WO2019035651A1 - Nayf4 thin film, laminate, pattern, and method for manufacturing same - Google Patents

Abstract

The invention NaYF ₄ relates to a film, laminate, a pattern and a method of manufacturing the same, more specifically, by adjusting the NaYF ₄ Number of films, lamination of a thin film that is capable of controlling the thickness of the thin film adjust the light intensity to control the emission color NaYF _4, which relates to a laminate and a NaYF ₄ pattern, and a manufacturing method that can form a pattern to control the light emission efficiency.

Description

NAYF4 thin film, laminate, pattern and manufacturing method thereof

The invention NaYF ₄ relates to a film, laminate, a pattern and a method of manufacturing the same, more specifically, by adjusting the NaYF ₄ Number of films, lamination of a thin film that is capable of controlling the thickness of the thin film adjust the light intensity to control the emission color NaYF _4, which relates to a laminate and a NaYF ₄ pattern, and a manufacturing method that can form a pattern to control the light emission efficiency.

Recently, interest in nanotechnology is increasing due to the rapid development of electronics, information communication and biotechnology industries. As a method for synthesizing nano powder, there are gas condensation method and pyrolysis method. However, gas condensation method requires that the oxide film on the surface of nano powder should be able to block oxygen diffusion, and pyrolysis method has a disadvantage that impurities are obtained due to oxygen which is a source of heat .

Thin films can be formed by thermal evaporation or electrodeposition. However, the thermal evaporation method requires a high vacuum and the electrodeposition method has a rough surface because it is made of nano powder having a size of about 500 nm. In addition, although the hydrothermal synthesis method which can be synthesized at a relatively low temperature (100 to 300 ° C.) has been proposed in the Journal of Korean Ceramic Society (Vol. 48. pp. 86 to 93) This is a disadvantage.

In addition, there are disadvantages such as photolithography, electron beam writing, focused ion beam lithography, X-ray lithography, scanning probe lithography, etc., which are methods of forming a nano pattern, but their precision and equipment are complicated. Accordingly, it is required to develop new technologies for synthesis of high-purity nano powder, production of a thin film having smooth surface, and precise pattern formation.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a NaYF ₄ thin film capable of controlling light emission intensity.

Another object of the present invention is to provide a NaYF ₄ laminate capable of controlling the luminescent color.

It is another object of the present invention to provide a NaYF ₄ pattern capable of controlling the luminous efficiency.

A further object of the present invention is to provide a method for producing a smooth surface NaYF ₄ thin film and a laminate, and a method for producing a sophisticated NaYF ₄ pattern.

In order to achieve the above object, the NaYF ₄ thin film doped with A ³⁺ and Yb ³⁺ is represented by the following Chemical Formula 1 and the surface roughness value (Ra) is 3 nm or more and 10 nm or less.

 [Chemical Formula 1]

A is Er or Tm, x is a real number with 0.001 = x? = 0.03, and y is a real number with 0.1 = y? = 0.7.

The thickness of the thin film may be 100 nm or more and 400 nm or less.

In order to achieve the above object, a NaYF ₄ laminate doped with A ³⁺ and Yb ³⁺ is represented by the following Chemical Formula 1, and a NaYF ₄ thin film having a surface roughness value (Ra) of 3 nm or more and 10 nm or less Stacked.

 [Chemical Formula 1]

A is Er or Tm, x is a real number with 0.001 = x? = 0.03, and y is a real number with 0.1 = y? = 0.7.

In order to achieve the above object, the NaYF ₄ pattern doped with A ³⁺ and Yb ³⁺ is represented by the following Chemical Formula 1, and has a columnar shape and a height and a diameter of nanosize.

[Chemical Formula 1]

A is Er or Tm, x is a real number with 0.001 = x? = 0.03, and y is a real number with 0.1 = y? = 0.7.

In order to accomplish the above-mentioned other object, a method for producing a NaYF ₄ thin film doped with A ³⁺ and Yb ³⁺ represented by the following Chemical Formula 1 comprises reacting a sodium compound, a compound A, a yttrium compound and an ytterbium compound with trifluoroacetic acid, poly Acrylic acid and 2-propanol to form a first mixed solution, and coating the first mixed solution on the substrate.

 [Chemical Formula 1]

A is Er or Tm, x is a real number with 0.001 = x? = 0.03, and y is a real number with 0.1 = y? = 0.7.

In order to accomplish the above object, a method for producing a NaYF ₄ laminate, which is represented by the following Chemical Formula 1 and doped with A ³⁺ and Yb ³⁺ , comprises reacting a sodium compound, a compound A, a yttrium compound and an ytterbium compound with trifluoroacetic acid, Polyacrylic acid and 2-propanol to form a first mixed solution, and coating the first mixed solution on the substrate.

[Chemical Formula 1]

A is Er or Tm, x is a real number with 0.001 = x? = 0.03, and y is a real number with 0.1 = y? = 0.7.

In order to accomplish the above-mentioned other object, a method for producing a NaYF ₄ pattern doped with A ³⁺ and Yb ³⁺ represented by the following Chemical Formula 1 comprises reacting a sodium compound, a compound A, a yttrium compound and an ytterbium compound with trifluoroacetic acid, poly Acrylic acid and 2-propanol to form a first mixed solution, preparing the first mixed solution on a substrate, and pressing a stamp having a columnar pattern on the substrate on which the first mixed solution is prepared to form a pattern .

[Chemical Formula 1]

A is Er or Tm, x is a real number with 0.001 = x? = 0.03, and y is a real number with 0.1 = y? = 0.7.

According to the NaYF ₄ thin film of the present invention, the light emission intensity can be controlled by controlling the thickness of the thin film.

Further, according to the NaYF ₄ laminate of the present invention, the luminescent color can be controlled by adjusting the number of laminated thin films.

Further, according to the NaYF ₄ pattern of the present invention, there is an effect that a light emission efficiency can be controlled by forming a pattern.

In addition, the NaYF ₄ thin film and laminate manufacturing method of the present invention provides a smooth surface thin film and a laminate by using a sol-gel method applicable to materials of various compositions.

Further, according to the method of producing a NaYF ₄ pattern of the present invention, there is an effect of providing a sophisticated NaYF ₄ pattern by using a simple and low-cost soft lithography process.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a photograph showing the emission of NaYF ₄ precursor powder according to one embodiment of the present invention, an energy level diagram and an X-ray diffraction image. FIG.

FIG. 2 is X-ray diffraction, differential scanning calorimetry, and thermogravimetric images of the NaYF ₄ precursor powder according to one embodiment of the present invention.

3 is a scanning electron microscope (SEM), a cost-graft microscope and an X-ray diffraction image of a NaYF ₄ thin film according to an embodiment of the present invention.

FIG. 4 is a photograph showing light emission of the NaYF ₄ thin film and the laminate according to an embodiment of the present invention, the emission spectrum, and the positions on the chromaticity coordinates.

5 is a flowchart showing a method of manufacturing a NaYF ₄ thin film, a laminate, and a pattern according to an embodiment of the present invention.

6 is an image showing a method of manufacturing a NaYF ₄ pattern according to an embodiment of the present invention.

7 is a scanning electron microscope image of a NaYF ₄ pattern according to an embodiment of the present invention.

8 is an image showing emission spectra and emission intensity of a NaYF ₄ thin film and a pattern according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings according to the present invention.

In order to achieve the above object, A ³⁺ and Yb ³⁺ -doped NaYF ₄ thin films are represented by the following Chemical Formula 1 and the surface roughness value (Ra) is 3 nm or more and 10 nm or less. More preferably, the surface roughness value (Ra) may be 2 nm or more and 4 nm or less. When the surface roughness is below the lower limit, the luminous efficiency is significantly lowered due to the increase of the surface area as the size of the constituent particles is decreased. When the surface roughness value exceeds the upper limit, the transparency is decreased, It gets harder. Fig. 3 (e) is a schematic view of the surface roughness value Ra.

The surface roughness value Ra can be calculated by the following equation (1). Equation (1) has significance as a formula for calculating a center line average calculation method.

[Equation 1]

In the above equation (1), Ra denotes a surface roughness (arithmetic mean), x denotes a variable of an average linear axis, L denotes a reference length, and f (x) denotes a roughness curve function.

 [Chemical Formula 1]

A is Er or Tm, and x is a real number with 0.001 = x? = 0.03, preferably 0.003 = x? = 0.02. When x is less than the lower limit, the light-sensitive efficiency is remarkably reduced and the light-emitting efficiency is low. When x exceeds the upper limit, light emission may not be realized due to concentration quenching.

On the other hand, y is a real number with 0.1 = y? = 0.7, preferably 0.2 = y? = 0.6. When y is less than the lower limit, the excitation power is remarkably reduced and the luminous efficiency is low. When y exceeds the upper limit, light emission may not be realized by concentration quenching.

Meanwhile, the thickness of the thin film may be 100 nm or more and 400 nm or less, and preferably 120 nm or more and 300 nm or less. The light emission intensity can be controlled by controlling the thickness of the thin film, and the light emission photograph is shown in FIG. 4 described later. When the thickness is less than the above lower limit, the strength of the thin film is lowered, the amount of NaYF ₄ is decreased, and the luminous efficiency is significantly lowered. If the thickness exceeds the upper limit, the transparency of the thin film is decreased, and application to an optical device such as a solar cell becomes difficult.

Er ³⁺ and Tm ³⁺ are erbium and thulium ions, respectively, acting as sensitizers or activators for energy transfer in the NaYF ₄ matrix. Yb ³⁺ acts as a sensitizer as ytterbium ion. 1 (d) shows energy levels and energy transfer diagrams of Tm ³⁺ , Yb ³⁺ , and Er ³⁺ ions.

In order to achieve the above object, a NaYF ₄ laminate doped with A ³⁺ and Yb ³⁺ is represented by the following Chemical Formula 1, and a NaYF ₄ thin film having a surface roughness value (Ra) of 3 nm or more and 10 nm or less Stacked. The surface roughness value Ra can be more preferably 2 nm or more and 4 nm or less. When the surface roughness is below the lower limit, the luminous efficiency is significantly lowered due to the increase of the surface area as the size of the constituent particles is decreased. When the surface roughness value exceeds the upper limit, the transparency is decreased, It gets harder.

[Chemical Formula 1]

A is Er or Tm, and x is a real number with 0.001 = x? = 0.03, preferably 0.003 = x? = 0.02. When x is less than the lower limit, the light-sensitive efficiency is remarkably reduced and the light-emitting efficiency is low. When x exceeds the upper limit, light emission may not be realized due to concentration quenching.

On the other hand, y is a real number with 0.1 = y? = 0.7, preferably 0.2 = y? = 0.6. When y is less than the lower limit, the excitation power is remarkably reduced and the luminous efficiency is low. When y exceeds the upper limit, light emission may not be realized by concentration quenching. The luminescent color can be controlled by laminating the thin film, which is shown in Fig.

In order to achieve the above object, A ^{3 +} and Yb ^{3 +} -doped NaYF ₄ patterns are columnar as shown in FIG. The columns are nano-sized with a height and a diameter of 1000 nm or less, respectively. When the pillar is implemented in the nano size, the light trapped in the thin film is scattered due to the total reflection, thereby improving the light extraction efficiency and improving the light emitting efficiency.

[Chemical Formula 1]

A is Er or Tm, and x is a real number with 0.001 = x? = 0.03, preferably 0.003 = x? = 0.02. When x is less than the lower limit, the light-sensitive efficiency is remarkably reduced and the light-emitting efficiency is low. When x exceeds the upper limit, light emission may not be realized due to concentration quenching.

On the other hand, y is a real number with 0.1 = y? = 0.7, preferably 0.2 = y? = 0.6. When y is less than the lower limit, the excitation power is remarkably reduced and the luminous efficiency is low. When y exceeds the upper limit, light emission may not be realized by concentration quenching.

7 (a) is a perspective view and a side view of a single column of Example 11 NaYF ₄ pattern observed through a scanning electron microscope. Referring to FIG. 7 (a), the spacing of the columnar pattern may be 350 nm or more. This value corresponds to the diameter value of the columnar pattern. FIG. 7 (b) is a top view of the image seen from the top of the Example 11 NaYF ₄ pattern observed through a scanning electron microscope and the interval between the columns. FIG.

Unlike the smooth thin film having no pattern, when the pattern is formed, the light extraction efficiency can be increased by providing an effect of up-conversion out coupling effect, that is, light trapped in the thin film due to total reflection, and light extraction efficiency is increased through scattering.

In order to accomplish the above-mentioned other object, a method for producing a NaYF ₄ thin film doped with A ³⁺ and Yb ³⁺ represented by the following Chemical Formula 1 comprises reacting a sodium compound, a compound A, a yttrium compound and an ytterbium compound with trifluoroacetic acid, poly Acrylic acid and 2-propanol to form a first mixed solution, and coating the first mixed solution on the substrate.

[Chemical Formula 1]

A is Er or Tm, and x is a real number with 0.001 = x? = 0.03, preferably 0.003 = x? = 0.02. When x is less than the lower limit, the light-sensitive efficiency is remarkably reduced and the light-emitting efficiency is low. When x exceeds the upper limit, light emission may not be realized due to concentration quenching.

On the other hand, y is a real number with 0.1 = y? = 0.7, preferably 0.2 = y? = 0.6. When y is less than the lower limit, the excitation power is remarkably reduced and the luminous efficiency is low. When y exceeds the upper limit, light emission may not be realized by concentration quenching.

Examples of the sodium compound include sodium silicate, sodium glutamate, sodium lauryl sulfate, montmorillonite, borax, sodium cyanide, sodium oxide, sodium percarbonate, sodium hydroxide, sodium thiosulfate, sodium iodide But are not limited to, sodium hydride, sodium hydride, sodium chlorate, sodium chloride, sodium nitrate, sodium carbonate, sodium hydrogen carbonate, sodium fluoride, sodium sulfate, sodium hydrogen sulfate, sodium hydrogen sulfide and sodium hydrogen sulfide .

Examples of the erbium compound include erbium oxide, erbium acetate, erbium nitrate, and erbium fluoride, but are not limited thereto.

Examples of thulium compounds include, but are not limited to, thulium oxide, thulium acetate, thulium nitrate, thulium fluoride, and the like.

Examples of the yttrium compound include, but are not limited to, yttrium oxide, yttrium acetate, yttrium nitrate, yttrium fluoride, and the like.

Examples of the ytterbium compound include ytterbium oxide, ytterbium acetate, ytterbium nitrate, and ytterbium fluoride. However, the present invention is not limited thereto.

Meanwhile, the coating step may be performed by spin coating, spray coating, vacuum filtration, dip coating, rod coating or the like. More preferably, it can be performed by uniformly casting the coating solution onto the substrate and spin-coating the substrate to rotate.

5 (a) is a flowchart of the thin film manufacturing method of the present invention. The thin film manufacturing method of the present invention is a kind of sol-gel process. Through the thin film manufacturing method of the present invention, it becomes possible to make a material having a composition which was impossible to manufacture by the previous method. Further, through the thin film manufacturing method of the present invention, a thin film including a multi-component material can be made uniform and easily. It is possible to obtain a smooth thin film having a surface roughness value Ra of not less than 3 nm and not more than 10 nm and more preferably not less than 2 nm and not more than 4 nm by a sol-gel process. The thin film manufacturing method of the present invention may further include a heat treatment step.

In order to accomplish the above object, a method for producing a NaYF ₄ laminate, which is represented by the following Chemical Formula 1 and doped with A ³⁺ and Yb ³⁺ , comprises reacting a sodium compound, a compound A, a yttrium compound and an ytterbium compound with trifluoroacetic acid, Polyacrylic acid and 2-propanol to form a first mixed solution, and coating the first mixed solution on the substrate.

[Chemical Formula 1]

A is Er or Tm, and x is a real number with 0.001 = x? = 0.03, preferably 0.003 = x? = 0.02. When x is less than the lower limit, the light-sensitive efficiency is remarkably reduced and the light-emitting efficiency is low. When x exceeds the upper limit, light emission may not be realized due to concentration quenching.

On the other hand, y is a real number with 0.1 = y? = 0.7, preferably 0.2 = y? = 0.6. When y is less than the lower limit, the excitation power is remarkably reduced and the luminous efficiency is low. When y exceeds the upper limit, light emission may not be realized by concentration quenching.

A heat treatment step can be added to the above step.

The types of sodium compound, erbium compound, thulium compound, yttrium compound, ytterbium compound, coating step and heat treatment step are described above. The above procedure is shown in Fig. 5 (b).

In order to accomplish the above-mentioned other object, a method for producing a NaYF ₄ pattern doped with A ³⁺ and Yb ³⁺ represented by the following Chemical Formula 1 comprises reacting a sodium compound, a compound A, a yttrium compound and an ytterbium compound with trifluoroacetic acid, poly Acrylic acid and 2-propanol to form a first mixed solution, preparing the first mixed solution on a substrate, and pressing a stamp having a columnar pattern on the substrate on which the first mixed solution is prepared to form a pattern .

[Chemical Formula 1]

A is Er or Tm, and x is a real number with 0.001 = x? = 0.03, preferably 0.003 = x? = 0.02. When x is less than the lower limit, the light-sensitive efficiency is remarkably reduced and the light-emitting efficiency is low. When x exceeds the upper limit, light emission may not be realized due to concentration quenching.

On the other hand, y is a real number with 0.1 = y? = 0.7, preferably 0.2 = y? = 0.6. When y is less than the lower limit, the excitation power is remarkably reduced and the luminous efficiency is low. When y exceeds the upper limit, light emission may not be realized by concentration quenching.

A heat treatment step can be added to the above step.

The types of sodium compounds, erbium compounds, thulium compounds, yttrium compounds, ytterbium compounds and heat treatment steps are described above.

The step of forming the pattern may be performed by soft lithography. Soft lithography has the advantage of being less costly and applicable to flexible substrates than photolithography, electron-beam writing, focused ion beam lithography, X-ray lithography, and scanning probe lithography. Examples of such soft lithography types include fine contact printing, decal transfer fine lithography, optical stamping, replica molding, capillary force lithography, capillary micro molding, micro transfer molding, liquid mediation transfer molding and nanoimprinting. Can be performed by nanoimprinting using a simple and inexpensive apparatus. The order of pattern formation is shown in Fig. 5 (c) and Fig. 6 is a substrate, a dotted line represents a first mixed solution, and an upper dotted pattern represents a patterned stamp.

The interval of the columnar pattern may be 350 nm or more. This value corresponds to the diameter value of the columnar pattern. FIG. 7 (b) is a top view of the NaYF ₄ pattern of Example 11 observed through a scanning electron microscope and showing the distance between the images and the columns.

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 contents of the present invention are not limited to the following examples.

1. Example 1

(3.0 mmol, 246 mg), yttrium acetate (2.34 mmol, 623 mg), ytterbium (0.6 mmol, 210 mg), erbium acetate (0.06 mmol, 20 mg) and polyacrylic acid Were mixed in a mixed solution of acetic acid (1 ml) and 2-propanol (1 ml). A transparent solution was made through magnetic stirring for 20 minutes on a 100 hot plate. The clarified solution was evaporated in a solvent on a 150 hot plate to give a dried precursor powder. The dried powder was heat treated in a tube furnace at 150 ° C for 1 hour and then at 350 ° C for 1 hour to obtain NaYF ₄ : Er ³⁺ _0.02 , Yb ³⁺ _0.2 powder.

2. Example 2

NaYF ₄ : Er ³⁺ _0.02 and Yb ³⁺ _0.6 powder were obtained in the same manner as in Example 1 except that the ytterbium acetate content was 1.8 mmol and 630 mg, and the yttrium acetate content was 1.14 mmol and 303 mg, respectively.

3. Example 3

Trimethyl acetic acid (0.009 mmol, 3 mg) was used in place of erbium acetate (0.06 mmol, 20 mg) and the content of yttrium acetate was 2.4 mmol and 636 mg, respectively. NaYF ₄ : Tm ^{3 +} _0.003 , Yb ³⁺ _0.2 powder was obtained.

4. Example 4

(246 mg), yttrium acetate (623 mg), ytterbium acetate (0.6 mmol, 210 mg), erbium acetate (20 mg) and polyacrylic acid (250 mg) were dissolved in trifluoroacetic acid (1 ml). A transparent solution was made by magnetic stirring for 20 minutes on a 100 占 폚 hot plate. 1 ml of the transparent solution and 7 ml of 2-propanol were mixed to dilute. 35 μl of the diluted solution was placed on a 1.5 mm × 1.5 cm slide glass and made into a thin film by spin coating. The precursor thin film was heat treated in a tube furnace at 150 ° C for 1 hour and then at 350 ° C for 1 hour to obtain NaYF ₄ : Er ³⁺ _0.02 and Yb ³⁺ _0.2 thin films with a thickness of 120 nm.

5. Example 5

And 5 ml of 2-propanol were used as a diluting solution. NaYF ₄ : Er ³⁺ _0.02 and Yb ³⁺ _0.2 thin films were obtained in the same manner as in Example 4 except that the thickness was 190 nm.

6. Example 6

And 4 ml of 2-propanol were used as a diluting solution. NaYF ₄ : Er ³⁺ _0.02 and Yb ³⁺ _0.2 thin films were obtained in the same manner as in Example 4 except that the thickness was 300 nm.

7. Example 7

A thin film of NaYF ₄ : Er ³⁺ _0.02 and Yb ³⁺ _0.6 was obtained in the same manner as in Example 4 except that the ytterbium acetate content was 1.8 mmol and 630 mg and the yttrium acetate content was 1.14 mmol and 303 mg, respectively.

8. Example 8

Tymolyte acetate (0.009 mmol, 3 mg) was used in place of erbium acetate (0.06 mmol, 20 mg) and the yttrium acetate content was 2.4 mmol and 636 mg, respectively. NaYF ₄ : Tm ³⁺ _0.003 , Yb ³⁺ _0.2 thin film was obtained.

9. Example 9

The thin film of Example 4 and the thin film of Example 8 were laminated to obtain a laminate of NaYF ₄ : Er ³⁺ _0.02 , Yb ³⁺ _0.2 / NaYF ₄ : Tm ³⁺ _0.003 , Yb ³⁺ _0.2 .

10. Example 10

The thin film of Example 4 and the thin film of Example 7 were laminated to obtain a laminate of NaYF ₄ : Er ³⁺ _0.02 , Yb ³⁺ _0.2 / NaYF ₄ : Er ³⁺ _0.02 , and Yb ³⁺ _0.6 .

11. Example 11

(246 mg), yttrium acetate (623 mg), ytterbium acetate (0.6 mmol, 210 mg), erbium acetate (20 mg) and polyacrylic acid (250 mg) were dissolved in trifluoroacetic acid (1 ml). A transparent solution was made by magnetic stirring for 20 minutes on a 100 占 폚 hot plate. A 35 μl clear solution was placed on a 1.5 mm x 1.5 cm slide glass, the PDMS mold was raised, and the precursor pattern was formed by evaporating the solvent on a 150 ° C hot plate. The precursor pattern was heat treated in a tube furnace at 150 ° C for 1 hour and then at 350 ° C for 1 hour to obtain a NaYF ₄ : Er ³⁺ _0.02 , Yb ³⁺ _0.2 pattern.

{evaluation}

The thickness and shape of the NaYF ₄ thin film and pattern were measured using a scanning electron microscope (SEM, Hitachi, S-4800) and atomic force microscope (AFM, Park Systems, XE-100). The crystallographic structure of the NaYF ₄ thin film and the precursor powder was analyzed using an X-ray diffractometer (Rigaku D, max-250 V / PC). The thermogravimetry / differential scanning calorie was measured at a heating rate of 10 ° C / min using TGA / DSC (TA instruments, SDT Q600). The up-conversion luminescence spectrum of the NaYF ₄ thin film and pattern was measured using a continuous wave diode laser with a wavelength of 980 nm (Changchun New Industries Optoelectronics Tech Co. Ltd., MDL-H-980) and a spectrophotometer (Ocean Optics, HR 2000+) . The functional groups of NaYF ₄ precursor powder were confirmed by Fourier transform infrared spectroscopy (FT-IR, Agilent, Cary 630). Photos of NaYF ₄ thin film and precursor powder were obtained using a digital single lens reflex camera (DSLR camera, Sony, Sony alpha A900).

1. NaYF ₄  Emission properties and structure of precursor powder

Figs. 1 (a) to 1 (c) show emission patterns of the precursor powder before the heat treatment step of Example 2, Example 1 and Example 3, respectively, which emit up-converted light under irradiation with 980 nm light. According to the results, it was confirmed that the luminescent color was adjusted according to the kind of the lanthanide ions doped and the doping concentration, and the luminescent color was shown to be orange, Fig. 1 (b), and Fig. 1 (c)

Fig. 1 (e) is an X-ray diffraction pattern of the precursor powders of Examples 1 to 3. According to this, it can be confirmed that all the precursor powders have a hexagonal crystal structure. The hexagonal structure shows higher up conversion efficiency than the cubic system.

2. NaYF ₄  Differential scanning calorie and thermal weight of powder

2 (a) is an X-ray diffraction pattern of NaYF ₄ powder of Examples 1 to 3 obtained by heat-treating the precursor powder. FIG. 2 (b) shows the differential scanning calorimetry and thermogravimetric analysis of the precursor powder. According to this, it can be confirmed that as the NaYF ₄ powder is formed through the heat treatment step of the precursor powder, the crystallographic structure changes from amorphous to equiaxed crystal system depending on the temperature. The hexagonal structure shows higher up conversion efficiency than the cubic system.

Fig. 2 (c) is a Fourier transform infrared spectroscopy spectrum of the precursor powders of Examples 1 to 3 and NaYF ₄ powder. According to this, the carbonyl group contained in the precursor is lost in the heat treatment step. That is, referring to FIG. 2 (c), it can be confirmed that after the heat treatment step, all of the organic compounds are removed and inorganic powders are formed.

3. NaYF ₄  Thin film morphology and structure

3 (a) to 3 (c) are side-view images of NaYF ₄ thin films of Examples 4 to 6 taken through a scanning electron microscope, respectively. According to this, it can be confirmed that the thickness of the NaYF ₄ thin film can be controlled.

3 (d) is a surface image of the NaYF ₄ thin film of Example 5 taken through a scanning electron microscope. 3 (e) is the surface roughness of the NaYF ₄ thin film of Example 4 taken through an atomic force microscope. According to this, it can be confirmed that a thin film having a smooth surface with a surface roughness of 3.38 nm was fabricated.

3 (f) is an X-ray diffraction pattern of the NaYF ₄ thin film of Example 4. Fig. According to this, it can be confirmed that the NaYF ₄ thin film has a hexagonal crystal structure. The hexagonal structure shows higher up conversion efficiency than the cubic system.

4. NaYF ₄  Luminescent properties of thin films and laminates

4 (a), 4 (c) and 4 (e) show the NaYF ₄ thin films of Examples 8, 4 and 7, respectively, which emit light upwardly under irradiation with 980 nm light. 4 (e)), green (Example 4, Fig. 4 (c)), and blue (Example 7, (Fig. 4 (a)).

Fig. 4 (b) and Fig. 4 (d) are views of the NaYF ₄ laminate of the ninth and tenth embodiments, each of which emits up-converted light under irradiation with 980 nm light. According to this, it can be confirmed that the luminescent color is controlled through the laminated structure, and the luminescent light is emitted in the form of cyan and green.

Fig. 4 (f) shows the luminescence spectra of the NaYF ₄ thin films of Example 8, Example 4, and Example 7 and the NaYF ₄ laminate of Example 9 and Example 10 under 980 nm light irradiation.

FIG. 4 (g) is the notation on the CIE (International Lighting Commission) color coordinates of the NaYF ₄ thin films of Examples 8, 4 and 7 and the NaYF ₄ laminate of Examples 9 and 10 under 980 nm light irradiation .

5. NaYF ₄  Luminescent properties of thin films and patterns

Figure 8 (a) is up-converted emission spectrum of NaYF ₄ patterns of the Example 4 of the thin film NaYF ₄ and Example 11. FIG. 8 (b) is a graph of light emission intensity change by the ⁴ S _3/2 → ⁴ I _15/2 transition of the NaYF ₄ thin film of Example 4 and the NaYF ₄ pattern of Example 11 according to the intensity of incident light. FIG. 8 (c) is a graph showing the intensity of the incident light beam of Example 4, NaYF ₄ NaYF ⁴ of ₄ patterns of the thin film and Example 11 F _9/2 → ⁴ is a light intensity change due to the I _15/2 transition graph. According to this, it is confirmed that the up-conversion efficiency of light emission by the ⁴ F _9/2 → ⁴ I _15/2 transition of the NaYF ₄ pattern is improved 2.7 times as compared with that of the smooth NaYF ₄ thin film.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications and variations without departing from the spirit and scope of the invention. Accordingly, it is intended that the appended claims cover all such modifications and variations as fall within the true spirit of the invention.

Claims (7)

A NaYF ₄ thin film represented by the following Chemical Formula 1 and doped with A ³⁺ and Yb ³⁺ , The surface roughness value (Ra) NaYF ₄ films, characterized in that a range from 3 nm 10 nm: [Chemical Formula 1]

Wherein A is Er or Tm, X is a real number with 0.001 = x < = 0.03, Y is a real number with 0.1 = y < = 0.7. The method according to claim 1, NaYF ₄ films, characterized in that the thickness of the film is less than 100 nm 400 nm. A NaYF ₄ laminate represented by the following formula (1) and doped with A ³⁺ and Yb ³⁺ , The surface roughness value (Ra) is more than 3 nm 10 nm or less NaYF ₄ films are laminated NaYF _4, it characterized in that the laminated body is more than one: [Chemical Formula 1]

Wherein A is Er or Tm, X is a real number with 0.001 = x < = 0.03, Y is a real number with 0.1 = y < = 0.7. As a pattern of NaYF ₄ represented by the following formula 1 and doped with A ³⁺ and Yb ³⁺ , NaYF ₄ pattern as the pattern is a columnar form, it characterized in that the height and diameter of nano-size: [Chemical Formula 1]

Wherein A is Er or Tm, X is a real number with 0.001 = x < = 0.03, Y is a real number with 0.1 = y < = 0.7. Mixing the sodium compound, the compound A, the yttrium compound and the ytterbium compound with trifluoroacetic acid, polyacrylic acid and 2-propanol to form a first mixed solution; And And coating the first mixed solution on a substrate. A method for preparing a NaYF ₄ thin film doped with A ³⁺ and Yb ³⁺ represented by the following formula 1: [Chemical Formula 1]

Wherein A is Er or Tm, X is a real number of 0.001? X? 0.03, Y is a real number of 0.1? Y? 0.7. Mixing the sodium compound, the compound A, the yttrium compound and the ytterbium compound with trifluoroacetic acid, polyacrylic acid and 2-propanol to form a first mixed solution; And Coating the first mixed solution on a substrate, and repeating the coating twice or more. A process for producing a NaYF ₄ laminate represented by the following formula 1 and doped with A ³⁺ and Yb ³⁺ : [Chemical Formula 1]

Wherein A is Er or Tm, X is a real number of 0.001? X? 0.03, Y is a real number of 0.1? Y? 0.7. Mixing the sodium compound, the compound A, the yttrium compound and the ytterbium compound with trifluoroacetic acid, polyacrylic acid and 2-propanol to form a first mixed solution; Preparing the first mixed solution on a substrate; And And forming a pattern by pressing a stamp having a columnar pattern on the substrate on which the first mixed solution is prepared. A method for producing a NaYF ₄ pattern represented by the following formula 1 and doped with A ³⁺ and Yb ³⁺ : [Chemical Formula 1]

Wherein A is Er or Tm, X is a real number with 0.001 = x < = 0.03, Y is a real number with 0.1 = y < = 0.7.

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