KR101353931B1 - Novel organic compound, and an organic electronic device comprising the same - Google Patents

Abstract

The present invention provides a novel organic compound used in the form of a thin film in the electron transport layer or hole blocking layer of the organic electronic device. The organic compound of the present invention improves the interfacial properties due to the stable imide compound properties and the coordination bond between the nitrogen compound and the metal material, thereby prolonging the life of the organic electronic device, and improving the organic affinity with the effect of improved electron affinity and electron mobility. The driving voltage of the electronic device is lowered. When the organic compound of the present invention is used in the form of a thin film in the electron transport layer of the organic electronic device, it has the effect of blocking holes in the organic electroluminescent layer. In addition, the present invention has very high luminescence and energy efficiency, and can be used in various electric semiconductor fields such as organic electroluminescent display, organic TFT, organic memory or organic light emitting device.

Description

Novel organic compound and organic electronic device comprising the same {NOVEL ORGANIC COMPOUND, AND AN ORGANIC ELECTRONIC DEVICE COMPRISING THE SAME}

The present invention relates to a novel organic compound and an organic electronic device comprising the same.

In the last decades, many have simplified the process, lower production costs and various applications, such as organic light-emitting diodes (OLEDs), organic photovoltaic devices (OPVs), organic field effect transistors ( Organic field-effect transistors (OFETs)) and other fields such as electronic and optoelectronic devices have been studied for organic semiconductor materials or organic semiconductor devices [1-7]. In addition, electron and hole transporting layers (hole transporting layers) are located between the two electrodes (electrodes) of the organic light emitting device. Compared to inorganic semiconductor liquid crystal displays (LCDs), phosphorescent OELDs can achieve fast response, high color purity, wide viewing angle, high contrast, thin thickness and fluidity. Has been successfully introduced in display markets such as car audio, MP3, flat panel televisions and lighting [8-9].

Nano-layer organic semiconductor devices rely on materials based on small molecules in device organisms that play a crucial role in charge transfer as well as charge generation and injection. In addition to long life and stability, high device efficiency, low drive voltage, high color purity and light emission can be realized in full color flat-panel displays and lighting. For high device performance, the material responsible for charge transfer and implantation is key. It is essential to develop organic materials with high charge flowability and increase charge concentration [10, 11].

The organic layer manufactured by the conventional vacuum deposition method, for example, the hole transport layer, has a problem in that the life of the device is shortened because the thin film is deformed or destroyed due to heat generated when driving the device. Recently, in order to solve such problems, active materials such as hole transport materials and polymethyl methacrylate (PMMA) or polycarbonate (PC) and other vinyl-based polymers such as An organic layer in which an organic light emitting material was dispersed was prepared. However, such a polymer is the stability of the organic layer produced is low in heat resistance is not satisfactorily (Kido et al, Appl Phys Lett , 61, No. 7171, (1992);.... Jpn, J. Appl.Phys , 31, No. 78. L960, (1992)).

U.S. Pat.Nos. 5,609,970, 5571626, 5414069 and 5376456 disclose new electroluminescent polymers. However, high driving voltage and heat instability do not solve the problem of low luminous efficiency and short life.

Therefore, there is a need for a novel organic compound in which the above problems are solved, and such a novel organic compound and an organic electronic device including the same have not been reported yet.

Numerous papers and patent documents are referenced and cited throughout this specification. The disclosures of the cited papers and patent documents are incorporated herein by reference in their entirety to better understand the state of the art to which the present invention pertains and the content of the present invention.

DETAILED DESCRIPTION OF THE INVENTION [

The present inventors have tried to develop an organic electronic device having low driving voltage and heat stability, and having high efficiency and long life. As a result, a novel organic compound having improved electron affinity and electron mobility and an organic electronic device including the novel organic compound were developed, and it was confirmed that low driving voltage and lifespan were greatly improved.

Accordingly, it is an object of the present invention to provide novel organic compounds.

Another object of the present invention is to provide an organic electronic device, wherein the novel organic compound is contained in a thin film form in an electron transport layer or a hole blocking layer.

Other objects and advantages of the present invention will become more apparent from the following detailed description of the invention, claims and drawings.

According to one aspect of the present invention, the present invention provides an organic compound having the structure of Formula 1:

Formula 1

A is a moiety of a dianhydride; R _{1 to} R ₁₄ are each independently an aliphatic group, an aryl group, or hydrogen.

The present inventors have tried to develop an organic electronic device having low driving voltage and heat stability, and having high efficiency and long life. As a result, a novel organic compound having improved electron affinity and electron mobility and an organic electronic device including the novel organic compound were developed, and it was confirmed that low driving voltage and lifespan were greatly improved.

According to a preferred embodiment of the present invention, in the organic electron transport compound used in the present invention, A is pyromellitic dianhydride, 3,4,3 ', 4'-biphenyltetracarboxylic dianhydride, 3,4,3 ', 4'-benzophenone tetracarboxylic dianhydride, 4,4'-(hexafluorologylidene) diphthalic hydride, 4,4 '-(dimethylsilicone) dip Talic anhydride, 4,4'-oxydiphthalic anhydride, 3,3 ', 4,4'-diphenylsulfone tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetra Carboxylic dianhydrides, naphthalene-1,4,5,8-tetracarboxylic dianhydrides, 3,4,9,10-perylene tetracarboxylic dianhydrides, 4- (2,5- Dioxotetrahydrofuran-3-yl) tetraline-1,2-dicarboxylic anhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1 , 2-dicarboxylic anhydride, bissai Chloro [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 2,2'-di-tert-butylbiphenyl-bis (etherphthalic anhydride) Lead), 2,5-di-tert-butylphenyl-bis (etherphthalic anhydride) or bisphenol A-bisA-bis (etherphthalic anhydride), most preferably pyro It is a moiety of metician dianhydride.

More specifically, A may include a compound having the following structure.

In formula (1), R ₁ -R ₁₄ are each independently an aliphatic group, an aryl group, or hydrogen. As used herein, the term "aliphatic group" includes alkyl, cycloalkyl, alkylene, alkenyl, alkenylene, alkynyl and alkynylene.

When any one of R ₁ -R ₁₄ is an aliphatic group, preferably, any one of R ₁ -R ₁₄ is alkyl or alkylene, more preferably alkyl.

The term "alkyl" means a straight or pulverized saturated hydrocarbon group having the specified carbon number, preferably "C ₁ -C ₄ straight or branched chain alkyl", which is low-cost alkyl as methyl, ethyl, n -propyl, isopropyl, Isobutyl, n -butyl and t -butyl. The term "alkenyl group" refers to a straight chain or branched unsaturated hydrocarbon group having the specified carbon number, preferably C ₂ -C ₆ straight or branched chain alkenyl, which is a hydrocarbon group having 2 to 6 carbon atoms having at least one double bond. Examples include ethenyl, propenyl, isopropenyl, butenyl, isobutenyl, t -butenyl, n -pentenyl and n -hexenyl.

The term "cycloalkyl" means a cyclic hydrocarbon radical having the specified carbon number, preferably "C ₃ -C ₈ cycloalkyl", which includes cyclopropyl, cyclobutyl and cyclopentyl.

As used herein, the term "aryl" refers to a substituted or unsubstituted monocyclic or polycyclic carbon ring which is wholly or partially unsaturated, preferably monoaryl or biaryl. It is preferable that monoaryl has 5-6 carbon atoms, and it is preferable that biaryl has 9-10 carbon atoms. Most preferably said aryl is substituted or unsubstituted phenyl. When monoaryl, such as phenyl, is substituted, substitutions may be made by various substituents at various positions, but preferably halo, hydroxy, nitro, cyano, C ₁ -C ₄ substituted or unsubstituted straight chain Or branched alkyl, C ₁ -C ₄ straight or branched alkoxy, alkyl substituted sulfanyl, phenoxy, C ₃ -C ₆ cycloheteroalkyl or substituted or unsubstituted amino groups.

According to the most preferred embodiment of the invention, in formula 1, R ₁ -R ₁₄ is hydrogen.

In the organic electronic device according to an embodiment of the present invention, the compound mixed or doped in the electron transport layer or the hole blocking layer is 2,6-Bis- (1,10) -phenanthroline-5-yl-pyrrolo (3 Isoindole-1,3,5,7-tetraon (2,6-Bis- (1,10) -phenanthroline-5-yl-pyrrolo (3,4-f) isoindole-1,3 , 5,7-tetraone: BiPhPyIsTe), and the compound is synthesized by the following reaction.

According to a preferred embodiment of the present invention, the organic compound of the present invention is used in the form of a thin film on the electron transport layer or the hole blocking layer of the organic electronic device (organic electron device), more preferably the organic compound Organic light emitting diodes (OLEDs), organic photovoltaic devices (OPV), organic field effect transistors (OFETs), organic lasers, electromagnetic shielding film, capacitors (Capacitor) is used in the form of a thin film in the electron transport layer or hole blocking layer of the memory device, Even more preferably, it is used in the form of a thin film in the electron transport layer or the hole blocking layer of the organic light emitting diode, the organic photovoltaic device, the organic field effect transistor, and most preferably the thin film is formed in the electron transport layer or the hole blocking layer of the organic light emitting diode. It is used in the form.

According to another aspect of the present invention, the present invention provides an organic electronic device, characterized in that the compound of formula 1 is included in the form of a thin film in the electron transport layer or hole blocking layer. :

Formula 1

A is a moiety of a dianhydride; R _{1 to} R ₁₄ are each independently an aliphatic group, an aryl group, or hydrogen.

Since the organic electronic device of the present invention uses the above-described compounds of the present invention as essential components, the contents common between the two are omitted in order to avoid excessive complexity of the present specification.

According to a preferred embodiment of the present invention, the electron transport layer or the hole blocking layer of the organic electronic device is configured by mixing or doping the electron transport material and the compound of Formula 1, the electron transport material is a tri- (8-hydroxy- Quinolinato) aluminum (Tris (8-hydroxy-quinolinato) aluminium (Alq ₃ ), vasocuproin, oxadiazole derivatives (tBu-PBC), triazole derivatives, phenylkinocysarin derivatives, sirol derivatives or mixtures thereof to be.

According to a specific embodiment of the present invention, the organic compound of Chemical Formula 1 is doped into tri (8-hydroxyquinolinato) aluminum (Alq ₃ ) as the electron transport material. Preferably by the formula (1) it is doped with the compound to 0.01-10% by weight of the Alq _3, preferably doped with 0.05-7%, and more, particularly 0.01-5% more preferably, based on the weight of Alq ₃ Doping, most preferably 0.2-2%.

The organic electronic device of the present invention includes a part of a conventional organic electronic device. For example, the organic electronic device of the present invention may include an anode, a cathode, a hole transport layer, a light emitting layer, and an electron transport layer.

In the organic electronic device of the present invention, the anode includes any material conventionally used in the art, and is preferably ITO, more preferably ITO vacuum deposited on an organic plastic substrate or glass.

In the organic electronic device of the present invention, the cathode is preferably a metallic cathode, more preferably Al, In, Al: Li alloy, LiF: Al alloy, Mg / Ag, Mg: Ag alloy, Ca / Ag or Ca / Al Or the like.

The light emitting layer in the organic electronic device of the present invention includes any material commonly used in the art.

One of the biggest features of the present invention is that the compound of Formula 1 is included in the form of a thin film in the electron transport layer of the organic electronic device. Although it may be included in various forms in the electron transport layer, it is very advantageous in the operation of the organic electronic device to include the compound of Formula 1 in the form of a thin film.

According to a specific embodiment of the present invention when manufacturing an organic electronic device as follows.

First, indium tin oxide (ITO) of 10Ω / square (□), which is an anode material, is deposited on a transparent substrate. 4,4 ', 4''-tris (N- (2-naphthyl) -N-phenyl-amino) triphenylamine (4,4', 4 ''-Tris (N- ( 2-naphthyl) -N-phenyl-amino) triphenylamine: 2-TNATA) was deposited at 400 kPa, and N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) as the hole transport layer. -Benzidine (N, N'-Bis (naphthalen-1-yl) -N, N'-bis (phenyl) -benzidine: NPB) is deposited at 300 kPa. Then, in order to form the light emitting layer, 5% tris in 4,4'-bis (carbazol-9-yl) biphenyl (4,4'-Bis (carbazol-9-yl) biphenyl (CBP)) was used. 2-phenylpyridine) iridium (III) (Tris (2-phenylpyridine) iridium (III): Ir (ppy) ₃ ) was simultaneously deposited by weight and 15% bis (2-benzo [b] ti for red devices Open-2-yl-pyridine) (acetylacetonate) iridium (III) (Bis (2-benzo [b] thiophen-2-yl-pyridine) (acetylacetonate) iridium (III): Ir (btp) 2 (acac) ) Is deposited on CBP at the same time by weight 300 mm thick. Balq (Bis (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminium) is deposited at 100 kPa to block holes and limit excitons in the light emitting layer.

Then, the electron transport layer can be manufactured in two ways.

First, BiPhPyIsTe in the form of a thin film is deposited to a thickness of 0.5 nm. A 3 mm x 3 mm opening mask was used to form a cathode consisting of a 10 μs LiF layer and an 100 nm Al layer. In the case of depositing BiPhPyIsTe as a thin film as the electron transport layer, it has not only a very good luminous efficiency and a low driving voltage, but also prevents the loss of unnecessary materials in the electron transport layer, unlike the conventional method of 200 nm deposition. There is this.

The other is 300 kW-thickness co-doped with Tri (8-hydroxy-quinolinato) aluminum (Alq ₃ ) and BiPhPyIsTe according to various doping ratios. The electron transport layer of is used as the final organic layer in the form of a thin film. A 3 mm x 3 mm opening mask was used to form a cathode consisting of a 10 μs LiF layer and an 100 nm Al layer.

When BiPhPyIsTe is deposited in Alq ₃ in the form of a thin film as the electron transport layer, an organic electronic device having a much improved lifespan may be manufactured due to a lower driving voltage and higher luminous efficiency than the conventional electron transport layer.

The features and advantages of the present invention are summarized as follows:

(Iii) The present invention provides a novel organic compound used in the form of a thin film in an electron transport layer or a hole blocking layer of an organic electronic device.

(Ii) The organic compounds of the present invention have improved interfacial properties due to the stable imide compound properties and the coordination bonds between nitrogen compounds and metal materials, thereby prolonging the life of organic electronic devices and improving the electron affinity and electron mobility. The effect is to lower the driving voltage of the organic electronic device.

(Iii) When the organic compound of the present invention is used in the form of a thin film in the electron transport layer of an organic electronic device, it has the effect of blocking holes in the organic electroluminescent layer.

(Iii) In addition, the present invention has very high luminescence and energy efficiency and can be used in various electric semiconductor fields such as organic electroluminescent display, organic TFT, organic memory or organic optical element.

Figure 1 shows the chemical formula of the novel organic compound of the present invention.
2A-2D shows 2,6-Bis- (1,10) -phenanthroline-5-yl-pyrrolo (3,4-f) isoindole-1,3,5,7-tetraon (2, 6-Bis- (1,10) -phenanthroline-5-yl-pyrrolo (3,4-f) isoindole-1,3,5,7-tetraone: BiPhPyIsTe. 2A is MALDI-TOF mass spectrometry showing the molecular weight of the synthesized material. Among the peaks, the peak corresponding to 558.39 is the peak corresponding to BiPhPyIsTe of the present invention. 2B and 2C show DSC thermograms of BiPhPyIsTe powder. Figure 2d is the result of measuring the thermal stability of BiPhPyIsTe using TGA.
3A-3C show the results of UV-vis absorption and photoluminance spectra (PL spectra) of a BiPhPyIsTe thin film on a glass substrate. Figure 3a is the result showing the UV-vis absorption for BiPhPyIsTe. 3B shows the PL spectra for BiPhPyIsTe. FIG. 3C shows the work function for BiPhPyIsTe using cyclovoltametry. FIG.
4A-4D show the device characteristics of BiPhPyIsTe. 4A is a result of the relationship between the voltage and the luminous efficiency of BiPhPyIsTe as the electron transport layer. 4B is a result of the relationship between current density, voltage, and luminescence of BiPhPyIsTe as an electron transport layer. 4C is a result of the relationship between the luminous efficiency and voltage of BiPhPyIsTe doped in ALq ₃ as the electron transport layer. 4D is a result of the relationship between current density, voltage, and luminescence of BiPhPyIsTe doped with ALq ₃ as the electron transport layer.
5 is the result for standard EL spectra detected at 1000 cd / cm 2.
6 is a schematic view of an organic light emitting display device according to the present invention.
7 shows the FT-IR spectrum of Bphen-BCDI.
8 is a generalization of BCDA-PTA by measuring the UV-vis absorption spectrum. In Figure 8 (a) is a generalization of 50 nm thick BCDA-PTA by measuring the UV-vis absorption spectrum. (b) shows photoluminescence of BCDA-PTA and shows fluorescence of 400 nm wavelength.
9A-9B show results of a thermogram of BCDA-PTA. FIG. 10A shows the DSC thermogram of BCDA-PTA, and FIG. 10B shows the thermal stability of BCDA-PTA through thermogravimetric analysis.
10 shows a cyclic voltametry (CV) curve. The CV curve shows an irreversible form and it can be seen that it oxidizes at 0.97 V vs. Ag / Ag ⁺ .
Description of the Related Art
1: glass
2: ITO
3: 2-TNATA
4: a-NPB
5: CBP-Host
1) Green dopant: Ir (ppy) ₃ or 2) Red dopant: Ir (btp) ₂ (acac))
6: Balq
7: 1) BiPhPyIsTe or 2) ALq ₃ and BiPhPyIsTe
8: LiF-Al cathode
9: voltage
Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not to be construed as limiting the scope of the present invention. It will be self-evident.

[Mode for Carrying Out the Invention]

Throughout this specification, "%" used to indicate the concentration of a particular substance is (weight / weight)% solids / solid, (weight / volume)%, unless otherwise indicated, and Liquid / liquid is (volume / volume)%.

Materials and methods

Materials and Analytical Methods

Pyromellitic dianhydride (Aldrich, USA) and (1,10) phenanthroline-5-ylamine ((1,10) phenanthrolin-5-ylamine; Aldrich, USA in dimethyl acetamide under nitrogen ) To 2,6-Bis- (1,10) -phenanthrolin-5-yl-pyrrolo (3,4-f) isoindole-1,3,5,7-tetraone (2,6-Bis -(1,10) -phenanthroline-5-yl-pyrrolo (3,4-f) isoindole-1,3,5,7-tetraone: BiPhPyIsTe) was synthesized in 82% yield. The synthesis process is shown in Scheme 1.

Scheme 1

First, 1 g (4.5 mmol) of pyromellitic dianhydride is sufficiently dissolved in 90 ml of dimethylacetamide, followed by 2.04 g (10.5 mmol) of (1,10) phenanthroline-5-ylamine. After stirring the mixture, an appropriate amount of triethylamine (0.24 g) acting as a catalyst was added thereto, followed by heating with sufficient stirring. The solution was stirred at 160 ° C. for 24-36 hours and then cooled to room temperature. This was extracted using methanol, the glass was filtered and the organic solvent was evaporated in a vacuum oven. This was separated using a sublimation apparatus to finally obtain BiPhPyIsTe of the present invention.

On the other hand, in addition to BiPhPyIsTe, a compound in which the A part in Formula 1 is biphenyl, diphenylsulfone, benzophenone, naphthalene, perylene, or hexafluoroisopropylidene biphenyl may be substituted for (1,10) phenanthroline-5-ylamine. 3,4,3 ', 4'-biphenyltetracarboxylic dianhydride, 3,4,3', 4'-benzophenone tetracarboxylic dianhydride, 4,4 '-(hexafluorolog, respectively) Polyallyne) diphthalic anhydride, 4,4 '-(dimethylsilicone) diphthalic anhydride, 4,4'-oxydiphthalic anhydride, 3,3', 4,4'-diphenyl Sulfone tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, 3,4, 9,10-perylene tetracarboxylic dianhydride, 4- (2,5-dioxotetrahydrofuran-3-yl) tetraline-1,2-dicarboxylic anhydride, 5- ( 2,5-dioxotetrahydrofuryl) -3-meth Butyl-3-cyclohexene-1,2-dicarboxylic anhydride, bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 2,2'-di-tert-butylbiphenyl-bis (etherphthalic anhydride), 2,5-di-tert-butylphenyl-bis (etherphthalic anhydride) or bisphenol A-bisA- Prepared using bis (etherphthalic anhydride) in a similar manner to the preparation method.

Purification was carried out using a homebuilt vacuum sublimation system equipped with a precise temperature controller according to Thermogravimetric Analysis (TGA) thermal analysis with 20% weight loss. Before and after sublimation, weight loss was shown with increasing temperature (FIGS. 1A-1D) and the BiPhPyIsTe material was purified at about 200 ° C.

The molecular weight of the synthesized material is shown in Figure 2a using MALDI-TOF mass spectrometry (Reflex III). As a result of comparing the molecular weight of the BiPhPyIsTe molecule and the MALDI-TOF mass spectrometry, the ratio of each molecule of BiPhPyIsTe was consistent with the MALDI-TOF mass spectrometry (Table 1). Material thermal stability was verified by differential scanning calorimetry (DSC, TA Instruments / TA 4000) and thermal gravimetric analysis (TGA, Seiko, TG / DTA 320), and by cyclovoltametry Electrical stability was verified. Films of Alq ₃ films and synthetic materials doped with Alq ₃ (doping ratios of 0, 0.2, 0.5 and 1.0%) were subjected to ultraviolet-visible absorption spectroscopy (UV-vis, Mecasys, Optizen 2120+) and emission spectroscopy (PL, The optical properties were analyzed by the JASCO FP-6500 flourescence spectrometer.

Table 1

Device Fabrication and Evaluation

A device was prepared from an ITO glass substrate of about 10 Ω / square (square) precleaned with acetone and isopropyl alcohol for 30 minutes each. In order to improve device performance, the hole injection layer is 400 kV, 4,4 ', 4''-tris (N- (2-naphthyl) -N-phenyl-amino) triphenylamine (4,4', 4 '' -Tris (N- (2-naphthyl) -N-phenyl-amino) triphenylamine: 2-TNATA) was deposited, and the hole transport layer was 300 mW N, N'-bis (naphthalen-1-yl) -N It was deposited with, N'-bis (phenyl) -benzidine (N, N'-Bis (naphthalen-1-yl) -N, N'-bis (phenyl) -benzidine: NPB). Then, 5% of 4,4'-bis (carbazol-9-yl) biphenyl (4,4'-Bis (carbazol-9-yl) biphenyl; CBP) was used for the green device to form a 300 Å light emitting layer. Tris (2-phenylpyridine) iridium (III): Ir (ppy) ₃ was deposited simultaneously by weight, and 15% bis (2-benzo [b] for the red device. ] Thiophen-2-yl-pyridine) (acetylacetoneate) iridium (III) (Bis (2-benzo [b] thiophen-2-yl-pyridine) (acetylacetonate) iridium (III): Ir (btp) 2 ( acac)) was simultaneously deposited by weight in CBP. Balq (Bis (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminium) was deposited at 100 kPa to block holes and limit excitons in the light emitting layer.

The electron transport layer was prepared in two ways.

First, BiPhPyIsTe in the form of a thin film was deposited to a thickness of 0.5 nm. Using a 3 mm x 3 mm opening mask, a cathode consisting of a 10 μs LiF layer and an Al layer of 100 nm was formed.

The other co-dopes Tri (8-hydroxy-quinolinato) aluminum (Alq ₃ ) and BiPhPyIsTe under varying doping ratios with different parameters fixed. A 300 Å-thick electron transport layer was used as the final organic layer. Using a 3 mm x 3 mm opening mask, a cathode consisting of a 10 μs LiF layer and an Al layer of 100 nm was formed.

All deposition processes were carried out in -situ without damaging the vacuum. Keithley source meter 236 and Konica Minolta Spectroradiometer CS-1000S with current density-voltage (JV) and emission-voltage: LV) characteristics were measured.

BCDA-PTA (Bphen-BCDI) Synthesis

BCDA (bicyclo- [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride) -PTA ([1,10] phenanthrolin according to PMDA-PTA (Bphen-PMDI) manufacturing process -5-yl-amine). 0.9307 g BCDA (3.75 mmol; Aldrich, USA), 1.680 g PTA (8.625 mmol; Aldrich, USA) and 0.4 g triethylamine (Aldrich, USA) were dissolved in 50 mL DMAc (dimethylacetamide; Aldrich, USA). The mixture was reacted through a reflux apparatus with vigorous mixing at 160-170 ° C. for 36 hours. Color change was observed during the reaction. After cooling to room temperature, the synthesized mixture was filtered, washed with DMAc and dried in a vacuum oven to obtain a material of 80% yield.

(2)

Experiment result

Thermal Characteristics of BiPhPyIsTe

BiPhPyIsTe obtained by heating to 350 ° C. at the first, room temperature, cooling to room temperature at the second 350 ° C. and then heating to 350 ° C. at the third room temperature in order to remove the preceding thermal history and to measure the glass transition temperature. Thermal properties of the DSC thermogram of the powder are shown in FIGS. 2B and 2C. The glass transition temperature of BiPhPyIsTe started at 240 ° C. and stopped at 260 ° C.

In order to measure the thermal stability, TGA of BiPhPyIsTe indicating the weight loss (%) with temperature was used (FIG. 2D), and it was confirmed that it was thermally decomposed at about 400 ° C. and completely decomposed at 600 ° C. or higher. Given that the typical deposition temperature is above 200 ° C., the properties of BiPhPyIsTe as described above means that it is thermally very stable as the active material of OLEDs.

Optical Properties of BiPhPyIsTe Thin Films

UV-vis absorption and photoluminance spectra (PL spectra) of BiPhPyIsTe thin films were measured on a glass substrate. From the absorption edge at 350 nm, the spacing of the BiPhPyIsTe energy bands was 3.54 eV and the UV-vis peaks were approximately 240 nm and 270 nm. Compared to the native Alq ₃ film, there was no specific change in the film co-deposited with Alq ₃ and BiPhPyIsTe, and these results show that Alq ₃ was mainly deposited on the film (FIGS. 3A-3B).

Also, even though the native BiPhPyIsTe film was approximately 400 nm, the PL spectra of the doped films (which changed to green in 0.2, and 0.5%, but 2.0% film) were identical to the native Alq ₃ . This property means that the conjugate length of the sample is similar compared to the native Alq ₃ .

Electric Characteristic of BiPhPyIsTe

The work function was confirmed to be 3.9 eV through cyclovoltametry (FIG. 3C).

The LUMO level of BiPhPyIsTe for the device was calculated to be 2.9 eV.

Device Characteristics of BiPhPyIsTe

Trends in device current density were higher for devices with lower doping ratios (0.2 and 0.5%) compared to inherent Alq ₃ and 1.0% devices. This property is believed to be due to holes that do not confine the Balq (Bis (2-methyl-8-quinolinolato-N1,08)-(1,1'-Biphenyl-4-olato) aluminum) hole blocking layer. . Homo of BiPhPyIsTe showed 6.4 eV even though Balq and Alq ₃ homo were 6.7 eV and 5.9 eV, respectively.

In the case of using a 0.5 nm thick BiPhPyIsTe thin film as the electron transport layer, low driving voltage and luminous efficiency were exhibited, and thermal stability of BiPhPyIsTe improved the stability of the organic electronic device (FIGS. 4A-4B).

In addition, when the BiPhPyIsTe thin film is used in the electron transport layer as compared with the conventional electron transport layer having a thickness of 200 nm or more, unnecessary waste of material can be prevented, and the organic electronic device manufacturing process can be performed more simply and energy efficiently.

Compared to the intrinsic Alq ₃ electron transport layer having a driving voltage of 7.0 V at 100 cd / m 2, the red phosphorescent device fabricated with an electron transport layer doped with BiPhPyIsTe in Alq ₃ at a 0.2% ratio was as low as 6.5 V at 100 cd / m 2. While the drive voltage was shown, the turn-on voltage (luminescence at 1 cd / cm 2) in the devices showed values close to 4 V (FIGS. 4C-4D). The intrinsic Alq ₃ was 10 V at 1000 cd / m 2 while the device voltage doped with BiPhPyIsTe of 0.2% was 9.0 V, which contributes to higher charge concentrations. In addition, the device efficiency of 2% doped BiPhPyIsTe at a low voltage such as 4-5 V was higher than that of the ETL (Electron transporting Layer) consisting of Alq ₃ alone, and this characteristic may indicate a low driving voltage. It became.

FIG. 5 shows EL spectra of devices detected at 1000 cd / m 2 emission, with almost all devices showing the highest peak around 618 nm and another peak at 675 nm.

Of BCDA-PTA ¹³ C NMR, FT-IR, and EA

As the surrounding environment of carbon was changed through the imidization reaction, it was found that each peak appeared through ¹³ C NMR. Since the R3CH group shows peaks on the order of 20-60, the peaks 35 and 43 shown in the ¹³ C NMR spectrum correspond to the peaks of benzene in the range 110-175. Many peaks appeared, and the peak of the amide (RCONH ₂ ) was found to be in the range of 155-185 for the 176 peak outside the range.

In the FT-IR spectrum of Bphen-BCDI, imide groups showed absorption bands near 1737, 1639, 1362 and 745 cm ⁻¹ (FIG. 7). Among them, 1737 cm ⁻¹ represents C = 0 of the imide group. And 1362, 745 cm ^-1 bands indicate CNC coupling.

Element analysis (EA) showed that nitrogen, carbon, hydrogen, and oxygen constitute 13.8, 70.3, 3.7, and 11.0%, respectively. The molecular formula shows that C ₁₈ H ₁₁ N ₃ O ₂ is the same as BCDA-PTA. The results of EA analysis and NMR showed that the molecular formulas matched and the functional groups appeared, confirming the synthesis of the substances.

BCDA-PTA with a thickness of 50 nm was generalized by measuring UV-vis absorption spectra, and the results showed absorption regions at 225 nm and 270 nm. The energy band gap of BCDA-PTA was predicted to be about 3.78 eV because the absorption region was 330 nm at the end ((a) in FIG. 8). It can be seen that the photoluminescence of BCDA-PTA shows fluorescence of 400 nm wavelength ((b) in FIG. 8).

BCDA-PTA powder was analyzed by heating to 350 ℃ at room temperature three times over the glass transition temperature was found to be about 225 ℃ (Fig. 9a). Thermal stability of BCDA-PTA was measured by thermogravimetric analysis. As a result. In the case of the synthesized single molecule, decomposition could be seen to be thermally started at almost 400 ° C., and completely decomposed at 550 ° C. or more (FIG. 9B). In addition, even when the synthesized single molecule is applied to the OLED it can be seen that it can be driven at 200 ℃ or more (Fig. 9b).

FIG. 10 shows a cyclic voltametry (CV) curve, which shows an irreversible form and oxidizes at 0.97 V vs. Ag / Ag ⁺ . In the case of the CV graph, it indicates the HOMO level of the material, and in this case, it was found that it was about 5.7 eV, and this value was almost in agreement with the value shown in the photo electron spectrometer.

Review

In conclusion, we describe a material with an imide group of BiPhPyIsTe for OLEDs with electronic and optical properties and doped layers. OELDs doped with 2% BiPhPyIsTe in the Alq ₃ electron transport layer produced the brightest light and the lowest drive voltage at various doping ratios. These results indicate that OELDs made of new novel n-type organic materials with high flowability, thermal and electronic stability have potential applicability.

references

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While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (8)

An organic compound having the structure
Formula 1

In the above formula, A is

,

,

,

,

,

or

ego;
R ₁ -R ₁₄ are each independently straight or branched C ₁ -C ₄ alkyl or hydrogen.
delete The organic compound of claim 1, wherein the organic compound is used in the form of a thin film in an electron transport layer or a hole blocking layer of an organic electron device. The organic electronic device of claim 3, wherein the organic electronic device is an organic light emitting diode (OLED), an organic photovoltaic device (OPV), an organic field effect transistor (OFETs), an organic laser, an electromagnetic shielding film, a capacitor, or a memory device. Organic compounds. An organic electronic device comprising an electron transport layer or a hole blocking layer containing the organic compound of claim 1 in the form of a thin film.
delete The organic electronic device of claim 5, wherein the electron transport layer or the hole blocking layer is doped with an organic compound in an electron transport material. delete

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