontium-manganese oxide thin film represented by the following formula (1): [Formula 1] La _x Sr _1-x MnO ₃ (Wherein, 0 <x <1) The method of claim 1, The lanthanum precursor, the strontium precursor, and the manganese precursor are one selected from the group consisting of alkoxides, chlorides, hydroxides, oxyhydroxides, nitrates, carbonates, acetates, oxalates, and mixtures thereof, each containing strontium, manganese, or lanthanum. Method for producing a lanthanum-strontium-manganese oxide thin film. The method of claim 1, The lanthanum precursor is lanthanum nitrate hexahydrate, the strontium precursor is strontium chloride hexahydrate, and the manganese precursor is to use a manganese nitrate hexahydrate, lanthanum-strontium-manganese oxide thin film manufacturing method. The method of claim 1, The aqueous mixed solvent is a method for producing a lanthanum-strontium-manganese oxide thin film which is a mixed solvent of one lower alcohol selected from methanol, ethanol, propanol, isopropanol or butanol and water. The method of claim 1, The electric field atmosphere is performed by applying a voltage of 0.1 to 50kV lanthanum-strontium-manganese oxide thin film manufacturing method. The method of claim 1, The nozzle is a method for producing a lanthanum-strontium-manganese oxide thin film using an inner diameter of 0.02 to 0.04 mm, an outer diameter of 0.50 to 0.70 mm. The method of claim 1, When spraying the substrate is a method for producing a lanthanum-strontium-manganese oxide thin film is carried out by preheating to 127 ~ 330 ℃. The method of claim 1, The method of manufacturing a lanthanum-strontium-manganese oxide thin film is carried out by adjusting the distance between the nozzle and the substrate when the spraying is 3 to 8cm. The method of claim 1, Method for producing a lanthanum-strontium-manganese oxide thin film that the flow rate of the precursor solution during the spraying is carried out at 2.0 ml / h to 4.5 ml / h. The method of claim 1, The entire step is performed for 1 to 16 minutes to prepare a lanthanum-strontium-manganese oxide thin film. The method of claim 1, A method of producing a lanthanum-strontium-manganese oxide thin film further having a perovskite structure by heat treatment at 800 to 950 ° C.

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