KR20200144978A - A green nano-phosphor with high stability and ultra-narrow full-width at half-maximum for display application, and preparing method the same - Google Patents

Abstract

The present invention relates to a green nano-phosphor for a display with high stability and narrow half width, and to a production method thereof and, more specifically, to a nano-phosphor for a display showing a luminous peak in a wavelength range of 510 to 550 nm and having a half width (FWHM) of 10 to 25 nm, to a production method thereof, and to a display device comprising the nano-phosphor. According to the present invention, because it is not easily decomposed by water, heat, and moisture, it is stable. In addition, compared to the conventional nano-phosphor, it has an extremely narrow half-width so that a wide color area can be realized, it is safe because cadmium, which is harmful to the human body, is not included, the luminous properties are maintained for a long time, and economical efficiency is high.

Description

A green nano-phosphor with high stability and ultra-narrow full-width at half-maximum for display application, and preparing method the same}

The present invention relates to a green nano phosphor for a display having a high stability and a narrow half width, and a method for manufacturing the same. It relates to a method of manufacturing the same, and a display device including such a nano phosphor.

It is known that a conventional quantum dot emitting light in the visible light region has a full width at half maximum (FWHM) of 30-54 nm. It is reported that such quantum dots can implement a wide color gamut through a narrow half-width, and can cover up to 90% of the DCI-P3 (Digital Cinema Initiatives P3) color space defined by the movie industry. The narrower the full width of the phosphor is, the wider the color gamut can be realized than DCI-P3 such as BT 2020 (Rec 2020), and the display technology is more highly appreciated and ultimately, realistic colors can be reproduced.

However, there is a problem that the core of the quantum dot, which can realize a wide color gamut through a narrow half-width, is easily decomposed and vulnerable by water, heat, and moisture. In order to overcome this problem, the quantum dot is used by forming a shell surrounding the surface of the quantum dot by applying the same method as the quantum dot shell technology, but this entails another problem of higher manufacturing cost than LCD.

In recent years, through various research results, it was confirmed that a material having a perovskite structure not only has excellent luminescence properties, but also has relatively many advantages over conventional phosphors in terms of manufacturing time and manufacturing cost. Started doing. Initially, the purpose of the development of perovskite materials was the light absorbing layer of solar cells, but related research was accelerated, expanding the possibility of application to the fields of laser, light emitting diode (LED), and photocatalyst.

Accordingly,'Korea Patent Laid-Open No. 10-2016-0054736' provides an organic-inorganic hybrid perovskite nanocrystalline particle light emitter having a two-dimensional structure, a method for manufacturing the same, and a light emitting device using the same, but a method for manufacturing a light emitter There is a problem in that only is listed, the luminous properties of the luminous body are not disclosed, and the stability of the existing perovskite vulnerable to moisture is not disclosed.

Accordingly, an object of the present invention is to invent a nano-phosphor for display that is stable in moisture and can realize a wide color gamut by using zeolite, which is a porous material, focusing on the above problems.

KR 10-2016-0054736 A KR 10-1647764 B1

In order to solve the above problems, an object of the present invention is to provide a nano-phosphor for a display that exhibits an emission peak in a wavelength range of 510 to 550 nm.

In addition, it is an object of the present invention to provide a display nanophosphor represented by zeolite-Cs ₆ Pb(Br _a Y _1-a ) ₄ .

In addition, an object of the present invention is to provide a display nanophosphor having a half width (FWHM) of 10 to 25 nm.

In addition, it is an object of the present invention to provide a method of manufacturing a nano-phosphor for display.

In addition, an object of the present invention is to provide a display device comprising a nano-phosphor for display.

In order to solve the above object, the present invention,

It is represented by the following Equation 1 and provides a nano-phosphor for a display, characterized in that it exhibits an emission peak in a wavelength range of 510 to 550 nm:

[Equation 1]

Zeolite-Cs ₆ PbX ₄

X is at least one selected from the group consisting of bromine (Br), chlorine (Cl), and iodine (I).

In order to solve the above other object, the present invention,

It provides a nano-phosphor for a display, characterized in that represented by the following formula 2:

[Equation 2]

Zeolite-Cs ₆ Pb(Br _a Y _1-a ) ₄ (0.8<a≤1)

Y is at least one selected from chlorine (Cl) and iodine (I).

In order to solve the another object, the present invention,

Zeolite skeleton; And

It contains cesium (Cs), lead (Pb), and bromine (Br) introduced into the space created by the zeolite skeleton,

It provides a nano-phosphor for display, characterized in that it has a half width (FWHM) of 10 to 25 nm.

In order to solve the another object, the present invention,

A first step of reacting zeolite powder with an aqueous solution of cesium to form a zeolite in which cesium ions are exchanged;

A second step of adding the cesium ion-exchanged zeolite to an organic solvent and stirring to form a stirring solution;

_{Pb (Br a Y 1-a} ) a third step of the _second reagent to remove the gas in the mixed mixture to form the solution of _{Pb (Br a Y 1-a} ) _2, the reagents are completely dissolved under a nitrogen atmosphere;

A fourth step of adding and reacting a solution in which the Pb(Br _a Y _1-a ) ₂ reagent is completely dissolved in the stirred solution to form a reaction product;

Including a fifth step of washing the reactant;

A is greater than 0.8 and less than or equal to 1, and Y is at least one selected from chlorine (Cl) and iodine (I).

In order to solve the another object, the present invention,

It provides a display device comprising a nano-phosphor.

The present invention provides a green nano-phosphor for display with high stability and a narrow half-width, and a method for manufacturing the same, so that it is not easily decomposed by water, heat, and moisture, so it is stable, and has an extremely narrow half-value width compared to the conventional nano-phosphor. There is an effect to implement, and it does not contain cadmium harmful to the human body, so it is safe, the luminous property is maintained for a long time, and there is a high economic effect.

1 is a schematic diagram of a flask used in the manufacturing process of a nanophosphor according to an embodiment of the present invention.
2A shows the color and emission wavelength of the nanophosphor powder prepared according to an embodiment of the present invention, and the color and emission wavelength of the nanophosphor dispersed in distilled water.
2B shows the emission wavelength over time of the nanophosphor powder prepared according to an embodiment of the present invention.
3A is a graph showing the emission wavelength and half width of a nanophosphor powder prepared according to an embodiment of the present invention.
3B is a graph of attenuation time of a nano phosphor manufactured according to an embodiment of the present invention.
3C is a photograph of time-resolved light emission of a nano phosphor prepared according to an embodiment of the present invention.
4A is a graph showing the emission wavelength and half width when a nanophosphor prepared according to an embodiment of the present invention is dispersed in water.
4B is a graph showing the emission wavelength and half width when a nanophosphor prepared according to an embodiment of the present invention is dispersed in hexane.
5 is a powder XRD analysis graph of a nanophosphor and zeolite prepared according to an embodiment of the present invention.
6 is a Cs ₆ PbBr ₄ introduced in a nano phosphor prepared according to an embodiment of the present invention It shows the structure of the complex.
7 shows a comparison of the structure of a nano-phosphor prepared according to an embodiment of the present invention and a perovskite (CsPbBr ₃ ) including Cs, Pb, and Br.

In the present specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated. In addition, terms used in the present specification are for describing embodiments, and are not intended to limit the present invention. In the present specification, the singular form also includes the plural form unless specifically stated in the phrase.

The present invention relates to a green nano phosphor for a display having high stability and a narrow half width, and a method for manufacturing the same.

Hereinafter, the present invention will be described in more detail.

According to one aspect, the present invention provides a nano-phosphor for a display, characterized in that it is represented by Equation 1 below and exhibits a luminescence peak in a wavelength range of 510 to 550 nm:

[Equation 1]

Zeolite-Cs ₆ PbX ₄

X may be at least one selected from the group consisting of bromine (Br), chlorine (Cl), and iodine (I).

The nanophosphor of the present invention may exhibit an emission peak in a wavelength range of 510 to 550 nm, and preferably may exhibit an emission peak in a wavelength range of 515 to 530 nm. In addition, it may exhibit an emission wavelength range of 480 to 580 nm, and preferably may exhibit an emission wavelength range of 500 to 560 nm.

In the present invention, the zeolite may be at least one selected from zeolite-A, zeolite-X, zeolite-Y, and H-zeolite-Y, and preferably zeolite-X, and H-zeolite-Y. The skeletons of zeolite X and Y are the same structurally, but if the Si/Al ratio of the skeleton is 1.5 or more, it is called zeolite Y, and if it is less than 1.5, it is called zeolite X. The zeolite skeleton may be a skeleton of a zeolite or a skeleton of a synthetic zeolite. Physical and chemical properties of the zeolite may vary greatly depending on the aluminum content, i.e., Si / Al molar ratio of the framework, takes on the Al ^{3 +} a large zeolite framework negative charge on the zeolite framework and non-framework cations in the zeolite within the pores for these of the charge balance There will be a lot of this. Non-skeletal cations can be easily substituted with other cations, and the physicochemical properties of zeolites can be changed by the exchange of these cations.

In zeolite, the central atoms of silicon and aluminum are coordinated with four oxygen atoms in the form of a tetrahedron, and this unit is called TO ₄ . TO ₄ can form various structures by sharing and bonding with other central atoms and oxygen atoms. In this way, the part made of Si, Al, and O is called the skeleton, and the rest is called the non-skeleton. Accordingly, in the present invention, an element (ion) not included in the existing zeolite skeleton, such as an ion-exchanged element (ion), can be referred to as a'non-skeleton element (ion)', and the element (ion) constituting the zeolite skeleton is'skeleton. It can be called an element (ion).

In general, unprocessed zeolites have pores inside the skeleton filled with water molecules, but since they are structurally loosely bonded, moisture is easily released when heat is applied, and the skeleton remains as it is, and the inside of the pores is easily emptied into the zeolite skeleton. Other elements and particulate matter may be introduced. As described above, Cs ₆ PbX ₄ in [Equation 1] of the present invention may be introduced into a space where a skeleton of a zeolite is formed, and the nanophosphor formed by Cs ₆ PbX ₄ is a zeolite introduced into an internal space formed by a skeleton. It can mean.

Nano-phosphors may be combined with the zeolite framework elements of oxygen and Cs ₆ PbX ₄ cesium, and formed by the X and cesium Cs ₆ PbX ₄ combined, the nano fluorescent material by such a coupling relationship of the present invention is a moisture and heat It can exist stably even in an environment where there is.

Here, X may be at least one selected from the group consisting of bromine (Br), chlorine (Cl), and iodine (I), and preferably at least one selected from bromine, bromine-chlorine, and bromine-iodine. .

The full width at half maximum (FWHM) is also referred to as the full width at half maximum, and may mean the wavelength width corresponding to 1/2 of the maximum value of the curve representing the wavelength. The narrow half-width means that the area of color that can be implemented is wide, which may mean that it is possible to implement colors closer to natural colors.

Conventional quantum dots known as light-emitting materials in the visible region are known to have a half width of about 30 to 55 nm, but the nanophosphors of the present invention have a half width of 10 to 25 nm, and preferably have a half width of 15 to 25 nm. Can have

According to another aspect, the present invention provides a nano-phosphor for a display, characterized in that represented by the following formula 2:

[Equation 2]

Zeolite-Cs ₆ Pb(Br _a Y _1-a ) ₄ (0.8<a≤1)

Y may be at least one selected from chlorine (Cl) and iodine (I).

In the present invention, the zeolite may be at least one selected from zeolite-A, zeolite-X, zeolite-Y, and H-zeolite-Y, and preferably zeolite-X, and H-zeolite-Y.

In general, unprocessed zeolites have pores inside the skeleton filled with water molecules, but since they are structurally loosely bonded, moisture is easily released when heat is applied, and the skeleton remains as it is, and the inside of the pores is easily emptied into the zeolite skeleton. Other elements and particulate matter may be introduced. As described above, Cs ₆ Pb(Br _a Y _1-a ) ₄ of [Equation 2] of the present invention may be introduced into a space where the skeleton of a zeolite is formed, and the nanophosphor formed thereby is Cs ₆ Pb(Br _a Y _{1 -a} ) It may mean zeolite introduced into the inner space formed by the _tetravalent skeleton.

Nano fluorescent material of the present invention is formed by the combination Y and cesium in the zeolite framework elements of oxygen and _{Cs 6 Pb (Br a Y 1} -a) a combination of _four Cs, and _{Cs 6 Pb (Br a Y 1} -a) 4 The nano-phosphor can be stably present even in an environment with humidity or heat due to this coupling relationship.

Such a nanophosphor may emit green light, may exhibit an emission wavelength range of 480 to 580 nm, and may exhibit an emission peak in a wavelength range of 510 to 550 nm. Preferably, it may exhibit an emission wavelength range of 500 to 560 nm, and may exhibit an emission peak in a wavelength range of 515 to 530 nm.

In addition, the nano-phosphor of the present invention may have a half width of 10 to 25 nm, and preferably may have a half width of 15 to 25 nm.

According to another aspect, the present invention provides a zeolite skeleton; And cesium (Cs), lead (Pb), and bromine (Br) introduced into the space created by the zeolite skeleton, and has a half width (FWHM) of 10 to 25 nm. do.

In the nanophosphor of the present invention, the'zeolite skeleton' may be a skeleton of a zeolite or a skeleton of a synthetic zeolite.

In general, unprocessed zeolites have pores inside the skeleton filled with water molecules, but since they are structurally loosely bonded, moisture is easily released when heat is applied, and the skeleton remains as it is, and the inside of the pores is easily emptied into the zeolite skeleton. Other elements and particulate matter may be introduced.

Cesium (Cs), lead (Pb), and bromine (Br) introduced into the space created by the zeolite skeleton of the present invention can form a complex. Cesium can combine with oxygen, which is a zeolite skeleton element, and with bromine, and lead and bromine can form nanostructures. Preferably, cesium, lead, and bromine can form a Cs ₆ PbBr ₄ complex, and the Cs ₆ PbBr ₄ complex can be introduced into a space created by a zeolite skeleton, and the cesium of the complex can bind with oxygen, a zeolite skeleton element. And can be combined with bromine of the PbBr ₄ structure. Due to this binding relationship, the Cs ₆ PbBr ₄ complex can stably exist in the zeolite.

The nanophosphor of the present invention may emit green light, may exhibit an emission wavelength range of 480 to 580 nm, and may exhibit an emission peak in a wavelength range of 510 to 550 nm. Preferably, it may exhibit an emission wavelength range of 500 to 560 nm, and may exhibit an emission peak in a wavelength range of 515 to 530 nm.

In addition, the nano-phosphor of the present invention may have a half width of 10 to 25 nm, and preferably may have a half width of 15 to 25 nm.

According to another aspect, the present invention provides a first step of reacting a zeolite powder with an aqueous solution of cesium to form a zeolite in which cesium ions are exchanged; A second step of adding the cesium ion-exchanged zeolite to an organic solvent and stirring to form a stirring solution; _{Pb (Br a Y 1-a} ) a third step of the _second reagent to remove the gas in the mixed mixture to form the solution of _{Pb (Br a Y 1-a} ) _2, the reagents are completely dissolved under a nitrogen atmosphere; A fourth step of adding and reacting a solution in which the Pb(Br _a Y _1-a ) ₂ reagent is completely dissolved in the stirred solution to form a reaction product; A fifth step of washing the reactant; wherein a is greater than 0.8 and 1 or less, and Y is at least one selected from chlorine (Cl) and iodine (I). Provides.

In the first step of the method for producing a nanophosphor of the present invention, the sodium ions or hydrogen ions of the zeolite powder may be ion-exchanged with the cesium ions of the aqueous solution of cesium, and preferably 60 to 70% of the sodium ions or hydrogen ions of the zeolite are It can be ion-exchanged with cesium ions.

Afterwards, in the second step, a stirring liquid can be formed in a vacuum state, and the stirring liquid thus formed removes gas in the liquid before reacting with the Pb(Br _a Y _1-a ) ₂ reagent, and changes to a nitrogen atmosphere by introducing nitrogen. I can. In addition, in the third step, a Pb(Br _a Y _1-a ) ₂ reagent may be added to an organic solvent to form a mixed solution, and after removing gas in the mixed solution, an organic solvent may be additionally added under a nitrogen atmosphere.

Any organic solvent used in the second and third steps may have a high boiling point and low reactivity, but preferably has a boiling point of 300°C or higher.

The fourth step of forming the reactant is to react the zeolite in which cesium ions in the stirring solution are exchanged at 100 to 200°C and Pb(Br _a Y _1-a ) ₂ , and the nano phosphor is finally produced depending on the temperature during the reaction. The center wavelength of can be changed.

Finally, in the fifth step, the reactant may be repeatedly washed with an organic solvent, and preferably, it may be repeatedly washed 2 to 5 times with at least one selected from hexane and alcohols.

According to another aspect, the present invention provides a display device comprising a nano-phosphor. The description of the nano-phosphor is the same as or similar to the description of the nano-phosphor for display of the present invention, and thus will be omitted.

The display device including the nano-phosphor of the present invention may be any device that visually displays data, but is preferably a Back Light Unit LED display, and more preferably a Quantum Dots display.

Hereinafter, examples will be described in detail in order to describe the present specification in detail. However, the embodiments according to the present specification may be modified in various forms, and the scope of the present specification is not construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely describe the present specification to those of ordinary skill in the art.

< Example >

Example 1-Synthesis of nanophosphors ( Cs,Na -X ( Si /Al = 1.40))

A mixture of zeolite X (Na-X) powder (<5 m) 0.5 g Cs acetate and 0.1 M aqueous solution of 100 mL, and then the reaction was stirred for one day replace the Na ⁺ ions with Cs ⁺ ions zeolite powder (Cs, Na- X powder) was prepared, and 0.5 g of the prepared Cs,Na-X powder was added to 5 mL of 1-octadecene and stirred in a vacuum state.

Thereafter, 0.067 g (0.188 mmol) of PbBr ₂ reagent was added to 5 mL of 1-octadecene and reacted for 15 to 30 minutes in a vacuum at 100°C to remove gas from the solution, and 1 mL of oleylamine and 1 mL of oleic acid were added to a nitrogen atmosphere. And reacted at 120° C. until the PbBr ₂ reagent was completely dissolved.

Remove the gas of the previously stirred Cs,Na-X powder solution, and add nitrogen to make a nitrogen atmosphere, and then inject 6 mL of the solution in which the PbBr ₂ reagent is completely dissolved into the Cs, Na-X powder solution using a syringe. Reacted at 150℃ for 30 minutes, cooled at room temperature, washed twice with hexane and once with isopropyl alcohol, dried at 60℃, and finally introduced Cs, Pb, and Br to the non-skeleton position of the zeolite to prepare a green nanophosphor. I did.

Example 2-Synthesis of nanophosphors ( Cs,Na -A ( Si /Al = 1.00))

A mixture of zeolite A (Na-A) powder (<5 m) 0.5 g Cs acetate and 0.1 M aqueous solution of 100 mL, and then the reaction was stirred for one day replace the Na ⁺ ions with Cs ⁺ ions zeolite powder (Cs, Na- A powder) was prepared, and 0.5 g of the prepared Cs,Na-A powder was added to 5 mL of 1-octadecene and stirred in a vacuum state.

Thereafter, 0.067 g (0.188 mmol) of PbBr ₂ reagent was added to 5 mL of 1-octadecene and reacted for 15 to 30 minutes in a vacuum at 100°C to remove gas from the solution, and 1 mL of oleylamine and 1 mL of oleic acid were added to a nitrogen atmosphere. And reacted at 120° C. until the PbBr ₂ reagent was completely dissolved.

After removing the gas of the previously stirred Cs,Na-A powder solution, adding nitrogen to make a nitrogen atmosphere, and then injecting 6 mL of the solution in which the PbBr ₂ reagent is completely dissolved into the Cs, Na-A powder solution using a syringe. Reacted at 150℃ for 30 minutes, cooled at room temperature, washed twice with hexane and once with isopropyl alcohol, dried at 60℃, and finally introduced Cs, Pb, and Br to the non-skeleton position of the zeolite to prepare a green nanophosphor. I did.

Example 3-Synthesis of nanophosphors ( Cs,Na -Y ( Si /Al = 2.55))

Was mixed with 0.5 g zeolite Y (Na-Y) powder (<5 m) and Cs acetate 0.1 M aqueous solution of 100 mL to exchange Na ⁺ ions was reacted by stirring for one day the Cs ⁺ ion-zeolite powder (Cs, Na- Y powder) was prepared, and 0.5 g of the prepared Cs,Na-Y powder was added to 5 mL of 1-octadecene and stirred in a vacuum state.

Thereafter, 0.067 g (0.188 mmol) of PbBr ₂ reagent was added to 5 mL of 1-octadecene and reacted for 15 to 30 minutes in a vacuum at 100°C to remove gas from the solution, and 1 mL of oleylamine and 1 mL of oleic acid were added to a nitrogen atmosphere. And reacted at 120° C. until the PbBr ₂ reagent was completely dissolved.

After removing the gas of the previously stirred Cs,Na-Y powder solution, adding nitrogen to make a nitrogen atmosphere, and then injecting 6 mL of the solution in which the PbBr ₂ reagent is completely dissolved into the Cs, Na-Y powder solution using a syringe. Reacted at 150℃ for 30 minutes, cooled at room temperature, washed twice with hexane and once with isopropyl alcohol, dried at 60℃, and finally introduced Cs, Pb, and Br to the non-skeleton position of the zeolite to prepare a green nanophosphor. I did.

Example 4-Synthesis of nanophosphors ( Cs,H -Y ( Si /Al = 2.55))

By mixing the zeolite H- -Y (HY) powder (<5 m) 0.5 g Cs acetate and 0.1 M aqueous solution of 100 mL, and then the reaction was stirred for one day replace the H ⁺ ion in the zeolite powder Cs ⁺ ions (Cs, HY Powder) was prepared, and 0.5 g of the prepared Cs,HY powder was added to 5 mL of 1-octadecene and stirred in a vacuum state.

Thereafter, 0.067 g (0.188 mmol) of PbBr ₂ reagent was added to 5 mL of 1-octadecene and reacted for 15 to 30 minutes in a vacuum at 100°C to remove gas from the solution, and 1 mL of oleylamine and 1 mL of oleic acid were added to a nitrogen atmosphere. And reacted at 120° C. until the PbBr ₂ reagent was completely dissolved.

After removing the gas of the previously stirred Cs,HY powder solution, adding nitrogen to make a nitrogen atmosphere, and then injecting 6 mL of the solution in which the PbBr ₂ reagent is completely dissolved into the Cs, HY powder solution using a syringe and injecting it at 150℃ for 30 The reaction was performed for a minute, cooled at room temperature, washed twice with hexane and once with isopropyl alcohol, and then dried at 60°C to prepare a green nanophosphor in which Cs, Pb, and Br were finally introduced into the non-skeleton position of the zeolite.

Example 5-Synthesis of nanophosphors ( Cs,H -Y ( Si /Al = 30))

By mixing the zeolite H- -Y (HY) powder (<5 m) 0.5 g Cs acetate and 0.1 M aqueous solution of 100 mL, and then the reaction was stirred for one day replace the H ⁺ ion in the zeolite powder Cs ⁺ ions (Cs, HY Powder) was prepared, and 0.5 g of the prepared Cs,HY powder was added to 5 mL of 1-octadecene and stirred in a vacuum state.

Thereafter, 0.067 g (0.188 mmol) of PbBr ₂ reagent was added to 5 mL of 1-octadecene and reacted for 15 to 30 minutes in a vacuum at 100°C to remove gas from the solution, and 1 mL of oleylamine and 1 mL of oleic acid were added to a nitrogen atmosphere. And reacted at 120° C. until the PbBr ₂ reagent was completely dissolved.

After removing the gas of the previously stirred Cs,HY powder solution, adding nitrogen to make a nitrogen atmosphere, and then injecting 6 mL of the solution in which the PbBr ₂ reagent is completely dissolved into the Cs, HY powder solution using a syringe and injecting it at 150℃ for 30 The reaction was performed for a minute, cooled at room temperature, washed twice with hexane and once with isopropyl alcohol, and then dried at 60°C to prepare a green nanophosphor in which Cs, Pb, and Br were finally introduced into the non-skeleton position of the zeolite.

The preparation of the PbBr ₂ reagent solution and the reaction between the cesium ion-exchanged zeolite and the PbBr ₂ reagent in the manufacturing process of the nanophosphors of Examples 1 to 5 were performed using the three-neck flask shown in FIG. 1 below.

< Experimental example >

Experimental example 1-Water stability test of nano phosphor

0.2 g of the green nano-phosphor sample prepared according to Examples 1 to 5 was added to 5 mL of tertiary distilled water and irradiated with UV at 365 nm to observe the wavelength change of the nano-phosphor over time and to check the degree of luminescence, Through this, the stability against moisture was confirmed.

Experimental example 2-Test to confirm the luminescence properties of nano phosphors

The emission wavelength and attenuation time of the nanophosphor powder prepared according to Example 1 were measured (F-7000, Hitachi). In addition, a nano-phosphor powder sample was placed on a confocal microscope (MicroTime-200, Picoquant, Germany) and excited with a 375 nm single-mode diode laser having a 30 ps pulse to measure a time-resolved fluorescence image of 200 x 200 pixels. .

Experimental example 3-Test to confirm the emission wavelength according to the sample condition of the nano phosphor

After dispersing 0.1 g each of the green nanophosphor powder sample prepared according to Example 1 in tertiary distilled water and 5 mL of hexane, 365 nm UV was irradiated and the emission wavelength was confirmed using a spectrometer of ocean optics.

Experimental example 4-Analytical test on nano-phosphor ( XRD )

The nanophosphors prepared according to Example 1, the nanophosphors of Example 1 dispersed in distilled water, the cesium ion-exchanged zeolite powder (Cs, Na-X), and zeolite X were analyzed through XRD.

First, zeolite X (Na-X), which is a starting material, was purchased from Union Carbide, and was compared with Na-X of JCPDS card to confirm whether it has an actual Na-X structure, and Cs, Na-X and Example 1 XRD analysis of the thus prepared nanophosphors was performed. In addition, in order to test the stability of the nano-phosphor to water, the nano-phosphor was put in tertiary distilled water for about a month, and then the water was removed and the XRD pattern of the dried powder sample was analyzed to confirm whether the crystallinity was maintained.

Experimental example 5-Structure confirmation test of nano phosphor

A single crystal sample of the nanophosphor prepared according to Example 1 was prepared and a diffraction test was performed using X-rays of a Pohang accelerator.

For the test, a 2D-SMC beamline of Pohang accelerator was used, and the wavelength of the X-ray used at this time was set to 0.62 Å, the distance between the sample and the detector was set to 62 mm, and the exposure time was set to 72 frames for a total of 72 seconds for 1 second per frame. . For the diffraction pattern, a space group of F23 was selected using the HKL3000 program, and refinement was performed with SheleX 2016. The three-dimensional three-dimensional structure was drawn using a crystal maker program, through which Cs ₆ PbBr ₄ introduced into the nano phosphor and the nano phosphor. The structure of the composite was confirmed.

<Evaluation and results>

Results 1-Light emission and moisture stability of nanophosphors

According to Examples 1 to 5 and Experimental Example 1, the light emission and moisture stability of each of the nano-phosphors were confirmed, which are illustrated in FIGS. 2A to 2B.

In Figure 2a, (a) and (c) show each nano-phosphor under fluorescent lamp illumination, and (b) and (d) to (i) show each nano-phosphor when irradiated with 365 nm UV. In addition, (d) to (i) show the degree of luminescence over time of each nanophosphor dispersed in distilled water, and from the left of each photograph, Examples 2, 1, 3, 4, And the nanophosphors according to Example 5.

As a result of confirming this, it was confirmed that green light was emitted from all of the nanophosphors according to Examples 1 to 5, and the degree of luminescence was different over time. Comparing with FIG. 2B showing the degree of luminescence of each nanophosphor in a powder state, the nanophosphor of Example 1 and the nanophosphor of Example 4 maintained fluorescence for a longer time than the other examples. It was confirmed that the nanophosphor immediately loses its fluorescence. In addition, it was confirmed that when the nanostructure was dispersed in water, it exhibited remarkably excellent light emission in Example 1.

In general, the skeletons of zeolite X and Y are the same structurally, but when the Si/Al ratio of the skeleton is 1.5 or more, it is called zeolite Y, and when it is less than 1.5, it is called zeolite X. When there is a lot of Al in the zeolite skeleton, there are many non-skeletal cations in the pupil of the zeolite, and when there is little Al, there are fewer non-skeletal cations. In the case of zeolite X used to prepare the nanophosphor in Example 1, since the Al content was higher than that of zeolite Y, it contained more cations in the non-skeletal position in the supercage pupil, thereby further stabilizing the introduced nanostructure in the pupil in the zeolite. It is judged to give the best moisture stability among the examples.

On the other hand, zeolite A used to prepare the nanophosphor in Example ₂ has a high Al content like zeolite X, but it is determined that the PbBr ₂ solution is difficult to pass through due to a small pupil entrance, so that the phosphor cannot be properly introduced. It is confirmed to lose fluorescence.

Results 2-Luminescent properties of nanophosphors

In the result 1, the luminescence properties of the nanophosphor prepared according to Example 1 showing excellent moisture stability were confirmed according to Experimental Example 2, and the results are shown in FIGS. 3A to 3C.

As a result, in FIG. 3A, the nanophosphor powder exhibited a central wavelength of 524 nm, and it was confirmed that the half width was 18 nm.

3B is a result of measuring the decay time of the nano phosphor powder, and the measured values were fitted with four exponential equations. As a result of the calculation, four types of attenuation times are shown, and the attenuation times are τ ₁ = 19 ns and τ ₂ , respectively. = 445 ns, τ ₃ = 83 ns, τ ₄ = 2.9 ns. Accordingly, it was found that the attenuation time of the nano-phosphor of the present invention is similar to that of the currently commercially-used display-use phosphors, and satisfies the conditions that can be used for display.

3C is a time-resolved fluorescence image of the nano phosphor powder, as a result of confirming this, it was confirmed that the color appeared evenly. This means that the attenuation time distribution of the nanophosphor powder sample is constant, and the color distribution appears evenly in green (about 250 ns), indicating that the synthesis was uniformly well. If a part of the phosphor is not synthesized or the composition is changed, the attenuation time may be different, resulting in a result that only a certain part is displayed differently in color.

In addition, the more the number of light emitting centers of the nano-phosphor is, the more different the attenuation time is, so that various colors may appear on the time-resolved fluorescence image. It could be confirmed that only light emission related to Cs ₆ PbBr ₄ inside the supercage appeared.

Results 3-Comparison of emission wavelengths according to the state of nanophosphors

In order to compare the emission wavelength according to the state of the nanophosphor prepared according to Example 1, the emission wavelength was confirmed according to Experimental Example 3, and the results are shown in FIGS. 4A to 4B.

As a result, in FIG. 4A, the nanophosphors dispersed in distilled water exhibited a central wavelength of 520 nm, and as time passed, the half width became narrower, so that green color was more clearly realized.

In addition, in FIG. 4B, the nanophosphors dispersed in hexane, which is an organic solvent, exhibited a central wavelength of 517 nm, and it was confirmed that the half width was very narrow, as 23 nm.

This is determined to be due to the Cs ₆ PbBr ₄ nanostructure in the supercage, and it means that the nanophosphor according to Example 1 may exhibit a narrower half width than the conventional quantum dots. Immediately after the initial synthesis, there may be nanostructures having various types of luminescence properties in the supercage, but it is expected that most of the luminous bodies other than the Cs ₆ PbBr ₄ nanostructures, which are very stably bound as water molecules are adsorbed into the zeolite pupils, are decomposed . That is, it is determined that only the Cs ₆ PbBr ₄ nanostructure remains in the nanophosphor existing in the liquid phase to emit green light with a narrow half width.

Result 4-Nano Phosphor XRD exam

According to Experimental Example 4, the nanophosphor of Example 1, the nanophosphor of Example 1 dispersed in distilled water, the cesium ion-exchanged zeolite powder (Cs, Na-X), and zeolite X were analyzed through XRD, The results are shown in FIG. 5.

As a result, both zeolite powder (Cs, Na-X) in which cesium ions were exchanged compared to zeolite X (Na-X) and the nano-phosphor of Example 1 (when PbBr ₂ was introduced into the cesium ion-exchanged zeolite) It was confirmed that the crystallinity was maintained, and in particular, through XRD analysis of the powder sample of nanophosphors (Cs, Pb, Br, Na-X) that was put in water for about a month and then dried again, it was found that the crystal structure was not decomposed even when water was adsorbed. I could confirm.

This is a result that means that the nanophosphor according to an embodiment of the present invention exhibits excellent stability in water.

Result 5-Structure of nano phosphor

According to Experimental Example 5, the structure of the nanophosphor of Example 1 was confirmed, and the results are shown in FIGS. 6 to 7. Figure 7 (a) shows the structure of the CsPbBr ₃ perovskite, (b) shows the structure of the Cs ₆ PbBr ₄ .

As a result of checking FIGS. 6 to 7, it was found that the structure of Cs ₆ PbBr ₄ introduced into the zeolite according to Example 1 and the structure of the conventional CsPbBr ₃ perovskite, which are known to have excellent luminescence properties, are different from each other. Although Cs ₆ PbBr ₄ introduced into zeolite is similar in composition to CsPbBr ₃ perovskite, it cannot be regarded as a perovskite because it does not show the structure of ABX ₃ of a cube, and can be regarded as a complex or nanostructure that exhibits a kind of luminescent property. have.

In addition, the nano fluorescent material of Example 1 was combined with Cs ₆ PbBr to ₄ is introduced into the space within the zeolite form, Cs ₆ PbBr ₄ 6 Cs cation is Br in combination with oxygen in the zeolite framework and PbBr ₄ inside the zeolite supercage As a result, it was confirmed that the introduced complex was stabilized, and the PbBr ₄ structure greatly contributed to the light emission of the nano phosphor.

These nanophosphors are in the form of introducing a complex exhibiting fluorescence properties into a porous material zeolite, and the Cs cation of the complex maintains a strong bond with the skeleton oxygen and the complex of the zeolite, so that the stability against moisture as shown in result 1 It is judged to be very superior to conventional fluorescent materials (perovskite, quantum dot).

In addition, as shown in result 2, it was confirmed that the half-width of the emission wavelength of the nanophosphor of Example 1 is very narrow, which is because there is only one PbBr ₄ structure in the zeolite of the nanophosphor, so that Br ions are connected to several Pb ions. It is believed that this is because the energy transfer between the light emitting centers is minimized because it does not form a continuum that is formed and exists independently. Alternatively, in the conventional fluorescent material, Pb forms a bond (O _h ) of 6 Br anions and an octahedron, but in the PbBr ₄ structure of the present invention, Pb forms a tetrahedral bond (T _d ) with 4 Br anions. It is also believed that this is because the energy difference between e _g and t _2g is smaller than that of the conventional fluorescent material.

For this reason, it is determined that the half-width of the emission wavelength emitted when ultraviolet rays are irradiated to the nanophosphors of the present invention is very narrow, and such nanophosphors will be able to implement a wider color gamut.

Claims (15)

Nano phosphor for display, characterized in that it is represented by Equation 1 below and exhibits an emission peak in a wavelength range of 510 to 550 nm:
[Equation 1]
Zeolite-Cs ₆ PbX ₄
X is at least one selected from the group consisting of bromine (Br), chlorine (Cl), and iodine (I).
The method of claim 1,
The zeolite is at least one selected from zeolite-A, zeolite-X, zeolite-Y, and H-zeolite-Y.
The method of claim 1,
The Cs ₆ PbX ₄ is a nano-phosphor for display, characterized in that introduced into the space formed by the skeleton of the zeolite.
The method of claim 1,
The nano-phosphor is a nano-phosphor for display, characterized in that having a half width (FWHM) of 10 to 25 nm.
Nano phosphor for display, characterized in that represented by the following formula 2:
[Equation 2]
Zeolite-Cs ₆ Pb(Br _a Y _1-a ) ₄ (0.8<a≤1)
Y is at least one selected from chlorine (Cl) and iodine (I).
The method of claim 5,
The zeolite is at least one selected from zeolite-A, zeolite-X, zeolite-Y, and H-zeolite-Y.
The method of claim 5,
The nano-phosphor is a nano-phosphor for display, characterized in that having a half width (FWHM) of 10 to 25 nm.
The method of claim 5,
The nano fluorescent substance for a display, characterized in that the green light emission.
Zeolite skeleton; And
It contains cesium (Cs), lead (Pb), and bromine (Br) introduced into the space created by the zeolite skeleton,
Nano phosphor for display, characterized in that it has a half width (FWHM) of 10 to 25 nm.
The method of claim 9,
The cesium (Cs), lead (Pb), and bromine (Br) form a composite nano-phosphor for a display.
The method of claim 9,
The nano fluorescent substance for a display, characterized in that the green light emission.
A first step of reacting zeolite powder with an aqueous solution of cesium to form a zeolite in which cesium ions are exchanged;
A second step of adding the cesium ion-exchanged zeolite to an organic solvent and stirring to form a stirring solution;
_{Pb (Br a Y 1-a} ) a third step of the _second reagent to remove the gas in the mixed mixture to form the solution of _{Pb (Br a Y 1-a} ) _2, the reagents are completely dissolved under a nitrogen atmosphere;
A fourth step of adding and reacting a solution in which the Pb(Br _a Y _1-a ) ₂ reagent is completely dissolved in the stirred solution to form a reaction product;
Including; a fifth step of washing the reactant,
Wherein a is greater than 0.8 and 1 or less, and Y is at least one selected from chlorine (Cl) and iodine (I).
The method of claim 12,
The second step is a method for producing a nano-phosphor for display, characterized in that forming a stirring liquid in a vacuum state.
The method of claim 12,
The fourth step is _a method of producing a nano-phosphor for display, characterized in that the zeolite in which cesium ions have been exchanged in the stirring solution at 100 to 200° C. is reacted with Pb(Br _a Y _1-a ) ₂ .
A display device comprising the nano-phosphor according to any one of claims 1, 5, and 9.

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