WO2020013438A1 - Luminescent nanocrystals using electronically delocalized carbamate derivative - Google Patents

Abstract

The present invention relates to luminescent nanocrystals and, to luminescent nanocrystals using an electronically delocalized carbamate derivative, the luminescent nanocrystals being substituted with a carbamate ligand, which has a strong coordination ability and has an electrically resonant structure, so as to adjust an exciton Bohr radius, thereby enabling the size of the nanocrystals to be precisely controlled.

Description

Luminescent Nanocrystals Using Electronically Unlocalized Carbamate Derivatives

The present invention relates to luminescent nanocrystals, and more particularly to electronically delocalized carbamate derivatives capable of precisely controlling the size of nanocrystals by substituting carbamate ligands having strong coordination ability and having an electrically resonant structure. It relates to a light emitting nanocrystal using.

Nanocrystalline materials are nano-sized semiconductor crystals made of inorganic semiconductor materials. Ligands, which are organic materials on the surface of nanocrystalline shells in order to increase their solubility in cores, shells and organic solvents Consists of a structure that is combined. Nanocrystalline materials generally have the characteristic that the energy band gap (Eg) between the valence band and the conduction band varies with size. In addition, the nanocrystalline material has various material advantages such as excellent absorption coefficient, high electron mobility, and emission wavelength control function according to particle size control. In particular, nanocrystalline materials are in the spotlight as next-generation display device materials having excellent light stability because the luminescent core is an inorganic material rather than an organic material.

The size of the nanocrystals is determined by the reaction temperature and time at which the crystals are made. For example, InPZnS nanocrystals that emit green light are produced at 150 ° C reaction temperature and 30 minutes reaction time, and red light is emitted. InPZnS nanocrystals are made at 210 ° C reaction temperature and 1 hour reaction time. The green and red InPZnS nanocrystals produced at this time were 3.31 ± 0.22 nm and 3.83 ± 0.22 nm, respectively, with an average size difference of only 0.5 nm. Since nanocrystalline materials vary greatly in the wavelength of light emitted by the size change, it is difficult to finely control the wavelength of emitted light only by controlling the size of nanocrystals.

Accordingly, the present invention has been proposed to solve the above problems, and an object of the present invention is to replace a carbamate ligand having a strong coordination ability and an electrically resonant structure, and thus the active region of excitons formed by energy transfer is nanocrystalline. In addition, the present invention provides a light emitting nanocrystal using an electronically delocalized carbamate derivative which can be expanded to a ligand to obtain an effect of increasing nanocrystals.

In one embodiment of the present invention, in the light-emitting nanocrystals consisting of a core (Core), a shell (Shell) and a ligand (Ligand) bonded to the shell (Shell) surface, the ligand has an electrical resonance structure It has a carbamate derivative of the formula (1), the size of the nanocrystals are determined according to the carbamate derivatives, the light emitting nanocrystals using an electronically unlocalized carbamate derivative, characterized in that for controlling the wavelength of the emitted light May be provided.

[Formula 1]

[Formula 2]

Wherein R ₁ and R ₂ are each hydrogen, an alkyl group, an alkenyl group, an alkynyl group or an aryl group, and X ₁ and X ₂ are each O, S, Se or Te, M is a main group metal, a base metal or a transition metal, n is an integer from 1 to 8, and m is an integer from 0 to 18.

In one embodiment of the present invention, luminescent nanocrystals using an electronically delocalized carbamate derivative, wherein M is an alkali metal or an alkaline earth metal, can be provided.

In one embodiment of the present invention, luminescent nanocrystals using electronically delocalized carbamate derivatives can be provided wherein the alkali metal is H, Li, Na or K and the alkaline earth metal is Be, Mg or Ca. have.

In one embodiment of the present invention, a light emitting nanocrystal using an electronically delocalized carbamate derivative, characterized in that R ₁ and R ₂ is a cyclic saturated or unsaturated hydrocarbon linked to each other as shown in the formula (2).

In one embodiment of the invention, an alkyl group, alkenyl group, alkynyl group or aryl group is selected from -NR, wherein at least one hydrogen imparts electrical and steric properties. -NHR, -NH ₃ , -OR, -CH ₃ , -CF ₃ , -CCl ₃ , -CN, -NO ₂ , -COR and -CONH ₂ is substituted with one selected from the group wherein R is each hydrogen A light emitting nanocrystal using an electronically delocalized carbamate derivative, which is an alkyl group, an alkenyl group, an alkynyl group or an aryl group, may be provided.

In one embodiment of the present invention, the core portion and the shell portion, respectively, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, PbS, PbSe, PbTe, InP, InAs GaP, InGaP, AgGaS ₂ , AgGaSe ₂ , AgGaTe ₂ , AgInS ₂ , AgInSe ₂ , AgInTe ₂ , CuInS ₂ , CuInSe ₂ , CuInTe ₂ , CuGaS ₂ , CuGaSe ₂ and CuGaTe ₂ Light-emitting nanocrystals using electronically delocalized carbamate derivatives are provided. Can be.

The light emitting nanocrystals using the electronically delocalized carbamate derivatives according to the present invention can precisely control the emission wavelength depending on the elements or functional groups to be bonded.

The luminescent nanocrystals using the electronically delocalized carbamate derivatives according to the present invention can be applied to non-Cd-based nanocrystals that satisfy a policy of restricting certain harmful substances (RoHS, Restriction of Hazardous Substances).

The luminescent nanocrystals using the electronically delocalized carbamate derivatives according to the present invention can be applied to solar cells as well as displays by controlling the electrical properties of ligands.

1 is a schematic diagram showing that the ligand according to an embodiment of the present invention is substituted on the surface of the nanocrystals.

Figure 2 is a schematic diagram showing the change in the fluorescence spectrum of the nanocrystals substituted with para- toluidine dithio carbamate according to an embodiment of the present invention.

Figure 3 is a schematic diagram showing the change in the fluorescence spectrum of the nanocrystals substituted with normal hexyl aniline carbamate according to an embodiment of the present invention.

Figure 4 is a schematic diagram showing that the fluorescence spectrum of the nanocrystals substituted with 4-trifluoromethylaniline carbamate according to an embodiment of the present invention is changed.

With reference to the accompanying drawings will be described in detail with respect to the light emitting nanocrystals using the electronically delocalized carbamate derivatives according to the embodiments of the present invention. As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific form disclosed, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar elements. In the accompanying drawings, the dimensions of the structure is shown to be larger than the actual size for clarity of the invention, or to reduce the actual size to understand the schematic configuration.

In addition, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. On the other hand, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Reducing the nanocrystalline material to nanometer size limits the movement of electrons and holes spatially, demonstrating quantum mechanical phenomena to the unique energy structures and optical properties of bulk semiconductors. Since the emission wavelength of the nanocrystals is determined by the size of the bohr radius of the exciton (electron-hole pair) formed in the valence and conduction bands of the nanocrystals, the energy band gap between the valence band and the conduction band is controlled. The wavelength of light emitted from the crystal can be controlled.

As the core size of the nanocrystalline material decreases, the quantum confinement effect increases the discontinuous energy levels of the conduction and valence bands (larger energy band gap) and emits blue shift light. Larger core diameters lead to lower discrete energy levels (smaller energy band gaps), which emit bathochromic shifts. That is, the nanocrystalline material can control the wavelength of the emitted light due to the change in particle size, unlike conventional fluorescent materials.

1 is a schematic diagram showing that the ligand according to an embodiment of the present invention is substituted on the surface of the nanocrystals.

The present invention relates to a technology for controlling the emission color of the nanocrystalline material, the light emitting nanocrystal according to an embodiment of the present invention, the core (Core), shell (shell) and the shell (Shell) surface (Shell) surface Ligand is a light-emitting nanocrystal consisting of a ligand, the ligand has an electrical resonance structure, the carbamate derivative of Formula 1 or Formula 2, the size of the nanocrystals are determined according to the carbamate derivative It is a light emitting nanocrystal using an electronically delocalized carbamate derivative characterized by controlling the wavelength of emitted light.

[Formula 1]

[Formula 2]

Wherein R ₁ and R ₂ are each hydrogen, an alkyl group, an alkenyl group, an alkynyl group or an aryl group, and X ₁ and X ₂ are each O, S, Se or Te, M is a main group metal, a base metal or a transition metal, n is an integer from 1 to 8, and m is an integer from 0 to 18.

M may be a main group metal, a base metal or a transition metal having a positive oxidation state. n may be 1 to 8 and depends on the oxidation state of M. For example, n is 1 when M is an alkali metal such as H, Li, Na, or K, and n is 2 when M is an alkaline earth metal such as Be, Mg, or Ca. When n is 2 or more, the carbamate derivative may be the same or different. In addition, m in the formula (2) is an integer of 0 to 18, when 0 is a form in which R ₁ and R ₂ are directly connected. Formula 2 is a carbon atom in which R ₁ and R ₂ each form a covalent bond with a nitrogen atom, and include a ring hydrocarbone group composed of a nitrogen atom and m + 2 carbons. Cyclic hydrocarbon groups consist of aryl rings or exist as carbon-carbon single bonds, double bonds, or triple bonds.

As used herein, an alkyl group refers to a straight or branched monovalent hydrocarbon composed of 1 to 50 carbon atoms, for example methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, n-hexyl, n-octyl, n-decyl, and the like.

Alkenyl group as used herein refers to a straight or branched unsaturated hydrocarbon composed of 2 to 50 carbon atoms having one or more carbon-carbon double bonds, for example, ethyleneyl, propenyl, butenyl, pentenyl, etc. Include but are not limited to.

As used herein, an alkynyl group refers to a straight or branched unsaturated hydrocarbon composed of 2 to 50 carbon atoms having one or more carbon-carbon triple bonds, including, for example, acetylenyl, propynyl, butynyl and the like. It is not limited to this.

As used herein, aryl groups include both aromatic and heteroaromatic groups and their partially reduced derivatives. The aromatic group is a simple or fused cyclic cyclic consisting of 5 to 15 (please check the range possible in the present technology), a heteroaromatic group means an aromatic group containing one or more oxygen, sulfur or nitrogen. Examples of representative aryl groups include phenyl, naphthyl, pyridinyl, furanyl, thiophenyl, indolyl, quinolinyl, imidazolinyl, Oxazolyl, thiazolyl, tetrahydronaphthyl, and the like, but are not limited thereto.

According to the present invention, when the organic material ligand bound to the shell surface of the nanocrystals is replaced with a carbamate derivative, the emission color can be easily adjusted finely and finely than the conventional method of controlling color through size. The reason that color control is possible with ligands bound to the surface of nanocrystals is because of the resonance structure of carbamate derivatives, which results in delocalization of excitons formed in nanocrystals, resulting in the effect of increasing nanocrystal size. That is, due to ligand delocalization, the bore radius of the excitons formed inside the nanocrystals is increased, and as a result, a long wavelength (Bathochromic shift) light is emitted from the nanocrystal matrix.

Carbamate derivatives are compounds having various types of resonant molecular structures, and the carbamate derivatives used in the present invention are hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, or aryls. It is a compound in which an amine functional group having two group substituents and two group 6 atoms are bonded to carbon. When the existing ligand bound to the surface of the nanocrystalline matrix is replaced with a carbamate derivative (ligand exchange), the bore radius of the exciton formed in the valence and conduction bands of the nanocrystals is changed, thereby changing the energy band gap between the valence band and the conduction band. And depending on the characteristics of the Group 6 atoms, which form a resonance structure with the electrical and steric properties of the alkyl, alkenyl, alkynyl, or aryl group groups bonded to the amine functional group. It is possible to control the emission spectrum of the nanocrystalline material.

The light emitting nanocrystal using the electronically delocalized carbamate derivative according to the embodiment of the present invention is characterized in that R ₁ and R ₂ are cyclic saturated or unsaturated hydrocarbons connected to each other as shown in Chemical Formula 2.

Through the form in which R ₁ and R ₂ are connected to each other, various electrical and three-dimensional characteristics can be imparted.

Formula 3 below is a carbamate derivative exhibits various electrical resonance structures.

[Formula 3]

By binding ligands with electrically resonant structures to the surface of nanocrystals, the active region of excitons formed by energy transfer can be extended to ligands as well as nanocrystals. In other words, the delocalization of exciton can be obtained, the effect of increasing the size of the nanocrystals. As a result, the exciton bore radius increases according to the ligand delocalization characteristics, thereby obtaining the effect of long wavelength light emission compared to the nanocrystalline matrix.

The luminescent nanocrystal according to the embodiment of the present invention implements the emission color control function of the nanocrystalline material by replacing the existing monodentate ligand bound to the nanocrystalline matrix with a carbamate derivative ligand having excellent coordination ability and various resonance structures. .

The light emitting nanocrystals according to the embodiment of the present invention, the core portion and the shell portion, respectively, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, PbS, PbSe, PbTe, InP, InAs GaP, InGaP, AgGaS ₂ , AgGaSe ₂ , AgGaTe ₂ , AgInS ₂ , AgInSe ₂ , AgInTe ₂ , CuInS ₂ , CuInSe ₂ , CuInTe ₂ , CuGaS ₂ , CuGaSe ₂ and CuGaTe ₂ .

The light emitting nanocrystals according to an embodiment of the present invention are made of metal and nonmetal, and nanocrystals of each group can be applied as a single material, and can also be used as double and multiple structure nanocrystals composed of a core part and a shell part. In Examples 1 to 3 of the present invention, the nanocrystals of the InP core portion and the ZnS shell multiple structure were used.

X ₁ and X ₂ of the light emitting nanocrystals according to an embodiment of the present invention are O, S, Se, Te, which can be bonded to the central carbon in the form of homonuclear diatomic or heteronuclear diatom. .

In the alkyl group, the alkenyl group, the alkynyl group, or the aryl group of the light emitting nanocrystal according to the embodiment of the present invention, at least one hydrogen imparts electrical characteristics and three-dimensional characteristics Is substituted with one selected from the group consisting of -NR, -NHR, NH ₃ , -OR, -CH _3, -CF ₃ , -CCl ₃ , -CN, -NO ₂ , -COR and -CONH ₂ , wherein R is Are hydrogen, an alkyl group, an akenyl group, an alkynyl group, or an aryl group, respectively. Wherein -NR, -NHR, NH ₃ and -OR are electron donating groups, and -CF ₃ , -CCl ₃ , -CN, -NO ₂ , -COR and -CONH ₂ are groups that pull electrons As an electron withdrawing group, electrical and three-dimensional characteristics can be imparted to the light emitting nanocrystals. Formulas 4 to 6 are electronically delocalized carbamate derivatives according to one embodiment of the present invention.

[Formula 4]

[Formula 5]

[Formula 6]

Figure 2 is a schematic diagram showing the change in the fluorescence spectrum of the nanocrystals substituted with para- toluidine dithio carbamate according to an embodiment of the present invention. The light emitting nanocrystal according to the embodiment of the present invention is characterized in that R ₁ is H, R ₂ is an aryl group, and the hydrogen of the aryl group is substituted with -CH ₃ .

Example 1:

2.75 g (15 mmol) of para-toluidinedithiocarbamate acid and 5 ml of chloroform are placed in a one neck glass flask. 263mg of InPZnS (Oleylamine) nanocrystals dissolved in 5ml chloroform was added dropwise to the solution for 4 hours. 20 mL of methanol is added to the finished solution to precipitate an orange solid. The friendly orange solid is separated from the solution using a centrifuge. The separated orange solid is dissolved again in chloroform and precipitated with methanol to separate and purify only pure solid components. Vacuum drying of the purified solid yields 83 mg of orange nanocrystals. The fluorescence spectra of InPZnS nanocrystals substituted with InPZnS (oleylamine) nanocrystals and para-toluidine dithiocarbamate showed that the emission wavelength after the ligand substitution was 22 nm toward the longer wavelength.

Figure 3 is a schematic diagram showing the change in the fluorescence spectrum of the nanocrystals substituted with normal hexyl aniline carbamate according to an embodiment of the present invention. The light emitting nanocrystal according to the embodiment of the present invention, R ₁ is an alkyl group, R ₂ is an aryl group, the alkyl group is -C ₆ H ₁₃ , The aryl group is -C ₆ It is characterized in that H ₅ .

Example 2:

1.9 g (7.5 mmol) of n-hexylanilinedithiocarbamate acid and 5 ml of chloroform are placed in a one neck glass flask. 127mg of InPZnS (Oleylamine) nanocrystals dissolved in 5ml chloroform was added dropwise to the solution for 4 hours. 20 mL of methanol is added to the finished solution to precipitate an orange solid. The friendly orange solid is separated from the solution using a centrifuge. The separated orange solid is dissolved again in chloroform and precipitated with methanol to separate and purify only pure solid components. Vacuum drying of the purified solid yields 80 mg of orange nanocrystals. The fluorescence spectra of InPZnS nanocrystals substituted with InPZnS (oleylamine) nanocrystals and normal hexylaniline carbamate showed that the emission wavelength was 19 nm toward long wavelength after ligand replacement.

Figure 4 is a schematic diagram showing that the fluorescence spectrum of the nanocrystals substituted with 4-trifluoromethylaniline carbamate according to an embodiment of the present invention is changed. The light emitting nanocrystal according to the embodiment of the present invention is characterized in that R ₁ is H, R ₂ is an aryl group, and the hydrogen of the aryl group is substituted with -CF ₃ .

Example 3:

1.47 g (6.2 mmol) of 4-trifluoromethylanilinedithio carbamate acid is placed in a one neck glass flask. 5 ml chloroform dissolved InPZnS (Oleylamine) nanocrystals were added dropwise to the solution and reacted for 4 hours. 20 mL of methanol is added to the finished solution to precipitate an orange solid. The friendly orange solid is separated from the solution using a centrifuge. The separated orange solid is dissolved again in chloroform and precipitated with methanol to separate and purify only pure solid components. Vacuum drying of the purified solid yields 102 mg of orange nanocrystals. The fluorescence spectra of InPZnS (oleylamine) nanocrystals and 4-trifluoromethylaniline carbamate-substituted InPZnS nanocrystals were controlled by 8 nm emission wavelength after ligand substitution.

In the above description of the configuration and features of the present invention based on the embodiment according to the present invention, the present invention is not limited thereto, and various changes or modifications can be made within the spirit and scope of the present invention. It will be apparent to those skilled in the art that such changes or modifications fall within the scope of the appended claims.

The luminescent nanocrystals using the electronically delocalized carbamate derivatives according to the present invention can be finely controlled in wavelength, and thus used in the display industry as a display display material that is required to control red, green, and blue color coordinates and finely control white balance. Most likely.

Claims (9)

1. In the light-emitting nanocrystals consisting of a core (Core), Shell (Shell) and the ligand (Ligand) bonded to the shell (Shell) surface,

   The ligand has an electrical resonance structure, and is a carbamate derivative of Formula 1 or Formula 2,

   According to the carbamate derivative, the size of the nanocrystals are determined to control the wavelength of the emitted light, characterized in that the light emitting nanocrystals using an electronically delocalized carbamate derivative. :

   [Formula 1]

   

   [Formula 2]

   

   Wherein R ₁ and R ₂ are each hydrogen, an alkyl group, an alkenyl group, an alkynyl group or an aryl group,

   X ₁ and X ₂ are each O, S, Se or Te,

   M is a main group metal, a base metal or a transition metal,

   n is an integer from 1 to 8,

   m is an integer of 0-18.
2. The method of claim 1,

   M is an luminescent nanocrystal using an electronically delocalized carbamate derivative, characterized in that the alkali metal or alkaline earth metal.
3. The method of claim 2,

   The alkali metal is H, Li, Na or K, and the alkaline earth metal is Be, Mg or Ca luminescent nanocrystals using an electronically delocalized carbamate derivative.
4. The method of claim 1,

   Light-emitting nanocrystals using an electronic delocalized carbamate derivative, characterized in that R ₁ and R ₂ are cyclic saturated or unsaturated hydrocarbons connected to each other.
5. The method according to claim 1 or 4,

   The alkyl group, alkenyl group, alkynyl group and aryl group,

   One or more hydrogens to -NR, -NHR, NH ₃ , -OR, -CH ₃ , -CF ₃ , -CCl ₃ , -CN, -NO ₂ , -COR and -CONH ₂ which impart electrical and steric properties Substituted with one selected from the group consisting of: wherein R is each hydrogen, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group Luminescent nanocrystals using carbamate derivatives.
6. The method of claim 1,

   The core portion and the shell portion, respectively

   CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, PbS, PbSe, PbTe, InP, InAs GaP, InGaP, AgGaS ₂ , AgGaSe ₂ , AgGaTe ₂ , AgInS ₂ , AgInSe ₂ , AgInTe ₂ , CuInS ₂ , CuInSe ₂ , CuInTe ₂ , CuGaS ₂ , CuGaSe ₂ and CuGaTe ₂ A light-emitting nanocrystal using an electronically delocalized carbamate derivative comprising one selected from the group consisting of:
7. The method of claim 5,

   R ₁ is H, R ₂ is an aryl (aryl) group, the light emitting nanocrystals using an electronically delocalized carbamate derivative, characterized in that the hydrogen of the aryl group is substituted with -CH ₃ .
8. The method of claim 5,

   R ₁ is an alkyl group, R ₂ is an aryl group, the alkyl group is —C ₆ H ₁₃ , and the aryl group is —C ₆ H ₅ . Luminescent nanocrystals using carbamate derivatives.
9. The method of claim 5,

   R ₁ is H, R ₂ is an aryl (aryl) group, the light emitting nanocrystals using an electronically delocalized carbamate derivative, characterized in that the hydrogen of the aryl group is substituted with -CF ₃ .

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