KR20230006090A - Thermal cross-linkable hole transport material, light emitting diode including same and method for manufacturing the same - Google Patents

Abstract

The present invention discloses a thermal cross-linkable hole transport material, light emitting diode including the same, and a method for manufacturing the same. The thermal cross-linkable hole transport material of the present invention is indicated by the below formula 1. [Formula 1] (In the Formula 1, X is O or S, R is a cross-linking arylamine-based compound, and n is 1 through 4.) Therefore, the morphological stability of hierarchy can be increased.

Description

Thermal crosslinkable hole transport material, light emitting device including the same, and manufacturing method thereof

The present invention relates to a thermally cross-linkable hole transport material, a light emitting device including the same, and a method for manufacturing the same. It relates to a cross-linkable hole transport material capable of increasing morphological stability and lowering solubility, a light emitting device including the same, and a manufacturing method thereof.

An organic light-emitting diode (OLED) is a light-emitting device in which an organic light-emitting material is laminated on a substrate, and a light-emitting phenomenon appears by injecting current into the device. These organic light emitting devices are semiconductor devices that generate self-luminescence by directly converting electrical energy into light energy. Based on this, it is receiving great attention as a next-generation display following the liquid crystal display (LCD).

In addition, quantum dots have high color purity, luminous efficiency, wide color reproducibility, etc., and can easily adjust the energy band gap according to their size, so that quantum dot light-emitting diodes (Quantum dot light-emitting diodes) ; QLED) is attracting attention as a next-generation light emitting diode technology.

Quantum dot light-emitting diodes (QLEDs), like organic light-emitting diodes (OLEDs), are used to transport charges such as holes or electrons between a light emitting layer and an electrode. It has a charge transport layer. In the above, the light emitting layer includes quantum dots. A charge transport layer capable of transporting electrons or holes is included between the light emitting layer and the electrode.

These organic light emitting devices or quantum dot light emitting devices are generally manufactured by vacuum deposition or solution processes.

The solution process has the advantage of being able to manufacture a large area with a roll-to-roll process and is efficient in terms of manufacturing cost, but the light emitting device manufactured by the solution process is superior to the light emitting device manufactured by vacuum deposition. There is a problem with low life.

More specifically, the light emitting device has a multi-layered structure consisting of several layers that process specific functions. When this multi-layered structure is formed by a solution process, the solvent used in the upper layer directly contacts the lower layer, and the lower layer is melted by the upper layer solution to each other. This is because there are problems such as mixing. Due to these problems, it is very difficult to manufacture an organic light emitting device or a quantum dot light emitting device using a solution process.

Therefore, when a light emitting device is manufactured by a solution process, research is required to increase the morphological stability of each layer and lower the solubility.

Korean Patent Registration No. 10-2076855, "Polymer type thermal crosslinkable hole transport material and organic light emitting diode using the same"

Embodiments of the present invention are intended to provide a thermally crosslinkable hole transport material capable of thermal crosslinking, thereby increasing the morphological stability of a layer and lowering solubility, by including a crosslinkable arylamine-based compound.

Embodiments of the present invention are to provide a light emitting device capable of improving the lifetime of an organic or quantum dot light emitting device by using a hole transport layer containing a hole transport material capable of thermal crosslinking, and a method for manufacturing the same, by solving the problem of mixing of upper and lower layers. do.

A thermally crosslinkable hole transport material according to an embodiment of the present invention is represented by Formula 1 below.

[Formula 1]

(In Formula 1, X is O or S, R is a crosslinkable arylamine compound, and n is 1 to 4)

The crosslinkable arylamine-based compound includes a styrene unit,

The styrene unit may be selected from the group represented by Chemical Formulas 2-1 to 2-30 below.

(In Chemical Formulas 2-1 to 2-30, R' is an alkyl group)

The crosslinkable arylamine-based compound includes an oxetane unit,

The oxetane unit may be selected from the group represented by Chemical Formulas 3-1 to 3-37 below.

(In Chemical Formulas 3-1 to 3-37, R' is an alkyl group)

The crosslinkable arylamine-based compound includes a trifluorovinyl ether unit,

The trifluorovinyl ether unit may be selected from the group represented by Chemical Formulas 4-1 to 4-30 below.

(In Chemical Formulas 4-1 to 4-30, R' is an alkyl group)

The thermally cross-linkable hole transport material represented by Formula 1 may be represented by Formula 5 below.

[Formula 5]

(In Formula 1, X is O or S)

The hole transport material represented by Chemical Formula 1 may be a p-type semiconductor polymer.

The solubility of the hole transport material represented by Chemical Formula 1 may be adjusted depending on the cross-linkable arylamine-based compound.

A light emitting device according to an embodiment of the present invention includes a first electrode formed on a substrate; a hole injection layer formed on the first electrode; a hole transport layer formed on the hole injection layer and comprising the thermally cross-linkable hole transport material according to claim 1; a light emitting layer formed on the hole transport layer; an electron transport layer formed on the light emitting layer; and a second electrode formed on the electron transport layer.

The hole transport layer may further include a p-dopant.

The light emitting layer may include organic compounds or quantum dots.

A method of manufacturing a light emitting device according to an embodiment of the present invention includes forming a first electrode on a substrate; forming a hole injection layer on the first electrode; coating a hole transport solution including a thermally cross-linkable hole transport material according to an embodiment of the present invention on the hole injection layer; heat-treating the hole transport solution coated on the hole injection layer to form a hole transport layer including the thermally cross-linkable hole transport material according to claim 1; forming a light emitting layer on the hole transport layer; forming an electron transport layer on the light emitting layer; and forming a second electrode on the electron transport layer.

The thermally cross-linkable hole transport material may be cross-linked by radical polymerization.

The thermally cross-linkable hole transport material may be cross-linked by cationic ring-opening polymerization.

The heat treatment may be performed at a temperature of 150 °C to 350 °C.

According to an embodiment of the present invention, by including a crosslinkable arylamine-based compound, it is possible to provide a thermally crosslinkable hole transport material capable of thermal crosslinking, thereby increasing morphological stability of the layer and lowering solubility.

Embodiments of the present invention provide a light emitting device capable of improving the lifetime of an organic or quantum dot light emitting device by using a hole transport layer including a hole transport material capable of thermal crosslinking, and a method for manufacturing the same, by solving the problem of mixing of upper and lower layers. can

1 is a cross-sectional view showing a light emitting device according to an embodiment of the present invention.
2 is a flowchart illustrating a method of manufacturing a light emitting device according to an embodiment of the present invention.
Figure 3 is a schematic diagram showing the synthesis process of the thermally crosslinkable hole transport material according to Example 1 of the present invention.
4A is a graph comparing UV-vis absorbance intensity after spin washing the surface of the hole transport layer prepared using the thermally crosslinkable hole transport material according to Example 1 of the present invention.
4B is a graph showing differential scanning calorimetry (DSC) results of a hole transport layer prepared using a thermally crosslinkable hole transport material according to Example 1 of the present invention.
5 is a cross-sectional view showing a light emitting device (OLED) according to a second embodiment of the present invention.
6 is a cross-sectional view showing a light emitting device (QLED) according to a third embodiment of the present invention.
7A is a graph showing current density-voltage-luminance (JVL) characteristics of a light emitting device according to Example 2 of the present invention, and FIG. 7B is a current density-voltage-luminance (JVL) characteristic of a light emitting device according to Comparative Example 1. 8A is a graph showing the electroluminescence (EL) spectrum of a light emitting device according to Example 2 of the present invention, and FIG. 8B is a graph showing the electrical properties of a light emitting device according to Comparative Example 1. It is a graph showing an electroluminescence (EL) spectrum.
9A is a graph showing current density-voltage-luminance (JVL) characteristics of a light emitting device according to Example 3 of the present invention, and FIG. 9B is a graph showing current density-voltage-luminance (JVL) of a light emitting device according to Comparative Example 2. 10A is a graph showing the electroluminescence (EL) spectrum of a light emitting device according to Example 3 of the present invention, and FIG. 10B is a graph showing the electrical properties of a light emitting device according to Comparative Example 2. It is a graph showing an electroluminescence (EL) spectrum.

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

Terminology used herein is for describing the embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. As used herein, "comprises" and/or "comprising" does not exclude the presence or addition of one or more other elements or steps in a stated component or step.

As used herein, “embodiments,” “examples,” “aspects,” “examples,” and the like should not be construed as indicating that any aspect or design described is preferred or advantageous over other aspects or designs. It is not.

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

Also, the singular expressions “a” or “an” used in this specification and claims generally mean “one or more,” unless indicated otherwise or clear from context to refer to the singular form. should be interpreted as

The terms used in the description below have been selected as general and universal in the related technical field, but there may be other terms depending on the development and / or change of technology, convention, preference of technicians, etc. Therefore, terms used in the following description should not be understood as limiting technical ideas, but should be understood as exemplary terms for describing the embodiments.

In addition, in certain cases, there are also terms arbitrarily selected by the applicant, and in this case, their meanings will be described in detail in the corresponding description section. Therefore, terms used in the following description should be understood based on the meaning of the term and the contents throughout the specification, not simply the name of the term.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined.

Meanwhile, in the description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, the terminology used in this specification is a term used to appropriately express the embodiment of the present invention, which may vary according to the intention of a user or operator or customs in the field to which the present invention belongs. Therefore, definitions of these terms will have to be made based on the content throughout this specification.

Hereinafter, referring to FIG. 1 , a thermally crosslinkable hole transport material according to an embodiment of the present invention and a light emitting device including the same according to an embodiment of the present invention will be described.

1 is a cross-sectional view showing a light emitting device according to an embodiment of the present invention.

A light emitting device according to an embodiment of the present invention includes a first electrode 120 formed on a substrate 110, a hole injection layer 131 formed on the first electrode 120, and a hole injection layer 131 formed on the substrate 110. formed, a hole transport layer 132 including a thermally cross-linkable hole transport material according to Chemical Formula 1, a light emitting layer 140 formed on the hole transport layer, and an electron transport layer 150 formed on the light emitting layer 140 ), and a second electrode 160 formed on the electron transport layer 150 .

A light emitting device according to an embodiment of the present invention includes a first electrode 120 formed on a substrate 110 .

As the substrate 110, a substrate 110 used in a conventional light emitting device may be used, but it is preferable to use a glass substrate or a transparent plastic substrate having excellent transparency, surface smoothness, ease of handling, and water resistance.

Also, according to embodiments, the first electrode 120 may simultaneously serve as an electrode and a substrate without using the substrate 110 .

For example, the first electrode 120 may be an anode.

The first electrode 120 may be made of a known electrode material used in a light emitting device, and preferably, the first electrode 120 is lithium fluoride/aluminum (LiF/Al), aluminum (Al), silver ( Ag), gold (Au), copper (Cu), palladium (Pd), platinum (Pt), magnesium (Mg), magnesium silver (Mg:Ag), ytterbium (Yb), indium tin oxide (ITO), aluminum Zinc oxide (AZO), fluorine tin oxide (FTO), indium zinc oxide (IZO), zinc oxide (ZnO), carbon nanotube (CNT), graphene, polyethylenedioxythiophene:polystyrenesulfonate (PEDOT: PSS), magnesium (Mg), ytterbium (Yb), calcium (Ca), and silver nanowires (AgNWs).

Preferably, the first electrode 120 is made of indium tin oxide (ITO), which is a transparent electrode with a large work function to facilitate hole injection into the highest occupied molecular orbital (HOMO) level of the light emitting layer 140. ) may be included.

A light emitting device according to an embodiment of the present invention includes a hole injection layer 131 formed on the first electrode 120 .

The hole injection layer 131 may appropriately select the type of hole injection material from the viewpoint of improving the light emitting efficiency and luminance of the light emitting device. For example, the hole injection layer 131 may include a conductive polymer. there is.

The conductive polymer may include at least one of poly(ethylenedioxy)thiophene (PEDOT), polyaniline, polypyrrole, polythiophene, polyacetylene, polyphenylene, polyethylene, or mixtures thereof. Preferably, the hole injection layer 131 may be formed using PEDOT alone or in a state in which PEDOT is bound to another polymer chain, such as PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate). PEDOT:PSS used as the hole injection layer 131 has excellent stability due to the strong electrostatic interaction force between PEDOT+ and PSS-, and thus has the advantage of being suitable for a solution process and a printing process.

A light emitting device according to an embodiment of the present invention includes a hole transport layer 132 formed on the hole injection layer 131 and including a thermally crosslinkable hole transport material according to an embodiment of the present invention.

A thermally crosslinkable hole transport material according to an embodiment of the present invention is represented by Formula 1 below.

[Formula 1]

(In Formula 1, X is O or S, R is a crosslinkable arylamine compound, and n is 1 to 4)

The hole transport material represented by Chemical Formula 1 may be a p-type semiconductor polymer.

As shown in Chemical Formula 1, the thermally crosslinkable hole transport material according to an embodiment of the present invention contains dibenzofuran or dibenzothiophene, and thus is rich in electrons, thereby increasing triplet energy and improving thermal stability.

The solubility of the thermally crosslinkable hole transport material according to an embodiment of the present invention may be adjusted according to the number (n) of the crosslinkable arylamine-based compound (R).

For example, in the thermally crosslinkable hole transport material according to an embodiment of the present invention, when the number (n) of the crosslinkable arylamine compound (R) increases, the number of alkyl groups of the crosslinkable arylamine compound (R) increases. Solubility can be increased because the alkyl group is lengthened.

In addition, the thermally crosslinkable hole transport material according to an embodiment of the present invention is based on the number (n) of crosslinkable reactive groups (styrene, oxetane or trifluorovinyl ether) included in the crosslinkable arylamine-based compound (R). Since the degree of crosslinking can be controlled according to the crosslinkable arylamine-based compound (R), when the number (n) of the crosslinkable arylamine-based compound (R) increases, the crosslinking forms a network to form a more rigid thin film.

In addition, in the thermally crosslinkable hole transport material according to an embodiment of the present invention, crosslinking may occur at a lower temperature when the number (n) of the crosslinkable arylamine-based compound (R) is increased.

The thermally crosslinkable hole transport material according to an embodiment of the present invention may have an asymmetric structure.

The asymmetric structure means a structure in which only one benzene ring of dibenzofuran or dibenzothiophene in Formula 1 is substituted with a crosslinkable arylamine-based compound (R).

Since the thermally crosslinkable hole transport material according to an embodiment of the present invention requires at least two crosslinking reactive groups to occur in one molecule in order for a crosslinking reaction to occur, in the case of an asymmetric structure, the crosslinkable arylamine compound (R) has two crosslinking groups Reactors may be included.

Since the thermally crosslinkable hole transport material according to the embodiment of the present invention has an asymmetric structure, the solubility of the hole transport material is improved compared to the case of a symmetric structure, enabling a high-concentration solution process, which is advantageous to the solution process.

In addition, since an asymmetric structure lowers crystallinity, an amorphous hole transport layer 132 may be formed when manufacturing a light emitting device.

In addition, the thermally crosslinkable hole transport material according to an embodiment of the present invention has an asymmetric structure, so that it can be crosslinked even at a low temperature of 170°C.

In the thermally crosslinkable hole transport material according to an embodiment of the present invention, the bandgap energy can be controlled by adjusting the position where R is bonded in Chemical Formula 1.

Therefore, the thermally crosslinkable hole transport material according to an embodiment of the present invention can prepare a hole transport material having various band gaps, HOMO and LUMO energies by adjusting the band gap energy, and when manufacturing a light emitting device, other layers ( Efficiency of the light emitting device can be improved by selecting a hole transport material having an appropriate band gap energy compared to the band gap of the layers.

In addition, the thermally crosslinkable hole transport material according to an embodiment of the present invention may function as a hole transport layer 132 and an electron blocking layer by controlling the position where R is bonded in Formula 1. can

In addition, since the thermally crosslinkable hole transport material according to an embodiment of the present invention has a different steric effect depending on the position where R in Formula 1 is bonded, the heat treatment temperature for crosslinking can be adjusted.

In addition, since the degree of crystallinity of the thermally crosslinkable hole transport material according to an embodiment of the present invention is adjusted according to the position where R is bonded in Formula 1, the surface uniformity of the hole transport layer 132 can be controlled. there is.

In the case of dibenzothiophene in which S is used as X, the hole transport material represented by Chemical Formula 1 has a high molecular weight, and thermal stability may be improved compared to dibenzofuran in which O is used as X.

Since the thermally crosslinkable hole transport material according to an embodiment of the present invention includes a crosslinkable arylamine-based compound, when cross-linking is performed by heat treatment, the hole transport layer 132 is insoluble and insoluble ( Since it has an infusible property, it does not dissolve in the solution for forming the light emitting layer 140, and it is possible to prevent the hole transport layer 132 and the light emitting layer 140 from being mixed.

More specifically, since the thermally crosslinkable hole transport material according to the embodiment of the present invention has an insoluble property, it is not dissolved in the solution for forming the light emitting layer 140, so that pin holes or trap sites are formed on the surface. does not occur, and a uniform surface can be maintained, so that holes can be transported efficiently.

In addition, since the thermally crosslinkable hole transport material according to an embodiment of the present invention has high thermal characteristics because it has insoluble properties, a layer crosslinked at the heat treatment temperature of the upper layer (light emitting layer 140) when manufacturing a light emitting device using a solution process. (Hole transport layer 132) is not melted or thermally decomposed, so a stable thin film can be formed.

Cross-linking includes photo cross-linking and thermal cross-linking. Photo cross-linking uses photoinitiators. Since crosslinking proceeds, by-products may be generated during the crosslinking reaction, which may shorten the lifespan of the light emitting device. In addition, the photoinitiator may remain as a residue in the thin film and act as a trap site when driving the light emitting device, thereby reducing the efficiency of the light emitting device.

However, since the thermal cross-linkable hole transport material according to the embodiment of the present invention is capable of thermal cross-linking, it can solve the problem caused by the photoinitiator, and it is less difficult to manufacture a light emitting device than light-induced cross-linking. It has the advantage of being easy.

The cross-linkable arylamine-based compound used as R in Formula 1 is a reactive group capable of thermal cross-linking, and the cross-linkable arylamine-based compound includes a styrene unit, an oxetane unit and A trifluorovinyl ether unit may be included.

In addition, the heat treatment temperature may be adjusted according to the type of a crosslinkable reactive group included in the crosslinkable arylamine compound (R).

When the crosslinkable reactive group included in the crosslinkable arylamine compound (R) is styrene, crosslinking can occur at a temperature of 150 ° C to 300 ° C, and in the case of oxetane, a temperature higher than that of styrene, 200 ° C to 350 ° C Crosslinking may occur at a temperature, and in the case of trifluoro ether, crosslinking may occur at a temperature of 150° C. to 300° C.

In addition, the thermally crosslinkable hole transport material according to an embodiment of the present invention is crosslinked at the lowest heat treatment temperature (150 ° C to 250 ° C) when a styrene unit is used as the crosslinkable arylamine compound (R) It can be, and if an oxetane unit is used as the crosslinkable arylamine compound (R), crosslinking can be performed at the highest heat treatment temperature (200 ° C to 350 ° C), and the crosslinkable arylamine compound ( The use of trifluorovinyl ether units as R) allows crosslinking at high temperatures (150° C. to 300° C.) and longest heat treatment times (1 hour to 2 hours).

The styrene unit may be selected from the group represented by Formula 2-1 to Formula 2-30 below.

(In Chemical Formulas 2-1 to 2-30, R' is an alkyl group)

Here, the styrene unit represented by Formula 2-1 is N,N-diphenyl-4-vinylaniline, Formula 2-2 is 4-methoxy-N-phenyl-N-(4-vinylphenyl)aniline, and Formula 2-3 is 3 -methoxy-N-phenyl-N-(4-vinylphenyl)aniline, formula 2-4 is 2-methoxy-N-phenyl-N-(4-vinylphenyl)aniline, 2-5 is N-phenyl-4-vinyl- N-(4-vinylphenyl)aniline, Formula 2-6 is N-phenyl-4-vinylaniline, Formula 2-7 is 4-methoxy-N-(4-vinylphenyl)aniline, Formula 2-8 is 3-methoxy-N -(4-vinylphenyl)aniline, Formula 2-9 is 2-methoxy-N-(4-vinylphenyl)aniline, Formula 2-10 is bis(4-vinyl phenyl)amine, Formula 2-11 is 4-methyl-N -phenyl-N- (4-vinylphenyl)aniline, Formula 2-12 is 3-methyl-N-phenyl-N- (4-vinylphenyl)aniline, Formula 2-13 is 2-methyl-N-phenyl-N- ( 4-vinylphenyl)aniline, Formula 2-14 is 4-methyl-N-(4-vinylphenyl)aniline, Formula 2-15 is 3-methyl-N-(4-vinylphenyl)aniline, Formula 2-16 is 2-methyl -N- (4-vinylphenyl) aniline, Formula 2-17 is 4-ethyl-N-phenyl-N- (4-vinylphenyl) aniline, Formula 2-18 is 3-ethyl-N-phenyl-N- (4- vinylphenyl)aniline, Formula 2-19 is a 2-ethyl-N-phenyl-N-(4-vinylphenyl)aniline derivative, Formula 2-20 is a 4-ethoxy-N-phenyl-N-(4-vinylphenyl)aniline derivative, Formula 2-21 is 3-ethoxy-N-phenyl-N-(4-vinylphenyl)aniline derivative, Formula 2-22 is 2-ethoxy-N-phenyl-N-(4-vinylphenyl)aniline derivative, Formula 2-23 is 4-ethyl- N- (4-vinylphenyl)aniline derivative, formula 2-24 is 3-ethyl-N- (4-vinylphenyl)aniline derivative, formula 2-25 is 2-ethyl-N- (4-vinylphenyl)aniline derivative, formula 2 -26 is 3-ethoxy-N- (4-vinylphenyl)aniline derivative, formula 2-27 is 4-ethoxy-N- (4-vinylphenyl)aniline derivative, formula 2-28 is 2-ethoxy-N- (4- A vinylphenyl)aniline derivative, Formula 2-29 is a N,N-diphenyl-4-vinylaniline derivative, and Formula 2-30 is an N-phenyl-4-vinylaniline derivative.

During the crosslinking reaction, the styrene units can be rapidly polymerized by simply heating without using an initiator to generate radicals.

also, The thermally crosslinkable hole transport material according to an embodiment of the present invention can lower the heat treatment temperature by using a styrene unit as the crosslinkable arylamine-based compound (R), and preferably, at a temperature of 250 ° C. It can be cross-linked with a heat treatment of 30 minutes.

The oxetane unit may be selected from the group represented by Formula 3-1 to Formula 3-37 below.

(In Chemical Formulas 3-1 to 3-37, R' is an alkyl group)

Here, the oxetane unit represented by Formula 3-1 is 4-((3-ethyloxetan-3-yl)methoxy)-N,N-diphenylaniline, and Formula 3-2 is 4-((3-ethyloxetan-3-yl )methoxy)-N-(4-methoxyphenyl)-N-phenylaniline, formula 3-3 is N-(4-((3-ethyloxetan-3-yl)methoxy)phenyl)-3-methoxy-N-phenylaniline, formula 3-4 is N-(4-((3-ethyloxetan-3-yl)methoxy)phenyl)-2-methoxy-N-phenylaniline, Formula 3-5 is 4-((3-ethyloxetan-3-yl)methoxy )-N-(4-((3-ethyloxetan-3-yl)methoxy)phenyl)-N-phenylaniline, 3-6 is 4-((3-ethyloxetan-3-yl)methoxy)-N-phenylaniline, chemical formula 3-7 is 4-((3-ethyloxetan-3-yl)methoxy)-N-(4-methoxyphenyl)aniline, Formula 3-8 is N-(4-((3-ethyloxetan-3-yl)methoxy) phenyl)-3-methoxyaniline, Formula 3-9 is N-(4-((3-ethyloxetan-3-yl)methoxy)phenyl)-2-methoxyaniline, Formula 3-10 is bis(4-((3-ethyloxetan -3-yl)methoxy)phenyl)amine, Formula 3-11 is 4-((6-((3-ethyloxetan-3-yl)methoxy)hexyl)oxy)-N,N-diphenylaniline, Formula 3-12 is 4-(((3-ethyloxetan-3-yl)methoxy)methoxy)-N-phenyl-N-(p-tolyl)aniline derivative, Formula 3-13 is N-(4-(((3-ethyloxetan-3 -yl) methoxy) methoxy) phenyl) -3-methyl-N-phenylaniline derivative, Formula 3-14 is N -(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)-2-methyl-N-phenylaniline derivative, Formula 3-15 is 4-(((3-ethyloxetan-3-yl)methoxy )methoxy)-N-(p-tolyl)aniline derivative, formula 3-16 is N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)-3-methylaniline derivative, formula 3- 17 is N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)-2-methylaniline derivative, Formula 3-18 is 4-(((3-ethyloxetan-3-yl)methoxy) methoxy)-N-(4-methoxyphenyl)-N-phenylaniline derivative, formula 3-19 is N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)-3-methoxy-N- A phenylaniline derivative, Formula 3-20 is N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)-2-methoxy-N-phenylaniline derivative, Formula 3-21 is 4-((( 3-ethyloxetan-3-yl)methoxy)methoxy)-N-(4-methoxyphenyl)aniline derivative, Formula 3-22 is N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl) -3-methoxyaniline derivative, formula 3-23 is N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)-2-methoxyaniline derivative, formula 3-24 is 4-ethyl-N- (4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)-N-phenylaniline derivative, Formula 3-25 is 3-ethyl-N-(4-(((3-ethyloxetan-3-yl )methoxy)methoxy)pheny l) -N-phenylaniline derivative, formula 3-26 is 2-ethyl-N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)-N-phenylaniline derivative, formula 3-27 4-ethyl-N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)aniline derivative, Formula 3-28 is 3-ethyl-N-(4-(((3-ethyloxetan- 3-yl)methoxy)methoxy)phenyl)aniline derivative, formula 3-29 is 2-ethyl-N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)aniline derivative, formula 3- 30 is 4-ethoxy-N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)-N-phenylaniline derivative, Formula 3-31 is 3-ethoxy-N-(4-(( (3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)-N-phenylaniline derivative, Formula 3-32 is 2-ethoxy-N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy) phenyl) -N-phenylaniline derivative, formula 3-33 is 4-ethyl-N- (4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)aniline derivative, formula 3-34 is 3-ethyl -N-(4-(((3-ethyloxetan-3-yl)methoxy)methoxy)phenyl)aniline derivative, Formula 3-35 is 2-ethyl-N-(4-(((3-ethyloxetan-3-yl )methoxy)methoxy)phenyl)aniline derivative, formula 3-36 is 4-(((3-ethyloxetan-3-yl)methoxy)methoxy)-N,N-diphenylaniline derivative, formula 3-37 is 4-((( 3-ethyloxetan-3-yl)methoxy)methoxy)- It is an N-phenylaniline derivative.

Since the oxetane unit is completely stable to the nucleophile during synthesis of the hole transport material, the polymerization process of the thermally crosslinkable hole transport material according to embodiments of the present invention comprising an oxetane unit is accompanied by very low volumetric shrinkage to form a film. of microcracks can be avoided.

The trifluorovinyl ether unit may be selected from the group represented by Formula 4-1 to Formula 4-30 below.

(In Chemical Formulas 4-1 to 4-30, R' is an alkyl group)

Here, the trifluorovinyl ether unit represented by Formula 4-1 is N,N-diphenyl-4-((1,2,2-trifluorovinyl)oxy)aniline, and Formula 4-2 is 4-methoxy-N-phenyl -N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline, Formula 4-3 is 3-methoxy-N-phenyl-N-(4-((1,2,2-trifluorovinyl) oxy)phenyl)aniline, Formula 4-4 is 2-methoxy-N-phenyl-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline, Formula 4-5 is N-phenyl-4 -((1,2,2-trifluorovinyl)oxy)-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline, 4-6 is N-phenyl-4-((1,2 ,2-trifluorovinyl)oxy)aniline, Formula 4-7 is 4-methoxy-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline, Formula 4-8 is 3-methoxy-N- (4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline, 4-9 is 2-methoxy-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline, 4- 10 is bis(4-((1,2,2-trifluorovinyl)oxy)phenyl)amine, Formula 4-11 is 4-methyl-N-phenyl-N-(4-((1,2,2-trifluorovinyl) oxy)phenyl)aniline, Formula 4-12 is 3-methyl-N-phenyl-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline, Formula 4-13 is 2-methyl-N -phenyl-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline, Formula 4-14 is 4-methyl-N-(4-((1,2,2-trifluorovinyl)oxy) phenyl)a Niline, Formula 4-15 is 3-methyl-N- (4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline, Formula 4-16 is 2-methyl-N-(4-((1, 2,2-trifluorovinyl)oxy)phenyl)aniline, Formula 4-17 is 4-ethyl-N-phenyl-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline derivative, Formula 4- 18 is a 3-ethyl-N-phenyl-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline derivative, Formula 4-19 is 2-ethyl-N-phenyl-N-(4- ((1,2,2-trifluorovinyl)oxy)phenyl)aniline derivative, formula 4-20 is 4-ethyl-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline derivative, formula 4 -21 is a 3-ethyl-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline derivative, Formula 4-22 is 2-ethyl-N-(4-((1,2,2 -trifluorovinyl)oxy)phenyl)aniline derivative, Formula 4-23 is 4-ethoxy-N-phenyl-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline derivative, Formula 4-24 is 3-ethoxy-N-phenyl-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline derivative, formula 4-25 is 2-ethoxy-N-phenyl-N-(4-(( 1,2,2-trifluorovinyl)oxy)phenyl)aniline derivative, formula 4-26 is 4-ethoxy-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline derivative, formula 4-27 Silver 3-ethoxy-N-(4-((1,2,2-trifluorovinyl)oxy)phenyl)aniline derivative, Formula 4-28 is 2-ethoxy-N-(4-((1,2 ,2-trifluorovinyl)oxy)phenyl)aniline, Formula 4-29 is N,N-diphenyl-4-((1,2,2-trifluorovinyl)oxy)aniline derivative, Formula 4-30 is N-phenyl-4- ((1,2,2-trifluorovinyl)oxy)aniline derivative.

Since the thermally crosslinkable hole transport material according to an embodiment of the present invention including a trifluorovinyl ether unit forms an aromatic perfluorocyclobutane (PFCB) ether-bonded polymer through a crosslinking reaction, it has a high glass transition temperature and a high may have thermal stability.

In addition, since the polymerization of the trifluorovinyl ether unit proceeds through a one-step polymerization reaction, a longer polymerization reaction time may be required than that of the styrene unit and the oxetane unit.

For example, a thermally crosslinkable hole transport material according to an embodiment of the present invention including a styrene unit and an oxetane unit requires a heat treatment time of 30 minutes, but an embodiment of the present invention including a trifluorovinyl ether unit A thermally crosslinkable hole transport material according to may require a heat treatment time of 1 hour to 2 hours.

Preferably, the thermally cross-linkable hole transport material represented by Formula 1 may be represented by Formula 5 below.

[Formula 5]

(In Formula 1, X is O or S)

In the cross-linkable hole transport material represented by Formula 5, when O is used as X, the cross-linkable hole transport material represented by Formula 5 is 4-(dibenzo[b,d ]furan-n-yl)-N,N-bis(4-vinylphenyl)aniline. At this time, 4-(dibenzo[b,d]furan-n-yl)-N,N-bis(4-vinylphenyl)aniline is N-phenyl-4-vinyl-N-(4-vinylphenyl)aniline in Formula 5 Depending on the position to be substituted, n = 1, 2, 3, 4 may be.

In the cross-linkable hole transport material represented by Formula 5, when S is used as X, the cross-linkable hole transport material represented by Formula 5 is 4-(dibenzo[b,d ]thiophen-n-yl)-N,N-bis(4-vinylphenyl)aniline. At this time, 4-(dibenzo[b,d]thiophen-n-yl)-N,N-bis(4-vinylphenyl)aniline is N-phenyl-4-vinyl-N-(4-vinylphenyl)aniline in Formula 5 Depending on the position to be substituted, n = 1, 2, 3, 4 may be.

When the material represented by Chemical Formula 5 is used as the thermally crosslinkable hole transport material according to an embodiment of the present invention, the heat treatment temperature for crosslinking can be very low to 170° C., and the thermal crosslinkable hole transport material according to an embodiment of the present invention can be very low. A light emitting device including a material (eg, a blue OLED device) emits light of a shorter wavelength in electroluminescence compared to a light emitting device that does not include the thermally crosslinkable hole transport material according to an embodiment of the present invention, resulting in more blue light. can represent

Depending on the embodiment, the hole transport layer 132 may be a mixture of thermally crosslinkable hole transport materials according to an embodiment of the present invention having different crosslinkable arylamine-based compounds (R), or a thermally crosslinkable hole transport material according to an embodiment of the present invention. The hole transport ability of the light emitting device may be adjusted or the hole transport capability may be balanced by using a mixture of the transport material and the existing commercially available hole transport material.

In addition, the hole transport layer 132 may further include a p-dopant to improve hole transport capability or prevent electrons from moving from the light emitting layer to the hole transport layer, and the p-dopant is NPD-9. (Novaled), TCNQ (F6-TCNNQ, F4-TCNQ, etc.) and TMOs (Transition-metal oxides, ReO ₃ , MoO ₂ , etc.).

A light emitting device according to an embodiment of the present invention includes a light emitting layer 140 formed on the hole transport layer 132 .

In the light emitting layer 140, holes injected from the first electrode 120 and passed through the hole transport layer 132 and electrons injected from the second electrode 160 and passed through the electron transport layer 150 recombine to form excitons. A layer that generates light and emits light while the generated excitons change from an excited state to a ground state, and may be composed of a single layer or a multi-layer.

The light emitting layer 140 may be a green light emitting layer, a red light emitting layer, or a blue light emitting layer, preferably a blue light emitting layer.

The light emitting layer 140 may include organic compounds or quantum dots.

When the light emitting layer 140 is the organic light emitting layer 140 containing an organic compound, the light emitting device according to the embodiment of the present invention may be an organic light emitting device, and the light emitting layer 140 is the quantum dot light emitting layer 140 including quantum dots. In this case, the light emitting device according to the embodiment of the present invention may be a quantum dot light emitting device.

When the emission layer 140 includes an organic compound, the organic emission layer 140 may emit phosphorescent light due to triplet excitons.

Phosphorescence used as the organic light emitting layer 140 may have a very high quantum efficiency compared to fluorescence, and thus the efficiency of the organic light emitting device may be increased.

In addition, the organic light emitting layer 140 may improve the efficiency of the organic light emitting device by improving the internal quantum efficiency of the organic light emitting device by using a phosphorescent material that emits phosphorescent light by triplet excitons.

The light emitting material included in the organic light emitting layer 140 may include a host for charge (holes or electrons) transfer and a phosphorescent dopant for phosphorescent properties. Preferably, a blue phosphorescent dopant may be used as the phosphorescent dopant.

The host is conventional, and the host is 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole ; BCzPh), 1,3-N,N-dicarbazolebenzene (mCP), 4,4'-N,N-dicarbazolbiphenyl (CBP), 1,3,5-tris(carbazol-9-yl ) Benzene (1,3,5-Tris (carbazole-9-yl) benzene; TCP), TCTA, 4,4'-bis (carbazole-9-yl) -2,2'-dimethylbiphenyl (4, 4'-Bis(carbazole-9-yl)-2,2'-dimethylbipheyl; CDBP), 2,7-bis(carbazole-9-yl)-9,9-dimethylfluorene (2,7-Bis( carbazole-9-yl) -9,9-dimethylfluorene (DMFL-CBP), 2,2',7,7'-tetrakis (carbazol-9-yl) -9,9-spirofluorene (2, 2',7,7'-Tetrakis(carbazole-9-yl)-9,9-spirofluorene; Spior-CBP), DPEPO, 4'-(9H-carbazole-9-yl)biphenyl-3,5- Dicarbonitrile (4'-(9H-carbazol-9-yl)biphenyl-3,5-dicarbonitrile; PCzB-2CN), 3'-(9H-carbazol-9-yl)biphenyl-3,5-dicarbonitrile Bonitrile (3'-(9H-carbazol-9-yl)biphenyl-3,5-dicarbonitrile; mCzB-2CN) and 3,6-bis(carbazol-9-yl)-9-(2-ethyl-hexyl ) -9H-carbazole (3,6-Bis (carbazole-9-yl) -9- (2-ethyl-hexyl) -9H-carbazole; TCz1), (4,4'-bis (2,2-di Phenyl-ethen-1-yl) diphenyl (DPVBi), bis (styryl) amine (DSA) based, bis (2-methyl-8-quinolinolato) (triphenylsiloxy) aluminum (III) (SAlq ), bis(2-methyl-8-quinolinolato)(para-phenolato)aluminum(III)(BAlq), 3-(biphenyl-4-yl)-5-(4-dimethylamino)4- (4-ethylphenyl)-1,2,4-triazole (p-EtTAZ), 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2, 4 -triazole (TAZ), 2,2',7,7'-tetrakis (bi-phenyl-4-yl) -9,9'-spirofluorene (Spiro-DPVBI), tris (para-ter-phenyl -4-yl) amine (p-TTA), 5,5-bis (dimethyl boril) -2,2-bithiophene (BMB-2T) and perylene may contain at least one of .

As a phosphorescent dopant usable for the organic light emitting layer 140, for example, as a blue light emitting material, perylene, 4,4'-bis[4-(di-p-tolylamino)styryl ]Biphenyl (4,4'-Bis[4-(di-p-tolylamino)styryl]biphenyl; DPAVBi), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino) Styryl] stilbene (4-(Di-p-tolylamino)-4-4'-[(di-p-tolylamino)styryl]stilbene; DPAVB), 4,4'-bis[4-(diphenylamino) Styryl] biphenyl (4,4'-Bis [4- (diphenylamino) styryl] biphenyl; BDAVBi), 2,5,8,11-tetra-tert-butylperylene (2,5,8,11-Tetra -tetr-butylperylene; TBPe), Bepp2, 9-(9-phenylcarbazole-3-yl)-10-(naphthalen-1-yl)anthracene (9-(9-Phenylcarbazole-3-yl)-10-( naphthalene-1-yl)anthracene; PCAN), mer-tris(1-phenyl-3-methylimidazoline-2-ylidene-C,C(2)'iridium(III)(mer-Tris(1-phenyl -3-methylimidazolin-2-ylidene-C,C(2)'iridium(III), mer-Ir(pmi)3), pac-tris(1,3-diphenyl-benzimidazolin-2-ylidene -C,C(2)'iridium((III)(fac-Tris(1,3-diphenyl-benzimidazolin-2-ylidene-C,C(2)'iridium(III), fac-Ir(dpbic)3) , Bis (3,4,5-trifluoro-2- (2-pyridyl) phenyl- (2-carboxypyridyl) iridium (III) (Bis (3,4,5-trifluoro-2- (2- pyridyl)phenyl-(2-carboxypyridyl)iridium(III); Ir(tfpd)2pic), tris(2-(4,6-difluorophenyl)pyridine)iridium(?Ir(Fppy)3) and bis[2 -(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III)(Bis[2-(4,6-difluorophenyl)p yridinato-C2,N](picolinato)iridium(III); FIrpic) may include at least one of them.

In addition, as a green light emitting material, tris(2-phenylpyridinato-N,C2')iridium(III) (Ir(ppy) ₃ ), bis(2-phenylpyridinato-N,C2')iridium (III) acetylacetonate (Ir(ppy) ₂ (acac)), bis(1,2-diphenyl-1H-benzimidazolato)iridium(III)acetylacetonate (Ir(pbi) ₂ (acac) ) and bis(benzo[h]quinolinato)iridium(III)acetylacetonate (Ir(bzq) ₂ (acac)).

In addition, as a yellow light emitting material, bis(2,4-diphenyl-1,3-oxazolato-N,C2')iridium(III)acetylacetonate (Ir(dpo) ₂ (acac)), bis [2-(4′-perfluorophenylphenyl)pyridinato]iridium(III)acetylacetonate (Ir(p-PF-ph) ₂ (acac)) and bis(2-phenylbenzothiazolato-N , C2') iridium (III) acetylacetonate (Ir (bt) ₂ (acac)) may include at least one.

In addition, as an orange light emitting material, tris(2-phenylquinolinato-N,C2')iridium(III) ( Ir(pq) _-3 ) and bis(2-phenylquinolinato-N,C2') It may include at least one of iridium (III) acetylacetonate (Ir(pq) ₂ (acac)).

In addition, as a red light emitting material, bis[2-(2'-benzo[4,5-α]thienyl)pyridinato-N,C3']iridium(III)acetylacetonate (Ir(btp) ₂ ( acac)), bis(1-phenylisoquinolinato-N,C2′)iridium(III)acetylacetonate (Ir(ｐｉｑ) ₂ (acac)), (acetylacetonate)bis[2,3-bis( 4-fluorophenyl)quinoxalinato]iridium(III) (Ir(Fdpq) ₂ (acac)) and 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum ( II) (PtOEP).

In addition, tris (acetylacetonate) (monophenanthroline) terdium (III) (Tb (acac) ₃ (Phen)), tris (1,3-diphenyl-1,3-propanedioate) (monophenanate) throline) europium(III) (Eu(DBM) ₃ (Phen)) or tris[1-(2-thenoyl)-3,3,3-trifluoroacetonate](monophhenanthroline)europium(III )(Eu(TTA) ₃ (Phen)) can be used as a phosphorescent compound because it emits light from rare earth metal ions (electron transfer between different multiplicities).

Also, DCM1 (4-dicyanomethylene-2-methyl-6-(para-dimethylaminostilyl)-4H-pyran), dicyanomethylene-2-methyl-6-(juloridin-4-yl-vinyl) )-4H-pyran), dicyanomethylene)-2-methyl-6-(1,1,7,7-tetramethyljuloridyl-9-enyl)-4H-pyran), dicyanomethylene)-2- tert-butyl-6-(1,1,7,7-tetramethyljuloridyl-9-enyl)-4H-pyran) and dicyanomethylene)-2-isopropyl-6-(1,1,7, 7-tetramethyljuloridyl-9-enyl) -4H-pyran).

When the light emitting layer 140 is the quantum dot light emitting layer 140 including quantum dots, the quantum dots may be formed using inorganic or semiconductor materials. Suitable semiconductor materials may include at least one of group II-VI, III-V, IV-VI, and IV semiconductors. Specifically, semiconductor materials include Si, Ge, Sn, Se, Te, B, C (including diamond), P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si3N4, Ge3N4, Al2O3, (Al, Ga, In) ₂ (S , Se, Te) ₃ , Al ₂ CO and combinations of two or more semiconductors may be included, but are not limited thereto.

In addition, quantum dots may have a core-shell structure. Materials capable of forming core-shell quantum dots include Si, Ge, Sn, Se, Te, B, C (including diamond), P, Co, Au, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si ₃ N ₄ , Ge ₃ N ₄ , Al ₂ O ₃ , (Al, Ga, In) ₂ (S, Se, Te) ₃ , Al ₂ CO, ZnS, ZnSe, and any combination of two or more materials may be included, but are not limited to It is not.

Preferred, core-shell quantum dots may include at least one of ZnSe/Zns, CdSe/ZnS, InP/ZnS, PbSe/PbS, CdSe/CdS, CdTe/CdS and CdTe/ZnS, but are not limited thereto. not. Meanwhile, from the point of view of manufacturing an environmentally friendly light emitting device, non-cadmium (Cd-free) quantum dots may be used.

A light emitting device according to an embodiment of the present invention includes an electron transport layer 150 formed on the light emitting layer 140 .

The electron transport layer 150 formed on the light emitting layer 140 serves to move electrons injected from the second electrode 160 to the light emitting layer 140 .

The electron transport layer 150 is Alq ₃ (Tris (8-hydroxyquinoline) Aluminum), PCBM (Phenyl-C61-butyric acid methyl ester), TAZ (3- (4-biphenyl) -4-phenyl-5- (4-tertbutylphenyl )-1,2,4-triazole), TPBi(2,2′,2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)), BPhen(4,7 -Diphenyl-1,10-phenanthroline), BAlq (Bis(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum), TSPO1 (diphenylphosphine oxide-4-(triphenylsilyl)phenyl), B ₄ PyMPM [bis- 4,6-(3,5-di-4-pyridylphenyl)-2-methylpyrimidine], TmPyPB (Two pyridine-containing triphenylbenzene derivatives of 1,3,5-tri(m-pyrid- 3-yl-phenyl)benzene) , 3TPYMB (tris-[3-(3-pyridyl)mesityl] borane), TpPyPB (1,3,5-tri( p -pyrid-3-yl-phenyl)benzene), TPPB (1,3,5-tris At least one of [3,5-bis(3-pyridinyl)phenyl]benzene) and BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) may be included.

According to an embodiment, the electron transport layer 150 may further include an n-dopant. For example, the n-dopants may be independently selected from Li complexes, LiF, CsF, Li ₂ CO ₃ , Na ₂ CO ₃ , Al ₂ O ₃ , SiO ₂ , Si ₃ N ₄ , Cs ₂ CO ₃ , K ₂ CO ₃ , Rb ₂ CO ₃ , Ba ₂ CO ₃ , pyronin B, DMC (decamethylcobaltocene), BEDTTTF (bis(ethylenedithio)-tetrathiafulvalene), rhodamin B, TMBI (1,2,3-trimethyl-2-phenyl-2,3-dihydro-1H-benzoimidazole) , DMBI (1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzoimidazole), Cl-DMBI (dichlorophenyl-1,3-dimethyl-2,3-dihydro-1H-benzo imidazole), N-DMBI (4-(1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)-phenyl)-dimethyl-amine), OH-DMBI (2-( 1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)-phenol), PTCDI-C13 (N,N'-ditridecylperylene-3,4:9,10- tetracarboxylic diimide) and F-PTCDI-C4 (N,N'-dibutyl-1,7-difluoroperylene-3,4:9,10-tetracarboxylic diimide). may contain one.

The n-type dopant may be formed on the entire thickness of the electron transport layer 150 or included only in a portion of the entire thickness.

In the light emitting device according to the embodiment of the present invention, electron transport capability may be improved by further including an n-dopant in the electron transport layer 150 .

For example, when an alkali metal such as Cs is added to the electron transport layer 150, the electron injection barrier between the second electrode (eg cathode) and the light emitting layer 140 may be reduced, and the alkali metal and the second electrode (eg; An alloy may be formed between the cathodes) to have a work function smaller than that of an alkali metal single material, thereby reducing an electron injection barrier.

A light emitting device according to an embodiment of the present invention includes a second electrode 160 formed on the electron transport layer 150 .

The second electrode 160 may be provided to face the first electrode 120, and for example, the second electrode 160 may be a cathode.

The second electrode 160 is commonly connected to a power supply voltage to inject electrons into the electron transport layer 150 .

The second electrode 160 may be made of a known electrode material used in a light emitting device, and preferably, the second electrode 160 is lithium fluoride/aluminum (LiF/Al), aluminum (Al), silver (Ag), gold (Au), copper (Cu), palladium (Pd), platinum (Pt), magnesium (Mg), magnesium silver (Mg:Ag), ytterbium (Yb), indium tin oxide (ITO), Aluminum zinc oxide (AZO), fluorine tin oxide (FTO), indium zinc oxide (IZO), zinc oxide (ZnO), carbon nanotube (CNT), graphene, polyethylenedioxythiophene:polystyrenesulfonate (PEDOT) :PSS), magnesium (Mg), ytterbium (Yb), calcium (Ca), and silver nanowires (AgNWs).

Preferably, as the second electrode 160, a metal electrode having a low work function and excellent internal reflectance may be used to easily inject electrons into the highest occupied molecular orbital (HOMO) level of the light emitting layer 140, , As the second electrode 160, lithium fluoride/aluminum (LiF/Al), aluminum (Al), silver (Ag), gold (Au), copper (Cu), palladium (Pd), platinum (Pt), At least one of magnesium (Mg), magnesium silver (Mg:Ag), and ytterbium (Yb) may be included.

The first electrode layer 120 and the second electrode layer 160 are electrically separated from each other and provide power to the light emitting device. In addition, the first electrode layer 120 and the second electrode layer 160 may increase light efficiency by reflecting light generated from the light emitting device, and may serve to discharge heat generated from the light emitting device to the outside.

2 is a flowchart illustrating a method of manufacturing a light emitting device according to an embodiment of the present invention.

FIG. 2 may include the same components as the thermally crosslinkable hole transport material according to the embodiment of the present invention described in FIG. 1 and the light emitting device according to the embodiment of the present invention including the same, and the same components will be described in detail. to be omitted.

First, the method of manufacturing a light emitting device according to an embodiment of the present invention proceeds to forming a first electrode on a substrate (S110).

The first electrode is spin-coated, slit dye coating, ink-jet printing, spray coating, dip coating, thermal evaporation , sol-gel, spray pyrolysis, sputtering, chemical vapor deposition (CVD), atomic layer deposition (ALD) and e-beam deposition evaporation) may be formed using any one of the processes.

Depending on the embodiment, the first electrode may be formed using a coating method such as printing a paste metal ink in which a binder is mixed with metal flakes or particles, and the electrode is formed. It is not limited to this as long as it can be done.

According to the embodiment, the manufacturing method of the light emitting device according to the embodiment of the present invention proceeds with the step of forming the first electrode on the substrate (S110), and then the surface of the first electrode is treated with ultraviolet-ozone (UV-Ozone treatment) step.

The substrate on which the first electrode is formed is put into a vacuum chamber by UV-Ozone treatment and undergoes a UV ozone cleaning process. In this process, oxygen gas is supplied into the chamber. The substrate may be cleaned by ozone generated by reacting oxygen gas with ultraviolet light by operating a UV lamp while maintaining a degree of vacuum in the chamber at about (2 to 3) * 10 ^-1 torr.

Accordingly, the residual organic matter on the surface of the first electrode can be removed, thereby increasing the efficiency and stability of the light emitting device.

In addition, the substrate on which the first electrode is formed can increase the work-function of the first electrode and descum by UV-Ozone treatment.

In the method of manufacturing a light emitting device according to an embodiment of the present invention, a step of forming a hole injection layer on the first electrode (S120) is performed.

The hole injection layer is formed by using any one solution process of spin-coating, slit dye coating, ink-jet printing, spray coating, and dip coating. can be formed using

Preferably, the hole injection layer may be formed using spin coating, which is a method in which a certain amount of solution is dropped and the substrate is rotated at high speed to coat the solution with centrifugal force.

Since the hole injection layer is formed by a solution process, a large-area process is possible and process time can be shortened.

Thereafter, the method of manufacturing a light emitting device according to an embodiment of the present invention includes coating a hole transport solution including a thermally cross-linkable hole transport material according to an embodiment of the present invention on the hole injection layer ( S130) proceeds.

The hole transport solution may include a thermally cross-linkable hole transport material and a solvent according to an embodiment of the present invention. Since the cross-linkable hole transport material according to the embodiment of the present invention has been described in FIG. 1, it will be omitted.

The solvent is methanol, ethanol, isopropyl alcohol, acetone, butanol, dimethylformamide, dimethyl sulfoxide, water, acetonitrile, octane, heptane, nonane, hexane, xylene, toluene, chlorobenzene, 1,2-dichlorobenzene , It may include at least one of chloroform and cyclohexane.

The thickness of the hole transport layer may be adjusted according to the concentration of the hole transport solution, and the hole transport capability may be controlled according to the thickness of the hole transport layer. More specifically, the light emitting device exhibits high efficiency when the electron and hole injection abilities are similar when driven, and the electron and hole injection abilities may be controlled according to the thickness of the hole transport layer.

The concentration of the hole transport solution may be 1 mg/ml to 30 mg/ml, preferably, the concentration of the hole transport solution may be 4 mg/ml, and if the concentration of the hole transport layer is out of the above range, the light emitting layer The efficiency of the light emitting device may be reduced because the difference in injection capability of holes and electrons directed toward the light emitting device is increased.

The hole transport solution is a solution process of any one of spin-coating, slit dye coating, ink-jet printing, spray coating, and dip coating. can be coated using

Preferably, the hole transport solution can be coated using spin coating, which is a method in which a certain amount of the solution is dropped and the substrate is rotated at high speed to coat the solution with centrifugal force.

Since the hole transport layer is formed by a solution process, a large-area process is possible and process time can be shortened.

Thereafter, the method for manufacturing a light emitting device according to an embodiment of the present invention includes heat-treating the hole transport solution coated on the hole injection layer to form a hole transport layer including a thermally crosslinkable hole transport material according to an embodiment of the present invention. Step S140 is performed.

The heat treatment may be performed at a temperature of 150 ° C to 350 ° C, and if the heat treatment temperature is less than 150 ° C, the thermally crosslinkable hole transport material is not completely crosslinked, and there is a problem of melting by the light emitting layer solution, and if the heat treatment temperature exceeds 350 ° C, the high temperature There is a problem that the lower layer (eg, the hole injection layer) is damaged by the.

The heat treatment temperature can be controlled according to the molecular structure of the thermally crosslinkable hole transport material.

In the manufacturing method of the light emitting device according to an embodiment of the present invention, the hole transport material coated on the hole injection layer may be cross-linked by heat-treating the hole transport solution coated on the hole injection layer.

When the thermally crosslinkable hole transporting material contains styrene units, the thermally crosslinkable hole transporting material may be crosslinked by radical polymerization.

Styrene units may preferably be crosslinked by thermal polymerization among several types of radical polymerization reactions. First, when heat is applied to the hole transport solution coated on the hole injection layer, radicals may be generated from the monomer. Since radicals are unstable because they have only one electron, they take one electron to achieve a stable state. Therefore, the pi electrons of the C=C double bond in vinyl can easily react with radicals, so when a radical comes near the double bond, the double bond One electron in a bond can react with a radical. That is, the thermally crosslinkable hole transport material can be polymerized by repeating a process in which a radical generated by heat attacks a vinyl monomer and forms a new radical containing one molecule of the monomer, thereby being crosslinked.

When the thermally crosslinkable hole transporting material contains an oxetane unit, the thermally crosslinkable hole transporting material can be crosslinked by cationic ring-opening polymerization.

Oxetane units can be cross-linked in a ring-opening polymerization reaction in which the ring can be opened by an initiator and polymerized. For example, in the case of an oxetane unit, a proton is received from PSS of PEDOT:PSS, which is a lower layer (e.g., a hole injection layer), and the oxetane ring is opened, and the cationic end group generated at this time attacks the oxetane ring, thereby breaking the ring. It can be polymerized by repeating the opening process and cross-linking.

When the thermally crosslinkable hole transporting material includes trifluorovinyl ether units, the thermally crosslinkable hole transporting material can be crosslinked by step growth polymerization.

Preferably, trifluorovinyl ether units may be polymerized by cross-linking by thermal [2ð + 2ð] cyclodimerization during step-growth polymerization.

Thereafter, in the method of manufacturing a light emitting device according to an embodiment of the present invention, a step of forming a light emitting layer on the hole transport layer (S150) is performed.

The light emitting layer is formed by using any one solution process of spin-coating, slit dye coating, ink-jet printing, spray coating, and dip coating. can be formed

Preferably, the light emitting layer may be formed using spin coating, which is a method in which a certain amount of solution is dropped and the substrate is rotated at high speed to coat the solution with centrifugal force.

Since the light emitting layer is formed by a solution process, a large-area process is possible and process time can be shortened.

Thereafter, the method of manufacturing a light emitting device according to an embodiment of the present invention proceeds to forming an electron transport layer on the light emitting layer (S160).

The electron transport layer uses any one solution process of spin-coating, slit dye coating, ink-jet printing, spray coating, and dip coating. can be formed by

Preferably, the electron transport layer may be formed using spin coating, which is a method in which a certain amount of solution is dropped and the substrate is rotated at high speed to coat the solution with centrifugal force.

Since the electron transport layer is formed by a solution process, a large-area process is possible and process time can be shortened.

Finally, the method of manufacturing a light emitting device according to an embodiment of the present invention proceeds to forming a second electrode on the electron transport layer (S170).

The second electrode is thermal evaporation, sol-gel, spray pyrolysis, sputtering, chemical vapor deposition (CVD; Chemical Vapor Deposition), ALD; Atomic Layer deposition) and electron beam evaporation (e-beam evaporation).

Depending on the embodiment, the second electrode may be formed using a coating method such as a method of printing paste metal ink in which a binder is mixed with metal flakes or particles, and the electrode is formed. It is not limited to this as long as it can be done.

Example 1: Styrene-HTL

Figure 3 is a schematic diagram showing the synthesis process of the thermally crosslinkable hole transport material according to Example 1 of the present invention.

One) 4,4'-((4-bromophenyl)azanediyl)dibenzaldehyde (1)

4-bromotriphenylamine (5.00 g, 15.40 mmol) was dissolved in dimethylformamide (DMF, 24 ml, 308 mmol) at 0 °C, and then POCl ₃ (15.53 ml, 10.8 mmol) was dissolved at 0 °C. was injected slowly. After 30 minutes, raise the temperature to room temperature and when the mixture turns orange, stir at 90 ° C for 20 hours, slowly pour the mixture into a beaker filled with ice water, stir, and neutralize with sodium bicarbonate (0.5 M). After that, the product was extracted with MC (dichloromethane), water was removed with Na ₂ SO ₄ , and the organic solvent was evaporated under reduced pressure.

The product was purified by column chromatography using dichloromethane and hexane (1:3 ratio).

Yield = 4.3 g (73%). 1H NMR (400 MHz, CDCl3): 9.9 (s, 2H), 7.8 (d, 4H), 7.5 (d, 2H), 7.2 (d, 4H), 7.1 (d, 2H),

2) 4-bromo-N,N-bis(4-vinylphenyl)aniline (2)

After putting methyltriphenylphosphonium bromide (8.6 g, 24.3 mmol) in 60ml anhydrous tetrahydrofuran (anhydrous THF), potassium-t-butoxide (2.7 g, 24.3 mmol). When the solution turned yellow, the ice bath was removed and stirred for 1 hour.

Once again, the solution was lowered to 0°C, 4,4'-((4-bromophenyl)azanediyl)dibenzaldehyde (4.2 g, 11 mmol) was injected, the ice bath was removed, and the solution was incubated at room temperature for 12 hours. stirred

The product was extracted with MC (dichloromethane), water was removed with Na ₂ SO ₄ , and the organic solvent was evaporated under reduced pressure. The product was purified by column chromatography using dichloromethane and hexane (1:3 ratio).

Yield = 2.7 g (64%). 1H NMR (400 MHz, CDCl3): 7.3 (m, 6H), 7.0 (m, 6H), 6.7 (m, 2H), 5.7 (d, 2H), 5.2 (d, 2H).

3) 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N,N-bis(4-vinylphenyl)aniline (3)

4-bromo-N,N-bis(4-vinylphenyl)aniline (2.7 g, 7.2 mmol), bis(pinacolato)diboron (1.82 g, 7.2 mmol), [1,1′-Bis(diphenylphosphino)ferrocene]dichloropalladium( II) (0.26 g, 0.36 mmol) and potassium acetate (potassium acetate, 2.11 g, 21.53 mmol) were added to 50 ml of 1,4-dioxane and stirred for 12 hours while refluxing at 110 ° C. After 12 hours, the reaction mixture was cooled and extracted with distilled water and dichloromethane. Moisture was removed with Na ₂ SO ₄ and the organic solvent was evaporated under reduced pressure. The product was purified by column chromatography using dichloromethane and hexane (1:3 ratio).

Yield = 1.8 g (59%). 1H NMR (400 MHz, CDCl3): 7.7 (d, 2H), 7.3 (d, 4H), 7.1 (d, 4H), 6.7 (m, 4H), 5.7 (dd, 2H), 5.2 (dd, 2H) , 1.3 (s, 12H).

4) 4-(dibenzo[b,d]furan-4-yl)-N,N-bis(4-vinylphenyl)aniline (4, Styrene-HTL)

4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N,N-bis(4-vinylphenyl)aniline (1.2 g, 2.83 mmol), 4-bromodibenzo[b ,d]furan (0.7 g, 2.83 mmol), tetrakis(triphenylphosphine)-palladium(0) (0.16 g, 0.14 mmol) and potassium carbonate (1.18 g, 8.5 mmol) dissolved in 25 ml distilled water ) was stirred while refluxing for 6 hours at 60 ℃ in 50ml THF.

An excess of chloroform and distilled water were added to the mixture, stirred at 50 ° C to dissolve the product, the product was extracted with an organic solvent, water was removed with Na ₂ SO ₄ and the organic solvent was evaporated under reduced pressure. . The product was purified by column chromatography using dichloromethane and hexane (1:4 ratio).

Yield = 0.4 g (30%). 1H NMR (400 MHz, CDCl3): 8.0 (d, 1H), 7.92 (d, 1H), 7.85 (d, 2H), 7.85 (d, 2H), 7.62 (m, 7H), 7.26 (d, 2H) ,7.15 (d,4H) 6.73 (m,2H), 5.7 (dd,2H) 5.2 (dd, 2H)

Experimental Example 1: Cross-linking experiment

The hole transport material (Styrene-HTL) according to Example 1 dissolved in chlorobenzene was spin-coated on a glass substrate, followed by cross-linking at 170 ° C. for 30 minutes. UV-vis absorbance of the hole transport layer before (Styrene-HTL) / after (Rinsed Styrene-HTL) spin-washing (Rinsed Styrene-HTL) three times with chlorobenzene intensity) was compared.

4A is a graph comparing UV-vis absorbance intensity after spin washing the surface of the hole transport layer prepared using the thermally crosslinkable hole transport material according to Example 1 of the present invention.

Referring to FIG. 4A, the hole transport layer prepared using the thermally crosslinkable hole transport material according to Example 1 of the present invention has visible inertia absorption intensity (UV-vis) before and after spin-washing is performed on the surface. It can be seen that there is no difference in absorbance intensity).

Therefore, since the heat crosslinkable hole transport material according to Example 1 of the present invention shows no change in intensity before and after crosslinking, the heat crosslinkable hole transport material according to Example 1 of the present invention It can be seen that it has insoluble properties that do not dissolve in solvents.

That is, in the light emitting device including the thermally crosslinkable hole transport material according to an embodiment of the present invention, even if an upper layer (eg, light emitting layer) is formed on the hole transport layer by a solution process, the hole transport layer is formed by a solution of the upper layer (eg, light emitting layer). It can be seen that it prevents the melting and miscibility of

4B is a graph showing differential scanning calorimetry (DSC) results of a hole transport layer prepared using a thermally crosslinkable hole transport material according to Example 1 of the present invention.

부근에서 발열 피크가 나타났으며, 이는 가교결합 반응에 의해 나타나는 피크이다.Referring to FIG. 4B, when the thermally crosslinkable hole transport material according to Example 1 of the present invention is first heated (1st), 200

An exothermic peak appeared in the vicinity, which is a peak caused by a crosslinking reaction.

The thermally crosslinkable hole transport material according to Example 1 of the present invention does not show endothermic or exothermic peaks in the second heating (2nd) after crosslinking is formed in the first heating (1st), so it is not melted by heat. It can be seen that it has Jungian properties.

Therefore, it can be seen that the thermally crosslinkable hole transport material according to the embodiment of the present invention has insoluble and insoluble properties because the molecular chains are densely located between the monomers due to crosslinking.

Experimental Example 2: Evaluation of light emitting device characteristics

Comparative Example 1: Organic light emitting device (OLED)

A glass substrate coated with ITO (sheet resistance of 15 ohm/sq) was washed with acetone, distilled water (DI water) and isopropyl alcohol, followed by UV-ozone treatment for 20 minutes.

에서 10분간 건조(annealing)시켰다. 이후, 모든 공정은 질소 분위기의 글러브 박스(N2-filled glove box)에서 이루어진다.PEDOT:PSS (CleviosTM P CH8000) dispersed in water using a 0.45 μm filter was spin-coated on an ITO substrate to a thickness of 30 nm, and then coated with a hot plate in air at 200 °C.

was dried for 10 minutes (annealing). Thereafter, all processes are performed in a nitrogen atmosphere glove box (N2-filled glove box).

PVK dissolved at 4 mg/ml in chlorobenzene was spin-coated on an ITO substrate coated with PEDOT:PSS, and then dried (annealed) for 10 minutes at 110 ^° C. with a hot plate. TCPy: 8 wt% at a concentration of 8.5 mg/ml in 1,2-dichloroethane The light-emitting layer solution in which Ir(Fppy) ₃ was dissolved was spin-coated on the hole transport layer and then dried (annealed) for 10 minutes at 100 ^° C. with a hot plate.

Thereafter, an electron transport layer solution in which TPBi: 10 wt% Cs ₂ CO ₃ was dissolved in methanol at a concentration of 5.0 mg/ml was spin-coated on the light emitting layer, and then dried with a hot plate at 50 ^° C for 10 minutes ( annealing). Al was deposited to a thickness of 100 nm using thermal evaporation.

Comparative Example 2: Quantum dot light emitting device (QLED)

A glass substrate coated with ITO (sheet resistance of 15 ohm/sq) was washed with acetone, distilled water (DI water) and isopropyl alcohol, followed by UV-ozone treatment for 20 minutes.

에서 10분간 건조(annealing)시켰다. 이후, 모든 공정은 질소 분위기의 글러브 박스(N2-filled glove box)에서 이루어진다.PEDOT:PSS (CleviosTM P CH8000) dispersed in water using a 0.45 μm filter was spin-coated on an ITO substrate to a thickness of 30 nm, and then coated with a hot plate in air at 200 °C.

was dried for 10 minutes (annealing). Thereafter, all processes are performed in a nitrogen atmosphere glove box (N2-filled glove box).

TFB dissolved in 8 mg/ml in chlorobenzene was spin-coated on an ITO substrate coated with PEDOT:PSS, and then dried (annealed) with a hot plate at 110 ^° C. for 30 minutes. CdSe/ZnS dispersed in cyclohexane (core is CdSe, shell is an alloyed structure of CdSe and ZnS, ligand is dodecanethiol (DDT), , As the solvent, cyclohexane (cyclohexane_ is used) was spin-coated on the hole transport layer as a solution for the light emitting layer, and then dried (annealed) for 20 minutes at 80 ^° C. with a hot plate.

Thereafter, a ZnO electron transport layer solution dispersed in isopropyl alcohol was spin-coated on the light emitting layer, followed by annealing with a hot plate at 80 ^° C for 20 minutes, and Ag was thermally deposited (thermal evaporation). evaporation) to a thickness of 100 nm.

Example 2: Organic Light-Emitting Device (OLED)

A glass substrate coated with ITO (sheet resistance of 15 ohm/sq) was washed with acetone, distilled water (DI water) and isopropyl alcohol, followed by UV-ozone treatment for 20 minutes.

PEDOT:PSS (CleviosTM P CH8000) dispersed in water using a 0.45 μm filter was spin-coated to a thickness of 30 nm on an ITO substrate, and then dried (annealed) at 200° C. for 10 minutes in the air on a hot plate. Thereafter, all processes are performed in a nitrogen atmosphere glove box (N ₂ -filled glove box).

After spin-coating the hole transport material (Styrene-HTL) according to Example 1 dissolved at 4 mg/ml in chlorobenzene on an ITO substrate coated with PEDOT:PSS, the mixture was coated at 170° C. with a hot plate. After cross-linking for 30 minutes, it was spin-rinse with chlorobenzene.

Thereafter, a light emitting layer solution in which TCPy: 8 wt% Ir(Fppy) ₃ was dissolved in 1,2-dichloroethane at a concentration of 8.5 mg/ml was spin-coated on the hole transport layer, followed by a hot plate ( It was dried (annealed) at 100 ° C. for 10 minutes on a hot plate.

On the light emitting layer, an electron transport layer solution in which TPBi: 10 wt% Cs ₂ CO ₃ was dissolved at a concentration of 5.0 mg/ml in methanol was spin-coated, and then dried (annealing) with a hot plate at 50° C. for 10 minutes. , Aluminum (Al) was deposited to a thickness of 100 nm using thermal evaporation.

A light emitting device (OLED) according to Example 2 of the present invention is shown in FIG. 5 .

Example 3: Quantum dot light emitting device (QLED)

A glass substrate coated with ITO (sheet resistance of 15 ohm/sq) was washed with acetone, distilled water (DI water) and isopropyl alcohol, followed by UV-ozone treatment for 20 minutes.

PEDOT:PSS (CleviosTM P AV AI4083) dispersed in water using a 0.45 μm filter was spin-coated to a thickness of 30 nm on an ITO substrate, followed by annealing at 140 °C for 20 minutes in the air on a hot plate. . Thereafter, all processes are performed in a nitrogen atmosphere glove box (N ₂ -filled glove box).

After spin-coating the hole transport material (Styrene-HTL) according to Example 1 dissolved at 4 mg/ml in chlorobenzene on an ITO substrate coated with PEDOT:PSS, the mixture was coated at 170° C. with a hot plate. After cross-linking for 30 minutes, it was spin-rinse with chlorobenzene.

CdSe/ZnS dispersed in cyclohexane (core is CdSe, shell is an alloyed structure of CdSe and ZnS, ligand is dodecanethiol (DDT), , As a solvent, cyclohexane (cyclohexane_ is used) was spin-coated on the hole transport layer as a solution for the light emitting layer, followed by annealing at 80° C. for 20 minutes with a hot plate.

After spin-coating the ZnO electron transport layer solution dispersed in isopropyl alcohol on the light emitting layer, drying (annealing) at 80 ℃ for 20 minutes with a hot plate (hot plate), and then Ag thermal evaporation (thermal evaporation) was deposited to a thickness of 100 nm.

A light emitting device (QLED) according to Example 3 of the present invention is shown in FIG. 6 .

Figure 7a is a graph showing current density-voltage-luminance (J-V-L) characteristics of a light emitting device according to Example 2 of the present invention, Figure 7b is a current density-voltage-luminance (J-V-L) of a light emitting device according to Comparative Example 1 8A is a graph showing the electroluminescence (EL) spectrum of a light emitting device according to Example 2 of the present invention, and FIG. 8B is a graph showing the electrical properties of a light emitting device according to Comparative Example 1. It is a graph showing an electroluminescence (EL) spectrum.

Table 1 is a table showing device characteristics of light emitting devices according to Comparative Example 1 and Example 2 of the present invention.

[Table 1]

Referring to Figures 7a to 8b and Table 1, the light emitting device (OLED) according to Example 2 of the present invention is considered to be located in a shorter wavelength region than the light emitting device (OLED) according to Comparative Example 1, the implementation of the present invention It can be seen that the light emitting device OLED according to Example 2 emits stronger blue light than the light emitting device OLED according to Comparative Example 1.

In addition, since the light emitting device (OLED) according to Example 2 of the present invention includes a hole transport material capable of thermal crosslinking, the hole transport ability is improved, so that the light emitting device (OLED) according to Comparative Example 1 has a lower turn-on voltage value, Hole injection ability is improved so that current can flow better.

9A is a graph showing current density-voltage-luminance (J-V-L) characteristics of a light emitting device according to Example 3 of the present invention, and FIG. 9B is a current density-voltage-luminance (J-V-L) of a light emitting device according to Comparative Example 2. 10A is a graph showing the electroluminescence (EL) spectrum of a light emitting device according to Example 3 of the present invention, and FIG. 10B is a graph showing the electrical properties of a light emitting device according to Comparative Example 2. It is a graph showing an electroluminescence (EL) spectrum.

Table 2 is a table showing device characteristics of the light emitting device according to Example 2 of the present invention.

[Table 2]

9A to 10B and Table 2, in the case of the light emitting device (QLED) device according to Example 3 of the present invention, the maximum external quantum efficiency, maximum current efficiency, and maximum power efficiency are the light emitting device (QLED according to Comparative Example 2) ) can be seen to be improved.

In addition, by including a thermally crosslinkable hole transport material in the light emitting device (QLED) according to Example 3 of the present invention, the hole transport ability is further improved, so that the turn-on voltage value is lower than that of the light emitting device (QLED) according to Comparative Example 2. With this, it can be seen that the hole injection ability is improved and the current flows better.

As described above, although the present invention has been described by the limited embodiments and drawings, the present invention is not limited to the above embodiments, and those skilled in the art in the field to which the present invention belongs can make various modifications and variations from these descriptions. this is possible Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, and should be defined by not only the claims to be described later, but also those equivalent to these claims.

110: substrate 120: first electrode
131: hole injection layer 132: hole transport layer
140: light emitting layer 150: electron transport layer
160: second electrode

Claims (14)

A thermally cross-linkable hole transport material, characterized in that it is represented by Formula 1 below.
[Formula 1]

(In Formula 1, X is O or S, R is a crosslinkable arylamine compound, and n is 1 to 4)
According to claim 1,
The crosslinkable arylamine-based compound includes a styrene unit,
The thermal cross-linkable hole transport material, characterized in that the styrene unit is selected from the group represented by the following formulas 2-1 to 2-30.

(In Chemical Formulas 2-1 to 2-30, R' is an alkyl group)
According to claim 1,
The crosslinkable arylamine-based compound includes an oxetane unit,
The thermal cross-linkable hole transport material, characterized in that the oxetane unit is selected from the group represented by the following formulas 3-1 to 3-37.

(In Chemical Formulas 3-1 to 3-37, R' is an alkyl group)
According to claim 1,
The crosslinkable arylamine-based compound includes a trifluorovinyl ether unit,
The thermally cross-linkable hole transport material, characterized in that the trifluorovinyl ether unit is selected from the group represented by the following formulas 4-1 to 4-30.

(In Chemical Formulas 4-1 to 4-30, R' is an alkyl group)
According to claim 2,
A cross-linkable hole transport material represented by Formula 1 is a cross-linkable hole transport material represented by Formula 5 below.
[Formula 5]

(In Formula 1, X is O or S)
According to claim 1,
The hole transport material represented by Formula 1 is a thermal cross-linkable hole transport material, characterized in that the p-type semiconductor polymer.
According to claim 1,
The hole transport material represented by Formula 1 is a thermally cross-linkable hole transport material, characterized in that the solubility is controlled depending on the cross-linkable arylamine-based compound.
A first electrode formed on the substrate;
a hole injection layer formed on the first electrode;
a hole transport layer formed on the hole injection layer and comprising the thermally cross-linkable hole transport material according to claim 1;
a light emitting layer formed on the hole transport layer;
an electron transport layer formed on the light emitting layer;
a second electrode formed on the electron transport layer;
A light emitting device comprising a.
According to claim 8,
The light emitting device, characterized in that the hole transport layer further comprises a p-dopant (p-dopant).
According to claim 8,
The light emitting layer is characterized in that it comprises an organic compound or quantum dots.
forming a first electrode on the substrate;
Forming a hole injection layer on the first electrode;
coating a hole transport solution containing the thermally cross-linkable hole transport material according to claim 1 on the hole injection layer;
heat-treating the hole transport solution coated on the hole injection layer to form a hole transport layer including the thermally cross-linkable hole transport material according to claim 1;
forming a light emitting layer on the hole transport layer;
forming an electron transport layer on the light emitting layer; and
Forming a second electrode on the electron transport layer
Method for manufacturing a light emitting device comprising a.
According to claim 11,
The method of manufacturing a light emitting device, characterized in that the thermal cross-linkable (cross-linkable) hole transport material is cross-linked by a radical polymerization (radical polymerization).
According to claim 11,
The method of manufacturing a light emitting device, characterized in that the cross-linkable hole transport material is cross-linked by cationic ring-opening polymerization.
According to claim 11,
The heat treatment method of manufacturing a light emitting device, characterized in that proceeding at a temperature of 150 ℃ to 350 ℃.

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