KR20170064180A - Low molecular luminous compound enabled solution process, organic light emiting didoe and display devie having the compound - Google Patents

Abstract

The present invention relates to an organic light emitting diode device and an organic light emitting diode (OLED) display device in which a low molecular weight luminescent compound capable of solution process and a luminescent compound are applied to an organic material layer of the device. The luminescent compound according to the present invention can be applied not only to a device through a solution process but also to a deep blue device with improved color purity and excellent luminescent characteristics such as luminescent efficiency.

Description

TECHNICAL FIELD [0001] The present invention relates to a low-molecular light-emitting compound capable of performing a solution process, a light-emitting diode including the light-emitting compound, and a display device. BACKGROUND OF THE INVENTION 1. Field of the Invention [0002]

More particularly, the present invention relates to a blue light emitting compound capable of a solution process, a light emitting diode including the organic compound layer in the organic compound layer, and a display device.

Recently, as the size of display devices has been increased, the demand for flat display devices with less space occupation is increasing. The technology of an organic light emitting diode device, also called an organic electroluminescent device (OELD) .

When an electric charge is injected into a light emitting material layer formed between an electron injection electrode (cathode) and a hole injection electrode (anode), the organic light emitting diode device emits light while paired with electrons. The device can be formed on a flexible transparent substrate such as a plastic substrate and can be driven at a lower voltage (10 V or less) than a plasma display panel or an inorganic electroluminescence (EL) It also has a relatively low power consumption and excellent color purity. In addition, organic light emitting diode devices are capable of displaying three colors of green, blue, and red, making them a next-generation rich color display device and attracting many people's attention. Here, the process of fabricating the organic light emitting diode device will be briefly described.

(1) First, a material such as indium tin oxide (ITO) is deposited on a transparent substrate to form an anode.

(2) A hole injecting layer (HIL) is formed on the anode.

(3) Next, a hole transporting layer (HTL) is formed on the hole injection layer. If necessary, an electron blocking layer (EBL) may be formed to confine the excitons in the light emitting material layer.

(4) Next, an emitting material layer (EML) is formed on the hole transport layer. At this time, a dopant is added as needed.

(5) Next, an electron transporting layer (ETL) and an electron injecting layer (EIL) are formed on the light emitting material layer. Alternatively, a hole blocking layer (HBL) may be formed to a thickness of 5 to 10 nm in order to confine the exciton in the light emitting material layer.

(6) Next, a cathode is formed on the electron injection layer, and a protective film is formed on the cathode.

As described above, in order to improve the efficiency, the organic light emitting diode device has a structure in which a hole injecting layer, a hole transporting layer, a light emitting material layer, an electron transporting layer, and an electron injecting layer are laminated between an anode and a cathode. In addition, an electron blocking layer (EBL) and a hole blocking layer (HBL) may be additionally included to prevent quenching of the exciton. Such a complicated structure increases the cost and the productivity.

In addition, in the conventional organic light emitting diode device, efficient hole injection is difficult due to a hole injection barrier, while electron injection and delivery speed is relatively fast. Therefore, the coupling region of holes and electrons is not located in the light emitting material layer but is located between the layer and the layer, that is, between the light emitting material layer and the hole transporting layer, thereby reducing the luminous efficiency. In order to solve the above-mentioned problem, it is necessary to simplify the structure of the organic light emitting diode device, and at the same time, the mobility of electrons and holes must be balanced so that the coupling region of electrons and holes exists in the light emitting material layer.

Particularly, blue light emission requires a material having a broad energy bandgap compared to green and red, which makes it difficult to develop materials. However, since the blue luminescent material has a large energy gap, there is a common applicability for green and red luminescence.

With respect to the blue light emitting material, U.S. Patent No. 6,455,720 discloses a 2,2- (diaryl) vinylphosphine compound, and US Patent Publication No. 2007-0292714 discloses a Discloses a blue light emitting compound having a pyrene structure and having a diphenylamino group substituted at the terminal thereof. Korean Patent Publication No. 2002-0070333 discloses a blue light emitting compound having a diphenyl anthracene structure and an aryl group substituted at the center thereof. Korean Patent Publication No. 2007-0023335 discloses a blue light emitting compound having a dipyrene- A blue light-emitting compound is disclosed. However, the light emitting materials disclosed in these patents have insufficient lifetime, luminous efficiency, and brightness, and have low color purity, making it difficult to implement deep blue, which poses a problem in realizing full-color displays of full color.

Meanwhile, a conventional vacuum deposition process is used to dope a light emitting material into an organic material layer constituting the organic light emitting diode, for example, a hole injection layer, a hole transport layer, and a light emitting material layer. However, in recent years, attempts have been made to apply a solution process instead of a vacuum deposition method. The combination of the solution process and the printing process makes it possible to print the organic material solution only in a desired place when OLED pixels are manufactured, so that consumption of the organic material is reduced as compared with the vacuum deposition method of vaporizing the organic material in the entire vacuum chamber , The use efficiency of the organic material increases.

In addition, since the solution process is relatively less expensive than the vacuum deposition, it is cost competitive. In order to realize a full-color display, the three primary colors of red-green-blue are respectively patterned to form unit pixels. In the vacuum deposition method, only the specific region opened through a fine metal mask (FMM) . However, as the size of the substrate increases and the required resolution increases, there is a restriction on the process conditions that can be implemented by the FMM method. The solution process has advantages in cost competitiveness, fairness, enlargement and high resolution compared with the conventional vacuum deposition process.

Conventionally, a light emitting compound developed by a solution process is mostly a polymer compound, and a film can be formed by a simple method such as spin coating. However, the polymer compound has a relatively low luminous efficiency as compared with the low molecular materials produced by the vapor deposition process. In particular, since the color luminescent material used in the conventional solution process has a color coordinate of 0.13 or more, it is troublesome to fabricate a device using a hard cavity or a soft cavity on a lower substrate for application to a display device.

Due to these problems, a hybrid structure was adopted in which a solution process was applied to the red region and the green region among the three pigments, and a deposition process was applied to the blue region. However, in this case, it is difficult to form a uniform charge balance due to the interface difference between the HTL applying the solution process and the BCL (blue common layer) applying the deposition process. Therefore, charges are accumulated in a specific region in the light emitting diode, charge balance is lowered, and holes and electrons are not combined in EML such as BCL, and are coupled between HTL and EML to emit light. Therefore, there is a problem in that the color characteristics of the blue device are deteriorated, and the efficiency and the life are deteriorated.

It is an object of the present invention to provide a low-molecular light-emitting compound capable of solution processing and a light-emitting diode and a display device to which the compound is applied to an organic material layer.

Another object of the present invention is to provide a low molecular weight luminescent compound having excellent color purity, low driving voltage, high efficiency and long lifetime, and a light emitting diode and a display device using the compound.

Another object of the present invention is to provide a light emitting compound which can improve cost competitiveness and fairness, and can realize a large size and high resolution, and a light emitting diode and a display device to which the compound is applied.

According to an aspect of the present invention, there is provided a low molecular weight blue light emitting compound capable of performing a solution process and satisfying excellent color purity, low driving voltage, high luminous efficiency and long lifetime.

According to another aspect of the present invention, there is provided a light emitting device comprising the above-described light emitting compound in at least one layer of an organic material layer, for example, a light emitting material layer, a hole injecting layer and a hole transporting layer, Lt; / RTI >

According to another aspect of the present invention, there is provided a display device in which the above-mentioned blue light emitting compound has a light emitting diode applied to at least one of organic layers.

The low molecular weight luminescent compound synthesized according to the present invention is implemented so that a solution process is possible. Therefore, unlike the deposition process, doping can be performed through a solution process only in a region requiring a light emitting compound, thereby achieving the efficiency of the organic material.

In addition, the luminescent compound of the present invention has excellent color purity, low driving voltage, high efficiency and long lifetime, and can realize a large-sized and high-resolution display by applying a solution process.

1 is a schematic cross-sectional view of an organic light emitting diode according to an exemplary embodiment of the present invention.
2 is a schematic cross-sectional view of an organic light emitting diode display device according to an exemplary embodiment of the present invention.
3A and 3B are graphs showing the results of measuring the thermal stability of a synthesized light emitting compound according to an exemplary embodiment of the present invention, wherein FIG. 3A is a graph showing the results of TGA analysis, FIG. 3B is a graph showing DSC FIG.
4A and 4B are graphs showing the results of measurement of ultraviolet spectrum and PL spectrum of the synthesized luminescent compound according to an exemplary embodiment of the present invention, respectively. FIG. 4A shows a luminescent compound dissolved in an organic solvent, and FIG. 4B shows a luminescent compound in a thin film state.
5 is a schematic cross-sectional view of a light emitting diode device manufactured according to an exemplary embodiment of the present invention, in which energy levels are indicated.
FIG. 6 is a graph schematically illustrating HOMO, LUMO, and energy levels of representative materials constituting a light emitting diode device manufactured according to an exemplary embodiment of the present invention.
FIG. 7 is a graph illustrating a current density and a light emission characteristic according to a driving voltage of a light emitting diode device manufactured according to an exemplary embodiment of the present invention.
8 is a graph showing EL intensity of a light emitting diode device manufactured according to an exemplary embodiment of the present invention.
FIG. 9 is a graph illustrating an external quantum efficiency (EQE) of a light emitting diode device manufactured according to an exemplary embodiment of the present invention.
10 is a graph illustrating luminous efficiency and voltage efficiency of a light emitting diode device manufactured according to an exemplary embodiment of the present invention.

According to an aspect of the present invention, there is provided a luminescent compound capable of being subjected to a solution process represented by the following general formula (1).

Formula 1

(R ₁ and R ₂ are each independently a hydrogen atom or a C ₁ -C ₂₀ alkyl group in the formula (1); or R ₃ and R ₄ are each independently hydrogen, C ₁ -C ₂₀ alkyl group, a substituted or heavy hydrogen, C ₁ - C ₁₀ alkyl group, C ₁ -C ₁₀ alkylsilyl group, a nitro group, -CN, a homopolymer or a heteroaryl group substituted with at least one functional group selected from a group consisting of a halogen and a phenyl group; R ₅ is unsubstituted or substituted with heavy hydrogen, R ₆ is a substituted or unsubstituted alkylene group substituted with at least one functional group selected from the group consisting of a C ₁ -C ₁₀ alkyl group, a C ₁ -C ₁₀ alkylsilyl group, a nitro group, -CN, halogen and a phenyl group; or heavy hydrogen, C ₁ -C ₁₀ alkyl, C ₁ -C ₁₀ alkylsilyl group, a nitro group, -CN, a homopolymer or a heteroaryl group substituted with at least one functional group selected from a group consisting of a halogen and a phenyl group; R ₇ And R ₈ are each independently a hydrogen atom, deuterium, a C ₁ -C ₁₀ alkyl group , A C ₁ -C ₁₀ alkylsilyl group, a nitro group, -CN, a halogen or a phenyl group)

In one exemplary embodiment, the luminescent compound that can be subjected to the solution process of Formula 1 may include a compound represented by Formula 2 or Formula 3 below.

(2)

(3)

(Wherein R ₁ to R ₄ , R ₇ and R ₈ are the same as defined in formula (1), R ₉ and R ₁₀ are each independently a hydrogen atom, deuterium, a C ₁ -C ₁₀ alkyl group, A C ₁ -C ₁₀ alkylsilyl group, a nitro group, -CN, a halogen or a phenyl group)

In one specific embodiment, R ₁ and R ₂ are each a C ₁ -C ₁₀ alkyl group, R ₃ and R ₄ are each a C ₁ -C ₁₀ alkyl group, R ₅ is phenylene, R ₆ may be a phenyl group.

According to another aspect of the present invention, there is provided a plasma display panel comprising: a first electrode; A second electrode facing the first electrode; And at least one organic compound layer disposed between the first electrode and the second electrode, wherein the organic compound layer includes a light emitting compound capable of performing the solution process described above.

In one exemplary embodiment, the organic layer may include a layer of a light emitting material.

In an alternative embodiment, the light-emitting compound capable of being subjected to the solution process may be included in at least one organic material layer between the first electrode and the light-emitting material layer and between the hole injection layer and the hole transport layer.

According to another aspect of the present invention, there is provided a plasma display panel comprising: a first substrate; A driving thin film transistor located on the first substrate; A light emitting diode disposed on the first substrate and connected to the driving thin film transistor, the light emitting diode including a light emitting compound capable of performing the solution process described above in at least one organic layer; And a second substrate covering the light emitting diode and being attached to the first substrate.

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

[Luminescent compound]

The present invention relates to a low-molecular blue light-emitting compound capable of being subjected to a solution process represented by, for example, the following formula (1).

Formula 1

(R ₁ and R ₂ are each independently a hydrogen atom or a C ₁ -C ₂₀ alkyl group in the formula (1); or R ₃ and R ₄ are each independently hydrogen, C ₁ -C ₂₀ alkyl group, a substituted or heavy hydrogen, C ₁ - C ₁₀ alkyl group, C ₁ -C ₁₀ alkylsilyl group, C ₁ -C ₁₀ alkyl halide, nitro, -CN, a homo or heteroaryl group substituted with at least one functional group selected from a group consisting of a halogen and a phenyl group; R ₅ is unsubstituted or substituted with at least one group selected from the group consisting of deuterium, C ₁ -C ₁₀ alkyl group, C ₁ -C ₁₀ alkylsilyl group, C ₁ -C ₁₀ alkyl halide, nitro group, -CN, a homo or hetero arylene group substituted with one functional group; R ₆ is unsubstituted or substituted with heavy hydrogen, C ₁ -C ₁₀ alkyl, C ₁ -C ₁₀ alkylsilyl group, C ₁ -C ₁₀ alkyl halide, nitro, -CN, halogen ≪ / RTI > and phenyl groups substituted with at least one functional group selected from the group consisting of < RTI ID = 0.0 >Group; R ₇ and R ₈ are each independently being a hydrogen atom, a heavy hydrogen, C ₁ -C ₁₀ alkyl, C ₁ -C ₁₀ alkylsilyl group, C ₁ -C ₁₀ alkyl halide, nitro, -CN, halogen or a phenyl group )

That is, the low-molecular blue light-emitting compound of the present invention is an acridine derivative, which is directly connected to the acridine derivative and has a fluorene structure in which a phenanthroimidazole derivative is connected via an arylene group (R ₅ ) The balance of electrons and holes in the organic light emitting diode device can be improved by the strong hole characteristic. In addition, the solution process can be applied using various substituents to the acridine derivative, the phenanthroididazole derivative and the fluorene which constitute the core.

In one preferred embodiment, the C ₁ -C ₂₀ alkyl group constituting R ₁ and R ₂ is a C ₁ -C ₁₀ alkyl group, more preferably methyl, ethyl, n-propyl, i-propyl, n-butyl, can be a C ₁ -C ₆ alkyl group, such as i- butyl, t- butyl, but the present invention is not limited to this.

The aryl group constituting R ₃ , R ₄ , R ₆ , R ₇ and R ₈ constituting the formula (1) and the arylene group constituting R ₅ are, for example, C ₅ -C ₃₀ substituted or unsubstituted homo Or a heteroaryl group, or may be a homo or heteroarylene group.

More specifically, the homoaryl group is unsubstituted or substituted in the group consisting of deuterium, a C ₁ -C ₁₀ alkyl group, a C ₁ -C ₁₀ alkylsilyl group, a C ₁ -C ₁₀ alkyl halide, a nitro group, a -CN, a halogen and a phenyl group Phenyl, naphthyl, indenyl, anthracenyl, fluorenyl, phenalenyl, phenanthrenyl, phenanthrenyl, etc. substituted with at least one functional group selected. May be selected from the group consisting of pyrenyl, tetraphenyl, biphenyl, terphenyl and spiro-fluorenyl, but the present invention is not limited thereto.

The heteroaryl group may be unsubstituted or selected from the group consisting of deuterium, a C ₁ -C ₁₀ alkyl group, a C ₁ -C ₁₀ alkylsilyl group, a C ₁ -C ₁₀ alkyl halide, a nitro group, a -CN, a halogen and a phenyl group Pyridazine, pyrazine, imidazole, pyrazole, oxadiazole, triazole, and the like substituted with at least one functional group which is substituted by at least one functional group, Pyrimidine, oxazole, pyrrole, pyridine, triazine, thiazole, thiophene, and N-substituted spies, such as furan, pyrimidine, oxazole, Fluorenyl, and the like, but the present invention is not limited thereto.

In one exemplary embodiment, in the substituent of the aryl group constituting R ₃ , R ₄ , R ₆ , R ₇ and R ₈ constituting the formula (1), the C ₁ -C ₁₀ alkyl group is methyl, ethyl, i- propyl, n- butyl, i- butyl, and C ₁ -C ₆ alkyl group, such as t- butyl, C ₁ -C ₁₀ alkyl silyl group is a silyl C ₁ -C ₆ alkyl, such as trimethylsilyl group, C ₁ - The C ₁₀ alkyl halide is a C ₁ -C ₆ alkyl halide, such as trifluoromethyl, and the halogen may be fluorine.

In another exemplary embodiment, R ₃ and R ₄ in formula (1) may each independently be a C ₁ -C ₂₀ alkyl group, preferably a C ₁ -C ₁₀ alkyl group.

The arylene group constituting R ₅ of formula (1) is a C ₅ -C ₃₀ unsubstituted or substituted homo or heteroarylene group derived from an aryl group constituting R ₃ , R ₄ , R ₆ , R ₇ and R ₈ . For example, R < ₅ > in formula (1) may be selected from the group consisting of phenylene, naphthylene, flurenylene, biphenylene, terphenylene, Spiro-fluorenylene, and the like. For example, R < ₅ > in formula (1) may be an arylene group connecting a fluorene derivative constituting the core and a phenanthroididazole derivative at a meta position or a para position.

According to an exemplary embodiment, the low molecular weight blue fluorescent compound capable of the solution process of the present invention may include a compound represented by the following formula (2) or (3).

(2)

(3)

(Wherein R ₁ to R ₄ , R ₇ and R ₈ are the same as defined in formula (1), R ₉ and R ₁₀ are each independently a hydrogen atom, deuterium, a C ₁ -C ₁₀ alkyl group, A C ₁ -C ₁₀ alkylsilyl group, a nitro group, -CN, a halogen or a phenyl group)

In one specific embodiment, R ₁ and R ₂ are each a C ₁ -C ₁₀ alkyl group, R ₃ and R ₄ are each a C ₁ -C ₁₀ alkyl group, R ₅ is phenylene, R ₆ may be a phenyl group. Examples of such compounds include 2- (4- (7- (9,9-dimethylacridin-10 (9H) -yl) -9,9-diethyl-9H-fluoren- 1-phenyl-1H-phenanthro [9,10-d] imidazole (hereinafter referred to as AFpPPI) or 2- (3- (7- (9,9-dimethylacridin- 9H) -yl) -9,9-diethyl-9H-fluoren-2-yl) phenyl) -1-phenyl-1H-phenanthro [9,10-d] imidazole (hereinafter referred to as AFmPPI) can do.

Formula 4

Formula 5

[Light Emitting Diodes and Display Devices]

For example, a luminescent compound capable of being subjected to a solution process represented by Chemical Formulas 1 to 5 has excellent thermal stability (see Figs. 3A and 3B), has a good PL characteristic dissolved in an organic solvent as well as a thin film state 4A and 4B), it may be doped into one or more organic layers constituting the light emitting diode through a solution process. Therefore, solution and printing processes such as spin coating, blade coating and roll-slot coating can be applied. Since a liquid material is used, the process is simple, low-cost equipment can be utilized, and doping can be performed only on a desired pixel region, thereby improving the use efficiency of the material.

In addition, since these luminescent compounds can emit blue wavelength light, they can be used not only as a blue dopant for a luminescent material layer but also for a triplet energy value (see Fig. 6) Layer bipolar host for the phosphorescent material.

Further, since the compound of the present invention has a wide energy band gap (see FIG. 6) and exhibits excellent current density at a low driving voltage (see FIG. 7), the hole transporting property can be improved. Accordingly, the luminescent compound of the present invention can be used as another organic layer such as a hole injecting layer and a hole transporting layer in green (G) and red (R) pixel regions in an organic light emitting diode device.

An embodiment of an organic light emitting diode device to which the blue fluorescent compound of the present invention is applied is shown in Fig. 2) formed between the first substrate 101 (see FIG. 2) and the second substrate 102 (see FIG. 2) facing each other and the light emitting diodes E ).

The light emitting diode E includes a first electrode 110 serving as an anode, a second electrode 130 serving as a cathode, and an organic light emitting layer 120 formed between the first and second electrodes 110 and 130 .

The first electrode 110 may be formed of a material having a relatively high work function value such as indium tin oxide (ITO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , SnO ₂ -Sb ₂ O ₃ And the like, preferably ITO. The second electrode 130 is made of a material having a relatively low work function value, for example, aluminum (Al) or aluminum alloy (AlNd).

On the other hand, the organic light emitting layer 120 includes organic light emitting patterns of red, green, and blue. The organic light emitting layer 120 may include a hole injection layer (HTL) 121, a hole transporting layer (HIL) 121, and a hole transporting layer (HIL) 121 sequentially from the first electrode 110 in order to maximize luminous efficiency. An emitting layer 122, an emitting material layer (EML) 123, an electron transporting layer 124 and an electron injection layer 125. In this case, the organic light emitting layer 120 may include a hole injection layer 121, a hole transport layer 122, an electron transport layer 124, an electron injection layer 125). ≪ / RTI >

At least one organic layer of the hole injection layer 121, the hole transport layer 122, and the light emitting material layer 123 may include a blue fluorescent compound represented by Chemical Formulas 1 to 5. For example, when the organic compound layer, for example, the hole injection layer 121, the hole transport layer 122, and the light emitting material layer 123 are formed using the light emitting compound according to the present invention, Coating, spin coating, spray coating, dip coating, and the like can be applied. When the solution process is applied, the luminescent compound of the present invention can be dissolved in an organic solvent such as chloroform (CHCl ₃ ), toluene, chlorobenzene (CB), ortho-dichlorobenzene (ODCB) .

In another alternative embodiment, a compound other than the luminescent compound of the present invention may be used in the hole injection layer 121 and / or the hole transport layer 122. For example, materials that can be used for the hole injection layer 121 include PEDOT: PSS (poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonate)), 4,4 ' -Tris [methylphenyl (phenyl) amino] -triphenylamine (m-MTDATA), 4,4 ', 4 "-tris [1-naphthyl Aromatic amines may be included. On the other hand, in order to form the hole transport layer 122, for example, N, N'-bis (3-methylphenyl) -N, N'-diphenyl- [1,1'- (TPD), N, N'-bis (1-naphthyl) -N, N'-biphenyl- (Diphenylamino) phenyl] cyclohexane (TAPC), 4,4'-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine -4 "-tris (carbazol-9-yl) -triphenylamine (TCTA) can be used.

In one exemplary embodiment, when the light emitting compound of the present invention is used as a host material for the light emitting material layer 123, a well known blue dopant is added in a ratio of about 1-30 parts by weight to emit blue light. In another alternative embodiment, when the light emitting compound of the present invention is used as a dopant of the light emitting material layer 123, the light emitting compound of the present invention may be contained in the light emitting material layer 123 at a ratio of 1-30 parts by weight. The material used as the host of the light emitting material layer 123 may be selected from the group consisting of 9,9'- (2,6-Pyridinediydi-3,1-phenylene) bis-9H-carbazole (26DCzPPy) -Dicarbazole-biphenyl (CBP), N, N-dicarbazoyl-3,5-benzene (mCP), polyvinylcarbazole (PVK) and polyfluorene.

On the other hand, the electron transport layer 124 may be made of a material containing a chemical component that attracts electrons, such as tris (8-hydroxyquinolinato) aluminum (Alq ₃ ), 2,9- Diphenyl-1,10-phenanthroline (DDPA), 4,7-diphenyl-1,10-phenanthroline (bphen), 2- (4-biphenyl) -Oxadiazole (PBD), or quinoxaline derivatives such as 1,3,4-tris [(3-phenyl-6-trifluoromethyl) quinoxalin-2- yl] benzene (TPQ) ) Derivatives and the like can be used.

In addition, the electron injection layer 125 is for inducing smooth electron injection, and may be in the form of alkali metal or alkaline earth metal ion such as LiF, BaF ₂ , CsF and the like.

The light emitting diode manufactured according to the exemplary embodiment of the present invention has excellent current density and light emission characteristics and is driven at a low voltage (FIG. 7), EL intensity (FIG. 8), external quantum efficiency (EQE The efficiency and the voltage efficiency are excellent (see FIG. 10). Therefore, the present invention can be applied to a display device such as an organic light emitting diode display device by adopting the light emitting diode of the present invention. 2 is a schematic cross-sectional view of a display device according to an exemplary embodiment of the present invention.

2, in the display device 100, a non-display area NDR is defined around the display area DR and the display area DR, and the first substrate 101 and the second substrate 102 Are spaced apart from each other by a predetermined distance. In addition, the display device 100 includes a driving thin film transistor DTr, a planarization layer 149 covering the driving thin film transistor DTr, and a driving thin film transistor DTr located on the planarization layer 149 and connected to the driving thin film transistor Td And a light emitting diode element (E) including a light emitting diode (E).

The first substrate 101 and / or the second substrate 102 may be formed of glass or a flexible plastic. The second substrate 202 is bonded to the first substrate 101 through an adhesive or a filler sealant 170 for encapsulation of the first substrate 101 and the light emitting diode device 104. The driving thin film transistor DTr includes a semiconductor layer 146, a gate electrode 142, a source electrode 152, and a drain electrode 154.

Specifically, the semiconductor layer 146 is formed on the first substrate 101 made of glass or plastic. For example, the semiconductor layer 146 is formed of silicon and includes an active region 146a forming a central channel and source and drain regions 146b and 146c doped with a high concentration of impurities on both sides of the active region 146a Lt; / RTI > Alternatively, the semiconductor layer 146 may be made of an oxide semiconductor material. In this case, a light shielding pattern (not shown) and a buffer layer (not shown) may be formed under the semiconductor layer 146. The light shielding pattern prevents light from being incident on the semiconductor layer 146, ) Is prevented from being deteriorated by the light.

A gate insulating layer 144 made of an insulating material is formed on the entire surface of the first substrate 101 on the semiconductor layer 146. The gate insulating film 144 may be made of an inorganic insulating material such as silicon oxide or silicon nitride.

A gate electrode 142 made of a conductive material such as a metal is formed on the gate insulating layer 144 to correspond to the center of the semiconductor layer 146. A gate line (not shown) and a first capacitor electrode (not shown) may be formed on the gate insulating layer 144. The gate wiring may extend along the first direction, and the first capacitor electrode may be connected to the gate electrode 142. [ The gate insulating layer 144 is formed on the entire surface of the first substrate 101. The gate insulating layer 144 may be patterned to have the same shape as the gate electrode 142. [

An interlayer insulating layer 148 made of an insulating material is formed on the entire surface of the first substrate 101 on the gate electrode 142. The interlayer insulating film 148 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride, or an organic insulating material such as benzocyclobutene or photo-acryl.

The interlayer insulating film 148 has first and second contact holes 147a and 147b that expose both upper surfaces of the semiconductor layer 146. [ The first and second contact holes 147a and 147b are located apart from the gate electrode 142 on both sides of the gate electrode 142. [ Here, the first and second contact holes 147a and 147b are formed in the gate insulating film 144 as well. Alternatively, when the gate insulating film 144 is patterned to have the same shape as the gate electrode 142, the first and second contact holes 147a and 147b are formed only in the interlayer insulating film 148. [

A source electrode 152 and a drain electrode 154 formed of a conductive material such as metal are formed on the interlayer insulating layer 148. Further, a data line (not shown), a power supply line (not shown), and a second capacitor electrode (not shown) may be formed on the interlayer insulating layer 148 in the second direction.

The source electrode 152 and the drain electrode 154 are spaced apart from each other around the gate electrode 142 and are in contact with both sides of the semiconductor layer 146 through the first and second contact holes 147a and 147b . Although not shown, the data wiring extends along the second direction and intersects the gate wiring to define the pixel region, and the power wiring for supplying the high potential voltage is located apart from the data wiring. The second capacitor electrode is connected to the drain electrode 154 and overlaps the first capacitor electrode to form a storage capacitor with the dielectric layer between the first and second capacitor electrodes as a dielectric layer.

The semiconductor layer 146 and the gate electrode 142, the source electrode 152 and the drain electrode 154 constitute a driving thin film transistor DTr. The driving thin film transistor DTr includes a semiconductor layer 146, And has a coplanar structure in which the gate electrode 142, the source electrode 152, and the drain electrode 154 are located on the upper portion.

Alternatively, the driving thin film transistor DTr may have an inverted staggered structure in which a gate electrode is positioned below the semiconductor layer and a source electrode and a drain electrode are located above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Further, a switching thin film transistor (not shown) having substantially the same structure as the driving thin film transistor DTr is further formed on the first substrate 101. [ The gate electrode 142 of the driving thin film transistor DTr is connected to a drain electrode (not shown) of a switching thin film transistor (not shown), and the source electrode 152 of the driving thin film transistor DTr is connected to a power supply wiring . A gate electrode (not shown) and a source electrode (not shown) of a switching thin film transistor (not shown) are connected to the gate wiring and the data wiring, respectively.

A planarization layer 149 is formed on the entire surface of the first substrate 101 above the source electrode 152 and the drain electrode 154. The planarization layer 149 has a flat upper surface and a drain contact hole 156 exposing the drain electrode 154 of the driving thin film transistor DTr. Here, although the drain contact hole 156 is illustrated as being spaced apart from the second contact hole 147b, it may be formed directly on the second contact hole 147b.

The light emitting diode E constituting the light emitting diode element 104 includes a first electrode 110 located on the planarization layer 149 and connected to the drain electrode 154 of the driving thin film transistor DTr, And an organic light emitting layer 120 and a second electrode 130 sequentially stacked on the first electrode 110.

As described above, the first electrode 110 is made of a relatively large work function material and functions as an anode, and the second electrode 130 is made of a material having a relatively low work function value, thereby acting as a cathode. Further, the organic luminescent layer 120 includes the blue fluorescent compound represented by the above-mentioned general formulas (1) to (5). 5), a hole transport layer (122 of FIG. 5), a light emitting material layer (123 of FIG. 5), an electron transport layer (not shown) (124 in FIG. 5) and an electron injection layer (125 in FIG. 5), the light emitting material layer 123 includes the fluorescent compound represented by the above formulas 1 to 5 as a dopant, and emits blue light .

The first electrode 110 is formed for each pixel region. A bank layer (bank) 158 is located between the first electrodes 110 formed in each pixel region. The bank layer 253 may be in the form of an organic insulating film.

In addition, a second substrate, that is, an encapsulation substrate 102 covering the light emitting diode E may be attached to the first substrate 101. A barrier layer 160 may be formed between the encapsulation substrate 102 and the light emitting diode E to prevent moisture or oxygen from penetrating into the light emitting diode E, . Such a light emitting diode and a display device can be used in various electronic devices such as a video display device or a lighting device.

Hereinafter, the present invention will be described in more detail with reference to the following Examples. However, the present invention is not limited to the technical ideas described in the following Examples.

Synthetic example  1: Methyl 2- ( phenylamino ) benzoate (2)

2- (phenylamino) benzoic acid (10 g, 46.8 mmol) was dissolved in methanol (200 mL) and SOCl ₂ (8.5 mL, 117.2 mmol) was slowly added to the 100 mL three-necked flask at 0 ° C. After the reaction mixture was refluxed for 12 hours, the reaction was terminated and the reaction mixture was poured into cold water to give a solid which was washed with water. The resulting solid was dissolved again in methylene chloride (MC), washed with NaHCO ₃ aqueous solution, dried over anhydrous Na ₂ SO ₄ and the solvent was removed by vacuum distillation to obtain a yellow product liquid (yield: 9.6 g, 90%).

¹ H NMR (300 MHz, CDCl ₃ ,?): 9.48 (s, 1 H), 7.99-7.95 (m, 1 H), 7.37-7.24 (m, 6H), 7.12-7.07 (m, 1 H), 3.90 (s, 3 H).

Synthetic example  2: 2- (2- ( Phenylamino ) phenyl) propane -2- be  (3) Synthesis of

Methyl 2- (phenylamino) benzoate (5.0 g, 22.0 mmol) synthesized in Synthesis Example 1 was dissolved in THF (75 mL) and then CH ₃ MgBr (3.0 M in ether) (33.7 mL, 101.2 mmol) Is added slowly at -78 [deg.] C, the reaction mixture turns orange to brown and finally shows yellow color. The reaction mixture was kept at room temperature for 12 hours and poured into cold water to terminate the reaction. After separating the organic layer with ethyl acetate (EA), the organic layer is washed again with water and brine solution. Finally, the organic layer is washed with anhydrous Na ₂ SO ₄ and the organic solvent is vacuum distilled to obtain a brown colored liquid product (Yield 4.85 g, 97%).

^{1 H NMR (300 MHz, DMSO} -d 6, δ): 8.47 (s, 1H), 7.22-7.12 (m, 5H), 6.97 (d, J = 6.6 Hz, 2H), 6.84-6.79 (m, 2H ), 5.78 (s, 1 H), 1.49 (s, 6 H).

Synthetic example  3: 9,9- Dimethyl -9,10- 다 디아라디드ine  ( DMACR ) Synthesis of

Polyphosphoric acid (PPA, 60 mL) was added to a 2- (2- (phenylamino) phenyl) propan-2-ol (3.0 g, 13.2 mmol) synthesized in Synthesis Example 2, Lt; / RTI > To terminate the reaction, the reaction mixture was poured into water and neutralized to give a solid. After filtration, it was dissolved again in MC, neutralized with NaHCO ₃ aqueous solution and washed with water and brine solution. Finally, after removing water with anhydrous Na ₂ SO ₄ , the product is formed by vacuum distillation, and a white solid product can be obtained by column chromatography using EA / hexane (0.5: 9.5) as a developing solvent (Yield 2.70 g, 98%).

^{1 H NMR (300 MHz, CDCl} 3, δ): 7.40 (d, J = 9.0 Hz, 2H), 7.12 (t, J = 9 Hz, 2H), 6.94 (t, J = 9 Hz, 2H), 6.70 (d, J = 9.0 Hz, 2H), 6.14 (bs, 1H), 1.60 (s, 6H).

Synthetic example  4: 10- (7- Bromo -9,9-diethyl-9H- fluoren -2- yl ) -9,9- dimethyl -9,10-dihydroacridine (5)

9,9-dimethyl-9,10-dihydroacridine (DMACR, 1.00 g, 4.78 mmol) synthesized in Synthesis Example 3 was dissolved in toluene (30 mL), and sodium tert-butoxide (1.14 g, 11.95 mmol ) And 2,7-dibromo-9,9-diethyl-9H-fluorene compound (4.54 g, 11.95 mmol). The reaction mixture was refluxed in argon atmosphere for 30 minutes and then treated with tris (dibenzylideneacetone) dipalladium (0) (Pd ₂ (dba) ₃ , 88 mg, 0.095 mmol) and 1,1'-bis (diphenylphosphino) ferrocene mg, 0.191 mmol). The reaction mixture was stirred at 110 < 0 > C for 12 hours and EA and water were added to terminate the reaction. After separating the organic layer, the organic layer was washed with water and brine, and then the organic layer was dehydrated with anhydrous Na ₂ SO ₄ and the solvent was removed by vacuum distillation. The resulting compound was separated by column chromatography using EA / hexane (0.1: 9.9) as eluent to give a white solid product (yield: 1.70 g, 71%).

¹ H NMR (300 MHz, CDCl ₃ ,?): 7.92 (d, J = 7.5 Hz, 1H), 7.65-7.62 (m, 1H), 7.54-7.47 (m, 4H), 7.38-7.25 ), 6.95-6.92 (m, 4H), 6.33-6.30 (m, 2H), 2.04-2.01 (m, 4H), 1.73 (s, 6H), 0.38 (t, J = 7.5 Hz, 6H).

Synthetic example  5: 10- (9,9-Diethyl-7- (4,4,5,5- tetramethyl -1,3,2- dioxaborolan -2-yl) -9H-fluoren-2-yl) -9,9- dimethyl -9,10- 다 디아라디드ine  (6) Synthesis of

To a 150 mL three-necked flask was added 10- (7-bromo-9,9-diethyl-9H-fluoren-2-yl) -9,9-dimethyl-9,10- dihydroacridine (2.30 g, 4.52 mmol ) Was dissolved in dioxane (50 mL), bis (pinacolato) diboron (1.40 g, 5.43 mmol) and potassium acetate (1.10 g, 11.31 mmol) were added. The reaction mixture was refluxed in an argon atmosphere for 30 minutes, and PdCl ₂ (dppf) (165 mg, 0.23 mmol) was added thereto, followed by reaction at 100 ° C for 12 hours. The 1,4-dioxane solvent was removed and EA and water were added to terminate the reaction. After separating the organic layer, the water was removed with anhydrous Na ₂ SO ₄ , and the organic layer was removed by vacuum distillation. The product was purified by column chromatography using EA / hexane (0.5: 9.5) as a developing solvent to give a white solid (Yield: 1.50 g, 60%).

^{1 H NMR (300 MHz, CDCl3} , δ): 7.97 (d, J = 8.7 Hz, 1H), 7.87-7.85 (m, 1H), 7.78-7.76 (m, 2H), 7.47 (dd, J = 6.9 Hz J = 1.8 Hz, 2H), 2.13-1.99 (m, 4H), 6.32 (dd, J = 8.1 Hz, 2H), 7.29-7.25 4H), 1.72 (s, 6H), 1.40 (s, 12H), 0.35 (t, J = 7.5 Hz, 6H).

Synthetic example  6: 2- (4- Bromophenyl ) -1-phenyl-1H- phenanthro [9,10-d] imidazole (Br-p-PPI)

(0.44 g, 2.40 mmol), aniline (0.26 mL, 2.88 mmol) and ammonium acetate (1.84 g, 24 mmol) were added to a 100 mL three-necked flask with glacial acetic acid (10 mL) and refluxed for 12 hours. The reaction mixture is cooled to room temperature and poured into methanol (200 mL) to terminate the reaction. The resulting solid was washed with methanol again after filtration and then dried in a vacuum oven to obtain Br-p-PPI in high yield.

Similar to the synthesis of Br-p-PPI, 2- (3-bromophenyl) -1-phenyl-1H-phenanthro [9,10- benzaldehyde. < / RTI >

Synthetic example  7: AFpPPI Wow AFmPPI ) Synthesis of

AFpPPI and AFmPPI can be synthesized as follows.

PPPI or Br-mPPI (0.49 g, 1.08 mmol) synthesized in Synthesis Example 6 and 2M Na ₂ CO ₃ (0.50 g, 0.90 mmol) synthesized in Synthesis Example 5 were added to a 100 mL three- 5.0 mL) was dissolved in toluene / ethanol (15/5 mL), and the reaction mixture was refluxed in an argon atmosphere for 30 minutes. Pd (PPh ₃ ) ₄ (42 mg, 0.04 mmol) Lt; / RTI > for 12 hours. After the reaction is completed, the organic layer is separated and washed with brine solution (2 x 50 mL). The organic layer was separated by column chromatography using EA / hexane (0.5: 9.5 to 1: 9) as a developing solvent after removing water with anhydrous Na ₂ SO ₄ , and recrystallized with ethanol to obtain AFpPPI and AFmPPI in 86% (0.60 g) and 63% (0.45 g).

^{AFpPPI - 1 H NMR (300 MHz} , CDCl 3, δ): 8.94 (d, J = 8.4 Hz, 1H), 8.76 (dd, J = 8.1 Hz, 2H), 7.96 (d, J = 8.1 Hz, 1H) (M, 4H), 7.82-7.47 (m, 17H), 7.29-7.18 (m, 3H), 7.00-6.91 (s, 6H), 0.42 (t, J = 6.9 Hz, 6H).

^{AFmPPI - 1 H NMR (300 MHz} , CDCl 3, δ): 8.94 (d, J = 7.2 Hz, 1H), 8.76 (dd, J = 8.1 Hz, 2H), 7.98-7.95 (m, 1H), 7.84- (M, 4H), 6.36 (d, J = 7.5 Hz, 2H), 2.11-2.08 (m, m, 4H), 1.74 (s, 6H), 0.43 (t, J = 5.1 Hz, 6H).

Example  One: AFpPPI Wow AFmPPI Thermal stability

TGA analysis and DSC analysis were performed to examine the thermal stability of the blue fluorescent compounds AFpPPI and AFmPPI synthesized in the synthesis examples of the present invention. The results are shown in Figures 3a and 3b. The temperature at which 5% decomposition proceeds is 447 ° C and 454 ° C for AFpPPI and AFmPPI, respectively, indicating a thermally stable compound.

Example  2: AFpPPI Wow AFmPPI Of UV-visible and Photoluminescence ( PL ) Spectrum measurement

UV-visible absorption spectra were measured using a Shimadzu UV-3100 spectrometer in a state in which AFpPPI and AFmPPI, which were synthesized in the synthesis examples of the present invention, were dissolved in chloroform and in a thin film state. 4A and 4B are graphs showing the UV-visible absorption spectrum and the PL measurement results of the blue fluorescent compound synthesized in the present invention. In the case of AFpPPI and AFmPPI, the maximum absorption peaks were measured at 264 nm and 263 nm have. PL was measured with Hitachi F-4500 while AFpPPI and AFmPPI were dissolved in chloroform. PL was measured with the excitation wavelength at the UV maximum absorption wavelength measured in each blue fluorescent compound. As shown in FIGS. 4A and 4B, it was found that AFpPPI and AFmPPI synthesized in the present invention had maximum emission peaks at 436 nm and 431 nm, respectively, indicating pure blue emission colors. Table 1 below shows the optical, electrochemical and thermal properties of the blue fluorescent compounds AFpPPI and AFmPPI synthesized in the present invention.

Example  3: Blue fluorescence  Substance AFpPPI Wow AFmPPI Using Organic field  Fabrication of light emitting device

An organic electroluminescent device was fabricated according to a conventional method using AFpPPI and AFmPPI, which are blue fluorescent compounds synthesized in the synthesis examples of the present invention, as a light emitting material in the light emitting layer. In order to fabricate an organic electroluminescent device, a transparent electrode substrate coated with ITO on a glass substrate was thoroughly cleaned, an anode was formed using a photosensitive resin and an etching solution, and then cleaned again. A thin film was formed by spin coating at a thickness of about 40 nm of PEDOT: PSS as a hole injection layer. In order to improve the luminous efficiency, TAPC was vacuum deposited as a hole transport layer with a thickness of 10 nm. AFpPPI and AFmPPI, which are blue fluorescent compounds synthesized in the examples of the present invention, were used as the light emitting material of the light emitting layer, and the light emitting layer was formed with a thickness of 50 nm by spin coating. TPBi was vacuum deposited to a thickness of 20 nm as an electron transport layer. Then, a thin film was sequentially formed by vacuum evaporation of LiF, which is an electron injection layer, and an Al electrode as a cathode was formed to fabricate an organic electroluminescent device. The vacuum for the vacuum deposition was maintained at 4 × 10 ^-6 torr or less while the thin film was formed by vapor deposition. The film thickness and film growth rate were controlled by using a crystal sensor. The emission area was 4 ㎟ and the driving voltage was a DC voltage and a forward bias voltage was used.

FIG. 5 shows the structure of the organic electroluminescent device and the energy levels of the hole injecting layer, the hole transporting layer, the light emitting layer, and the electron transporting layer applied to the present invention, and FIG. 6 shows energy levels according to the respective materials.

Example  4: Measurement of luminescence characteristics of light-emitting diodes

In this embodiment, the luminescent characteristics of the organic EL device fabricated in Example 3 were measured using a conventional method. FIG. 8 shows the electroluminescence (EL) intensity, FIG. 9 shows the external quantum efficiency (EQE), FIG. 10 shows the results of measuring the luminous efficiency and the voltage efficiency Respectively. As shown in the figure, the device fabricated according to the present invention showed the maximum electroluminescence spectrum in the blue wavelength region at 451 nm and 419 nm, and exhibited typical diode characteristics in which the luminescence brightness increased with increasing current density. The maximum emission luminance was 360 cd / m ² and the maximum external quantum efficiency was observed at 2.50%. Especially, the color coordinates were (0.157, 0.125) and (0.178, 0.119) And exhibited an improved pure blue luminescent color. Table 2 summarizes the physical properties of the light emitting diode devices measured according to this embodiment.

Although the present invention has been described based on the exemplary embodiments and examples of the present invention, the present invention is not limited to the technical ideas described in the above-described embodiments and examples. On the contrary, those skilled in the art can easily make various modifications and alterations based on the above-described embodiments and embodiments. It will be apparent, however, that such modifications and variations are all within the scope of the present invention.

100: display device 101: first substrate (base substrate)
102: second substrate (encapsulation substrate)
110: first electrode 120: organic light emitting layer
121: Hole injection layer 122: Hole transport layer
123: luminescent material layer 124: electron transport layer
125: electron injection layer 130: second electrode
DTr: driving thin film transistor E: organic light emitting diode

Claims (7)

A light-emitting compound capable of being subjected to a solution process represented by the following formula (1).
Formula 1

(R ₁ and R ₂ are each independently a hydrogen atom or a C ₁ -C ₂₀ alkyl group in the formula (1); or R ₃ and R ₄ are each independently hydrogen, C ₁ -C ₂₀ alkyl group, a substituted or heavy hydrogen, C ₁ - C ₁₀ alkyl group, C ₁ -C ₁₀ alkylsilyl group, C ₁ -C ₁₀ alkyl halide, nitro, -CN, a homo or heteroaryl group substituted with at least one functional group selected from a group consisting of a halogen and a phenyl group; R ₅ is unsubstituted or substituted with at least one group selected from the group consisting of deuterium, C ₁ -C ₁₀ alkyl group, C ₁ -C ₁₀ alkylsilyl group, C ₁ -C ₁₀ alkyl halide, nitro group, -CN, a homo or hetero arylene group substituted with one functional group; R ₆ is unsubstituted or substituted with heavy hydrogen, C ₁ -C ₁₀ alkyl, C ₁ -C ₁₀ alkylsilyl group, C ₁ -C ₁₀ alkyl halide, nitro, -CN, halogen ≪ / RTI > and phenyl groups substituted with at least one functional group selected from the group consisting of < RTI ID = 0.0 >Group; R ₇ and R ₈ are each independently being a hydrogen atom, a heavy hydrogen, C ₁ -C ₁₀ alkyl, C ₁ -C ₁₀ alkylsilyl group, C ₁ -C ₁₀ alkyl halide, nitro, -CN, halogen or a phenyl group )
The method according to claim 1,
The light-emitting compound capable of being subjected to the solution process of Formula 1 may be a solution process comprising a compound represented by Formula 2 or 3.
(2)

(3)

(Wherein R ₁ to R ₄ , R ₇ and R ₈ are the same as defined in formula (1), R ₉ and R ₁₀ are each independently a hydrogen atom, deuterium, a C ₁ -C ₁₀ alkyl group, being C ₁ -C ₁₀ alkylsilyl group, C ₁ -C ₁₀ alkyl halide, nitro, -CN, halogen or phenyl group)
The method according to claim 1,
Wherein R ₁ and R ₂ are each a C ₁ -C ₁₀ alkyl group, R ₃ and R ₄ are each a C ₁ -C ₁₀ alkyl group, R ₅ is phenylene, and R ₆ is a phenyl group Possible luminescent compounds.
A first electrode;
A second electrode facing the first electrode;
At least one organic compound layer disposed between the first electrode and the second electrode, wherein the organic compound layer includes a light-emitting compound capable of performing a solution process as recited in any one of claims 1 to 3,
.
5. The method of claim 4,
Wherein the organic layer includes a light emitting material layer.
6. The method of claim 5,
Wherein the light emitting compound capable of being subjected to the solution process is contained in at least one organic layer of a hole injecting layer and a hole transporting layer positioned between the first electrode and the light emitting material layer.
A first substrate;
A driving thin film transistor located on the first substrate;
A light emitting diode disposed on the first substrate and connected to the driving thin film transistor, the light emitting diode including a light emitting compound capable of performing a solution process according to any one of claims 1 to 3 in at least one organic layer;
A second substrate covering the light emitting diode and being attached to the first substrate,
.

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