KR20150070667A - Nanohybrid composite of quantum dot nanoparticle and porous silica for fluorescent body, optical module using the same, and manufacturing method thereof - Google Patents

Abstract

The present invention provides a nanohybrid composite for a fluorescent body, wherein a semiconductor quantum dot nanoparticle is deposited in a porous silica bead. According to the present invention, a nanohybrid composite can improve color reproduction ability (color rendering properties) using a quantum dot from which a fluorescent wavelength can be easily obtained in comparison with conventional fluorescent bodies, and prevent reduction in efficiency caused by moisture and light from an inorganic substance such as silica, thereby significantly improving reliability. In addition, a spherical nanohybrid bead with a proper size having excellent dispersibility can deposit a quantity of quantum dots, thereby improving luminance.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a nanohybrid composite for a phosphor, an optical module using the same, and a method of manufacturing the optical module. [0002]

The present invention relates to a nanohybrid composite for a phosphor, an optical module using the same, and a method of manufacturing the same. More particularly, the present invention relates to a nanohybrid composite for a fluorescent substance, To a nanohybrid composite for a fluorescent substance which can improve the luminance at the same time.

Recently, LED (Light-Emitting Diode), which is emerging as a promising next-generation light source, is a semiconductor device that converts electric power into ultraviolet rays, visible light, infrared rays by utilizing the characteristics of compound semiconductors. Display, and transmission. LEDs emitting red and green have been developed for a long time and widely used for signal display. However, blue LEDs developed a high-luminance red LED in the early 1990s, and a few years later Nichia of Japan used GaN-based semiconductors As the high-brightness blue LED is developed, it is applied to electric signboards, traffic lights, mobile phones and the like. Particularly, as LED elements each representing three primary colors of light, red, green and blue, are being developed, researches are actively conducted to use LEDs as illumination light sources.

Replacement of existing incandescent lamps or fluorescent lamps by using high-intensity LED light sources as illumination lamps is very energy-efficient, has a long life and low replacement cost, is resistant to vibration and shock, and does not require the use of toxic substances such as mercury, , Environmental protection, and cost reduction.

As a result, research and development are currently underway in the field of white LEDs for lighting and display devices. LEDs basically generate only light in a narrow wavelength range, so that it is difficult to emit white light in a single device level, and various methods such as obtaining white light by combining the three primary colors of red, green, and blue have been attempted. Among them, a method of applying a suitable phosphor powder on a blue or ultraviolet LED to emit white light through wavelength conversion is most likely to be put to practical use. Currently, many companies have been actively researched and developed, but it is necessary to improve the color rendering property to realize natural colors .

In addition, in the field of display devices, the development of new types of display devices such as OLEDs, quantum dot LEDs, and the like has been actively conducted in domestic and overseas companies and research institutes. In particular, when using semiconductor nanoparticles as phosphors in the OLED structure, it is expected that a display having a high color rendering index capable of realizing natural colors will be implemented, and it is expected to be commercialized through technology development in the future. In order to develop white light and display devices using quantum dots, it is essential to develop phosphors having excellent light efficiency and stability against heat and light for the application fields.

A conventional technique in which a high reliability quantum dot is applied to a light emitting device is as follows.

U.S. Patent No. 8,343,575 discloses a method of manufacturing a backlight module for a display using quantum dots by sealing a quantum dot formed of quantum dots between alumina or silica or glass substrate having excellent barrier properties in order to prevent a decrease in reliability caused by air or moisture The invention is patented to secure reliability by hermetically sealed. In the above-mentioned patent, a patent is filed which uses a method of packaging quantum dots between substrates where moisture and air can be easily blocked, instead of manufacturing the quantum dots themselves to block air or moisture by a sealing method. However, Of the patent application.

However, the above-mentioned patent fails to completely block fine gaps between the substrate and the substrate, which are unavoidably generated in the sealing process. In the case of optical films for displays to be manufactured using quantum dots, the brightness, stability, There are many problems to be improved in light efficiency.

An object of the present invention is to provide a nanohybrid composite for a fluorescent substance that can improve the color reproducibility (color rendering property), prevent deterioration of efficiency due to moisture and light, can support a large amount of quantum dot particles, and can improve reliability .

Another object of the present invention is to provide a display optical module comprising the nanohybrid composite.

It is still another object of the present invention to provide a method for producing the nanohybrid composite.

The present invention provides a nano hybrid composite for a phosphor in which semiconductive quantum dot nanoparticles are supported on a porous inorganic bead. The semiconducting quantum dot nanoparticle is a 12-16-band semiconductive compound; 13-15 semi-conductor compounds; And a Group 14 semiconducting compound.

The semiconductive nanoparticle nanoparticles may include one or more materials selected from the group consisting of ZnS, ZnSe, CdS, CdSe, CdTe, HgS, HgSe, GaAs, InGaAs, InP, InAs, Ge, Si and combinations thereof.

The semiconductive quantum dot nanoparticles have a core-shell structure, and the material constituting the core is a 12-16-band semiconductive compound; 13-15 semi-conductor compounds; And a Group 14 semiconducting compound; and the material constituting the shell is preferably a 1 to 10-fold ZnS monolayer.

It is preferable that the semiconductive nanoparticles have an inorganic coating.

The inorganic material for the inorganic coating may be at least one selected from the group consisting of silver, alumina and titania.

The thickness of the inorganic coating is preferably 1 to 100 nm.

Preferably, the porous inorganic bead is any one selected from the group consisting of silica, alumina, and titania having an average particle size of 500 nm to 10 탆.

The porous inorganic beads are preferably mesoporous silica having an average pore size of 5 to 50 nm.

The pores of the inorganic beads are preferably closed by an inorganic coating layer.

Also, the present invention provides a display optical module including the nanohybrid composite for a phosphor.

In addition, in the present invention, a first step of obtaining semiconductive quantum dot nanoparticles; A second step of coating an inorganic material on the surface of the semiconductive nanoparticle nanoparticles to modify the surface thereof; And a third step of supporting the surface modified semiconductive nanoparticle nanoparticles on the porous inorganic bead. The present invention also provides a method for manufacturing a nanocomposite composite for a fluorescent substance.

And coating the surface of the porous inorganic beads with an inorganic material to close the pores of the porous inorganic beads after the third step.

When the nanohybrid composite beads prepared as described above are used as a phosphor in a display optical module, brightness, stability, high color rendering property, and luminous efficiency can be improved. In particular, when the nanohybrid composite produced by the present invention is used, it is possible to improve not only the color reproducibility (color rendering property) by using a quantum dot which is easy to obtain a desired fluorescence wavelength as compared with the conventional phosphor, It is possible to prevent deterioration of efficiency due to moisture and light, thereby greatly improving the reliability. In addition, spherical nanohybrid beads having an appropriate size are excellent in dispersibility, so that a large amount of quantum dots can be carried, thereby improving brightness.

1 is a schematic view schematically showing a method for producing a nanohybrid composite for a phosphor according to the present invention.
FIG. 2 is a fluorescence microscope image of a nano hybrid complex carrying the quantum dot nanoparticles according to the present invention.
FIG. 3 is a fluorescence spectrum of a nanohybrid complex carrying quantum dot nanoparticles according to the present invention.

The present invention provides a nano hybrid composite for a phosphor in which semiconductive quantum dot nanoparticles are supported on a porous inorganic bead.

[Band-shaped quantum dot nanoparticles]

The semiconducting quantum dot nanoparticle is a 12-16-band semiconductive compound; 13-15 semi-conductor compounds; And at least one compound selected from the group consisting of Group 14 semiconducting compounds. Examples of the 12-16-group semiconducting compound to be used include ZnS, ZnSe, CdS, CdSe, CdTe, HgS, HgSe or a mixture thereof. Examples of the 13-15 group semiconductive compound include GaAs, InGaAs, InP, InAs , And mixtures thereof. As the Group 14 semiconducting compound, for example, Ge, Si and the like can be used.

It is preferable that the semiconductive nanoparticles have a spherical shape or a substantially spherical shape having a sphericity of 0.8 or more and a size of 2 to 10 nm.

It is preferable that the semiconductive quantum dot particles have a core-shell structure in that the semiconductive nanoparticles can prevent the storage of light or the decrease in fluorescence properties due to light. At this time, the material constituting the core structure is a 12-16-group semiconductive compound; 13-15 semi-conductor compounds; And a Group 14 semiconducting compound. The shell structure is preferably a structure in which 1 to 10 layers of ZnS monolayers are formed on the core structure.

[Inorganic coating]

The semi-conducting quantum dot nanoparticles are coated with quantum dot particles as an inorganic material to ensure stability against moisture and light. As the coating material used may be a silica (SiO _2), alumina (Al ₂ O _3), titania (TiO _2), or a combination thereof. The thickness of the inorganic coating is preferably 1-100 nm. When the thickness of the coating is less than 1 nm, the inorganic material may not completely coat the quantum dots, resulting in moisture or air penetration. When the thickness of the coating is greater than 100 nm, the light efficiency of the nanohybrid composite may deteriorate.

[Porous inorganic beads]

The nanohybrid composite according to the present invention is characterized in that semiconductive quantum dot nanoparticles, preferably semiconductive nanoparticles whose surfaces are coated with inorganic particles, are supported on pores of porous inorganic beads.

The inorganic beads may be any one selected from the group consisting of silica, alumina and titania. When the porous beads are in the form of powder, there is no particular limitation on their particle size. In order to use the porous beads as a material for realizing high color rendering properties of an OLED display or a backlight film for an LCD display, a thickness of 500 nm to 10 탆 is usually used.

The porous beads are preferably silica beads, especially spherical mesoporous silica. The pore size of the mesoporous silica beads is suitably such that the pore size is 5 to 50 nm so that the loading of the quantum dot particles can be easily carried out. When the pore size is less than 5 nm, it is difficult to support the QD nanoparticles. On the other hand, when it exceeds 50 nm, the pores become too large and the semiconductive nanoparticles of semiconducting nanoparticles are inefficient.

In a preferred embodiment according to the present invention, the nanohybrid composite may be such that the pores of the porous beads are closed after the deposition of the quantum dot particles. By closing the pores, the passage of moisture or air inside and outside the pores is blocked, thereby further improving the light stability of the semiconductive nanoparticles.

Closure of the pores can be achieved by supporting the quantum dot nanoparticles on the porous inorganic beads and then forming the second inorganic coating layer on the surface of the beads again. On the other hand, in the case of inorganic coating for pore closure, the thickness is in the range of 1 to 100 nm.

[Manufacturing method]

In the present invention, step (S1) of obtaining semiconductive quantum dot nanoparticles; Coating a surface of the semiconductive nanoparticle with an inorganic material to modify the surface (S2); And supporting (S3) supporting the surface-modified semiconductive nanoparticle nanoparticles on the porous inorganic bead. The present invention also provides a method for manufacturing a nano hybrid composite for a phosphor.

1 is a schematic view schematically showing a method for producing a nanohybrid composite for a phosphor according to the present invention. Hereinafter, a manufacturing method according to the present invention will be described with reference to the accompanying drawings.

The composition of the elements constituting the quantum dot nanoparticles in the step S1 is as described above, and the preparation method thereof is generally synthesized by using pyrolysis method using a well-known organometallic compound as a precursor. Particularly, to obtain quantum dot nanoparticles having a core-shell structure, a ZnS solution is slowly added to an aqueous solution of nanoparticles already formed using a syringe pump or the like, and the mixture is stirred for about 1-1.5 hours at 150-250 ° C., Layer.

The semiconductive quantum dot particles should be dispersible in an aqueous solution. For this purpose, the surface of the quantum dot nanoparticles may be pre-treated such that an amine, an amine salt or a carboxyl group is present on the surface. For the pretreatment purpose, hexadecyl trimethyl ammonium bromide (CTAB), cysteine, thiol acid, amino propyl trimethoxy silane and the like can be used.

The inorganic coating of step S2 is usually carried out by coating the precursor aqueous solution onto the quantum dot nanoparticles followed by drying. Examples of the precursor include aminotrimethoxysilane, alkyltrimethoxysilane having 3-22 carbon atoms, or a metal alkoxide compound such as aluminum, titanium, zirconium or the like, and the inorganic layer is coated by a sol-gel reaction .

In the third step, the surface modified semiconducting quantum dot nanoparticles are supported on the porous inorganic beads. The support is achieved by adding surface-modified semiconducting quantum dot nanoparticles and inorganic particles to an appropriate solvent and stirring. As a preferable solvent, a mixed solvent obtained by mixing one or two solvents selected from toluene, benzene, acetone, chloroform, benzene, butanol, ethanol, methanol and water may be used.

After the stirring is completed, the solids in the solution are filtered and dried to prepare the hybrid composite according to the present invention.

The manufacturing method according to the present invention may further include the step (S4) of closing the pores of the porous inorganic material carrier by coating an inorganic material on the surface of the porous inorganic material again. Closure of the pores is carried out by introducing the obtained hybrid composite obtained in the third step again into the solution of the inorganic precursor enumerated above, followed by filtering, drying and pyrolysis.

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention.

≪ Example 1 >

1. Fabrication of quantum dots

In order to obtain CdSe / ZnS quantum dots with a high efficiency core-shell structure, the CdSe quantum dots constituting the quantum dot core are formed by using cerium oxide (CdO), an organometallic precursor, and selenium powder at a reaction temperature of 300-320 ° C Pyrolysis.

The CdSe / ZnS core-cell quantum dot synthesis was carried out by using a syringe pump, a ZnS solution in which zinc stearate and Sulfur (S) powder were dissolved in tri-n-butylphosphine, , And the mixture was stirred at 190 캜 for about 1.5 hours.

Next, the synthesized quantum dots are removed by centrifugation of the unreacted organic material using methanol or acetone solvent, and then dispersed in toluene which is an organic solvent.

2. Silica-coated quantum dot manufacturing

The surface of the quantum dot prepared by the above method was coated with a silica precursor. First, 0.5 mg of a quantum dot was added to 15 mL of an aqueous solution of 15 mmol of sodium dodecyl sulfate, and the quantum dots were dispersed in water by a sonication method for 3 minutes.

To coat the thus prepared water-dispersed quantum dots with silica, 10 쨉 l of octadecyltrichlorosilane was added thereto, reacted at 10 캜 for 2 hours, 10 쨉 l of aminopropyltrimethylsilane was further added thereto The reaction was carried out at 10 ° C for 30 minutes, 10 μl of a 25% ammonia monohydrate solution was added, and the reaction was allowed to proceed for 24 hours to prepare a silica-coated quantum dot having a coating thickness of 2 nm.

3. Fabrication of nanohybrid composites

(1) Preparation of mesoporous silica

Spherical mesoporous silica was prepared by sol - gel reaction with surfactant template. As the surfactant template, a copolymer polymer P123 (BASF, HO (CH ₂ CH ₂ O) ₂₀ (CH ₂ CH (CH ₃ ) O) ₇₀ (CH ₂ CH ₂ O) ₂₀ H) was used. P123 in the 4g of 15% was dissolved in hydrochloric acid solutions, to increase the pore size of 4g was added to the swelling agent trimethylbenzene (1,3,5, Trimethylbenzene, Sigma-Aldrich ) to a 37-40 ^o C holding state 2 For a period of time. Tetraethoxy orthosilicate (TEOS) was added with stirring for 5 minutes to react the silica precursor on the surface of the thus prepared surfactant template, and the reaction was carried out for 20 hours at 40 ^° C without stirring. I made it. Further, in order to accelerate the reaction of the silica precursor, 46 mg of NH ₄ F was added, and the reaction was carried out with stirring at 100 ^° C for 24 hours. The mesoporous silica beads were prepared by heat treatment at 550 ^° C for 6 hours or more in order to remove the surfactant template, which is an organic substance in the recovered reactant. The size of the silica beads produced is 2-6 占 퐉 and the average pore size is 20 nm.

(2) Production of nanohybrid composite

As a method for producing a nanohybrid composite in which the quantum dots are densified, 2.5 mg of mesoporous silica is dispersed in 150 ml of butanol, 0.5 mg of a quantum dot solution is added, and the mixture is stirred vigorously using a magnetic stirrer The nanohybrid composite was obtained by diffusing and penetrating the quantum dots into the pores.

≪ Example 2 >

A nanohybrid composite was prepared in the same manner as in Example 1 except that InP quantum dots were used instead of CdSe / ZnS quantum dots in Example 1.

≪ Example 3 >

To disperse the quantum dots prepared in Example 1 in an aqueous solution, the synthesized quantum dots were dispersed in chloroform (CCl ₄ ) as an organic solvent, and hexadecyl trimethyl ammonium bromide (CTAB) solution And the mixture was stirred for 24 hours to modify the surface with hexadecyltrimethylammonium bromide and dispersed in an aqueous solution.

A nanohybrid composite was prepared in the same manner as in Example 1 except for the method of preparing a water-dispersed quantum dot.

<Example 4>

The water-soluble quantum dots prepared by the method of Example 3 were placed in mesoporous silica dispersed in a butanol solution and stirred vigorously The quantum dots are diffused into the pores and then the surface is again reacted with a silica precursor, Tetraethoxy orthosilicate (TEOS), to form a silica coating layer having a thickness of 2 nm so as to further enhance stability against heat or light, A nanohybrid composite having pores closed was prepared.

<Evaluation>

In order to evaluate the light efficiency and the light stability of the nanohybrid composite, the nanohybrid composite was dispersed in water and irradiated with a 8 W UV lamp for a predetermined period of time. The fluorescence intensity was compared using the fluorescence spectrum to reach 80% of the initial fluorescence intensity Was defined as the light stability maintenance time.

The light efficiency of the nanohybrid composite was measured by dispersing 2 wt% of the nanohybrid composite on the photo-curable silicone polymer, followed by bar coating to produce a film. Quantum efficiency and uniformity of dispersion were evaluated for the prepared film.

Quantum efficiency was evaluated using rhodamine (Rodamine 6G) as a reference material. The nanohybrid composite prepared as in the present invention and rhodamine as a reference material were measured with a UV spectrometer (Model: S 3100, manufacturer: Scinco) and a fluorescence spectrometer (Model: FluoroMate FS-2, manufactured by Scinco) And the slope (fluorescence intensity / absorbance) values obtained from the measured values were compared to calculate the quantum efficiency of the nanohybrid particles.

The uniformity of the dispersion was evaluated based on the light transmittance deviation in a 3 cm x 3 cm size film, and when it was 5% or less, it was evaluated as excellent (⊚), 5-10% was good (∘), and 10-20% . The results are summarized in Table 1.

Optical Stability Holding Time (hr) Quantum efficiency
(unit)  Uniformity (light transmittance deviation) Example 1 144 45 ◎ Example 2 24 31 ○ Example 3 48 49 ○ Example 4 165 46 ◎ Comparative Example 1 2 35 △

From Table 1, the quantum dot-silica hybrid composite according to the present invention had a light stability holding time of 20 hours or more regardless of the kind of the quantum dots. In particular, in the case of the CdSe / ZnS quantum dot particles, the photostability maintenance time is remarkably increased by 70 times or more when the quantum dot particles are present in the quantum dot-silica hybrid complex state rather than when they exist alone (Example 1 vs. Comparative Example 1 ). In the case where the inorganic coated QDs are supported on the pores of the mesoporous silica, an additional improvement of about 15% in the light stability is confirmed when the pores of the silica are closed (see Example 4 vs Example One).

On the other hand, when the quantum dots are dispersed in another polymer material, it is confirmed that the dispersibility of the quantum dots increases remarkably when the quantum dots coated with inorganic material are supported on the pores of the mesoporous silica, as compared with the case of the single quantum dot particles alone.

FIG. 2 is a fluorescence microscope image of a nanohybrid composite in which quantum dots are combined according to the present invention. FIG. 2 (a) is a fluorescence microscope image of a nanohybrid hybrid prepared in Example 1, in which the quantum dot loading is 5 nM, and (b) and (c) are 100 and 200 nM, respectively. From the photograph, it can be seen that as the amount of quantum dots increases, more amount is carried and brightened.

FIG. 3 is a fluorescence spectrum of a nanohybrid composite in which quantum dots are combined according to the present invention. From the above spectrum, it can be seen that the fluorescence intensity increases as the amount of the quantum dots supported increases.

The nanohybrid composite of the present invention can be used as a core material for realizing high color rendering illumination of OLED displays and backlight films for LCD displays as well as phosphors for displays.

Claims (18)

The nanocomposite nanoparticles of semiconducting quantum dots are supported on porous inorganic beads. The nanoparticle of claim 1, wherein the semiconductive nanoparticle is a 12-16-band semiconductive compound; 13-15 semi-conductor compounds; And a Group 14 semiconducting compound. The nanohybrid composite for a fluorescent substance according to claim 1, 2. The method of claim 1, wherein the semiconductive nanoparticle comprises one or more materials selected from the group consisting of ZnS, ZnSe, CdS, CdSe, CdTe, HgS, HgSe, GaAs, InGaAs, InP, InAs, Wherein the nanocomposite comprises a nanocomposite. The nanoparticle of claim 1, wherein the semiconductive nanoparticle has a core-shell structure, the material comprising the core is a 12-16-band semiconductive compound; 13-15 semi-conductor compounds; And a Group 14 semiconducting compound, and the material constituting the shell is a 1 to 10-fold ZnS monolayer. The nano hybrid composite for a phosphor according to claim 1, wherein the semiconductive nanoparticle nanoparticles are coated with an inorganic material. 6. The nanohybrid composite for a phosphor according to claim 5, wherein the inorganic material is at least one selected from the group consisting of silica, alumina and titania. 6. The nanohybrid composite of claim 5, wherein the inorganic coating has a thickness of 1 to 100 nm. The nano hybrid composite for a phosphor according to claim 1, wherein the porous inorganic bead is any one selected from the group consisting of silica, alumina or titania having an average particle size of 500 nm to 10 탆. The nano hybrid composite for a phosphor according to claim 1, wherein the porous inorganic bead is mesoporous silica having an average pore size of 5 to 50 nm. The nano hybrid composite for a phosphor according to claim 1, wherein the inorganic bead has pores closed by an inorganic coating layer. A display optical module comprising the nanohybrid composite for a phosphor according to claim 1. A first step of obtaining semiconductive quantum dot nanoparticles;
A second step of coating an inorganic material on the surface of the semiconductive nanoparticle nanoparticles to modify the surface thereof; And
And a third step of supporting the surface-modified semiconducting quantum dot nanoparticles on the porous inorganic beads. 13. The nanoparticle of claim 12, wherein the semiconductive nanoparticle is a 12-16-band semiconductive compound; 13-15 semi-conductor compounds; And a Group 14 semiconducting compound. The method for producing a nanohybrid hybrid for a fluorescent substance according to claim 1, 13. The method of claim 12, wherein the semiconductive nanoparticle comprises one or more materials selected from the group consisting of ZnS, ZnSe, CdS, CdSe, CdTe, HgS, HgSe, GaAs, InGaAs, InP, InAs, Wherein the method comprises the steps of: 13. The method of claim 12, wherein the inorganic coating is formed from a precursor of at least one material selected from the group consisting of silica, alumina, and titanate. 13. The method of claim 12, wherein the inorganic coating has a thickness of 3 to 100 nm. 13. The method according to claim 12, wherein the porous inorganic beads are mesoporous silica having a pore size of 5 to 50 nm. The method of claim 11, further comprising, after the third step, coating an inorganic material on the surface of the porous inorganic beads to close the pores of the porous inorganic beads.

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