KR20070087365A - Inorganic electroluminescence device - Google Patents

Abstract

Provided is an inorganic electroluminescent device to allow a thin film of large area to be prepared by solution process such as spin coating or dip coating using chalcogenide precursor and siloxane-based compounds, thereby reducing cost. An inorganic electroluminescent device comprises a first electrode; a second electrode which is arranged so as to face with the first electrode; and at least one pair of inorganic layers interposed between the first electrode and the second electrode, wherein the inorganic layers have a superlattice structure comprising a chalcogenide semiconductor layer and a SiOC insulating layer. Preferably the chalcogenide semiconductor layer is formed from a precursor compound represented by the formula(1), wherein L is a ligand having a nitrogen atom having an unpaired electron pair; M is a metal of group II, III or IV; X is a chalcogen atom; R is H, a substituted or unsubstituted C1-C30 alkyl, alkenyl, alkynyl or alkoxy group, a substituted or unsubstituted C6-C30 aryl or aryloxy group, or a substituted or unsubstituted C2-C30 heteroaryl, heteroaryloxy or heteroarylalkyl group; a is an integer of 0-2; and b is 2 or 3.

Description

Inorganic Electroluminescence Device

1 is a schematic cross-sectional view of an inorganic electroluminescent device according to a preferred embodiment of the present invention,

2 is a view for explaining an electroluminescence mechanism of the inorganic electroluminescent device having the structure of FIG.

3 is a result of measuring the thickness of the chalcogenide semiconductor thin films prepared in Examples 1 to 6,

4 is a result of measuring the thickness of the SiOC thin film prepared in Examples 7 to 10,

5 is a photograph observing a light emission phenomenon in each manufacturing step of the SiOC thin film prepared in Example 7,

6 is a result of absorbance of the SiOC thin film prepared in Example 7,

7 is a PL spectrum result of the SiOC thin film prepared in Example 7.

* Description of the symbols for the main parts of the drawings *

10: first electrode 20: second electrode

30: inorganic layer 31: chalcogenide semiconductor layer

32: SiOC insulating film

The present invention relates to an inorganic electroluminescent device, and more particularly, to an inorganic electroluminescent device having a superlattice structure including a chalcogenide semiconductor layer and a SiOC insulating film that can be formed into a nano-sized thin film by a solution process between electrodes. It is about.

Electroluminescent devices are attracting attention as next-generation display devices because they are active light emitting display devices and have a wide viewing angle, excellent contrast, and fast response speed.

The electroluminescent element forms an anode in a predetermined pattern on a transparent insulating substrate such as glass or plastic, forms an emission layer with an organic film or an inorganic film on the anode, and sequentially sequentially cathodes in a predetermined pattern so as to be perpendicular to the electrode. It is formed by laminating. In this case, the organic film or the inorganic film has a structure in which the hole transport layer, the light emitting layer, and the electron transport layer are sequentially stacked from the bottom, and the light emitting layer is made of an organic material or an inorganic material as described above.

When voltage is applied to the anode and the cathode of the electroluminescent device configured as described above, holes injected from the anode are moved to the light emitting layer via the hole transport layer, and electrons are injected from the cathode to the light emitting layer via the electron transport layer. In the light emitting layer, electrons and holes recombine to generate excitons, and as the excitons change from the excited state to the ground state, an image is formed by the fluorescent molecules of the light emitting layer emitting light.

In the electroluminescent device, the organic light emitting device and the inorganic electroluminescent device are classified according to the material of the light emitting layer. Among these, the organic electroluminescent device has excellent characteristics such as brightness and response speed as compared to the inorganic electroluminescent device. There are various advantages, such as the fact that it is possible, and recent research is being actively conducted. However, organic electroluminescent devices are very sensitive to moisture, oxygen, light, etc. in the air and are easily decomposed, and their durability against heat is so weak that the instability of such devices shortens the life of the devices.

On the contrary, the inorganic electroluminescent device has the advantage of being robust and stable in a wide temperature range and having a long life, and has the advantage of allowing a large flat plate.

As a material of the light emitting layer of the inorganic electroluminescent device, a photoluminescence phenomenon of a silicon oxide thin film has been reported (J. Appl. Phys. 1998, 83, 5386-5393). It is known that the PL intensity at 2.9 eV changes proportionally according to the strength of the Si—OH group.

In addition, studies have been reported on the electroluminescence spectra of Au / Si / SiO2 superlattices (Surface and Interface Anal. 2001, 32, 98-101). For the superlattice of such a structure, strong EL peaks were found at about 650 nm and 470 nm.

However, in the case of such silicon oxide, the precursor material for forming the silicon oxide thin film has a problem of high stress hysteresis and low mechanical properties, especially in plasma-enhanced chemicals, due to high intramolecular carbon content. Since the thin film is formed by a vacuum deposition method such as vapor deposition or metal-organic chemical vapor deposition (MOCVD), it is disadvantageous in terms of large area and cost.

An object of the present invention is to form an electron transport layer and a light emitting layer in a superlattice structure by using a chalcogenide precursor compound and a siloxane compound in a solution process such as spin coating or dip coating, thereby making the manufacturing process simple and low-cost large-area inorganic. It is to provide an electroluminescent device.

In order to achieve the above object, the present invention,

A first electrode;

A second electrode disposed to face the first electrode; And

At least one pair of inorganic layers interposed between the first electrode and the second electrode,

The inorganic layer provides an inorganic electroluminescent device having a superlattice structure composed of a chalcogenide semiconductor layer and an SiOC insulating film.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a schematic cross-sectional view of an inorganic electroluminescent device according to a preferred embodiment of the present invention. Referring to FIG. 1, in the inorganic electroluminescent device according to the present invention, at least one pair of inorganic layers 30 are formed on the first electrode 10, and the second electrode 20 is formed so that polarities thereof are reversed thereon. do. The inorganic layer 30 interposed between the first electrode 10 and the second electrode 20 may include a chalcogenide semiconductor layer 31 and an SiOC insulating layer 32, and the like. At least one pair of inorganic layers may be interposed to form a multilayer structure.

FIG. 2 is a view for explaining an electroluminescence mechanism of the inorganic electroluminescent device having the structure of FIG. 1. Referring to FIG. 1, electrons injected from the first electrode tunnel through the chalcogenide semiconductor layer and then form electron-hole pairs in holes and SiOC insulating films injected from the second electrode. Next, the recombination process is illuminated. In general, most semiconductors, especially those having a direct band gap, are suitable for emitting light. Since the chalcogenide semiconductor used in the present invention has an indirect energy band, Instead of the electron-hole pairs recombining and emitting light, the electrons and holes are tunneled to a neighboring SiOC insulating film in the relaxation process to emit light while recombining there. As such, the process can be performed by forming the SiOC insulating film into a nano-sized thin film.

This structure will be described in more detail below.

In the inorganic electroluminescent device of the present invention, the first electrode 10 functions as a cathode electrode for electron injection. The first electrode 10 may be patterned in a predetermined pattern. The first electrode 10 may be patterned on lines spaced apart from each other by a predetermined pattern, and an insulating layer may be further interposed between the lines of the first electrode 10. However, the pattern of the first electrode 10 is not necessarily limited thereto, and may be a through electrode formed on the entire surface without patterning. As the material of the first electrode 10, a metal having a small work function or an oxide thereof is used to facilitate electron injection. Specific examples thereof include, but are not limited to, ITO, Ca, Ba, Ca / Al, LiF / Ca, LiF / Al, BaF ₂ / Al, BaF ₂ / Ca / Al, Al, Mg, Ag: Mg alloys, and the like. It is not limited. It is preferable that the thickness of a 1st electrode is 50-200 nm.

The inorganic layer 30 formed on the first electrode 10 includes a chalcogenide semiconductor layer 31 and an SiOC insulating layer 32, and at least one pair of inorganic layers are stacked to form a single or multi-layer structure. Can be formed.

The chalcogenide semiconductor layer 31 is an inorganic semiconductor thin film that functions as an electron transfer layer (ETL). In general, in the case of forming a semiconductor thin film using an inorganic material, the mobility of the molecules may be very high due to the constant covalent bond expansion, but the high solubility in the organic solvent may be low to obtain a high quality superlattice thin film from the solution process. It is very difficult. In the present invention, a ligand such as lutidine is bonded, and an organic reactor capable of condensation to chalcogenide elements is connected to form a semiconductor layer 31 using a chalcogenide precursor compound having excellent solubility in organic solvents. Can be.

As the chalcogenide precursor compound used in the present invention, a compound represented by the following Chemical Formula 1 may be used.

[Formula 1]

Where

L is a ligand containing a nitrogen atom having a lone pair of electrons,

M is a metal atom selected from the group consisting of Group II, Group III and Group IV elements,

X is a group VI chalcogen element,

R is a hydrogen atom, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C1-C30 alkenyl group, a substituted or unsubstituted C1-C30 alkynyl group, a substituted or unsubstituted C1-C30 alkoxy Group, substituted or unsubstituted C6-C30 aryl group, substituted or unsubstituted C6-C30 aryloxy group, substituted or unsubstituted C2-C30 heteroaryl group, substituted or unsubstituted C2-C30 hetero An aryloxy group or a substituted or unsubstituted C2-C30 heteroarylalkyl group,

a is an integer of 0 to 2,

b is 2 or 3.

In Formula 1, L is specifically 2,3-lutidine, 2,4-lutidine, 2,5-lutidine, 2,6-lutidine, 3,4-lutidine, 3,5-lutidine, 3,6-lutidine, 2,6-lutidine-α ² , 3-diol, 2-hydroxypyridine, 3-hydroxypyridine, 4-hydroxypyridine, 2-hydroxyquinoline, 6-hydroxyquinoline , 8-hydroxyquinoline, 8-hydroxy-2-quinolinecarbonitrile, 8-hydroxy-2-quinolinecarboxylic acid, 2-hydroxy-4- (trifluoromethyl) pyridine, and N, N, It may be selected from the group consisting of N, N- tetramethylethylenediamine.

In addition, M of Formula 1 is specifically selected from the group consisting of cadmium (Cd), zinc (Zn), mercury (Hg), gallium (Ga), indium (In), lead (Pb) and tin (Sn) and , X is selected from the group consisting of oxygen (O), sulfur (S), selenium (Se) and tellurium (Te).

Specific examples of the chalcogenide precursor compound of Chemical Formula 1 used in the present invention include a compound represented by the following Chemical Formula 2.

[Formula 2]

In the inorganic electroluminescent device according to the present invention, the thickness of the chalcogenide semiconductor layer 31 is preferably 0.1 to 100 nm, more preferably 1 to 50 nm.

The chalcogenide semiconductor layer 31 can be formed by applying a precursor solution in which the chalcogenide precursor compound is dissolved in an organic solvent to form a thin film. The content of the chalcogenide precursor compound in the precursor solution is preferably 0.1 to 50% by weight, more preferably 1 to 10% by weight. In this case, the chalcogenide semiconductor layer may include spin coating, dip coating, roll coating, screen coating, spray coating, spin casting, After coating the precursor solution using flow coating, screen printing, ink jet, or drop casting to form a coating film, the coated coating film is baked and cured to form a thin film. do. The baking step can be carried out simply by exposing to the ambient environment, applying a vacuum in the initial stages of the curing process, or by heating for 1 to 10 minutes at a temperature of 50 to 200 ° C. In addition, the curing step may be carried out by thermosetting the coating film for 1 to 180 minutes at a temperature of 150 to 500 ℃, may be UV cured with ultraviolet light of 200 to 450nm in consideration of the absorption wavelength of the compound used.

The SiOC insulating layer 32 constituting the inorganic layer 30 of the inorganic electroluminescent device of the present invention together with the chalcogenide semiconductor layer 31 functions as an emission layer (EML).

The SiOC insulating film is a thin film having a structure of Si-O-C, according to an embodiment of the present invention may be made of a siloxane polymer prepared by hydrolysis and condensation polymerization of the cyclic siloxane compound represented by the following formula (3).

[Formula 3]

Wherein R ₁ is a substituted or unsubstituted C1-C3 alkyl group or a substituted or unsubstituted C6-C15 aryl group, and R ₂ is a substituted or unsubstituted C1-C10 alkyl group or SiX ₁ X ₂ X ₃ (Wherein X ₁ , X ₂ , X ₃ are each independently selected from the group consisting of a hydrogen atom, an alkyl group of C1-C3, an alkoxy group of C1-C10 and a halogen atom, at least one of which is a hydrolyzable functional group) , p is an integer of 3 to 8.

Specific examples of the cyclic siloxane compound include compounds represented by the following Chemical Formulas 4 to 8.

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

Compounds represented by Formulas 4 to 8 have advantages in that all Si elements in the molecule are connected by oxygen, thereby lowering carbon content, reducing stress hysteresis, and increasing mechanical properties. The polymer prepared therefrom may have a large amount of Si-OH, and thus has excellent compatibility with conventional pore-forming materials.

Since the cyclic siloxane compound grows randomly during polymerization, it is impossible to clearly identify the structure of the polymer. However, when the polymer is formed through sol-gel hydrolysis and polymerization, the terminal of the polymer is a hydroxyl group. A sol polymer substituted with (-OH) is formed. The polymer may be spaced around by an alkyl group or an aryl group of R ₁ bonded to an Si element, thereby forming mesoporous pores in the insulating film.

SiOC insulating film used in the present invention may be hydrolyzed and condensation polymerization using such a cyclic siloxane compound alone, Si monomer having an organic bridge represented by the following formula (9) or (10), alkoxy represented by the following formula (11) Hydrolysis and condensation polymerization may be performed together with at least one monomer selected from the group consisting of a silane monomer and a linear siloxane monomer represented by the following Chemical Formula 12.

[Formula 9]

Wherein R ₁ is selected from the group consisting of a hydrogen atom, a substituted or unsubstituted C1-C3 alkyl group and a substituted or unsubstituted C6-C15 aryl group, and X ₁ , X ₂ and X ₃ are each independently hydrogen An atom, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C10 alkoxy group, and a halogen atom, provided that at least one is a hydrolyzable functional group, m is 0 to The integer of 10 and p are integers of 3-8.

[Formula 10]

Wherein X ₁ , X ₂ and X ₃ Are each independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C10 alkoxy group and a halogen atom, provided that at least one is a hydrolyzable functional group , M is selected from the group consisting of a single bond, a substituted or unsubstituted C1-C10 alkylene group, and a substituted or unsubstituted C6-C15 arylene group.

[Formula 11]

(R ₁ ) _n Si (OR ₂ ) _4-n

Wherein R ₁ is selected from the group consisting of a hydrogen atom, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C6-C15 aryl group, and a halogen atom, and R ₂ is a hydrogen atom, substituted or unsubstituted C1-C3 ₃ alkyl group and substituted or unsubstituted C6-C15 aryl group, at least one of R ₁ and OR ₂ is a hydrolysable functional group, n is an integer from 0 to 3.

[Formula 12]

Wherein each R ₁ is independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted C 1 -C 3 alkyl group, a substituted or unsubstituted C 1 -C 10 alkoxy group, hydroxy and a halogen atom, at least one of them Is a hydrolyzable functional group, n is an integer from 0 to 30.

Specific examples of the Si monomer represented by Formula 9 or 10 include compounds represented by Formulas 13 to 15 below.

[Formula 13]

[Formula 14]

[Formula 15]

Specific examples of the alkoxy silane monomer represented by Formula 11 include compounds represented by the following Formulas 16 to 18.

[Formula 16]

[Formula 17]

[Formula 18]

In addition, specific examples of the linear siloxane monomer represented by Formula 12 include compounds represented by the following Formulas 19 to 23.

[Formula 19]

[Formula 20]

[Formula 21]

[Formula 22]

[Formula 23]

Wherein n is an integer from 1 to 30.

In the inorganic electroluminescent device according to the present invention, the thickness of the SiOC insulating film 32 is preferably 0.1 to 100 nm, more preferably 1 to 50 nm.

Such a SiOC thin film can be formed by applying a solution obtained by dissolving the siloxane polymer in an organic solvent to form a thin film. The content of the siloxane polymer in the solution is preferably 0.1 to 30% by weight. The solution may further include an acid or base catalyst such as HCl / H ₂ O, H ₂ SO ₄ / H ₂ O, NaOH / H ₂ O, LiOH / H ₂ O as needed.

As the method for applying the solution, spin coating, dip coating, roll coating, screen coating, spray coating, spray coating, like the chalcogenide semiconductor layer, Spin casting, flow coating, screen printing, ink jet or drop casting may be used.

After the coating film is formed as described above, the coated coating film is dried and vitrified to form an SiOC insulating film. The drying step is a process of wet gelation by evaporating the residual solvent, simply exposing to the surrounding environment, applying a vacuum in the initial stage of the curing process, or 0.1 to 5 at a temperature of 100 to 200 ℃ It may be carried out by heating under a nitrogen atmosphere for minutes. Subsequently, the vitrification step is preferably carried out under nitrogen atmosphere for 0.1 to 5 minutes at a temperature of 200 to 300 ℃.

It may further comprise a curing step after the vitrification step, the curing step (curing) is preferably carried out by heat-treating the vitrified SiOC insulating film in a vacuum for 1 to 180 minutes at a temperature of 350 to 450 ℃.

In the present invention, the chalcogenide semiconductor layer 31 and the SiOC insulating layer 32 may be alternately stacked between the first electrode 10 and the second electrode 20 to form an inorganic layer having a multilayer structure. have.

On the inorganic layer 30 formed as described above, the second electrode 20 serving as a cathode for hole injection is provided. The material of the second electrode 20 is a conductive metal or an oxide thereof, and specific examples thereof include indium tin oxide (ITO), indium zinc oxide (IZO), nickel (Ni), platinum (Pt), gold (Au), and silver. (Ag), iridium (Ir), polycrystalline silicon (p-Si), etc. can be used.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are for illustrative purposes only and are not intended to limit the present invention.

Production Example  One  : Lut ₂ CD (S ( CO ) CH ₃ ) ₂ (here, Lut = 3,5- Lutidine ) Synthesis

First 1.0 g (5.8 mmol) of cadmium carbonate, 1.2 g (11.6 mmol) of 3,5-lutidine and 20 ml of toluene were mixed in a round bottom flask. 0.9 g (11.6 mmol) of thioacetic acid was added dropwise while stirring the mixture rapidly, and the mixture was stirred at room temperature for 1 hour. As the reaction proceeded, solid cadmium carbonate disappeared, CO ₂ bubble formation was observed, and the solution turned yellow. Toluene and volatile reaction by-products were removed under reduced pressure to yield a white crystalline solid and a small amount of yellow solid, which appears to be cadmium sulfide. The solid was redissolved in toluene, filtered to remove cadmium sulfide, and then the solution was placed in a freezer, which was about 2.0-2.5 g of colorless crystals, Lut ₂ Cd (S (CO) CH ₃ ) ₂ (yield 59 ~). 74%).

NMR data (C ₆ D ₆ ): ¹ H NMR, 1.69 [12H, CH ₃ -lutidine], 2.58 [6H, SOC CH ₃ ], 6.55 [2H, lutidine para-CH], 8.50 [4H, lutidine ortho-CH ]; ¹³ C NMR, 17.8 [ C H ₃ -lutidine], 35.1 [SOC CH ₃ ], 133.7 [ C -CH ₃ -lutidine], 138.8 [para- C H-lutidine], 147.7 [ortho C H-lutidine], ¹¹³ Cd NMR, 353.5

Production Example  2 Annular Siloxane system  Synthesis of Monomers

2,4,6,8-tetramethyl-2,4,6,8-cyclotetrasiloxane (2,4,6,8-tetramethyl-2,4,6,8-cyclotetrasiloxane) 41.6 mmol (10.00 g) Into the flask and diluted with 100ml of tetrahydrofuran, 700mg of 10wt% Pd / C (palladium / charcol) was added. Subsequently, 177.8 mmol (3.20 ml) of distilled water were added, and hydrogen gas generated at this time was removed. After the reaction was conducted at room temperature for 5 hours, the reaction solution was filtered through celite and MgSO 4, diluted with 200 ml of THF (tetrahydrofuran), and then 177.8 mmol (13.83 g) of triethylamine was added. . After the temperature of the solution was lowered to −0 ° C., 177.8 mmol (25.0 g) of chlorotrimethoxysilane was slowly added, and the temperature was gradually raised to room temperature to allow the reaction to proceed for 12 hours. The reaction solution was filtered through celite and the filtrate was placed under reduced pressure of about 0.1 Torr to remove volatiles and concentrated to prepare a cyclic siloxane monomer represented by the above formula in a colorless liquid: ¹ H-NMR ( 300 MHz) δ 0.092 (s, 12H, 4 × [−CH ₃ ]), 3.58 (s, 36H, 4 × [−OCH ₃ ] ₃ ).

Production Example  3 : Siloxane system  Preparation of Polymer

8.24 mmol of the cyclic siloxane monomer synthesized in Preparation Example 2 and 3.53 mmol of methyltrimethoxysilane (MTMS, manufactured by Aaldrich) were placed in a flask, and tetrahydrofuran was added so that the total solution concentration was 0.05 to 0.07 M. After dilution, the reaction liquid temperature was -78 ° C. After adding 0.424 mmol of hydrochloric acid and 141.2 mmol of water to the flask, the temperature of the reaction solution was gradually raised from -78 ° C to 70 ° C for 16 hours. After the reaction solution was transferred to a separatory funnel, the same amount of tetraethylfuran and tetrahydrofuran in the same amount were added, washed three times with about 1/10 of the total solvent, and then the volatiles were removed under reduced pressure. Removal gave a polymer in the form of a white powder. The polymer obtained by the above method was dissolved in tetrahydrofuran to form a transparent solution, which was filtered through a filter having a pore of 0.2 μm, and water was slowly added to the filtrate to obtain a silicone polymer by precipitation of white powder. The white powder was dried for 10 hours at a temperature of 0 ~ 20 ℃ and 0.1 tor (torr) pressure to obtain 4.0g of siloxane-based polymer. Si-OH content, Si-OCH ₃ content and Si-CH ₃ in the polymer The contents were 28.80%, 0.95% and 70.25%, respectively. However, the Si-OH, Si-OCH ₃ and Si-CH ₃ The content was analyzed by nuclear magnetic resonance analyzer (NMR, Bruker) according to the following formula.

Si-OH (%) = Area (Si-OH) ÷ [Area (Si-OH) + Area (Si-OCH ₃ ) / 3 + Area (Si-CH ₃ ) / 3] x 100;

Si-OCH ₃ (%) = Area (Si-OCH ₃ ) / 3 ÷ [Area (Si-OH) + Area (Si-OCH ₃ ) / 3 + Area (Si-CH ₃ ) / 3] x 100; And

Si-CH ₃ (%) = Area (Si-CH ₃ ) / 3 ÷ [Area (Si-OH) + Area (Si-OCH ₃ ) / 3 + Area (Si-CH ₃ ) / 3] × 100

Example  One : Chalcogenide Semiconductor layer  formation

First, 0.40 g of the chalcogenide compound obtained in Preparation Example 1 was added to 1.60 g of pyridine to prepare a precursor solution of 20 wt%. The solution was spin coated onto a 4 "silicon wafer at 500 rpm for 20 seconds and baked on a hot plate in a nitrogen atmosphere at 100 ° C. for 1 minute to prepare a film. Chalcogenide thin films were prepared for minutes.

Example  2-4

0.20 g of the chalcogenide compound obtained in Preparation Example 1 was added to 1.80 g of pyridine to prepare a precursor solution using a 10 wt% solution (Example 2), and 0.10 g of the chalcogenide compound was added to 1.90 g of pyridine and 5 wt%. A precursor solution was prepared using a% solution (Example 3), and 0.06 g of a chalcogenide compound was added to 1.94 g of pyridine to prepare a precursor solution using a 3 wt% solution (Example 4). In the same manner as in Example 1, a chalcogenide semiconductor thin film was prepared.

Example  5-6

0.02 g of the chalcogenide compound obtained in Preparation Example 1 was added to 1.98 g of pyridine to prepare a precursor solution using 1 wt% of a solution (Example 5), and 0.01 g of the chalcogenide compound was added to 1.99 g of pyridine. A precursor solution was prepared using a wt% solution (Example 6), and the chalcogenide semiconductor thin film was manufactured in the same manner as in Example 1 except that each precursor solution was spin-coated at 2000 rpm. .

The thickness of the chalcogenide semiconductor thin films prepared in Examples 1 to 6 was measured and the results are shown in FIG. 3. Referring to Figure 3, it can be seen that it is possible to form a thin film having a nano-size thickness by adjusting the concentration of the precursor solution.

Example  7-10 : SiOC  Preparation of Insulation Film

First, a precursor solution was prepared by mixing the silicone polymer synthesized in Preparation Example 2 and PGMEA (propylene glycol mono ether acetate) as described in Table 1 below. The precursor solution was spin-coated on a 4 "silicon wafer for 30 seconds at 500 rpm and dried on a hot plate in a nitrogen atmosphere at 150 ° C. for 1 minute to remove the solvent. The dried coating film was 250 in a nitrogen atmosphere. SiOC thin film was prepared by vitrification by heat treatment at 1 ° C. for 1 minute.

TABLE 1

Silicone polymer PGMEA density Example 7 0.04 g 1.96 g 2.0wt% Example 8 0.02 g 1.98 g 1.0wt% Example 9 0.01 g 1.99 g 0.5wt% Example 10 0.002 1.998 g 0.1wt%

5 shows the results of observing light emission at UV 254 nm for each manufacturing step of the SiOC thin film prepared in Example 7. Referring to FIG. 5, it can be seen that after the vitrification at 250 ° C., the light emission effect was excellent.

The absorbance and PL intensity of the SiOC thin film prepared in Example 7 were measured, and the results are shown in FIGS. 6 and 7. Referring to FIG. 7, it can be seen that PL peaks are formed at about 470 nm, 510 nm, and 570 nm portions. Therefore, it was confirmed that the SiOC insulating film used in the present invention can be applied to the electroluminescent device.

As described above, according to the present invention, by using a chalcogenide precursor compound and a siloxane compound dissolved in an organic solvent, a large-area thin film can be coated in a solution process such as spin coating or dip coating, thereby allowing electrons of the electroluminescent device. By forming the transport layer and the light emitting layer in a superlattice structure, it is possible to provide an inorganic electroluminescent device which can simplify the manufacturing process and reduce costs.

Claims (16)

A first electrode; A second electrode disposed to face the first electrode; And At least one pair of inorganic layers interposed between the first electrode and the second electrode, The inorganic layer is an inorganic electroluminescent device having a superlattice structure consisting of a chalcogenide semiconductor layer and a SiOC insulating film. The inorganic electroluminescent device according to claim 1, wherein the chalcogenide semiconductor layer is formed from a precursor compound represented by Formula 1 below: [Formula 1]

Where L is a ligand containing a nitrogen atom having a lone pair of electrons, M is a metal atom selected from the group consisting of Group II, Group III and Group IV elements, X is a group VI chalcogen element, R is a hydrogen atom, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C1-C30 alkenyl group, a substituted or unsubstituted C1-C30 alkynyl group, a substituted or unsubstituted C1-C30 alkoxy Group, substituted or unsubstituted C6-C30 aryl group, substituted or unsubstituted C6-C30 aryloxy group, substituted or unsubstituted C2-C30 heteroaryl group, substituted or unsubstituted C2-C30 hetero An aryloxy group or a substituted or unsubstituted C2-C30 heteroarylalkyl group, a is an integer of 0 to 2, b is 2 or 3. The compound of claim 2, wherein L in Formula 1 is 2,3-lutidine, 2,4-lutidine, 2,5-lutidine, 2,6-lutidine, 3,4-lutidine, 3,5 -Lutidine, 3,6-lutidine, 2,6-lutidine-α ² , 3-diol, 2-hydroxypyridine, 3-hydroxypyridine, 4-hydroxypyridine, 2-hydroxyquinoline, 6 -Hydroxyquinoline, 8-hydroxyquinoline, 8-hydroxy-2-quinolinecarbonitrile, 8-hydroxy-2-quinolinecarboxylic acid, 2-hydroxy-4- (trifluoromethyl) pyridine, and Inorganic electroluminescent device, characterized in that it is selected from the group consisting of N, N, N, N-tetramethylethylenediamine. The method of claim 2, wherein M in Formula 1 is selected from the group consisting of cadmium (Cd), zinc (Zn), mercury (Hg), gallium (Ga), indium (In), lead (Pb), and tin (Sn). And X is selected from the group consisting of oxygen (O), sulfur (S), selenium (Se) and tellurium (Te). The inorganic electroluminescent device according to claim 2, wherein the precursor compound of Formula 1 is a compound represented by Formula 2 below: [Formula 2]

The inorganic electroluminescent device according to claim 1, wherein the chalcogenide semiconductor layer has a thickness of 0.1 to 100 nm. The inorganic electroluminescent device according to claim 1, wherein the chalcogenide semiconductor layer has a thickness of 1 to 50 nm. The inorganic electroluminescent device according to claim 1, wherein the SiOC insulating film is made of a siloxane polymer prepared by hydrolysis and condensation polymerization of a cyclic siloxane compound represented by Formula 3 below: [Formula 3]

Wherein R ₁ is a substituted or unsubstituted C1-C3 alkyl group or a substituted or unsubstituted C6-C15 aryl group, and R ₂ is a substituted or unsubstituted C1-C10 alkyl group or SiX ₁ X ₂ X ₃ (Wherein X ₁ , X ₂ , X ₃ are each independently selected from the group consisting of a hydrogen atom, an alkyl group of C1-C3, an alkoxy group of C1-C10 and a halogen atom, at least one of which is a hydrolyzable functional group) , p is an integer of 3 to 8. The SiOC thin film according to claim 8, wherein the cyclic siloxane compound is selected from the group consisting of compounds represented by the following Chemical Formulas 4 to 8. [Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

The method of claim 8, wherein the SiOC insulating film is a Si monomer having an organic leg represented by the cyclic siloxane compound represented by the following formula (9) or 10, alkoxy silane monomer represented by the formula (11) and a linear siloxane monomer represented by the formula (12) SiOC thin film, characterized in that the hydrolysis and condensation polymerization with at least one monomer selected from the group consisting of: [Formula 9]

Wherein R ₁ is selected from the group consisting of a hydrogen atom, a substituted or unsubstituted C1-C3 alkyl group and a substituted or unsubstituted C6-C15 aryl group, and X ₁ , X ₂ and X ₃ are each independently hydrogen An atom, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C10 alkoxy group, and a halogen atom, provided that at least one is a hydrolyzable functional group, m is 0 to The integer of 10 and p are integers of 3-8. [Formula 10]

Wherein X ₁ , X ₂ and X ₃ Are each independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C10 alkoxy group and a halogen atom, provided that at least one is a hydrolyzable functional group , M is selected from the group consisting of a single bond, a substituted or unsubstituted C1-C10 alkylene group, and a substituted or unsubstituted C6-C15 arylene group. [Formula 11] (R ₁ ) _n Si (OR ₂ ) _4-n Wherein R ₁ is selected from the group consisting of a hydrogen atom, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C6-C15 aryl group, and a halogen atom, and R ₂ is a hydrogen atom, substituted or unsubstituted C ₁ -C 3 ₃ alkyl group and substituted or unsubstituted C 6 -C 15 aryl group, at least one of R ₁ and OR ₂ is a hydrolysable functional group, n is an integer from 0 to 3. [Formula 12]

Wherein each R ₁ is independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted C 1 -C 3 alkyl group, a substituted or unsubstituted C 1 -C 10 alkoxy group, hydroxy and a halogen atom, at least one of them Is a hydrolyzable functional group, n is an integer from 0 to 30. The SiOC thin film according to claim 10, wherein the Si monomer represented by Formula 9 or 10 is selected from the group consisting of compounds represented by Formulas 13 to 15: [Formula 13]

[Formula 14]

[Formula 15]

The SiOC thin film of claim 10, wherein the alkoxy silane monomer represented by Formula 11 is selected from the group consisting of compounds represented by Formulas 16 to 18; [Formula 16]

[Formula 17]

[Formula 18]

The SiOC thin film according to claim 10, wherein the linear siloxane monomer represented by Formula 12 is selected from the group consisting of compounds represented by Formulas 19 to 23: [Formula 19]

[Formula 20]

[Formula 21]

[Formula 22]

[Formula 23]

Wherein n is an integer from 1 to 30. The inorganic electroluminescent device according to claim 1, wherein the SiOC insulating film has a thickness of 0.1 to 100 nm. The inorganic electroluminescent device according to claim 1, wherein the SiOC insulating film has a thickness of 1 to 50 nm. According to claim 1, wherein the chalcogenide semiconductor layer and the SiOC insulating film is spin coating (dip coating), dip coating (dip coating), roll coating (roll coating), screen coating (spray coating) And thinning by spin casting, flow coating, screen printing, ink jet, or drop casting.

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