KR20160142187A

KR20160142187A - Nanocrystal, method of preparing the same and electronic device including the same

Info

Publication number: KR20160142187A
Application number: KR1020150078225A
Authority: KR
Inventors: 김종기; 공의현; 권오범; 박온유; 우희제; 윤진섭; 이준우; 조성서; 한현주
Original assignee: 삼성에스디아이 주식회사
Priority date: 2015-06-02
Filing date: 2015-06-02
Publication date: 2016-12-12
Also published as: KR101852459B1

Abstract

A core particle composed of a first nanocrystal of indium phosphide (InP); At least one shell of a second nanocrystal selected from ZnS, GaP and combinations thereof surrounding the core particles; And a passivation layer made of indium oxide (In ₂ O ₃ ) which shines at the outermost part of the shell.

Description

TECHNICAL FIELD [0001] The present invention relates to a nanocrystal, a method of manufacturing the same, and an electronic device including the nanocrystal,

A nanocrystal, a method of manufacturing the same, and an electronic device including the same.

Nanocrystals are materials with a crystal structure of a few nanometers in size and are made up of hundreds to thousands of atoms. These small-sized materials have a large surface area per unit volume, so that most of the atoms are present on the surface and exhibit a quantum confinement effect. Thus, a unique electrical, magnetic, and optical , Chemical and mechanical properties. In other words, it is possible to control various properties by controlling the physical size of the nanocrystals.

Nanocrystals based on II-IV group compound semiconductors composed of elements of Group II and Group IV on the periodic table are the materials that can emit light of high luminous efficiency, Has come.

Studies on representative II-IV semiconductor nanocrystals have been carried out with a great deal of attention due to their advantages such as high luminescence efficiency and stability. However, since they contain Cd ² ⁺ and Se ² ^- , they cause serious problems in terms of environmental hazard and toxicity In recent years, ternary systems of Ⅲ-Ⅴ and ternary semiconductor nanocrystals of Ⅰ-Ⅲ-Ⅵ, which can replace Ⅱ-Ⅳ nanocrystals, have been developed. A lot of research has been done.

Among the III-V group nanocrystals, InP nanocrystals are the most extensively studied materials because of their non-toxicity advantages compared with II-IV group semiconductors and their luminescent region similar to CdSe nanocrystals and good luminous efficiency. InP nanocrystals are representative III-V group nanocrystals with a broad emission range from visible to near infrared.

However, since the stability of InP-based nanocrystals is low, studies for passivation of the surface of InP nanocrystals have been actively conducted.

One embodiment provides a nanocrystal that efficiently passivates the surface of nanocrystals to provide excellent stability to oxygen and moisture, and excellent thermal stability and light stability.

Another embodiment provides a method of making the nanocrystals.

Another embodiment provides an electronic device comprising the nanocrystals.

According to one embodiment, a core particle comprising a first nanocrystal of indium phosphide (InP); At least one shell of a second nanocrystal selected from ZnS, GaP and combinations thereof surrounding the core particles; And a passivation layer made of indium oxide (In ₂ O ₃ ) which shines at the outermost part of the shell.

The size of the core particles is in the range of 1 nm to 5 nm.

The total thickness of the shell may range from 2 nm to 5 nm.

The thickness of the passivation layer may be in the range of 2 nm to 5 nm.

In ₂ O ₃ forming the passivation times Orientation layer may have a lattice spacing of 10Å to 10.5Å.

The size of the nanocrystals may range from 2 to 5 times the size of the core.

According to another embodiment, the indium-containing precursor and the fatty acid are mixed to prepare the first mixture and then the temperature is raised; Wherein the first mixture comprises at least one shell of a second nanocrystal selected from ZnS, GaP, and combinations thereof, surrounding the core particles and core particles comprising first nanocrystals of indium phosphide (InP) Adding a nanocrystal to produce a second mixture; And adding the amine or alcohol to the second mixture to produce indium oxide in the indium-containing precursor by water produced by the reaction of the acid or anhydride produced in the fatty acid with the amine or alcohol. .

The indium-containing precursor may be an indium-containing salt. Specific examples of the indium-containing salt may be selected from indium chloride, indium bromide, indium fluoride, indium acetate, indium sulfate, indium nitrate, indium acetate, indium oleate, and combinations thereof.

The fatty acid may be a carboxylic acid having 10 or more carbon atoms.

The amine may be an amine having 10 or more carbon atoms.

The alcohol may be an alcohol having 10 or more carbon atoms.

After the first mixture is prepared, the temperature may be increased to 300 ° C at a rate of 20 ° C to 30 ° C per minute.

According to another embodiment, an indium-containing precursor; A combination of a zinc-containing precursor and a sulfur-containing precursor, a combination of a gallium-containing precursor and a phosphorus-containing precursor, and a shell precursor and a fatty acid selected from the combination, to raise the temperature; Adding a phosphorus-containing precursor to the first mixture to produce a second mixture; And adding the amine or alcohol to the second mixture to produce indium oxide from the indium-containing precursor by water generated by the reaction of the acid anhydride produced in the fatty acid with the amine or alcohol. &Lt; / RTI >

The fatty acid may be a carboxylic acid having 10 or more carbon atoms.

The amine may be an amine having 10 or more carbon atoms.

The alcohol may be an alcohol having 10 or more carbon atoms.

The phosphorus-containing precursor may be a compound represented by P (R) ₃ . Wherein R may be an alkylsilyl group, an arylsilyl group, an alkylamino group or an arylamino group, wherein alkyl means straight or branched chain C1 to C10 alkyl, and aryl means C6 to C12 aryl. More specific examples of the phosphorus-containing precursor include trimethylsilylphosphine, tris (dimethylamino) phosphine, P (N (CH ₃ ) ₂ ) ₃ , tris (trimethylsilyl) phosphine tris (trimethylsilyl) phosphine, tris (triethylsilyl) phosphine, and the like.

According to another embodiment, there is provided an electronic device including the nanocrystals.

The nanocrystals have excellent stability against oxygen and moisture, and are excellent in thermal stability and light stability.

1 is a schematic cross-sectional view of a nanocrystal including a core / shell / passivation layer according to one embodiment.
2 is a schematic cross-sectional view of an organic / inorganic electroluminescent device according to one embodiment.
3 and 4 are transmission electron microscope (TEM) photographs of the nanocrystals of Example 1 and Comparative Example 1, respectively.
FIGS. 5 and 6 are graphs showing the energy-dispersive X-ray spectroscopy (EDX) analysis results of the nanocrystals of Example 1 and Comparative Example 1, respectively.
FIG. 7 and FIG. 8 are graphs showing the results of measuring the PL characteristics with time of the nanocrystals according to Example 6 and Comparative Example 2 at a high temperature.
9 is a graph showing the measurement results of UV absorbance of the nanocrystals according to Example 1 and Comparative Example 1 after UV irradiation.
10 is a graph showing the results of measurement of PL light characteristics after UV irradiation of nanocrystals according to Example 1 and Comparative Example 1. FIG.
FIG. 11 is a graph showing the measurement results of UV absorbance and PL light characteristics after UV irradiation of the nanocrystals according to Example 6. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the drawings, the thickness is enlarged to clearly represent the layers and regions.

Whenever a portion of a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. Conversely, when a part is "directly over" another part, it means that there is no other part in the middle.

The term " combination "means a mixture or a multilayer structure in which two or more layers are stacked.

Hereinafter, a nanocrystal having a core / shell / passivation layer structure according to an embodiment will be described with reference to FIG.

1 is a schematic cross-sectional view of a nanocrystal having a core / shell passivation layer structure according to one embodiment.

1, a nanocrystal 1 according to an embodiment includes core particles 3 made of first nanocrystals of indium phosphide (InP), ZnS and GaP surrounding the core particles 3, At least one shell (5) consisting of a second nanocrystal selected from the combination; And a passivation layer 7 made of indium oxide (In ₂ O ₃ ) which shines at the outermost part of the shell.

When the passivation layer 7 made of indium oxide (In ₂ O ₃ ) is directly located on the core particle 3 made of the first nanocrystals of indium phosphide (InP) as described above, defects of InP and In ₂ O ₃ defects due to a large lattice mismatch, it is difficult to realize the structure of the InP core particle / In ₂ O ₃ passivation layer even at a high temperature and the yield is low. In addition, since the temperature and reaction time for synthesizing the InP core particles (3) are different from the temperature at which the In ₂ O ₃ passivation layer (7) is formed, precise temperature control and experiment setting must be overcome It has disadvantages. Accordingly, in one embodiment of the present invention, InP core particles (3) and In ₂ O ₃ And at least one shell 5 made of a second nanocrystal selected from ZnS, GaP, and a combination thereof is placed between the passivation layers 7. The energy barrier of the shell 5 is larger than the core particles 3 and the electrons or holes of the core particles 3 are well trapped in the energy barrier, In addition, since the energy barrier of the In ₂ O ₃ passivation layer 7 is larger than the energy barrier of the shell 5, the stability of the nanocrystal can be improved. That is, in one embodiment of the present invention, InP core particles (3), shell (5) and In ₂ O ₃ E1 < E2 < E3 when the energy barrier of the passivation layer 7 is E1, E2 and E3, respectively, to improve the stability of the nanocrystals.

The size of the core particles (3) is in the range of 1 nm to 5 nm. When the size of the core particles 3 is within the above range, light can be absorbed and emitted in all regions such as ultraviolet (UV), visible light, infrared (IR), and near infrared rays. The core particle 3 has a diameter when the shape of the core is spherical and a diameter with the longest length if it is a pseudo spherical shape and a length of the longest edge when it is a polygonal shape.

The total thickness of the shell layer 5 may range from 2 nm to 5 nm. When the total thickness of the shell layer 5 is in the above range, the quantum efficiency of the nanocrystals can be effectively improved.

The thickness of the passivation layer 7 may be in the range of 2 nm to 5 nm. When the thickness of the passivation layer 7 is within the above range, the optical stability and thermal stability of the nanocrystal can be effectively improved.

In ₂ O ₃ constituting the passivation layer 7 may have a lattice spacing of 10 Å to 10.5 Å. If the lattice spacing is within the above range, the energy bandgap of the nanocrystals can be reduced.

The size of the nanocrystals 1 may be in the range of 2 to 5 times the size of the core 3. When the ratio of the size of the nanocrystals (1) to the size of the core particles (3) is within the above range, the light degradation phenomenon can be prevented and excellent stability can be obtained.

The nanocrystals 1 having the above structure exhibit light absorption and light emission characteristics in all areas such as ultraviolet (UV), visible light, infrared (IR) and near infrared rays. The luminous efficiency of such a nanocrystal 1 is 0.1% to 100%, more specifically 20% to 100%.

The indium-containing precursor may be an indium-containing salt. Specific examples of the indium-containing salt include, but are not limited to, indium chloride, indium bromide, indium fluoride, indium acetate, indium sulfate, indium nitrate, indium acetate, indium oleate and combinations thereof.

The fatty acid may be a carboxylic acid having 10 or more carbon atoms and specifically includes saturated fatty acids such as myristic acid, palmitic acid and stearic acid, and combinations thereof. Can be selected.

The amine may be an amine having a carbon number of 10 or more, and specifically may be selected from oleylamine, 1-dodecylamine, 1-octadecylamine, and combinations thereof.

The alcohol may be an alcohol having 10 or more carbon atoms, and specifically may be selected from 1-decanol, 1-dodecanol, and combinations thereof.

The amine or alcohol may be used in a molar ratio of 1: 1 with the fatty acid.

In the nanocrystals, the In ³ ⁺ ions generated from the indium-containing precursor are present on the surface of the shell layer 5 to form an indium oxide passivation layer 7.

According to another embodiment, an indium-containing precursor; A combination of a zinc-containing precursor and a sulfur-containing precursor, a combination of a gallium-containing precursor and a phosphorus-containing precursor, and a shell precursor and a fatty acid selected from the combination, To produce an acid anhydride; Adding a phosphorus-containing precursor to the first mixture to produce a second mixture; And adding the amine or alcohol to the second mixture to produce indium oxide in the indium-containing precursor by the water generated by the reaction of the acid anhydride with the amine or the alcohol .

The phosphorus-containing precursor may be a compound represented by P (R) ₃ . Wherein R may be selected from an alkylsilyl group, an arylsilyl group, an alkylamino group, and an arylamino group, wherein alkyl means straight or branched chain C1 to C10 alkyl, and aryl means C6 to C12 aryl. More specific examples of the phosphorus-containing precursor include trimethylsilylphosphine, tris (dimethylamino) phosphine, P (N (CH ₃ ) ₂ ) ₃ , tris (trimethylsilyl) phosphine tris (trimethylsilyl) phosphine, tris (triethylsilyl) phosphine, and the like.

The amine or alcohol may be used in a molar ratio of 1: 1 with the fatty acid.

In one embodiment, there is provided a method of making a nanocrystal, comprising the steps of: forming core particles of a first nanocrystal of indium phosphide (InP) and a second nanocrystal of a second nanocrystal selected from ZnS, GaP, A nanocrystal including a shell of one layer is used as a raw material, or a core particle composed of indium phosphide (InP) first nanocrystals and a second nano-crystal selected from ZnS, GaP and combinations thereof surrounding the core particle A process for producing indium oxide from an indium-containing precursor by water produced by the reaction of an acid anhydride with an amine or an alcohol by adding an amine or an alcohol after preparing a nanocrystal including at least one layer of a crystal, Since the process proceeds separately from the synthesis process of the nanocrystals, the process of forming the indium oxide passivation layer is facilitated And the process for forming the indium oxide passivation layer can be repeatedly performed, so that the thickness of the passivation layer can be easily controlled.

The nanocrystals can be applied variously to electronic devices such as a display, an image sensor, a biosensor, a solar cell, and illumination, and are particularly useful for a light emitting layer of a blue light emitting device.

Hereinafter, an organic electroluminescent device including the nanocrystals will be described with reference to FIG.

2 is a schematic cross-sectional view of an organic / inorganic electroluminescent device according to one embodiment.

The structure of the organic / inorganic electroluminescent device according to one embodiment includes a substrate 10, a hole injecting electrode 20, a hole transporting layer 30, a light emitting layer 40, an electron transporting layer 50 and an electron injecting electrode 60 sequentially And the light emitting layer 40 includes the nanocrystals.

Optionally, a hole blocking layer 70 may be introduced between the light emitting layer 40 and the electron transport layer 50.

As the substrate 10 used for the electroluminescent device, a commonly used substrate can be used. Specifically, a glass substrate or a transparent plastic substrate having excellent transparency, surface smoothness, ease of handling, and water resistance can be used. More specific examples include glass substrates, polyester substrates such as polyethylene terephthalate, and polycarbonate substrates.

The material of the hole injection electrode 20 is a conductive metal or an oxide thereof. Specific examples thereof include indium tin oxide (ITO), indium zinc oxide (IZO), nickel (Ni), platinum (Pt) , Silver (Ag), iridium (Ir), or the like can be used.

As the material of the hole transport layer 30, any of commonly used materials may be used. Specific examples thereof include poly (3,4-ethylenedioephene) (PEDOT) / polystyrene para-sulfonate (PSS) Poly-N-vinylcarbazole derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polymethacrylate derivatives, poly (9,9-octylfluorene) ( poly (9,9-octylfluorene) derivatives, poly (spiro-fluorene) derivatives, TPD (N, N'-Bis- (3-methylphenyl) -N, - (phenyl) -benzidine). &Lt; / RTI > The thickness of the hole transporting layer may be 10 to 100 nm.

As the material of the electron transport layer 50, a material that is commonly used can be used. Specific examples thereof include oxazole-based compounds, isooxazole-based compounds, triazole-based compounds, isothiazole-based compounds, oxydiazole-based compounds, thiadiazole-based compounds, perylene-based compounds, tris (8-hydroxyquinoline) Alq3), bis (2-methyl-8-quinolato) (p-phenyl-phenolato) aluminum (Balq), bis (2-methyl-8- quinolinato) ) (Salq), but the present invention is not limited thereto. The thickness of the electron transporting layer may be 10 to 100 nm.

The material of the electron injection electrode 60 is metal having a small work function to facilitate electron injection, that is, I, Ca, Ba, Ca / Al, LiF / Ca, LiF / Al, BaF ₂ / Al, BaF ₂ / Ca / Al, Al, Mg, and Ag: Mg alloy, but is not limited thereto. The electron injection electrode may be divided into an electron injection layer, a metal layer, and the like. The thickness of the electron injection electrode is 50 nm to 300 nm.

As the material used for forming the hole blocking layer 70, materials commonly used in this technical field can be used. Specific examples thereof include 3-phenyl-4- (1'-naphthyl) -5-phenyl-1,2,4-triazole (TAZ), 2,9- But are not limited to, phenanthrolines, imidazole compounds, triazoles compounds, oxadiazoles compounds, aluminum complexes, and the like. The thickness of the hole blocking layer is 5 to 50 nm.

Hereinafter, embodiments of the present invention will be described in detail with reference to embodiments. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

Hereinafter, specific embodiments of the present invention will be described. It should be understood, however, that the embodiments described below are only for the purpose of illustrating or explaining the invention in detail, and thus the scope of the invention should not be limited thereto.

[ Example ]

Example One: InP core/ ZnS Shell / In ₂ O ₃ passivation Preparation of nanocrystals containing layers

A condenser, nitrogen and vacuum lines and the temperature detected 50 mL three-necked round bottom flask sensor is installed, indium acetate _{(In (acetate) 3) (} 30 mg, 0.1 mmol), pre-stick acid (myristic acid) (70.4 mg, 0.3 mmol) And a magnetic bar. 6.5 mL of 1-octadecene was added thereto, and stirring was carried out through the mantle, and nitrogen was blown into the reaction vessel. After raising the temperature to 110 ° C, vacuum is applied for 1 hour and 30 minutes. After changing to nitrogen atmosphere again, the temperature was rapidly increased to 270 ° C.

0.5 mL of an InP core / ZnS shell nanocrystal diluted in toluene was injected into the reaction vessel. Except that the dilution concentration of the nanocrystals was calculated by the optical intensity value for? _Max at the first absorption band edge obtained from the UV absorption measurement.

Approximately 2 minutes after the nanocrystals are dispersed stably, 0.04 mL of oleylamine is injected. The reaction mixture was maintained at a temperature of 250 to 270 ° C. for 30 minutes and then cooled to room temperature (24 ° C.) to terminate the reaction. The reaction solution was repeatedly centrifuged and purified using a mixture of chloroform / ethanol / acetone (1/1/10 volume ratio). After the addition of oleic acid as a stabilizer, the mixture was kept for about 6 hours and finally purified by centrifugation, redispersed in toluene organic solvent, transferred into a brown bottle, sealed and refrigerated .

Example 2: InP core/ ZnS Shell / In ₂ O ₃ passivation Preparation of nanocrystals containing layers

A nanocrystal was prepared in the same manner as in Example 1 except that InCl ₃ (21.1 mg, 0.1 mmol) was used instead of indium acetate (In (acetate) ₃ ) (30 mg, 0.1 mmol)

Example 3: InP core/ GaP Shell / ZnS Shell / In ₂ O ₃ passivation Preparation of nanocrystals containing layers

In Example 1, nanocrystals were prepared in the same manner as in Example 1 except that InP core / GaP shell / ZnS shell nanocrystals were used instead of InP core / ZnS shell nanocrystals.

Example 4: InP core/ ZnS Shell / In ₂ O ₃ passivation Preparation of nanocrystals containing layers

A condenser, nitrogen and vacuum lines and 50 mL three-necked temperature sensor is installed round bottom flask indium acetate _{(In (acetate) 3) (} 30 mg, 0.1 mmol), Zn (acetate) 2, (18.3 mg, 0.25 mmol), 6.5 mL of 1-octadecene was added to myristic acid (70.4 mg, 0.3 mmol), 1-dodecanthiol (20.2 mg, 0.1 mmol) And sufficiently stirred. The temperature is raised to 110 ° C and the vacuum is maintained for 1 hour and 30 minutes. After changing to nitrogen atmosphere, the temperature was rapidly raised to 300 ° C.

(TMS) ₃ P (12.5 mg, 0.05 mmol), which was stored in a glove box, was placed in a vial containing 1.6 mL of 1-octadecene solution and diluted in a glove box. This solution was rapidly injected into the reaction vessel at 300 캜. The temperature is maintained at 270 캜 for about 2 to 5 minutes, and 0.04 mL of oleylamine is then injected. The temperature was maintained at about 250 to 270 DEG C for 30 minutes, the temperature was lowered to room temperature, and the reaction was terminated. The reaction solution was repeatedly centrifuged and purified using a mixture of chloroform / ethanol / acetone (1/1/10 volume ratio). After the addition of oleic acid as a stabilizer, the mixture was maintained for about 6 hours, and finally purified by centrifugation, re-dispersed in toluene organic solvent, transferred to a brown bottle, sealed and refrigerated .

Example 5: InP core/ ZnS Shell / In ₂ O ₃ passivation Preparation of nanocrystals containing layers

A nanocrystal was prepared in the same manner as in Example 4 except that InCl ₃ (21.1 mg, 0.1 mmol) was used instead of indium acetate (In (acetate) ₃ ) (30 mg, 0.1 mmol)

Comparative Example One: InP core/ ZnS Shell containing Manufacture of nanocrystals

A condenser, nitrogen and vacuum lines and 50 mL three-necked temperature sensor is installed round bottom flask indium acetate _{(In (acetate) 3) (} 30 mg, 0.1 mmol), Zn (acetate) 2, (18.3 mg, 0.25 mmol), 6.5 mL of 1-octadecene was added to myristic acid (70.4 mg, 0.3 mmol) and stirred well in a nitrogen atmosphere. The temperature is raised to 110 ° C and the vacuum is maintained for 1 hour and 30 minutes. After changing to nitrogen atmosphere, the temperature was rapidly raised to 300 ° C.

(TMS) ₃ P (12.5 mg, 0.05 mmol), which was stored in a glove box, was placed in a vial containing 1.6 mL of 1-octadecene solution and diluted in a glove box. This solution was rapidly injected into the reaction vessel at 300 캜 and maintained at 270 캜. After 10-30 minutes, the temperature was lowered to 230 < 0 > C and 1-dodecanthiol (100 mg, 0.5 mmol) was slowly added. The reaction was maintained at a time interval of 5 hours or more, and then the temperature was lowered to room temperature and terminated.

passivation Identification of the floor

The passivation layer was confirmed through transmission electron microscope (TEM) photographs and energy-dispersive X-ray spectroscopy (EDX) analysis of the nanocrystals of Example 1 and Comparative Example 1.

3 and 4 are transmission electron microscope (TEM) photographs of the nanocrystals of Example 1 and Comparative Example 1, respectively. 3 and 4, it can be seen that the nanocrystals of Example 1 were larger in size than the nanocrystals of Comparative Example 1, and the passivation layer was formed to a thickness of about 2 nm.

FIGS. 5 and 6 are graphs showing EDX analysis results of the nanocrystals of Example 1 and Comparative Example 1, respectively. 5 and 6, it can be seen that the In and O components of the nanocrystals of Example 1 were much higher than those of Comparative Example 1.

Thermal stability evaluation

500 쨉 l of the nanocrystals of Examples 1 to 5 and the nanocrystals of Comparative Example 1 were added to 20 g of the monomer (A-DCP (tricyclodecane dimethanol diacrylate)) of the acrylate resin, and the chloroform solution was removed by depressurization. The vials were divided into 4 ml portions. The samples except for the double RT (24 ° C) conditions were placed in an oven at 120 ° C., and samples were taken out at predetermined times to measure PL characteristics.

The results of Example 2 and Comparative Example 1 are shown in FIG. 7 and FIG. FIGS. 7 and 8 are graphs showing the results of measurement of PL characteristics with time at a high temperature of the nanocrystals according to Example 2 and Comparative Example 1. FIG. Referring to FIG. 7, the nanocrystal according to Example 2 shows stable luminescence wavelength under a severe condition of 120 ° C, low rate of decrease in luminescence intensity with time, and luminescence characteristics even after 30 hours of exposure. Referring to FIG. 8, the nanocrystals of Comparative Example 1 were shifted toward the blue wavelength when exposed for 2 hours, and after 30 hours, the optical characteristics completely disappeared. As a result, it can be seen that the thermal stability of the nanocrystals according to Example 2 is significantly improved as compared with the nanocrystals according to Comparative Example 1.

Light stability evaluation

500 [micro] l of the nanocrystals of Example 1 and nanocrystals of Comparative Example 1 were added to 20 g of the monomer (A-DCP (tricyclodecane dimethanol diacrylate)) of the acrylate resin, and the chloroform solution was removed by depressurization, (vial). The samples were irradiated with UV light, and UV absorbance and PL light characteristics were measured.

The UV absorbance of the nanocrystals according to Example 1 and Comparative Example 1 is shown in FIG. 9, and the PL light characteristics of the nanocrystals according to Example 1 and Comparative Example 1 are shown in FIG. Referring to FIG. 9, it can be seen that the nanocrystal of Example 1 is superior to the nanocrystal of Comparative Example 1 in UV absorbance. 10, it can be seen that the nanocrystals according to Example 1 emitted light at the red wavelength, whereas the nanocrystals according to Comparative Example 1 migrated toward the blue wavelength. After UV irradiation of the nanocrystals according to Example 3, And PL light characteristics are shown in Fig. Referring to FIG. 11, it can be seen that the UV absorbance and PL light characteristics of the nanocrystals according to Example 3 are excellent.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, And falls within the scope of the invention.

1: nanocrystal 3: core particle
5: Shell 7: Passivation layer
10: substrate 20: hole injection electrode
30: hole transport layer 40: light emitting layer
50: electron transport layer 60: electron injection electrode
70: hole blocking layer

Claims

A core particle composed of a first nanocrystal of indium phosphide (InP);
At least one shell of a second nanocrystal selected from ZnS, GaP and combinations thereof surrounding the core particles; And
A passivation layer made of indium oxide (In ₂ O ₃ ) shouting at the outermost part of the shell
Containing nanocrystals.

The method of claim 1,
Wherein the core particles have a size in the range of 1 nm to 5 nm.

The method of claim 1,
Wherein the total thickness of the shell is in the range of 2 nm to 5 nm.

The method of claim 1,
Wherein the thickness of the passivation layer is in the range of 2 nm to 5 nm.

The method of claim 1,
In ₂ O ₃ constituting the passivation layer has a lattice spacing of 10 Å to 10.5 Å.

The method of claim 1,
Wherein the size of the nanocrystals is in the range of 2 to 5 times the size of the core.

Mixing the indium-containing precursor with a fatty acid to prepare a first mixture and then raising the temperature;
Wherein the first mixture comprises at least one shell of a second nanocrystal selected from ZnS, GaP, and combinations thereof, surrounding the core particles and core particles comprising first nanocrystals of indium phosphide (InP) Adding a nanocrystal to produce a second mixture;
Adding the amine or alcohol to the second mixture to produce indium oxide from the indium-containing precursor by water produced by the reaction of the acid or anhydride produced in the fatty acid with the amine or alcohol
&Lt; / RTI >

8. The method of claim 7,
Wherein the indium-containing precursor is an indium-containing salt.

9. The method of claim 8,
Specific examples of the indium-containing salt are selected from the group consisting of indium chloride, indium bromide, indium fluoride, indium acetate, indium sulfate, indium nitrate, indium acetate, indium oleate and combinations thereof.

8. The method of claim 7,
Wherein the fatty acid is a carboxylic acid having 10 or more carbon atoms.

8. The method of claim 7,
Wherein the amine is an amine having 10 or more carbon atoms.

8. The method of claim 7,
Wherein the alcohol is an alcohol having 10 or more carbon atoms.

8. The method of claim 7,
Wherein the temperature of the first mixture is raised to 300 DEG C at a rate of 20 DEG C to 30 DEG C per minute.

Indium-containing precursors; A combination of a zinc-containing precursor and a sulfur-containing precursor, a combination of a gallium-containing precursor and a phosphorus-containing precursor, and a shell precursor and a fatty acid selected from the combination, to raise the temperature;
Adding a phosphorus-containing precursor to the first mixture to produce a second mixture;
Adding the amine or alcohol to the second mixture to produce indium oxide from the indium-containing precursor by water generated by the reaction of the acid anhydride produced in the fatty acid with the amine or alcohol
&Lt; / RTI >

The method of claim 14,
Wherein the indium-containing precursor is an indium-containing salt.

16. The method of claim 15,
Specific examples of the indium-containing salt are selected from the group consisting of indium chloride, indium bromide, indium fluoride, indium acetate, indium sulfate, indium nitrate, indium acetate, indium oleate and combinations thereof.

The method of claim 14,
Wherein the fatty acid is a carboxylic acid having 10 or more carbon atoms.

The method of claim 14,
Wherein the amine is an amine having 10 or more carbon atoms.

The method of claim 14,
Wherein the alcohol is an alcohol having 10 or more carbon atoms.

The method of claim 14,
Wherein the temperature of the first mixture is raised to 300 DEG C at a rate of 20 DEG C to 30 DEG C per minute.

An electronic device comprising nanocrystals according to any one of claims 1 to 6.