KR20210080221A - A multi-functional wavelength conversion efficiency amplification structure and manufacturing method thereof - Google Patents

Abstract

The present invention provides a method for manufacturing a wavelength conversion efficiency amplifying structure. The method for manufacturing the wavelength conversion efficiency amplification structure includes preparing a mold having one or more hole patterns, and inserting a part of the plasmonic microbeads while exposing them in the hole patterns of the mold, coating the exposed plasmonic microbeads with a polymer sacrificial layer transferring to and fixing the substrate, removing the mold, and heat-treating the substrate from which the mold has been removed to remove the polymer sacrificial layer, plasmonic microbeads fixed on the substrate from which the polymer sacrificial layer has been removed Depositing metal nanoparticles, depositing a metal thin film on the plasmonic microbeads and the metal nanoparticles, and adsorbing the energy conversion nanoparticles on the metal thin film characterized in that it comprises.

Description

Multifunctional wavelength conversion efficiency amplifying structure and method for manufacturing the same {A MULTI-FUNCTIONAL WAVELENGTH CONVERSION EFFICIENCY AMPLIFICATION STRUCTURE AND MANUFACTURING METHOD THEREOF}

The present invention relates to a wavelength conversion structure and a method for manufacturing the same, and more specifically, to a wavelength conversion structure for amplifying wavelength conversion efficiency by adsorbing a wavelength conversion material to a spherical plasmonic microbead, and a method for manufacturing the same.

Upconversion luminescence (UCL) is a physical process in which two or more coherent low-energy photons, typically near infrared (NIR) photons, are absorbed and converted into a single high-energy photon. The wavelength of the emitted photon is generally in the visible range. In principle, upconversion luminescence (UCL) is a non-linear optical process that emits photons with a wavelength shorter than that of the absorbed photon. Despite the inherently low internal quantum efficiency (IQE) of upconversion luminescence (UCL), the realization of upconversion luminescence (UCL) in nanomaterials is largely due to multi-modal imaging. and nano photonics. In single-crystal NaYF4 upconversion nanoparticles (UCNPs), the lanthanide ion pair consists of Yb ³⁺ , a photon sensitizer and an activator such as ^{Er 3+ .} This ion pair is particularly important for highly efficient internal energy transfer because the energy levels ^{of the Yb 3+} and Er ^{3+ ions are closely matched.} A wide range of applications include integrated β-NaYF4:Yb3+/Er3+ UCNPs, including energy conversion devices, biosensors, photodetectors, display materials, and anti-counterfeiting devices. However, the intrinsic internal quantum efficiency (IQE) of upconversion luminescence (UCL) is still much lower than the practical application standards even for single crystal and monodisperse upconversion nanoparticles (UCNPs).

Efforts focused in recent years have focused on fabricating sophisticated photonic/plasmonic structures to optimize host/dopant combinations or to overcome the low intrinsic internal quantum efficiency (IQE) of upconversion luminescence (UCL). placed This has led to a sharp increase in the upconversion luminescence (UCL) intensity of plasmonic platforms, such as metal-insulator-metal (MIM) structures made of metal nanoparticles or nanowires with defined structural disturbances. This improvement is due to an increase in the absorption of incident near infrared photons and, at the same time, an enhancement of internal quantum processes that intervene in the radiative decay of photons in the visible range. In addition, the plasmonic platform can act as a resonator to receive and capture incident light. It also serves as a “hot spot” to form a strong proximity to the interface between the metal nanostructure and the underlying insulator to support the surface and/or gap plasmon polaritons. The total plasmonic effect increases the upconversion luminescence (UCL) intensity. Unfortunately, most plasmonic platforms proposed for upconversion luminescence (UCL) enhancement are based on thin films irreversibly integrated into solid substrates with multilayer MIM structures. These structural features make it difficult to develop broader and more functionally diverse applications, such as flexible and transparent NIR sensor arrays, transmissible (removable) films, and NIR-visible displays with wide viewing angles. Therefore, there is a need for the invention of a thin film upconversion luminescence (UCL) platform that is highly efficient and versatile for a wider range of applications.

Korean Patent Publication No. 10-2062549, "Composition containing inorganic nanoparticle structure, light conversion thin film using same, and display device using same" Korean Patent Publication No. 10-1633075, "Three-dimensional plasmonic nanostructure and its manufacturing method"

An embodiment of the present invention is to provide a method for adsorbing a wavelength conversion material to dielectric spherical particles such as plasmonic microbeads.

In addition, an embodiment of the present invention is to provide a two-dimensional lattice structure arrangement of dielectric spherical particles adsorbed with a wavelength conversion material.

In addition, an embodiment of the present invention is to provide a method capable of properly introducing metal nanoparticles through a solid non-wetting process into dielectric spherical particles having a two-dimensional lattice structure arrangement.

In addition, an embodiment of the present invention is to provide a wavelength conversion efficiency amplification structure having an optimal wavelength conversion amplification effect through the introduction of metal nanoparticles and adsorption of a wavelength conversion material.

In addition, an embodiment of the present invention is to provide a technique for forming a wavelength conversion film by forming dielectric spherical particles into which a metal wavelength conversion material and metal nanoparticles are introduced on a transparent or flexible substrate.

In the method for manufacturing a structure for amplifying wavelength conversion efficiency according to an embodiment of the present invention, a mold having one or more hole patterns is prepared, and a part of plasmonic microbead is inserted while exposing a part of the plasmonic microbead into the hole pattern of the mold. Step, transferring and fixing the exposed plasmonic microbeads to a substrate coated with a sacrificial layer of a polymer, removing the mold, and heat-treating the substrate from which the mold is removed to remove the sacrificial polymer layer , depositing metal nanoparticles on plasmonic microbeads fixed on the substrate from which the polymer sacrificial layer has been removed, depositing a metal thin film on the plasmonic microbeads and the metal nanoparticles, and energy on the metal thin film and adsorbing the transformation nanoparticles.

The inserting while exposing a portion of the plasmonic microbeads is characterized in that inserting so that 1/2 to 1/4 of the plasmonic microbeads inserted into the hole patterns of each of the molds are exposed.

The inserting while exposing a part of the plasmonic microbeads is characterized in that the plasmonic microbeads are rubbed in a circle in one direction on the mold with a polydimethylsiloxane (PDMS) block.

The plasmonic microbead is silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), yttrium oxide (Y ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), magnesium oxide (MgO), zinc oxide (ZnO), oxide Metal oxide plasmonic microstructure composed of tin (SnO), iron oxide (FeO), zirconium oxide (ZrO ₂ ), chromium oxide (Cr ₂ O ₃ ), hafnium oxide (HfO), beryllium oxide (BeO), and tungsten oxide (WO) It is characterized in that it is one selected from the group of beads.

The metal nanoparticles are characterized in that silver (Ag), copper (Cu), or gold (Ag) nanoparticles.

The metal thin film is zinc oxide (ZnO), titanium oxide (TiO ₂ ), yttrium oxide (Y ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), magnesium oxide (MgO), zinc oxide (ZnO), tin oxide ( SnO), iron oxide (FeO), zirconium oxide (ZrO ₂ ), chromium oxide (Cr ₂ O ₃ ), hafnium oxide (HfO), or beryllium oxide (BeO) is characterized in that the thin film.

The energy conversion nanoparticles are characterized in that the upconversion nanoparticles or downconversion nanoparticles.

The step of adsorbing the energy conversion nanoparticles may include substituting an _{amine group (Amine, -NH 2} ) on the surface of the plasmonic microbead on which the metal thin film is deposited; and adsorbing the energy conversion nanoparticles through a ligand exchange reaction between the amine group and the oleic acid ligand.

The step of removing the polymer sacrificial layer is characterized in that the heat treatment at 300 ℃ to 600 ℃.

The wavelength conversion efficiency amplifying structure manufactured by the method of manufacturing the wavelength conversion efficiency amplifying structure according to another embodiment of the present invention includes plasmonic microbeads, metal nanoparticles positioned on the surface of the plasmonic microbeads, the plasmonic microbeads, and the metal nano It is characterized in that it comprises a metal thin film positioned on the particles and energy nanoparticles adsorbed on the surface of the metal thin film.

The wavelength conversion efficiency amplifying structure is characterized in that 14.30 to 18.7 times the infrared absorption rate is increased than when the structure is flat.

The metal nanoparticles may be silver (Ag), copper (Cu), or gold (Ag) nanoparticles.

The metal thin film is zinc oxide (ZnO), titanium oxide (TiO ₂ ), yttrium oxide (Y ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), magnesium oxide (MgO), zinc oxide (ZnO) , tin oxide (SnO), iron oxide (FeO), zirconium oxide (ZrO ₂ ), chromium oxide (Cr ₂ O ₃ ), hafnium oxide (HfO), or beryllium oxide (BeO) thin film.

The energy conversion nanoparticles are characterized in that the upconversion nanoparticles or downconversion nanoparticles.

The upconversion nanoparticles are NaYF ₄ ;YB ³⁺ /Er ³⁺ , NaYF ₄ :Yb,TM or Na(Y,Gd)F ₄ :Yb,Er/NaGdF ₄ :Ce.

The downconversion nanoparticles are semiconductor quantum dots including core-shell colloidal quantum dots such as CdS/ZnS, CdSe/ZnS, CdSe/CdS, InAs/CdSe, and inorganic materials-based light-emitting nanoparticles.

According to an embodiment of the present invention, periodic patterns of various shapes and sizes based on spherical particles using imprinting transfer technology can be formed in a single process, and through this, the light guide phenomenon and pattern occurring in a single spherical resonant structure can be reduced. Various optical properties can be expected, such as the ability to improve light absorption due to the diffraction effect.

According to an embodiment of the present invention, various nanoparticles can be coated on the substrate surface regardless of metal, inorganic material, or organic material by easily substituting the surface of the _{silica (SiO 2 ) substrate with a desired functional group, so that the light guide effect in the dielectric spherical particle} can be efficiently used for nanoparticles.

According to an embodiment of the present invention, the up-conversion nanoparticles used in the present invention can be applied to improve the sensing ability in an image sensor by up-converting incident light of infrared light into visible light.

According to an embodiment of the present invention, since the application range of the solar spectrum can be expanded, it can be used for energy devices, photodetectors, and the like, and furthermore, it can be used for devices in green technology and extreme environments.

1 is a schematic diagram of a method for manufacturing a wavelength conversion efficiency amplification structure according to an embodiment of the present invention.
2 is a schematic diagram of a wavelength conversion efficiency amplifying structure manufactured according to an embodiment of the present invention.
3 is an image showing a mold insertion diagram of silica spherical particles according to the rubbing time according to an embodiment of the present invention.
Figure 4 (a) is a SEM image of the spin-coated polymer sacrificial layer according to an embodiment of the present invention, Figure 4 (b) is an image of silica spherical particles physically fixed to the polymer sacrificial layer.
FIG. 5 shows an SEM image of silica spherical particles patterned on a support. FIG. 5(a) shows a 4 μm-spaced square-lattice, and FIG. 5(b) shows a 4 μm-spaced hexagonal-lattice arrangement.
6 shows a schematic diagram of a surface treatment of silica spherical particles and an upconversion nanoparticle coating process according to an embodiment of the present invention. .
7 is an SEM image of silica spherical particles and a support on which upconversion nanoparticles are adsorbed as a single layer according to an embodiment of the present invention, (a) an SEM image of beads before upconversion nanoparticles are adsorbed, (b) is an SEM image of the bead after the upconversion nanoparticles are adsorbed, and (c) is an SEM image of the substrate after the upconversion nanoparticles are adsorbed.
8 is a schematic diagram for a solid non-wetting process, FIG. 8 (a) shows silica spherical particles on a support inclined by about 60° for vacuum deposition, and FIG. 8 (b) shows silica during vacuum deposition in both directions. It shows the deposition form of the metal thin film formed on the spherical particles, and FIG. 8( c ) shows the thickness of the deposition of the metal thin film and the size and the mutual spacing gradient of the metal nanoparticles formed during heat treatment.
9 shows an SEM image of silica spherical particles in which metal nanoparticles are formed according to an embodiment of the present invention.
10 is a scanning electron microscope (SEM) image of a wavelength conversion efficiency amplifying structure manufactured according to an embodiment of the present invention, (a) and (b) are wavelength conversion efficiency amplifying structures manufactured without forming a zinc thin film; The surface of and enlarged SEM images, (c) and (d) are the surface and cross-sectional SEM images of the wavelength conversion efficiency amplifying structure after forming the zinc thin film.
11 shows various upconversion structures manufactured according to an embodiment of the present invention and photoluminescence (PL) spectra results thereof.
12 shows a transfer process of a spherical particle-based resonant structure through an adhesive film (BOPP) according to an embodiment of the present invention.
13 shows a photoluminescence (PL) image by near infrared (NIR) after transferring the structure manufactured according to an embodiment of the present invention to a transparent and flexible support (PET substrate), at this time (b ) shows the PL image when the structure is bent, and (c) shows the PL image after the structure is folded.
Figure 14 shows a transparent and flexible support (PET substrate) to which the structure (nano resonator) manufactured according to an embodiment of the present invention is transferred, Figure 14 (a) is the transparency of the support, Figure 13 (b) ) shows an actual photograph of the support.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited by the embodiments.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. As used herein, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, "comprises" and/or "comprising" refers to the presence of one or more other components, steps, operations and/or elements mentioned. or addition is not excluded.

As used herein, “embodiment”, “example”, “aspect”, “exemplary”, etc. are to be construed as advantageous in which any aspect or design described is preferred or advantageous over other aspects or designs. it is not doing

Also, the term 'or' means 'inclusive or' rather than 'exclusive or'. That is, unless stated otherwise or clear from context, the expression 'x employs a or b' means any one of natural inclusive permutations.

Also, as used herein and in the claims, the singular expression "a" or "an" generally means "one or more" unless stated otherwise or clear from the context that it relates to the singular form. should be interpreted as

In addition, when a part such as a film, layer, region, configuration request, etc. is said to be “on” or “on” another part, not only when it is directly on the other part, but also another film, layer, region, or component in between. Including cases where etc. are interposed.

Hereinafter, a method for manufacturing a wavelength conversion efficiency amplifying structure and a wavelength conversion efficiency amplifying structure according to an embodiment of the present invention will be described with reference to the accompanying drawings.

1 shows a schematic diagram of a method for manufacturing a wavelength conversion efficiency amplifying structure according to an embodiment of the present invention.

Referring to FIG. 1 , the method for manufacturing a structure for amplifying wavelength conversion efficiency prepares a mold 110 having one or more hole 112 patterns, and a part of plasmonic microbeads 114 in the hole 112 pattern of the mold 110 . Inserting while exposing the plasmonic microbead 114, transferring and fixing the exposed plasmonic microbead 114 to the substrate 160 coated with the polymer sacrificial layer 130, removing the mold 110, and the mold 110 The step of removing the polymer sacrificial layer 130 by heat-treating the removed substrate 160, metal nanoparticles on the plasmonic microbead 114 fixed on the substrate 160 from which the polymer sacrificial layer 130 has been removed ( depositing 171); Depositing a metal thin film 180 on the plasmonic microbeads 114 and the metal nanoparticles 171 and adsorbing the energy conversion nanoparticles 190 on the metal thin film 180 are included.

When the step of adsorbing the energy conversion nanoparticles on the metal thin film is completed, a wavelength conversion structure is formed,

The step of adsorbing energy conversion nanoparticles on the metal thin film, the prepared wavelength conversion structure can be transferred to a transparent and flexible support (target substrate) through an adhesive film (Biaxially Oriented Polypropylene Films, BOPP film) It may further include a step (see FIG. 12).

The transparent substrate is polyimide (PI), polyethylene terephthalate (PET), polyethylene succinate (PES), polycarbonate (PC), polyethersulfone (PES), polyethylene It may be polyethylene naphthalate (PEN), polyarylate (PAR), glass fiber reinforced plastic (FPR), or polydimethylsiloxane (PDMS).

If the mold 110 may be a polyurethane acrylate (PUA) mold, the polyurethane acrylate mold is an ultraviolet curing material polyurethane acrylate on a Si master in which a cylindrical pattern is periodically etched and engraved. After dropping (PUA), put a polyethylene terephthalate (PET) film on it and expose it to UV light of 365 nm for 15 minutes while applying pressure to cure the PUA. After curing is completed, carefully remove it from the Si master to make a PUA mold with a hole pattern. can be manufactured.

The interval between the hole 112 and the hole 112 of the mold 110 is 200 nm to 100 μm, and the interval between the hole 112 and the hole 112 is the absorption wavelength of the wavelength conversion material. This interval is determined according to the emission wavelength, the size of the bead, the refractive index of the bead, and the like. Specifically, the interval between the hole 112 and the hole 112 may be 1 to 6 μm, preferably 2 to 4 μm, and more preferably 2 μm.

The arrangement of the holes 112 may be a square-lattice pattern, a hexagonal-lattice pattern having an interval of 4 μm between the holes, a rectangular-lattice pattern, a linear grating pattern, or It may have a pattern of a shape desired by the user. When manufacturing a PUA mold, a mold having a hole pattern of a desired pattern can be manufactured through a Si master, so there is no limit to the shape of the pattern created in the mold.

The inserting while exposing a part of the plasmonic microbeads 114 is inserted so that 1/2 to 1/4 of the diameter of the plasmonic microbeads 114 inserted into the hole 112 pattern of each of the mold 110 are exposed, and , preferably 1/3 is exposed.

When the exposure degree of the bead exceeds 1/2 of the bead diameter, it is difficult to form a pattern because it is not well fixed to the mold, and when it is less than 1/4, it is difficult to move the bead to a flexible substrate while maintaining the pattern of the bead formed with the pattern.

In addition, it means that the height of the hole is lower than the diameter of the silica spherical particle.

The step of inserting while exposing a part of the plasmonic microbeads 114 may be inserted by rubbing the plasmonic microbeads 114 in a circle in one direction on the mold 110 with a polydimethylsiloxane (PDMS) block. have.

The plasmonic microbeads 114 may be microbeads of silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), or tungsten oxide (WO).

The step of transferring and fixing the exposed plasmonic microbeads 114 to the substrate 160 coated with the polymer sacrificial layer 130 is to physically apply the plasmonic microbeads 114 to the substrate while curing the polymer sacrificial layer 130 . (160) can be fixed.

The polymer sacrificial layer 130 may use a variety of materials, such as positive-photoresist (PR), cyanoacrylate (CA), norland optical adhesive (NOA), and has a thickness of about 200 nm. less than the thickness. The polymer sacrificial layer 130 may be cured by heat treatment at 90° C. for about 1 minute when a positive-photoresist (positive-PR) is used.

The metal nanoparticles 171 may adsorb the self-assembled metal nanoparticles 171 by depositing the metal film 170 on the plasmonic microbeads 114 using a thermal evaporator. In this case, the metal film 170 and the metal nanoparticles 171 may be silver (Ag).

In order to adsorb the metal nanoparticles 171, a solid non-wetting process may be used, and the solid non-wetting process may be described as follows with reference to FIG. 8 .

Referring to FIG. 8, the solid non-wetting process is performed to form a metal film 170 to cover all parts except for the surface within ±30° from the axis connecting the contact point between the center of the spherical silica particle and the support. Depositing metal ions at an angle of 60° clockwise and counterclockwise from the normal substrate position. After that, when a sufficient temperature of 450-400°C is applied on a hot plate for about 3 minutes, 70 to 90 of the total surface area of the spherical silica particles Continuous metal nanoparticles 171 having a uniform or predetermined gradient diameter in % are formed.

The metal thin film 180 may be a zinc oxide (ZnO) thin film, and the zinc oxide (ZnO) thin film is an important factor in increasing the adsorption of the upconversion nanoparticles 190 .

The step of adsorbing the upconversion nanoparticles 190 is a step of replacing the surface of the plasmonic microbead 114 on which the metal thin film 180 is deposited with an amine group (Amine, -NH ₂ ) and a ligand between the amine group and the oleic acid ligand It further comprises adsorbing the upconversion nanoparticles 190 through the exchange reaction.

The step of replacing the surface of the plasmonic microbead 114 on which the metal thin film 180 is deposited with an amine group (Amine, -NH ₂ ) is a hydroxyl group (-Oh) on the surface of the plasmonic microbead 114 . ) is condensed with 3-Aminopropyl triethoxysilane (APTES) to replace it with an amine group (Amine, -NH2).

The adsorbing of the upconversion nanoparticles 190 uses a ligand exchange reaction between the amine group substituted on the surface of the plasmonic microbeads 114 and the oleic acid ligand present in the upconversion nanoparticles 190 as described above. At this time, the surface of the wavelength conversion efficiency amplifying structure finally generated by the ligand exchange reaction between the oleic acid and the ligand of the upconversion nanoparticles 190 is the amine group filling the surface of the plasmonic microbead 114. , there is an effect that the upconversion nanoparticles 190 are very densely attached.

The substrate 160 may be a quartz substrate or an IM substrate (SiO ₂ thin layer(I)/Ag film(M)/silicon substrate). The IM substrate was formed by depositing a silver (Ag) film 150 with a thickness of 100 nm on a Si substrate through an electron beam evaporator, and then oxidizing a silver (Ag) film 150 with a thickness of 5 nm through plasma enhanced chemical vapor deposition on the layer. It means a substrate on which a zinc (SiO ₂ ) thin film 120 layer is further formed.

The step of removing the polymer sacrificial layer 130 may be removed by heat treatment at a temperature of 300° C. to 600° C. for 1 to 4 hours, and is preferably removed by heat treatment at a temperature of 450° C. for 2 hours. In particular, in the step of removing the polymer sacrificial layer 130, if the heat treatment at a temperature less than 300 ℃ may cause a problem that the polymer remains without thermal decomposition, and if the heat treatment is performed at a temperature exceeding 600 ℃, the substrate is deformed. may occur.

This temperature range is determined according to the thermal decomposition temperature of the sacrificial polymer layer, and in FIG. 4, it is a result obtained by heat treatment at 450 degrees for 2 hours. Referring to FIG. 4 , it is possible to confirm the substrate on which the polymer sacrificial layer 130 is present, and the plasmonic microbead 114 inserted in the mold 110 in a predetermined pattern is transferred to the substrate and the polymer sacrificial layer 130 is transferred to the substrate It serves to keep it in place.

The wavelength conversion efficiency amplifying structure manufacturing method uses spherical particles in the form of a structure, so that in the infrared region using various light guide effects along with the Whispering gallery (WG) mode, which is unique in spherical dielectric particles. It is a resonant structure that effectively absorbs incident light.

The whispering gallery (WG) mode refers to a phenomenon in which a small whisper in a building structure such as a dome-shaped ceiling such as a cathedral is transmitted to a person far away without any distortion. Mode (Whispering gallery (WG) mode), a similar phenomenon occurs in transverse waves such as light, and due to this phenomenon, a small amount of light is amplified and transmitted without distortion.

The wavelength conversion efficiency amplifying structure manufacturing method utilizes a solid non-wetting process as a method of uniformly introducing metal nanoparticles 171 to the surface of a spherical dielectric substrate having a curved surface, that is, the plasmonic microbead 114, and the substrate 160 ), by controlling the position and/or orientation of the support, and optimizing it, the luminous efficiency of the upconverted nanoparticles 190 material present in the outermost part of the structure was maximized. The spherical dielectric substrate serves as a transporter for the upper metal nanoparticles 171 and upconversion nanoparticles 190 and at the same time can be easily transferred through an adhesive film, so it can be applied to a transparent and flexible film.

2 shows a schematic diagram of a wavelength conversion efficiency amplifying structure 200 manufactured according to an embodiment of the present invention.

2, the wavelength conversion efficiency amplification structure 200 is a plasmonic microbead 141, a metal nanoparticle 171 positioned on the surface of the plasmonic microbead 141, a plasmonic microbead 114, and a metal nanoparticle It includes the metal thin film 180 positioned on the 171 and the energy conversion nanoparticles 190 adsorbed on the surface of the metal thin film.

The plasmonic microbead 114 is characterized in that it has a spherical shape.

The wavelength conversion efficiency amplification structure 200 is a resonance structure that effectively absorbs incident light in the infrared region using various light guide effects along with the Whispering gallery (WG) mode, which appears uniquely in the spherical dielectric particles by using spherical particles.

The wavelength conversion efficiency amplification structure 200 increases infrared absorption by 14.30 to 18.7 times, that is, 1,430% to 1,870%, when the particles are spherical as described above than when the structure is flat.

The metal nanoparticles are characterized in that silver (Ag) nanoparticles.

The metal thin film is characterized in that it is a zinc oxide (ZnO) thin film.

The energy conversion nanoparticles are upconversion nanoparticles or downconversion nanoparticles.

The upconversion nanoparticles are NaYF4;YB3+/Er3+, NaYF4:Yb,TM, Na(Y,Gd)F4:Yb, Er/NaGdF4:Ce.

The downconversion nanoparticles include quantum dots such as CdSe, PbS, and CdS. However, it may be a semiconductor quantum dot including a core-shell colloidal quantum dot such as CdS/ZnS, CdSe/ZnS, CdSe/CdS, InAs/CdSe, or an inorganic material-based light emitting nanoparticle.

The transparent resonator using the wavelength conversion efficiency amplifying structure 200 may be used in an image sensor, a photodetector, an energy device, a solar cell, a display, and the like.

Hereinafter, the present invention will be described in more detail through examples. These Examples are for explaining the present invention in more detail, and the scope of the present invention is not limited by these Examples.

Preparation Example 1. Synthesis of upconversion nanoparticles (UCNPs)

β-NaYF ₄ :Yb ³⁺ /Er ³⁺ upconversion nanoparticles are synthesized through thermal decomposition of a lanthanide (Ln) trioleate (Ln(oleate) _{3 ) precursor.} The metal composition of the lanthanum (Ln) precursor contains 80% yttrium (Y), 18% ytter·m (Yb) and 2% erbium (Er). Trioleate (Ln(oleate) ₃ ) The precursor is YCl ₃ 6H ₂ O (0.8 mmol), YbCl ₃ 6H ₂ O (0.18 mmol), ErCl ₃ 6H ₂ O (0.02 mmol) and sodium oleate (3.1 mmol) in 3 ml deionized (DI) water. , 3.5 mL ethanol and 7 mL hexane are mixed at room temperature. The mixture is prepared by reacting at 343 K (69.85° C.) for 4 hours. Trioleate prepared as above (Ln (oleate) ₃ ) The precursor is mixed with oleic acid and 1-octadecene, heated to 423K (149.85°C), and then cooled to 323K (49.85°C). NaOH (2.5mmol) and NH ₄ F (4mmol) were added to methanol (10 mL) to prepare a mixture, the solution was cooled and stirred for 40 minutes. Thereafter, methanol was extracted and the remaining mixture was reacted at 593 K (319.85° C.) for 90 minutes in an Ar (99.9%) atmosphere to generate upconverted nanoparticles (UCNPs) having a hexagonal crystal phase. The reaction product is washed several times with ethanol and prepared by dispersing the reaction product in chloroform at the target concentration to the target concentration.

Preparation Example 2. IM substrate preparation (SiO ₂ thin layer(I)/Ag film(M)/silicon substrate)

First, the 2 Х 2 cm2 Si substrate was immersed in acetone (15 min), ethanol (15 min), and deionized water (15 min) and sonicated to clean the substrate (Si Substate), then 300K (26.85℃) under _{N 2 gas.} dried in A 100 nm thick Ag film was deposited on the substrate using an EBX-1000 electron beam evaporator (ULVAC Technologies, USA) at 300 K at ^{an operating pressure of 1 Х 10 −4 Torr.} The Ab film (Ag Film) onto the SiO ₂ thin-film layer (SiO ₂ thin film) 5 nm thick was deposited by evaporation on the Ag layer with the use of a mixture of ₄ and N ₂ O gas SiH plasma enhanced chemical vapor deposition (PECVD) IM board is manufactured. At this time, the SiO ₂ thin film layer was deposited using a Plasmalab 800 plus PECVD system (Oxford Instruments, UK) at 523K (249.85° C.) and ^{an operating pressure of 9×10 −1 Torr.}

Example 1. (Ref: quartz substrate + upconversion nanoparticles)

After preparing a quartz (SiO ₂ ) substrate (Si Substrate), a hydroxyl group (-Oh) mainly appearing on the surface of the quartz substrate is condensed with 3-Aminopropyl triethoxysilane (APTES) to react with an amine group (Amine, -NH _{2 )} ) is replaced with This refers to a process for forming self-assembled monolayers. This is prepared by immersing the quartz substrate in a combined solution of 5 vol% deionized water, 5 vol% APTES, and 90 vol% ethanol for about 30 minutes. 30 nm through a ligand exchange reaction between an amine group and an oleic acid ligand in a chloroform solution containing about 15 mg/ml of the upconversion nanoparticles prepared in Preparation Example 1 of the substrate whose surface is substituted with an amine group of upconversion nanoparticles (NaYF ₄ :Yb ³⁺ , Er ³⁺ ) are adsorbed.

Referring to FIG. 6 for the upconversion nanoparticle adsorption process.

Example 2. (UM: IM substrate + upconversion nanoparticles)

The same procedure as in Example 1 was performed, except that the IM substrate prepared in Preparation Example 2 was used instead of _{the quartz (SiO 2 ) substrate.}

Example 3. (UB: Ref + SiO ₂ micro beads)

A UV-curable polyurethane acrylate (PUA) was dropwise dispensed onto an etched silicon (Si) master substrate with square micropillars with a periodic spacing of 4 μm. A flexible and transparent PET film is placed on the drip-dispensed polyurethane acrylate and cured under UV light (λ=365 nm) for 15 minutes. After UV curing, it is peeled off from the Si master to prepare a PUA template, that is, a PUA mold having a hole pattern having a gap of 4 μm per hole.

The size of the PUA mold is a size of about 10mm × 10mm, the SiO ₂ microbeads hole side with a pattern having an average diameter of about 2㎛ (SiO ₂ microbead) Place the powder (1 ~ 2mg) polydimethylsiloxane (dimethylsiloxane, PDMS ) for 5 sec, 10 sec, 15 sec, and 30 sec on each patterned template by rubbing it in one direction so that the microbeads fill the holes so that the microbeads have a uniform pattern. Prepare a patterned microbead array. At this time, the bead inserted into the hole pattern is inserted such that about 1/3 of the bead is exposed to the outside of the hole pattern.

The patterned microbead array prepared as described above is transferred to the Si substrate.

First, an AZ GXR-601 positive photoresist (PR) layer (AZ Electronic materials, Ltd., Korea) is spin-coated on a Si substrate at 8000 rpm for 60 seconds to form a polymer sacrificial layer.

The polymer sacrificial layer formed as described above can be confirmed through FIG. 4(a).

As described above, the positive PR layer, which is a polymer sacrificial layer, is cured at 90 ° C. for 1 minute. In the step of curing the PR layer, the SiO ₂ microbead patterned in Example 3 is contact-printed on the Si substrate. The PUA mold is removed after the cured PR layer _{physically fixes and maintains the SiO 2 microbeads.}

As described above, _{it can be confirmed that the SiO 2} microbeads are physically fixed to the polymer sacrificial layer through Fig. 4(b), and through Fig. 5(a), a square-lattice pattern of 4 μm interval and Fig. 5(b). Hexagonal-lattice patterned SiO ₂ microbeads spaced 4 μm apart can be identified.

As described above, the SiO ₂ microbead-fixed Si substrate was annealed at 723K (449.85° C.) or higher for 2 hours to remove the PR film _{to obtain a patterned SiO 2} microbead monolayer array on the targeted substrate.

A hydroxyl group (-Oh) mainly appearing on the surface of the SiO ₂ microbead single-layer array is substituted with _{an amine group (Amine, -NH 2 ) by condensation reaction with 3-Aminopropyl triethoxysilane (APTES).} This refers to a process for forming self-assembled monolayers. This is prepared by immersing the quartz substrate in a combined solution of 5 vol% deionized water, 5 vol% APTES, and 90 vol% ethanol for about 30 minutes. 30 nm through a ligand exchange reaction between an amine group and an oleic acid ligand in a chloroform solution containing about 15 mg/ml of the upconversion nanoparticles prepared in Preparation Example 1 of the substrate whose surface is substituted with an amine group of upconversion nanoparticles (NaYF ₄ :Yb ³⁺ , Er ³⁺ ) are adsorbed.

Example 4. (UBM: UM + SiO ₂ microbead)

It was carried out in the same manner as in Example 3, except that the IM substrate of Preparation Example 2 was used instead of the Si substrate.

Example 5 (UIMB: UB + AgNP array + ZnO thin film)

A UV-curable polyurethane acrylate (PUA) was dropwise dispensed onto an etched silicon (Si) master substrate with square micropillars with a periodic spacing of 4 μm. A flexible and transparent PET film is placed on the drip-dispensed polyurethane acrylate and cured under UV light (λ=365 nm) for 15 minutes. After UV curing, it is peeled from the Si master to prepare a PUA template having a hole pattern, that is, a PUA mold.

_{Place SiO 2} microbead powder (1 to 2 mg) on the hole pattern side of the PUA mold and use dimethylsiloxane (PDMS) for 5 seconds, 10 seconds, 15 seconds, and 30 seconds on each patterned template. The microbead array patterned as described above is prepared by smooth and rubbing in one direction so that the microbeads are filled in the holes so that the microbeads have a uniform pattern. At this time, the bead inserted into the hole pattern is inserted such that about 1/3 of the bead is exposed to the outside of the hole pattern.

The patterned microbead array prepared as described above is transferred to the Si substrate.

First, an AZ GXR-601 positive PR (AZ Electronic materials, Ltd., Korea) layer was spin-coated on a Si substrate at 8000 rpm for 60 seconds. Thereafter, the PR layer was cured at 90 ° C. for 1 minute, and in the step of curing the PR layer, the SiO ₂ microbead patterned in Example 3 was contact-printed on the Si substrate, and the cured PR layer was SiO ₂ Remove the PUA mold after allowing the microbeads to be physically fixed and retained. The SiO ₂ microbead immobilized Si substrate was annealed at 723K (449.85° C.) or higher for 2 h to remove the PR film _{to obtain a patterned SiO 2} microbead monolayer array on the targeted substrate.

_{A 15 nm thick Ag film was then placed on the obtained SiO 2} microbead array using a KVT-D438 thermal evaporator (Korea Vacuum Technology, Gyeonggi-do, Korea) to generate the self-assembled Ag nanoparticles (Ag NPs). vaporize. A conformal Ag film was placed on _{SiO 2} microbeads by successively depositing Ag on a substrate tilted at a 60° angle at 300 K (26.85° C.) and ^{a pressure of 3 Х 10 −5 Torr.} Followed by forming a disordered array AgNP on SiO ₂ microbead surface on the SiO ₂ microbead array annealed for 3 minutes at 623K (349.85 ℃) using the Ag film is a hot plate. The AgNP array formed as described above can be confirmed through the SEM image of the silica spherical particles in which the metal nanoparticles are formed in FIG. 9 .

Then, a 5 nm thick ZnO thin film was deposited using an atomic layer deposition (ALD) module (CN1 Co., Ltd., Korea) at 393 K at ^{an operating pressure of 3.8 Х 10 −1 Torr.} deposited.

In order to change the surface properties of the deposited ZnO thin film layer, a hydroxyl group (-Oh) of the ZnO thin film layer is subjected to a condensation reaction with 3-Aminopropyl triethoxysilane (APTES) to replace it _{with an amine group (Amine, -NH 2 ).} This refers to a process for forming self-assembled monolayers. This is prepared by immersing the quartz substrate in a combined solution of 5 vol% deionized water, 5 vol% APTES, and 90 vol% ethanol for about 30 minutes. The substrate, the surface of which is substituted with an amine group, was reacted in a chloroform solution containing about 15 mg/ml of the upconversion nanoparticles prepared in Preparation Example 1 for 6 hours, and a ligand exchange reaction between the amine group and the oleic acid ligand. reaction), upconversion nanoparticles (NaYF ₄ :Yb ³⁺ , Er ³⁺ ) of 30 nm are adsorbed to form a plasmonic platform with a lattice arrangement.

Example 6. (UIMBM: UBM + AgNP array + ZnO thin film)

The same procedure as in Example 5 was performed except that the IM substrate of Preparation Example 2 was used instead of the Si substrate.

Comparative Example 1.

It was carried out in the same manner as in Example 6, except for the step of forming a ZnO thin film.

Comparative Example 2.

It is always performed in the same manner as in Example 6, but using a PUA mold having a gap between the holes of 2 μm to 6 μm.

Characteristic evaluation 1.

When the patterned microbead array was manufactured in Example 3, the spherical silica particles and residual particles filling the PUA mold with hole patterns and the PUA mold for each rubbing time were photographed with a Charge Coupled Device (CCD) camera.

The photographing result is shown in FIG.

Referring to FIG. 3 , it can be seen that silica spherical particles were inserted into the hole pattern when the process was performed for 30 seconds or more, and most of the remaining particles were adsorbed and removed by the PDMS block.

Characteristic evaluation 2.

The silica spherical particles and the support of the wavelength conversion efficiency amplifying structure prepared in Example 3 were confirmed with a scanning electron microscope (SEM).

The confirmation result is shown in FIG. 7 .

Referring to FIG. 7 , it can be confirmed that the upconversion nanoparticles are well adsorbed on the surface of the microbeads.

Characteristic evaluation 3.

The wavelength conversion efficiency amplifying structure prepared according to Example 6 and the wavelength conversion efficiency amplifying structure of Comparative Example 1 prepared as in Example 6 except for the ZnO thin film were subjected to a scanning electron microscope (SEM). Confirmed.

Confirmation results are shown in FIGS. 10(a) to 10(d).

Figure 10 (a) is a finished structure when the ZnO layer is not present, Figure 10 (b) is an enlarged image showing the upconverted nanoparticles selectively attached to the surface of the silica microbead. Figure 10 (c) is a completed structure when the ZnO layer is present, Figure 10 (d) is a cross-sectional image through a focused-ion beam (FIB).

10(a) to 10(d), it was confirmed that the ZnO layer well covered the metal surface formed by the non-wetting process (10(a), 10(b)), and it was upconverted to the surface above it. It was confirmed that the nanoparticles were well formed.

Characteristic evaluation 4.

The light emission intensity of the structures prepared according to Examples 1 to 6 was measured.

The measurement results are shown in FIG. 11 .

Referring to FIG. 11 , it was confirmed that the light emission intensity of Example 6 (UIMBM) was improved by about 1000 times compared to Example 1 (Ref). This means that the square lattice array of plasmonic microbeads and the metal nanoparticles amplified the emission intensity by causing a resonance phenomenon in the infrared absorption region and the emission region of the wavelength conversion material.

Characteristic evaluation 5.

After transferring the structure prepared in Example 6 to a transparent and flexible support (PET substrate) through an adhesive film (Biaxially Oriented Polypropylene Films, BOPP film), it is checked whether light is emitted.

A schematic diagram of the transcription process is shown in FIG. 12, and the results of confirming the light emission are shown in FIGS. 12 and 14 .

Referring to FIG. 13 , it can be seen that light emission is very easy even after being transferred to a transparent and flexible material, and referring to FIG. 14 , it can be confirmed that the transparency is not significantly impaired even after being transferred to a transparent and flexible material.

Characteristic evaluation 6.

A two-dimensional contour plot showing the measured value by measuring the scattering intensity according to the separation distance (period) of the SiO2 microbead array of a square lattice of the structures prepared in Comparative Example 2 It is shown in FIG. 15 as a graph.

Referring to FIG. 15, as in the contour plot of FIG. 15, 545 nm and 658 nm, which correspond to the upconversion wavelength, are the largest scattering intensity when arranged at a period of 2 µm among scattering intensities when arranged in a period of 1.5 to 3 µm. is showing

For reference, when the bead size (BEAD SIZE) is 2㎛, if the period is 2㎛, the bead is attached. When depositing Ag, Ag cannot be deposited evenly on the bead surface. Because it is covered, only the upper part is coated.

Therefore, in consideration of such fairness, the embodiment was performed by setting the interval between beads to an integer multiple of 4 μm so that the scattering intensity could be 2 μm, which is the maximum grating period, and actually set the spacing between beads to 4 μm. It was confirmed through an experiment using the example carried out that the grating period at which the scattering intensity is maximized, 2 μm, appears.

As described above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and variations from these descriptions are provided by those skilled in the art to which the present invention pertains. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, and should be defined by the following claims as well as the claims and equivalents.

110: mold
112: hole
114: plasmonic microbead
120: metal thin film
130: polymer sacrificial layer
150: silver (Ag) film
160: substrate
170: silver (Ag) thin film
171: metal nanoparticles
180: metal thin film
190: energy conversion nanoparticles

Claims (15)

preparing a mold having one or more hole patterns and inserting them while exposing a part of the plasmonic microbeads into the hole patterns of the mold;
transferring and fixing the exposed plasmonic microbeads to a substrate coated with a sacrificial polymer layer;
removing the mold and heat-treating the substrate from which the mold is removed to remove the polymer sacrificial layer;
depositing metal nanoparticles on plasmonic microbeads fixed on the substrate from which the polymer sacrificial layer has been removed;
depositing a metal thin film on the plasmonic microbeads and the metal nanoparticles; and
A method of manufacturing a structure for amplifying wavelength conversion efficiency comprising the step of adsorbing energy conversion nanoparticles on the metal thin film.
According to claim 1,
The inserting while exposing a part of the plasmonic microbeads is a method of manufacturing a wavelength conversion efficiency amplification structure, characterized in that inserting the plasmonic microbeads inserted into the hole patterns of each of the molds so that 1/2 to 1/4 are exposed .
According to claim 1,
The step of inserting while exposing a part of the plasmonic microbead is a polydimethylsiloxane (PDMS) block, the wavelength conversion efficiency amplification structure, characterized in that by rubbing the plasmonic microbead on the mold in a circle in one direction manufacturing method.
According to claim 1,
The plasmonic microbead is silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), yttrium oxide (Y2O3), aluminum oxide (Al2O3), magnesium oxide (MgO), zinc oxide (ZnO), tin oxide (SnO), iron oxide (FeO), zirconium oxide (ZrO2), chromium oxide (Cr2O3), hafnium oxide (HfO), beryllium oxide (BeO) and tungsten oxide (WO) characterized in that one selected from the group consisting of metal oxide plasmonic microbeads A method of manufacturing a structure for amplifying wavelength conversion efficiency.
According to claim 1,
The metal nanoparticles are silver (Ag), copper (Cu), or gold (Ag) nanoparticles, characterized in that the wavelength conversion efficiency amplifying structure manufacturing method.
According to claim 1,
The metal thin film is zinc oxide (ZnO), titanium oxide (TiO ₂ ), yttrium oxide (Y2O3), aluminum oxide (Al2O3), magnesium oxide (MgO), tin oxide (SnO), iron oxide (FeO), zirconium oxide (ZrO2) ), chromium oxide (Cr2O3), hafnium oxide (HfO), or berynium oxide (BeO), characterized in that the thin film wavelength conversion efficiency amplifying structure manufacturing method.
According to claim 1,
The energy conversion nanoparticles are up-conversion nanoparticles or down-conversion nanoparticles, characterized in that the wavelength conversion efficiency amplifier manufacturing method.
According to claim 1,
The step of adsorbing the energy conversion nanoparticles may include substituting an _{amine group (Amine, -NH 2} ) on the surface of the plasmonic microbead on which the metal thin film is deposited; and
The method of claim 1, further comprising adsorbing the energy conversion nanoparticles through a ligand exchange reaction between the amine group and the oleic acid ligand.
According to claim 1,
Removing the polymer sacrificial layer is a method for producing a wavelength conversion efficiency amplifier, characterized in that the heat treatment at 300 ℃ to 600 ℃.
The wavelength conversion efficiency amplifying structure manufactured according to claim 1 is
plasmonic microbeads;
metal nanoparticles located on the surface of the plasmonic microbeads;
a metal thin film positioned on the plasmonic microbeads and the metal nanoparticles; and
Wavelength conversion efficiency amplifying structure comprising energy conversion nanoparticles adsorbed on the surface of the metal thin film
11. The method of claim 10,
The metal nanoparticles are silver (Ag), copper (Cu), or gold (Ag) nanoparticles, characterized in that the wavelength conversion efficiency amplifying structure.
11. The method of claim 10,
The metal thin film is zinc oxide (ZnO), titanium oxide (TiO ₂ ), yttrium oxide (Y2O3), aluminum oxide (Al2O3), magnesium oxide (MgO), tin oxide (SnO), iron oxide (FeO), zirconium oxide (ZrO2) ), chromium oxide (Cr2O3), hafnium oxide (HfO), or beryllium oxide (BeO) wavelength conversion efficiency amplifying structure, characterized in that the thin film.
11. The method of claim 10,
The energy conversion nanoparticles are wavelength conversion efficiency amplification structure, characterized in that the upconversion nanoparticles or downconversion nanoparticles.
14. The method of claim 13,
The upconversion nanoparticles are NaYF4;YB3+/Er3+, NaYF4:Yb,TM or Na(Y,Gd)F4:Yb,Er/NaGdF4:Ce wavelength conversion efficiency amplification structure.
15. The method of claim 14,
The downconversion nanoparticles are semiconductor quantum dots including core-shell colloidal quantum dots such as CdS / ZnS, CdSe / ZnS, CdSe / CdS, InAs / CdSe, and inorganic material-based light-emitting nanoparticles, characterized in that the wavelength conversion efficiency amplification structure .

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