KR20220137240A - mechanoluminescence particle-quantum dot composite film - Google Patents

Abstract

A mechanoluminescent particle-quantum dot composite film is provided. The mechanoluminescent particle-quantum dot composite film includes: an elastic polymer matrix; quantum dots dispersed within the elastomeric matrix; and mechanoluminescent core particles dispersed together with the quantum dots in the elastic polymer matrix. The mechanoluminescent particle-quantum dot composite film can emit light by a mechanical stimulus that can occur in nature, while achieving high color purity and various colors.

Description

Mechanoluminescence particle-quantum dot composite film

The present invention relates to a light emitting film, and more particularly to a mechanical light emitting film.

Mechanoluminescence refers to the phenomenon in which light is generated when a mechanical force (pressure or stimulus) is applied to a material. Therefore, as light can be emitted by renewable energy such as wind power, there is a possibility of development for various uses.

However, the materials exhibiting such mechanoluminescence are inorganic crystals doped with micro-sized dopants, have very low color purity due to a trap state, and have limitations in color expression due to chemical instability and the like. In addition, it is known that pure red expression cannot be achieved by mechanical light emission.

The low color purity of the mechanoluminescent material and the limitation of expressive colors are becoming obstacles in manufacturing devices using the mechanoluminescent material.

The problem to be solved by the present invention is to provide a composite film capable of realizing high color purity and various colors while using a mechanoluminescent material capable of emitting light by renewable energy.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above technical problem, an embodiment of the present invention provides a mechanical light emitting particle-quantum dot composite film. The mechanoluminescent particle-quantum dot composite film includes an elastic polymer matrix; quantum dots dispersed in the elastic polymer matrix; and dispersed mechanoluminescent core particles with the quantum dots in the elastic polymer matrix.

The mechanoluminescent core particles are doped with any one dopant of Cu, Mn, Pb, Cl, Eu, Ce, Ho, Dy, Ba, Ca, Pr ³⁺ , Ti, Te, ZnS, CaZnOS, BaZnOS, MgF ₂ , La ₂ O ₂ S, Y ₂ O ₂ S, SrAl ₂ O ₄ , SrMgAl ₆ O ₁₁ , SrCaMgSi ₂ O ₇ , SrBaMg Si ₂ O ₇ , Sr ₂ MgSi ₂ O ₇ , Ca ₂ MgSi ₂ O ₇ , CaYAl ₃ O ₇ , ZnGa ₂ O ₄ , MgGa ₂ O ₄ , Ca ₂ Al ₂ SiO ₇ or ZrO ₂ . The quantum dots may be compound semiconductor quantum dots or perovskite quantum dots. The mechanoluminescent core particle may be a particle emitting light having an energy greater than a bandgap of the quantum dot. Specifically, the mechanoluminescent core particles may be particles emitting blue light, and the quantum dots may be quantum dots emitting green or red light.

A shell surrounding the mechanoluminescent core particle may be disposed on the surface of the mechanoluminescent core particle. The quantum dot may be a first quantum dot, and a plurality of second quantum dots may be disposed between the surface of the mechanoluminescent core particle and the shell. The mechanoluminescent core particle and the second quantum dot may be bound by a polydentate ligand. The ligand may be an amphoteric ligand (NH ₄ ) ₂ S. The mechanoluminescent core particle may be a particle emitting light having an energy greater than a bandgap of the first and second quantum dots. As an example, the mechanoluminescent core particle may be a particle emitting blue light, the first quantum dot may be a green light emitting quantum dot, and the second quantum dot may be a red light emitting quantum dot.

The shell may be a metal oxide film. Between the shell and the elastic polymer matrix, a monomolecular layer may be disposed on the surface of the shell. The monomolecular layer may be a layer including monomolecules represented by Formula 1 or Formula 2 below.

[Formula 1]

HS-(R ₁ -COO)nR ₂

In Formula 1, R ₁ is a C1 to C3 alkanediyl group or a C5-C6 areenediyl group, R ₂ is a C1 to C3 alkyl group, and n may be 0 or 1.

[Formula 2]

HS-R ₃ -SH

In Formula 2, R ₁ may be a C1 to C3 alkanediyl group or a C5-C6 areenediyl group.

The single molecule may be a C1-C3 alkyl thiol, a C1-C3 alkyl thioglycolate, or a C1-C3 alkyl 3-mercaptopropionate.

Another embodiment of the present invention in order to achieve the above technical object provides a mechanical light emitting particle-quantum dot composite film. The mechanical light emitting particle-quantum dot composite film is an elastic polymer matrix; first quantum dots dispersed in the elastic polymer matrix; and dispersed with the first quantum dots in the elastic polymer matrix, a mechanoluminescent core particle, a shell surrounding the mechanoluminescent core particle on a surface of the mechanoluminescent core particle, and a surface and the shell of the mechanoluminescent core particle It includes composite particles having a plurality of second quantum dots disposed therebetween.

The mechanoluminescent core particle and the second quantum dot may be bound by a polydentate ligand. The ligand may be an amphoteric ligand (NH ₄ ) ₂ S. Between the shell and the elastic polymer matrix, a monomolecular layer may be disposed on the surface of the shell. The monolayer includes a monomolecular of C1-C3 alkyl thiol, C1-C3 alkyl thioglycolate, or C1-C3 alkyl 3-mercaptopropionate. can do.

The mechanical light emitting particle-quantum dot composite film according to an embodiment of the present invention can realize high color purity and various colors while emitting light by mechanical stimulation that can occur in nature.

Figure 1a is a schematic view showing a mechanical light emitting particle-quantum dot composite film according to an embodiment of the present invention, Figure 1b is a partial crushing view showing the mechanical light emitting particles in the elastic polymer matrix enlarged.
Figure 2a is a schematic diagram showing a mechanical light emitting particle-quantum dot composite film according to another embodiment of the present invention.
2B and 2C are schematic views illustrating the mechanism in which the mechanoluminescent particle-quantum dot composite film described with reference to FIG. 2A emits light by external mechanical stimulation.
Figure 3 is a mechanical luminescent film according to Comparative Example 1, a mechanical luminescent particle-quantum dot composite film according to Preparation Example 1, and a mechanical luminescent particle-quantum dot composite film according to Preparation Example 2 A photograph (a) , SEM (scanning electron microscope) image of the mechanoluminescent particle-quantum dot composite film according to Preparation Example 1 (b), photoluminescence spectra of B-ZnS microparticles, G-QD, and R-QD (c), and Preparation Example The mechanical light emitting particles according to 1 - quantum dot composite film and the mechanical light emitting particles according to Preparation Example 2 - shows the photoluminescence spectrum (d) of the quantum dot composite film.
4 is a mechanical luminescent film (B-ZnS) according to Comparative Example 1, a mechanical luminescent film (G-ZnS) according to Comparative Example 2, a mechanical luminescent film (O-ZnS) according to Comparative Example 3, according to Preparation Example 1 Mechanical luminescent particle-quantum dot composite film (G-QMM), and mechanical luminescent particle-quantum dot composite film (R-QMM) according to Preparation Example 2 (a), mechanical luminescent film according to Comparative Example 2, Preparation Example Mechanoluminescent particles according to 1 - quantum dot composite film (G-QMM), the mechanical luminescent film according to Comparative Example 3, and the mechanoluminescent particle-quantum dot composite film according to Preparation Example 2 (R-QMM) of the emitted mechanoluminescence peaks Graph (b) showing the peak wavelength and full width at half maximum, the mechanical light emitting film according to Comparative Example 1 (B-ZnS), the mechanical light emitting film according to Comparative Example 2 (G-ZnS), and the mechanical light emitting film according to Comparative Example 3 (O- ZnS), the mechanical luminescence particle-quantum dot composite film (G-QMM) according to Preparation Example 1, and the mechanical luminescence particle-quantum dot composite film (R-QMM) according to Preparation Example 2 CIE 1931 color-coordinates showing the mechanical emission peaks (c), the photoluminescence and mechanoluminescence spectrum (d) of the mechanical light emitting film (B-MM) according to Comparative Example 1, and the photoluminescence of the mechanical light emitting particle-quantum dot composite film (R-QMM) according to Preparation Example 2 and The mechanoluminescence spectrum (e) is shown.
5 is a mechanoluminescence spectrum (a, b), a graph showing the quantum dot concentration in the quantum dot-PDMS dispersion and the intensity of light emitted by mechanoluminescence by B-ZnS microparticles (c), and CIE 1931 color-coordinates (d).
6 shows a photoluminescence spectrum (a), a mechanical luminescence spectrum (b), and a photograph (c) of a mechanical luminescence film of the mechanoluminescent particle-quantum dot composite film according to Preparation Example 3 (c).
7 shows an SEM image (a) and a TEM (Transmission Electron Microscopy) image (b) obtained by photographing the mechanoluminescent particle-quantum dot composite film according to Preparation Example 4;

Hereinafter, preferred embodiments according to the present invention will be described in more detail with reference to the accompanying drawings in order to describe the present invention in more detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms.

Throughout this 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.

As used throughout this specification, the terms "about," "substantially," and the like are used in or close to the numerical value when material tolerances are given in the stated meaning, and are intended to be accurate or to assist the understanding of the present application. Absolute figures are used to prevent unreasonable exploitation of the stated disclosure by unscrupulous infringers.

Figure 1a is a schematic view showing a mechanical light emitting particle-quantum dot composite film according to an embodiment of the present invention, Figure 1b is a partial crushing view showing the mechanical light emitting particles in the elastic polymer matrix enlarged.

1a and 1b, the mechanoluminescence particles-quantum dot composite film 10 is uniformly dispersed in the elastic polymer matrix 11, mechanoluminescence particles (MLPs, 13) and quantum dots (quantum dots, QDs) , 17) may be included.

The elastic polymer matrix 11 contains an elastic polymer, and the elastic polymer is, for example, polyisoprene, polybutadiene, polyisobutylene, polyurethane, polysiloxane, polydimethylsiloxane (PDMS), styrene-butadiene copolymer, styrene-butadiene-styrene copolymer, styrene-ethylene-butylene-styrene copolymer, ethylene propylene diene rubber, acrylic rubber, polychloroprene rubber, silicone rubber, or combinations thereof. In addition, the elastic polymer in the elastic polymer matrix 11 may be in a crosslinked state.

The mechanoluminescent particle 13 is a particle that emits light in response to a mechanical stimulus applied to the particle, and is a mechanoluminescent core particle 13a and the mechanoluminescent core particle 13a on the surface of the mechanoluminescent core particle 13a. ) may have a core/shell structure having a shell (SH) surrounding it. Accordingly, the mechanoluminescent core particles 13a may be uniformly dispersed in the elastic polymer matrix 11 .

The mechanoluminescent core particles 13a are ZnS, CaZnOS, BaZnOS, MgF ₂ , La ₂ O ₂ S, Y ₂ O ₂ S, SrAl ₂ O ₄ , SrMgAl ₆ O ₁₁ , SrCaMgSi ₂ O ₇ , SrBaMg Si ₂ O ₇ . , Sr ₂ MgSi ₂ O ₇ , Ca ₂ MgSi ₂ O ₇ , CaYAl ₃ O ₇ , ZnGa ₂ O ₄ , MgGa ₂ O ₄ , Ca ₂ Al ₂ SiO ₇ or ZrO ₂ particles, Cu, Mn, Pb, Cl, Eu, Ce, Ho, Dy, Ba, Ca, Pr ³⁺ , Ti, and Te may be doped with any one dopant. In one embodiment, the mechanoluminescent core particles 13a may be ZnS, CaZnOS, BaZnOS particles having a wurtzite crystal structure, Cu ⁺ , Mn ²⁺ , Al ³⁺ , Er ³⁺ , Sm ³⁺ . It may be a particle doped with any one dopant. The peak wavelength of the light emitted by the mechanoluminescence core particle 13a may vary depending on the type of the particle and even with the same particle, depending on the dopant. The mechanoluminescent core particles 13a may be particles having a diameter of 1 to 100 μm, specifically 5 to 30 μm, as an example of a micrometer size. In addition, the mechanoluminescent core particles 13a may exhibit dielectric polarization, that is, piezoelectricity by the mechanical stimulation.

The shell SH is an example of a metal oxide layer, and may be an Al ₂ O ₃ , MgO, or SiO ₂ light-transmitting layer capable of transmitting light. In the metal oxide layer, the metal includes a metalloid. The metal oxide film may be formed using a solution process such as atomic layer deposition, iCVD (initiated chemical vapor deposition), or hydrothermal synthesis. The shell SH may be a film having a thickness of several to several hundred nm. A monomolecular layer (not shown) may be disposed on the surface of the shell SH. For the description of the monomolecular layer, reference will be made to the embodiments described with reference to FIGS. 2A, 2B, and 2C below.

When vibrations such as wind and waves that may occur in nature, that is, a mechanical stimulus S, are applied to the mechanoluminescent particle-quantum dot composite film 10, the elastic polymer matrix 11 is elastically deformed, and thus the mechanical light emitting particles (13) Specifically, a triboelectric field is generated between the metal oxide shell SH exposed on the surface of the mechanoluminescent particles 13 and the elastic polymer matrix 11, and by this triboelectric field, the mechanical The electrons in the light emitting core particle 13a may emit light 13 ′ while being excited and then transitioning to the ground state. In other words, the mechanoluminescent particles 13 may be mechanoluminescent. In summary, the mechanoluminescent particles 13 may be triboluminescence particles.

The quantum dots 17 are semiconductor particles having a size of angstroms or nanometers, for example, 0.1 to 10 nm, and may be compound semiconductor quantum dots or perovskite quantum dots, and may have a core/shell structure. When the quantum dots 17 are compound semiconductor quantum dots, the core may be CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, InP, GaP, or InGaP, which are group II-VI or III-V compound semiconductors, and the shell may include The compound semiconductor having a large bandgap compared to the core may be ZnS or CdZnS. In addition, metal ions may be doped into the core of the quantum dots 17 . The band gap of the quantum dot 17 may be adjusted according to the type of doped metal ion or the size of the quantum dot 17 . In another example, when the quantum dots 17 are perovskite quantum dots, the core may be a particle having a structure of ABX ₃ corresponding to the perovskite crystal, and the shell may be ZnS or SiO ₂ . In ABX ₃ , A is Cs ⁺ , CH ₃ NH ₃ ⁺ (methylammonium, MA), or CH(NH ₂ ) ₂ ⁺ (formamidinium, FA), and B is Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , Bi ²⁺ , or Sb ²⁺ , and X may be Cl ^- , Br ^- , or I ^- as a halogen ion.

The mechanoluminescent particle 13 and the quantum dot 17, the mechanoluminescent particle 13, specifically, the light 13 ′ emitted from the mechanoluminescent core particle 13a makes the quantum dot 17 more than the band gap. The type of the mechanoluminescent core particle 13a and the type of the quantum dot 17 may be appropriately selected so as to have a large energy. In this case, the mechanoluminescent particles 13 may be mechanoluminescent by a mechanical stimulus applied from the outside, and accordingly, the quantum dots 17 may emit light by the light 13 ′ emitted from the mechanoluminescent particles 13 . It is excited (photoexcitation), and thus, the quantum dots 17 may photoluminescence.

In this way, the mechanoluminescent particle-quantum dot composite film 10 is in the quantum dot 17 along with the light 13 ′ emitted from the mechanoluminescent particle 13 by a mechanical stimulus S that may occur in nature. The emitted light 17 ′ may be emitted to the outside. At this time, the light 17 ′ emitted from the quantum dots 17 has a higher peak wavelength compared to the light 13 ′ emitted from the mechanoluminescent particles 13 , but the half width of the peak wavelength is decreased, etc. can do. As an example, the mechanoluminescent particles 13 may be particles capable of emitting blue-based light, and the quantum dots 17 may be quantum dots capable of emitting green-based or red-based light. When the quantum dot 17 is a red quantum dot, the mechanoluminescent particle-quantum dot composite film 10 may exhibit a red color that is not possible in general mechanical light emitting materials.

When the plurality of quantum dots 17 have different band gaps and are quantum dots capable of emitting light of different wavelengths, the mechanoluminescent particle-quantum dot composite film 10 is emitted from the quantum dots 17 . It can display multi-colored light. In another example, when the ratio of the mechanoluminescent particles 13 and the quantum dots 17 is adjusted, the light 13 ′ emitted from the mechanoluminescent particles 13 is emitted from the quantum dots 17 . They are not all consumed and can be emitted to the outside, and can also emit multi-colored light. In one embodiment, the mechanoluminescent particles 13 are particles capable of emitting blue-based light, and the quantum dots 17 are quantum dots emitting green-based light and red-based light. In the case of a mixture of quantum dots, the mechanoluminescent particles-quantum dot composite film 10 may emit white light.

This mechanoluminescent particle-quantum dot composite film 10 is a flexible display that emits light of various wavelengths by using vibrations such as wind and waves that may occur in nature, that is, mechanical stimulation (S) as an energy source, a wearable sensor, Alternatively, it may be used as a material for next-generation smart electronic devices such as electronic skin.

Figure 2a is a schematic diagram showing a mechanical light emitting particle-quantum dot composite film according to another embodiment of the present invention.

Referring to FIG. 2A , the mechanoluminescent particle-quantum dot composite film 20 may include mechanoluminescent core particles 23a and first quantum dots 27 dispersed in an elastic polymer matrix 21 .

The elastic polymer matrix 21 may be the elastic polymer matrix 11 described with reference to FIG. 1 .

The mechanoluminescent core particle 23a may be the mechanoluminescent core particle 13a described with reference to FIG. 1 . A shell SH surrounding the mechanoluminescent core particles 23a may be disposed on the surface of each of the mechanoluminescent core particles 23a. A plurality of second quantum dots 24 may be disposed on the surface of the mechanoluminescent core particle 23a, that is, between the surface of the mechanoluminescent core particle 23a and the shell SH. At this time, at least a part or the whole of the surface of the mechanoluminescent core particle 23a may be surrounded by the second quantum dots 24 , and the shell SH is at least a surface of the mechanoluminescent core particle 23a. It may be a coating film surrounding the second quantum dots 24 that partially or entirely surrounds. The mechanoluminescent core particle 23a, the shell SH, and the second quantum dots 24 may be referred to as a composite particle.

As an example, the mechanoluminescent core particle 23a and the second quantum dot 24 are polydentate ligands having a plurality of ligands in one molecule. For example, an amphoteric ligand. can be combined by In other words, one ligand of the polydentate ligand may bind to the mechanoluminescent core particle 23a and the other ligand may bind to the second quantum dot 24 . In one embodiment, the ligand may be (NH ₄ ) ₂ S as an amphoteric ligand. The binding of the mechanoluminescent core particle 23a and the second quantum dot 24 with various ligands involves exchanging the original ligand located on the surface of the second quantum dot with the multidentate ligand, and then This may be performed by mixing the ligand-exchanged second quantum dots 24 with the site ligand and the mechanoluminescent core particles 23a.

The shell SH is an example of a metal oxide layer, and may be an Al ₂ O ₃ , MgO, or SiO ₂ light-transmitting layer capable of transmitting light. In the metal oxide layer, the metal includes a metalloid. The metal oxide layer may be formed using a solution process such as atomic layer deposition, iCVD (initiated chemical vapor deposition), or hydrothermal synthesis. The shell SH may stably maintain the coupling between the second quantum dots 24 and the mechanoluminescent core particle 23a even when external mechanical stimulation is repeated. The shell SH may be a film having a thickness of several to several hundred nm.

A monomolecular layer 26 may be formed on the surface of the shell SH. The monomolecular layer 26 is a film capable of inducing a dipole on the surface of the shell SH, and a triboelectric field formed between the elastic polymer matrix 21 and the shell SH when an external mechanical stimulus is applied. can increase the size of The monomolecular layer 26 may be a layer including monomolecules represented by Formula 1 or Formula 2 below.

[Formula 1]

HS-(R ₁ -COO)nR ₂

In Formula 1, R ₁ may be a C1 to C3 alkanediyl group or a C5-C6 areenediyl group, R ₂ may be a C1 to C3 alkyl group, and n is 0 or 1 day can

In Formula 1, when n is 0, the unimolecular molecule is a C1 to C3 alkyl thiol, and may have a thiol group as the head group 26a in FIG. 2A and a C1 to C3 alkyl group as the end group (X). When n is 1 in Formula 1, the unimolecular molecule may be a carboxylate (R ₁ -COO, 26b) having a thiol group as the head group 26a and a C1 to C3 alkyl group as the terminal group (X).

[Formula 2]

HS-R ₃ -SH

In Formula 2, R ₁ may be a C1 to C3 alkanediyl group or a C5-C6 areenediyl group.

The monomolecule is an example, C1-C3 alkyl thiol, C1-C3 alkyl thioglycolate (C1-C3 alkyl thioglycolate), or C1-C3 alkyl 3-mercaptopropionate (C1-C3 alkyl 3-mercaptopropionate) can be

The mechanoluminescence core particle 23a may be a particle emitting light having an energy greater than a bandgap of the quantum dots 24 and 27 . The first quantum dot 27 and the second quantum dot 24 are the quantum dots 17 described with reference to FIG. 1 , and may be the same or different materials. As an example, the second quantum dot 24 may be a quantum dot having a smaller bandgap than the first quantum dot 27 . Specifically, the first quantum dot 27 may be a green light-emitting quantum dot, and the second quantum dot 24 may be a red light-emitting quantum dot.

2B and 2C are schematic views illustrating the mechanism in which the mechanoluminescent particle-quantum dot composite film described with reference to FIG. 2A emits light by external mechanical stimulation.

Referring to FIGS. 2A, 2B, and 2C simultaneously, an external mechanical stimulus S may be applied to the mechanoluminescent particle-quantum dot composite film 20 . As an example, vibrations such as wind and waves that may occur in nature, that is, a mechanical stimulus S, may be applied to the mechanical light emitting particle-quantum dot composite film 20 . At this time, the elastic polymer matrix 21 is elastically deformed, and thus a triboelectric field may be generated between the shell SH and the elastic polymer matrix 21 . Specifically, the elastic polymer matrix 21 has a large electronegativity compared to the shell (SH), so that electrons are obtained from the shell (SH) to have a negative charge, and the shell (SH) has a positive charge by subtracting electrons. It can be said

On the other hand, when the monomolecular layer 26 is bonded to the shell SH, the thiol group, which is the head group 26a of the monomolecular layer 26, has a lone pair of electrons and is an electron donor that gives electrons to the shell SH. can As a result, dipoles can be induced in the monomolecular layer 26 , and thus electrons are more easily moved from the shell SH to the elastic polymer matrix 21 , so that the shell SH and the elastic polymer matrix 21 are ), the friction field generated between them may be further strengthened. The electrons in the mechanoluminescent core particles 23a inside the shell SH are excited by this frictional field and then transition to the ground state to emit light 23 ′. In other words, the mechanoluminescent core particles 23a may be mechanoluminescent.

On the other hand, the excited electrons in the mechanoluminescent core particle 23a are transferred to the conduction band of the second quantum dots 24 bonded on the surface of the mechanoluminescent core particle 23a before being transferred to the ground state, and then the second quantum dot The light 24 ′ may be emitted while transitioning to the valence band of the fields 24 . In other words, the second quantum dots 24 may be electroluminescent.

On the other hand, the light 23 ′ emitted from the mechanoluminescent core particle 23a passes through the shell SH, and the quantum dots 27 are dispersed in the elastic polymer matrix 21 outside the shell SH. ) can be reached, and thus the quantum dots 27 can photoluminescence.

In this way, the mechanoluminescent particle-quantum dot composite film 20 has the quantum dots 24 together with the light 23 ′ emitted from the mechanoluminescent core particle 23a by a mechanical stimulus S that may occur in nature. , 27) may emit light 24', 27' to the outside. At this time, the peak wavelength of the light 24' and 27' emitted from the quantum dots 24 and 27 is increased compared to the light 23' emitted from the mechanoluminescent core particle 23a, but the half width of the peak wavelength The color purity may be excellent, such as this decrease. As an example, the mechanoluminescent core particles 23a may be particles capable of emitting blue-based light, and the quantum dots 24 and 27 may be quantum dots capable of emitting green-based or red-based light. can In one example, when the first quantum dot 27 is a green light-emitting quantum dot, and the second quantum dot 24 is a red light-emitting quantum dot, the mechanoluminescent particle-quantum dot composite film 20 emits multi-colored light. can do. In another example, when the ratio of the mechanoluminescent core particles 23a, the first quantum dots 27, and the first quantum dots 24 is adjusted, emission from the mechanoluminescent core particles 23a The light 23 ′ to be used may be emitted to the outside without being consumed by the first quantum dots 27 , so that the mechanoluminescent particle-quantum dot composite film 20 may emit white light.

This mechanoluminescent particle-quantum dot composite film 20 uses a mechanical stimulus (S) that can occur in nature as an energy source, and uses a flexible display that emits light of various wavelengths, a wearable sensor, or a next-generation smart electronic device such as an electronic skin. It can be used as a material for the device.

Hereinafter, a preferred experimental example (example) is presented to help the understanding of the present invention. However, the following experimental examples are only for helping understanding of the present invention, and the present invention is not limited by the following experimental examples.

Preparation Example 1: Mechanoluminescent particle-quantum dot composite film preparation

Step A: Quantum Dot-PDMS Dispersion Preparation

A quantum dot dispersion was obtained by dispersing green light-emitting quantum dots (G-QD, CdSe/CdZnS, size: 3-4 nm) in hexane. The quantum dot dispersion was put into the liquid PDMS prepolymer, and a vacuum was maintained for 10 minutes to remove hexane, a solvent contained in the quantum dot dispersion. During this process, the quantum dots sank into the PDMS prepolymer. The resultant was mixed and sonicated for 10 minutes to further disperse the aggregated quantum dots in the liquid PDMS prepolymer. A PDMS curing agent was added to the resultant so that the ratio of PDMS prepolymer to PDMS curing agent was 9:1 (w:w), and uniformly mixed to prepare a quantum dot-PDMS dispersion. The concentration of quantum dots in the dispersion was 43 mg/ml.

Step B: Mechanoluminescent particle-quantum dot composite film production

In the obtained quantum dot-PDMS dispersion, Ag ²⁺ doped blue light-emitting ZnS microparticles having an Al ₂ O ₃ shell (ZnS:Ag ²⁺ /Al ₂ O ₃ , B-ZnS) were mixed with the ZnS microparticles versus the PDMS prepolymer. After adding to have a ratio of 3: 7 (w:w), the mixture was uniformly mixed. 1 ㎖ of this mixture was applied on a slide glass having a width of 16 cm ² , and then heat-cured in a furnace at 100° C. for 10 minutes.

Preparation Example 1-1: Mechanoluminescent particle-quantum dot composite film preparation

A mechanoluminescent particle-quantum dot composite film was prepared using the same method as in Preparation Example 1, except that the concentration of quantum dots (G-QD) in the quantum dot-PDMS dispersion was 30 mg/ml.

Preparation Example 1-2: Mechanoluminescent particle-quantum dot composite film preparation

A mechanoluminescent particle-quantum dot composite film was prepared using the same method as in Preparation Example 1, except that the concentration of quantum dots (G-QD) in the quantum dot-PDMS dispersion was 22 mg/ml.

Preparation Example 2: Mechanoluminescent particle-quantum dot composite film preparation

In Preparation Example 1, instead of green light-emitting quantum dots (G-QD), red light-emitting quantum dots (R-QD, CdSe/CdZnS, size: 5-6 nm) were used, and the quantum dot concentration in the quantum dot-PDMS dispersion was 45 mg/ml A mechanical light emitting particle-quantum dot composite film was prepared using the same method as in Preparation Example 1, except that

Preparation Example 2-1: Mechanoluminescent particle-quantum dot composite film preparation

A mechanoluminescent particle-quantum dot composite film was prepared using the same method as in Preparation Example 2, except that the concentration of quantum dots (R-QD) in the quantum dot-PDMS dispersion was 30 mg/ml.

Preparation Example 2-2: Mechanoluminescent particle-quantum dot composite film preparation

A mechanoluminescent particle-quantum dot composite film was prepared using the same method as in Preparation Example 2, except that the concentration of quantum dots (R-QD) in the quantum dot-PDMS dispersion was 24 mg/ml.

Preparation Example 3: Mechanoluminescent particle-quantum dot composite film preparation

Blue light-emitting ZnS microparticles (B-ZnS), green light-emitting quantum dots (G-QD, CdSe/CdZnS, size: 3-4 nm), and red light-emitting quantum dots (R-QD, CdSe/CdZnS, size: 5-6 nm), a mechanoluminescent particle-quantum dot composite film was prepared using the same method as in Preparation Example 1, except that the volume ratio was 1:1:1.

Preparation Example 4: Mechanoluminescent particle-quantum dot composite film preparation

Step A: Quantum Dot Surface Ligand Exchange

Red light-emitting quantum dots (R-QD, CdSe/CdZnS, size: 5-6 nm) were dispersed in hexane, a non-polar solvent, to obtain an R-QD dispersion (12.8 nmol/ml). The R-QD dispersion was mixed with N-methyl formamide (NMF) as a polar solvent in a ratio of 1:1 (v:v) to obtain a double-layer solution in which the R-QD dispersion was positioned on the NMF layer. Here, 40 μl of ammonium sulfide solution (40-48 wt% in H ₂ O) was added to 1 ml of the R-QD dispersion, so that the ligand of R-QD dispersed in the R-QD dispersion was converted to ammonium sulfide. As exchanged, ligand-exchanged R-QDs were dispersed into the lower NMF layer. Thereafter, the volume of R-QD dispersed in the NMF layer was measured and EA (ethyl acetate) corresponding to 6 times the volume was added, followed by centrifugation at 7000 rpm for 5 minutes. After that, 0.5 ml of NMF and 3 ml of EA were added again to the resultant and centrifuged once more to disperse the surface ligand-exchanged R-QD in NMF.

Step B: Formation of ZnS microparticle-quantum dot composite core with quantum dots bonded to the surface of ZnS microparticles

2 g of Ag ²⁺ doped blue light-emitting ZnS micro-particles (ZnS:Ag ²⁺ , B-ZnS) were mixed in 10 ml of NMF to obtain a ZnS micro-particle dispersion. 4 ml of the dispersion in which red light-emitting quantum dots (R-QDs) having ammonium sulfide as a surface ligand obtained above were dispersed were added to the ZnS microparticle dispersion. Thereafter, after stirring at 100° C. for 30 minutes, purification and removal of NMF as a solvent for 10 minutes in vacuum were performed to obtain ZnS microparticle-quantum dot composite particles in which R-QDs were connected to the surface of ZnS microparticles by ammonium sulfide.

Step C: Formation of Shell on ZnS Microparticle-Quantum Dot Composite Core Surface

ZnS microparticle-quantum dot composite particles (hereinafter, referred to as core particles) were disposed on a silicon substrate, and hexane was applied to the core particles to fix the core particles on the silicon substrate. Thereafter, Al ₂ O ₃ shells were formed on the core particles using an atomic layer deposition method to obtain core-shell composite particles.

Step D: Preparation of Mechanoluminescence-Photoluminescence Composite Containing Core-Shell Composite Particles

The obtained core-shell composite particles were mixed with the core-shell composite particles and the G-QD-PDMS dispersion in the green light-emitting quantum dot (G-QD)-PDMS dispersion obtained in step A of Preparation Example 1 at 3:7 (w:w) It was mixed so that the ratio of After that, 1 ml of this mixture was applied on a slide glass having a width of 16 cm ² , and then heat-cured in a furnace at 100° C. for 10 minutes.

Comparative Example 1: Preparation of mechanical light emitting film

Ag ²⁺ doped blue light-emitting ZnS microparticles (ZnS:Ag ²⁺ /Al ₂ O ₃ , B-ZnS) having an Al ₂ O ₃ shell in the PDMS prepolymer were mixed with the ZnS microparticles versus the PDMS prepolymer 3: 7 ( After adding to have a ratio of w:w), the mixture was uniformly mixed. Thereafter, a PDMS curing agent was added so that the ratio of PDMS prepolymer to PDMS curing agent was 9:1 (w:w), and uniformly mixed to prepare a ZnS microparticle-PDMS mixture. 1 ㎖ of this mixture was applied on a slide glass having a width of 16 cm ² , and then heat-cured in a furnace at 100° C. for 10 minutes.

Comparative Example 2: Mechanoluminescent film preparation

Instead of blue light-emitting ZnS microparticles (B-ZnS), Cu ²⁺ doped green light-emitting ZnS microparticles (ZnS:Cu ²⁺ /Al ₂ O ₃ , G-ZnS) having an Al ₂ O ₃ shell were used. A mechanical light emitting film was prepared in the same manner as in Comparative Example 1, except that.

Comparative Example 3: Mechanoluminescent film preparation

Mn ²⁺ doped orange light emitting ZnS microparticles (ZnS:Mn ²⁺ /Al ₂ O ₃ , O-ZnS) with Al ₂ O ₃ shell were used instead of blue light emitting ZnS microparticles (B-ZnS). A mechanical light emitting film was prepared in the same manner as in Comparative Example 1, except that.

Figure 3 is a mechanical luminescent film according to Comparative Example 1, a mechanical luminescent particle-quantum dot composite film according to Preparation Example 1, and a mechanical luminescent particle-quantum dot composite film according to Preparation Example 2 A photograph (a) , SEM (scanning electron microscope) image of the mechanoluminescent particle-quantum dot composite film according to Preparation Example 1 (b), photoluminescence spectra of B-ZnS microparticles, G-QD, and R-QD (c), and Preparation Example The mechanical light emitting particles according to 1 - quantum dot composite film and the mechanical light emitting particles according to Preparation Example 2 - shows the photoluminescence spectrum (d) of the quantum dot composite film.

here. Photoluminescence measurement is to analyze the light emitted from the sample after irradiating 365 nm light to the sample.

Referring to FIG. 3(b) first, it was confirmed that blue light-emitting ZnS microparticles (B-ZnS) were dispersed in the mechanoluminescent particle-quantum dot composite film according to Preparation Example 1 in the PDMS matrix, and quantum dots in the PDMS matrix ( It can be seen that QD) is dispersed.

3(a), 3(c), and 3(d), the mechanoluminescent film according to Comparative Example 1 contains B-ZnS as mechanoluminescent particles in PDMS, and the peak wavelength is approximately 489nm. and emitted photoluminescence with a peak half-width of approximately 79 nm. On the other hand, the mechanoluminescent particle-quantum dot composite film according to Preparation Example 1 contains B-ZnS and G-QD in PDMS, and a peak (peak A) near 489 nm derived from B-ZnS and G-QD derived from Light was emitted with a peak with a peak wavelength of approximately 566 nm and a peak half-width at approximately 48 nm. On the other hand, the mechanoluminescent particle-quantum dot composite film according to Preparation Example 2 contains B-ZnS and R-QD in PDMS, and the peak at about 489 nm (peak A) derived from B-ZnS and R-QD derived from light having a peak wavelength of approximately 630 nm and a peak full width at half maximum is approximately 29 nm.

4 is a mechanical luminescent film (B-ZnS) according to Comparative Example 1, a mechanical luminescent film (G-ZnS) according to Comparative Example 2, a mechanical luminescent film (O-ZnS) according to Comparative Example 3, according to Preparation Example 1 Mechanical luminescent particle-quantum dot composite film (G-QMM), and mechanical luminescent particle-quantum dot composite film (R-QMM) according to Preparation Example 2 (a), mechanical luminescent film according to Comparative Example 2, Preparation Example Mechanoluminescent particles according to 1 - quantum dot composite film (G-QMM), the mechanical luminescent film according to Comparative Example 3, and the mechanoluminescent particle-quantum dot composite film according to Preparation Example 2 (R-QMM) of the emitted mechanoluminescence peaks Graph (b) showing the peak wavelength and full width at half maximum, the mechanical light emitting film according to Comparative Example 1 (B-ZnS), the mechanical light emitting film according to Comparative Example 2 (G-ZnS), and the mechanical light emitting film according to Comparative Example 3 (O- ZnS), the mechanical luminescence particle-quantum dot composite film (G-QMM) according to Preparation Example 1, and the mechanical luminescence particle-quantum dot composite film (R-QMM) according to Preparation Example 2 CIE 1931 color-coordinates showing the mechanical emission peaks (c), the photoluminescence and mechanoluminescence spectrum (d) of the mechanical light emitting film (B-MM) according to Comparative Example 1, and the photoluminescence of the mechanical light emitting particle-quantum dot composite film (R-QMM) according to Preparation Example 2 and The mechanoluminescence spectrum (e) is shown.

here. The photoluminescence measurement analyzes the light emitted from the sample after irradiating the sample with light of 365 nm, and the mechanoluminescence measurement analyzes the light emitted from the sample while a tensile force is applied to the sample.

Referring to FIG. 4( a ), the mechanical light emitting film (B-ZnS) according to Comparative Example 1 emitted light having a peak wavelength of about 502 nm and a peak half width of about 79 nm, and the mechanical light emitting film according to Comparative Example 2 (G-ZnS) emitted light having a peak wavelength of about 512 nm and a peak half width of about 78 nm, and the mechanoluminescent film (O-ZnS) according to Comparative Example 3 had a peak wavelength of about 580 nm and a peak half width Light of about 56 nm was emitted, and the mechanical light emitting particle-quantum dot composite film (G-QMM) according to Preparation Example 1 emitted light having a peak wavelength of about 566 nm and a peak half width of about 53 nm, and in Preparation Example 2 Mechanoluminescent particle-quantum dot composite film (R-QMM) according to the emission of light having a peak wavelength of approximately 630 nm and a peak half width of approximately 33 nm. Here, the mechanical emission peak wavelength of each of the mechanical light emitting particles-quantum dot composite film (G-QMM) according to Preparation Example 1 and the mechanical light emitting particle-quantum dot composite film (R-QMM) according to Preparation Example 2 is shown in FIG. 3(d) It is the same as the photoluminescence peak wavelength shown, and the mechanoluminescence obtained from the mechanoluminescent particle-quantum dot composite films according to Preparation Examples 1 and 2 was about 502 nm from the B-ZnS microparticles, which are mechanoluminescent particles, due to the applied mechanical stress. It was understood that light having a peak wavelength was emitted (mechanoluminescence), and quantum dots in each film were photoluminescent by this light, and that mechanoluminescence and photoluminescence proceeded sequentially.

4(b) and 4(c), compared to the mechanical light emitting film according to Comparative Example 2 which emits green light by mechanical light emission, mechanical light emission and photoluminescence proceed sequentially in Preparation Example 1 which emits green light It can be seen that the mechanical light emitting particle-quantum dot composite film (G-QMM) according to the present invention emits light with a narrower full width at half maximum (FWHM) of green light and higher color purity. From this, it can be seen that, compared to the film containing only the mechanoluminescent particles, the composite film containing both mechanoluminescent particles and quantum dots capable of photoluminescence from the light emitted therefrom can emit clearer light when mechanical stress is applied. have. This means that a film that emits clear light can be obtained by exploiting the mechanical stress that occurs in nature.

Referring to FIG. 4(d), it can be seen that the peak wavelength of the mechanical light emitting film (B-ZnS) according to Comparative Example 1 is longer than the photoluminescence of the mechanical light emission. It can be seen that the photoluminescence and the mechanoluminescence of the mechanoluminescent particle-quantum dot composite film (R-QMM) according to 2 show red light at the same peak wavelength.

Table 1 below shows the half width and peak wavelength of light emitted by photoluminescence and mechanoluminescence of the films according to Preparation Examples 1 to 2 and Comparative Examples 1 to 3 described above.

Full width at half maximum (FWHM, nm) Peak wavelength (nm) Photoluminescence (PL) Mechanoluminescence (ML) Photoluminescence (PL) Mechanoluminescence (ML) Comparative Example 1 (B-ZnS) 79 79 489 502 Comparative Example 2 (G-ZnS) 85 78 504 512 Comparative Example 3 (O-ZnS) 55 56 577 580 Preparation Example 1 (G-QMM) 48 53 566 566 Preparation 2 (R-QMM) 29 33 630 630

5 is a mechanical luminescence spectrum (a, b), a graph showing the quantum dot concentration in the quantum dot-PDMS dispersion and the intensity of light emitted by mechanoluminescence by B-ZnS microparticles (c), and CIE 1931 color-coordinates (d).

Table 2 below shows the mechanical light emitting particles according to Preparation Example 1, Preparation Example 1-1, Preparation Example 1-2, Preparation Example 2, Preparation Example 2-1, Preparation Example 2-2 - quantum dots used in manufacturing quantum dot composite films -The quantum dot concentration in the PDMS dispersion and the intensity of light emitted to the outside by mechanoluminescence by B-ZnS microparticles, and the mechanoluminescence particle film according to Comparative Example 1, emitted by mechanoluminescence by B-ZnS microparticles represents the intensity of the light.

mechanoluminescent particles photoluminescent particles Quantum Dot Concentration in PDMS Dispersion
(mg/ml) Mechanoluminescence intensity by B-ZnS microparticles
(Cd/m ² ) Comparative Example 1 B-ZnS - - 135 Preparation Example 1 B-ZnS G-QD 43 (high) 45 Preparation 1-1 B-ZnS G-QD 30 (middle) 110 Preparation 1-2 B-ZnS G-QD 22 (low) 131 Preparation 2 B-ZnS R-QD 45 (high) 28 Preparation 2-1 B-ZnS R-QD 30 (middle) 93 Preparation 2-2 B-ZnS R-QD 24 (low) 125

5(a), 5(b), 5(c), and 5(d), and with reference to Table 2, Preparation Example 1, Preparation Example 1-1, Preparation Example 1-2, Preparation Example 2, Preparation As the quantum dot concentration in the quantum dot-PDMS dispersion used in preparing the mechanoluminescent particle-quantum dot composite films according to Example 2-1 and Preparation Example 2-2 increased, the amount of light emitted to the outside by mechanical light emission by B-ZnS microparticles While the intensity decreases, the intensity of photoluminescence emitted after the quantum dots are excited by the light emitted by the mechanoluminescence by the B-ZnS microparticles is maintained. appeared to represent

6 shows a photoluminescence spectrum (a), a mechanical luminescence spectrum (b), and a photograph (c) of the mechanical luminescence film of the mechanoluminescent particle-quantum dot composite film according to Preparation Example 3 (c). here. The photoluminescence measurement analyzes the light emitted from the sample after irradiating the sample with 365 nm light, and the mechanoluminescence measurement analyzes the light emitted from the sample while a tensile force is applied to the sample.

Referring to FIG. 6 , the mechanoluminescent particle-quantum dot composite film according to Preparation Example 3 is blue luminescence by B-ZnS, green luminescence by G-QD, and R-QD in two modes of photoluminescence and mechanical luminescence. It can be seen that all of the red light is emitted and the overall color is white.

7 shows an SEM image (a) and a TEM (Transmission Electron Microscopy) image (b) of a mechanical light emitting particle-quantum dot composite film according to Preparation Example 4.

Referring to Figure 7, it can be seen that in the mechanoluminescent particle-quantum dot composite film according to Preparation Example 4, particles of a core/shell structure are dispersed in the PDMS matrix, and also quantum dots (QD) are dispersed in the PDMS matrix. have. In the core/shell structure of the particle, the core is a plurality of quantum dots bonded to the surface of the ZnS microparticles (ZnS:Ag ²⁺ , B-ZnS), but this was not confirmed on the image.

In the above, the present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications and changes are made by those skilled in the art within the technical spirit and scope of the present invention. This is possible.

Claims (20)

elastomeric matrix;
quantum dots dispersed in the elastic polymer matrix;
A mechanoluminescent particle-quantum dot composite film comprising mechanoluminescent core particles dispersed with the quantum dots in the elastic polymer matrix. According to claim 1,
The mechanoluminescent core particles,
Cu, Mn, Pb, Cl, Eu, Ce, Ho, Dy, Ba, Ca, Pr ³⁺ , Ti, or Te doped with any one dopant, ZnS, CaZnOS, BaZnOS, MgF ₂ , La ₂ O ₂ S, Y ₂ O ₂ S, SrAl ₂ O ₄ , SrMgAl ₆ O ₁₁ , SrCaMgSi ₂ O ₇ , SrBaMg Si ₂ O ₇ , Sr ₂ MgSi ₂ O ₇ , Ca ₂ MgSi ₂ O ₇ , CaYAl ₃ O ₇ , ZnGa ₂ O ₄ , MgGa ₂ O ₄ , Ca ₂ Al ₂ SiO ₇ or ZrO ₂ Mechanoluminescent particle-quantum dot composite film. According to claim 1,
The quantum dot is a mechanoluminescent particle-quantum dot composite film that is a compound semiconductor quantum dot or a perovskite quantum dot. According to claim 1,
The mechanoluminescent core particle is a particle emitting light having an energy greater than the band gap of the quantum dot. 5. The method of claim 4,
The mechanoluminescent core particles are particles emitting blue light,
The quantum dot is a quantum dot that emits green or red light, a mechanical light emitting particle-quantum dot composite film. According to claim 1,
Mechanoluminescent particle-quantum dot composite film further comprising a shell surrounding the mechanoluminescent core particle on the surface of the mechanoluminescent core particle. 7. The method of claim 6,
The quantum dot is a first quantum dot,
Mechanoluminescent particle-quantum dot composite film further comprising a plurality of second quantum dots disposed between the surface of the mechanoluminescent core particle and the shell. 8. The method of claim 7,
The mechanoluminescent core particle and the second quantum dot is a mechanoluminescent particle-quantum dot composite film bonded by a polydentate ligand. 9. The method of claim 8,
The ligand is an amphoteric ligand (NH ₄ ) ₂ S Mechanoluminescent particle-quantum dot composite film. 7. The method of claim 6,
The shell is a metal oxide film mechanoluminescent particles-quantum dot composite film. 11. The method of claim 10,
between the shell and the elastic polymer matrix,
Mechanoluminescent particle-quantum dot composite film further comprising a monomolecular layer disposed on the surface of the shell. 12. The method of claim 11,
The monomolecular layer is a mechanoluminescent particle-quantum dot composite film, which is a layer comprising a single molecule represented by the following Chemical Formula 1 or Chemical Formula 2:
[Formula 1]
HS-(R ₁ -COO)nR ₂
In Formula 1, R ₁ is a C1 to C3 alkanediyl group or a C5-C6 areenediyl group, R ₂ is a C1 to C3 alkyl group, n is 0 or 1,
[Formula 2]
HS-R ₃ -SH
In Formula 2, R ₁ is a C1 to C3 alkanediyl group or a C5-C6 areenediyl group. 13. The method of claim 12,
The single molecule is a C1-C3 alkyl thiol, a C1-C3 alkyl thioglycolate (C1-C3 alkyl thioglycolate), or a C1-C3 alkyl 3-mercaptopropionate (C1-C3 alkyl 3-mercaptopropionate) mechanoluminescent particles -Quantum dot composite film. 8. The method of claim 7,
The mechanoluminescent core particle is a particle emitting light having an energy greater than the band gap of the first and second quantum dots. 15. The method of claim 14,
The mechanoluminescent core particles are particles emitting blue light,
The first quantum dot is a green light-emitting quantum dot, and the second quantum dot is a red light-emitting quantum dot mechanoluminescent particle-quantum dot composite film. elastomeric matrix;
first quantum dots dispersed in the elastic polymer matrix; and
dispersed together with the first quantum dots in the elastic polymer matrix, a mechanoluminescent core particle, a shell surrounding the mechanoluminescent core particle on a surface of the mechanoluminescent core particle, and between the surface of the mechanoluminescent core particle and the shell A mechanical light emitting particle-quantum dot composite film comprising composite particles having a plurality of second quantum dots disposed on. 17. The method of claim 16,
The mechanoluminescent core particle and the second quantum dot is a mechanoluminescent particle-quantum dot composite film bonded by a polydentate ligand. 18. The method of claim 17,
The ligand is an amphoteric ligand (NH ₄ ) ₂ S Mechanoluminescent particle-quantum dot composite film. 17. The method of claim 16,
between the shell and the elastic polymer matrix,
Mechanoluminescent particle-quantum dot composite film further comprising a monomolecular layer disposed on the surface of the shell. 20. The method of claim 19,
The monolayer includes a monomolecular of C1-C3 alkyl thiol, C1-C3 alkyl thioglycolate, or C1-C3 alkyl 3-mercaptopropionate. Mechanoluminescent particle-quantum dot composite film.

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