KR20090018503A - Oxadiazole derivative containing compound and organic light emitting device comprising the same - Google Patents

Abstract

An oxadiazole derivative compound is provided to improve the thermal and electrical stability, thereby producing the organic light-emitting device having low driving voltage, excellent color purity and long durability property. The organic light-emitting device comprises a first electrode, a second electrode and an organic film between the first and second electrodes which comprises the oxadiazole derivative compound represented by the chemical formula(1), wherein R1 is substituted or unsubstituted C1-C20 alkylene group, substituted or unsubstituted C3-C20 cycloalkylene group, substituted or unsubstituted C1-C20 heteroalkylene group, substituted or unsubstituted C3-C20 arylene group, substituted or unsubstituted C1-C20 heteroarylene group, thiophenyl, silylene, carbazolylene, fluorenylene, -PH-, -O- or -SOO-; and R2 is substituted or unsubstituted C1-C20 heteroaryl or thiophenyl.

Description

Oxadiazole derivative compound and organic light emitting device comprising the same

The present invention relates to an oxadiazole derivative compound and an organic light emitting device having the same, and more particularly, has excellent electrical properties, excellent electrical and thermal stability, and low driving voltage, high color purity, and long life characteristics when applied to organic light emitting devices. The present invention relates to an organic light emitting device employing an oxadiazole derivative compound and an organic film containing the compound.

A light emitting device is a self-luminous device, and has a wide viewing angle, excellent contrast, and fast response time. The light emitting device includes an inorganic light emitting device using an inorganic compound and an organic light emitting device (OLED) using an organic compound as an emitting layer, and the organic light emitting device has higher luminance and driving than an inorganic light emitting device. Much research has been conducted in that the voltage and response speed characteristics are excellent and multicoloring is possible.

The organic light emitting device is an active light emitting display device using a phenomenon in which light is generated while electrons and holes are combined in an organic film when a current flows through a thin film of fluorescent or phosphorescent organic compound (hereinafter referred to as an organic film). It has a simple structure, simple manufacturing process, and secures a wide viewing angle at high quality. In addition, high color purity and video can be perfectly realized, and low power consumption and low voltage driving make it suitable for portable electronic devices.

A general organic light emitting device has an anode formed on the substrate, and a hole transport layer, a light emitting layer, an electron transport layer and a cathode are sequentially formed on the anode. Here, the hole transport layer, the light emitting layer and the electron transport layer are organic films made of an organic compound. The driving principle of the organic light emitting device having the structure as described above is as follows. When a voltage is applied between the anode and the cathode, holes injected from the anode are moved to the light emitting layer via the hole transport layer. On the other hand, electrons are injected from the cathode into the light emitting layer via the electron transport layer, and carriers are recombined in the light emitting layer to generate excitons. As the excitons are radiated decay, light of a wavelength corresponding to the band gap of the material is emitted.

The light emitting layer forming material of the organic light emitting device may be classified into a fluorescent material using an exciton in a singlet state and a phosphorescent material using a triplet state according to its light emitting mechanism. The fluorescent or phosphorescent material is doped on its own or in a suitable host material to form a light emitting layer, and as a result of electron excitation, singlet excitons and triplet excitons are formed in the host. At this time, the statistical ratio of singlet excitons and triplet excitons is 1: 3 (Baldo, et al., Phys. Rev. B, 1999, 60, 14422).

Since Van Slyke's report, organic light-emitting devices based on electroluminescence of organic thin film layers have attracted much attention. Device efficiency was improved by the introduction of an electron transport layer. By introducing a hole blocking layer, the exciton is more effectively confined to the emission region, thereby improving not only the device efficiency but also the lifetime.

Therefore, in order to reduce the layer, a material having both hole blocking and electron transport characteristics is required, which also improves the life characteristics of the device.

To date, there have been numerous studies on electron transport materials, "Electron-transporting materials for organic electroluminescent and electrophosphorescent devices " (G. Hughes and MR Bryce, Journal of Materials Chemistry, 2005, 15 , 94-107), " Electron transporting materials for organic light - emitting diodes " (AP Kulkarni, CJ Tonzola, A. Babel and SA Jenekhe, Journal of Materials Chemistry, 2004, 16 , 4556-4573) and references described in these papers are examples. Important moieties that contribute to electron transport properties include pyridyl, quinolyl, quinoxalinyl, imidazolyl, pyrazolyl, tetazolyl and oxadiazolyl.

There is still a need for the development of an organic light emitting device that improves excellent driving voltage, brightness, efficiency, and color purity by using a blue light emitting compound having excellent thermal stability and excellent organic film.

In order to solve the problems of the prior art, the present invention is to provide an organic light emitting compound having excellent electrical characteristics, electrical and thermal stability, and to provide an organic light emitting device with improved driving voltage, color purity and lifespan characteristics. .

The present invention provides an organic light emitting compound represented by the following Chemical Formula 1 in a first aspect for achieving the above object:

<Formula 1>

Where

R ₁ is substituted or unsubstituted C1-C20 alkylene, substituted or unsubstituted C3-C20 cycloalkylene group, substituted or unsubstituted C1-C20 heteroalkylene, substituted or unsubstituted C3-C20 arylene, substituted Or unsubstituted C1-C20 heteroarylene, thiophenyl, silylene, carbazolylene, fluorenylene, -PH-, -O- or -SOO-,

R ₂ is substituted or unsubstituted C1-C20 heteroaryl or thiophenyl,

R ₃ to R ₁₇ are each independently a hydrogen atom, a cyano group, a hydroxyl group, a nitro group, a halogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy group, substituted or Unsubstituted C6-C20 aryl group, substituted or unsubstituted C7-C20 arylalkyl group, substituted or unsubstituted C2-C20 alkylalkoxy group, substituted or unsubstituted C7-C20 arylalkoxy group, substituted or unsubstituted C6 -C20 arylamino group, substituted or unsubstituted C1-C20 alkylamino group, substituted or unsubstituted C6-C20 arylamino group, or substituted or unsubstituted C2-C20 heterocyclic group.

In addition, the present invention is a first electrode in a second aspect for achieving the above another object; Second electrode; And an organic light emitting device comprising at least an organic film between the first electrode and the second electrode, wherein the organic film comprises an oxadiazole derivative compound according to the present invention.

The oxadiazole derivative compound represented by Formula 1 according to the present invention has excellent electrical properties, excellent electrical and thermal stability. Therefore, by using the compound according to the present invention it is possible to obtain an organic light emitting device having a low driving voltage, excellent color purity and long life characteristics.

Hereinafter, the present invention will be described in more detail.

An oxadiazole derivative compound according to the present invention is represented by the following general formula (1):

Where

R ₁ is substituted or unsubstituted C1-C20 alkylene, substituted or unsubstituted C3-C20 cycloalkylene group, substituted or unsubstituted C1-C20 heteroalkylene, substituted or unsubstituted C3-C20 arylene, substituted Or unsubstituted C1-C20 heteroarylene, thiophenyl, silylene, carbazolylene, fluorenylene, -PH-, -O- or -SOO-,

R ₂ is substituted or unsubstituted C1-C20 heteroaryl or thiophenyl,

R ₃ to R ₁₇ are each independently a hydrogen atom, a cyano group, a hydroxyl group, a nitro group, a halogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy group, substituted or Unsubstituted C6-C20 aryl group, substituted or unsubstituted C7-C20 arylalkyl group, substituted or unsubstituted C2-C20 alkylalkoxy group, substituted or unsubstituted C7-C20 arylalkoxy group, substituted or unsubstituted C6 -C20 arylamino group, substituted or unsubstituted C1-C20 alkylamino group, substituted or unsubstituted C6-C20 arylamino group, or substituted or unsubstituted C2-C20 heterocyclic group.

In the oxadiazole derivative compound of Formula 1, the oxadiazole is an electron transporting moiety, and a layer formed by including the oxadiazole derivative compound of Formula 1 has a deeper HOMO level. . Such a film having a deep HOMO level is more useful to be used as an electron transport layer and a hole blocking layer.

In addition, in the oxadiazole derivative compound of Chemical Formula 1, spiro fluorene is an excellent bipolar (electropolar) electron transporting material, and has a very rigid structure, thereby enhancing thermal stability.

,

,

,

,

,

, -O-,

,

,

,

,

,

,

,

,

등이다.In addition, in the oxadiazole derivative compound of Formula 1, the group defined by R ₂ serves as an electron transport moiety, preferably,

,

,

,

,

,

, -O-,

,

,

,

,

,

,

,

,

And so on.

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,

,

,

,

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,

,

,

,

,

,

,

, -O-,

등이다.R ₁ is a spacer, and serves to modify thermal, electrical properties and energy levels, and preferably -CH _2- , -CH = CH-, -C≡C-,

,

,

,

,

,

,

,

,

,

,

,

,

,

, -O-,

And so on.

In particular, the properties required as an excellent electron transporting material should have high thermal stability, reversible electrochemical reduction process, and high device life characteristics. The oxadiazole derivative compound of Chemical Formula 1 according to the present invention has such characteristics. Satisfy all. It is therefore very useful as an electron transporting material.

Preferably, the oxadiazole derivative compound of Formula 1 has a structure of Formula 2.

Where

R ₁ is substituted or unsubstituted C1-C20 alkylene, substituted or unsubstituted C3-C20 cycloalkylene group, substituted or unsubstituted C1-C20 heteroalkylene, substituted or unsubstituted C3-C20 arylene, substituted Or unsubstituted C1-C20 heteroarylene, thiophenyl, silylene, carbazolylene, fluorenylene, -PH-, -O- or -SOO-,

R ₃ to R ₄ are each independently a hydrogen atom, a cyano group, a hydroxyl group, a nitro group, a halogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy group, a substituted or Unsubstituted C6-C20 aryl group, substituted or unsubstituted C7-C20 arylalkyl group, substituted or unsubstituted C2-C20 alkylalkoxy group, substituted or unsubstituted C7-C20 arylalkoxy group, substituted or unsubstituted C6 -C20 arylamino group, substituted or unsubstituted C1-C20 alkylamino group, substituted or unsubstituted C6-C20 arylamino group, or substituted or unsubstituted C2-C20 heterocyclic group.

Specific examples of the unsubstituted C1-C20 alkylene group used in the chemical formula of the present invention include methylene, ethylene, propylene, isobutylene, sec-butylene, pentylene, iso-amylene, hexylene and the like. At least one hydrogen atom of the alkylene group may be a halogen atom, hydroxy group, nitro group, cyano group, amino group, amidino group, hydrazine, hydrazone, carboxyl group or salt thereof, sulfonic acid group or salt thereof, phosphoric acid or salt thereof, C1-C30 To be substituted with an alkyl group, a C1-C30 alkenyl group, a C1-C30 alkynyl group, a C6-C30 aryl group, a C7-C30 arylalkyl group, a C2-C20 heteroaryl group, or a C3-C30 heteroarylalkyl group Can be.

Examples of the unsubstituted cycloalkylene group used in the chemical formula of the present invention include a cyclohexylene group, a cyclopentylene group, and the like, and at least one hydrogen atom of the cycloalkylene group may be substituted with the same substituent as in the alkylene group described above. Do.

The unsubstituted heteroalkylene group used in the formula of the present invention refers to a divalent organic compound having 3 to 20 carbon atoms in which at least one carbon of the alkylene group exemplified above is replaced by at least one heteroatom selected from N, O, P or S. it means. At least one hydrogen atom of the heteroalkylene group may be substituted with the same substituent as in the alkylene group described above.

Examples of the unsubstituted C6-C20 arylene group used in the chemical formula of the present invention include phenylene, biphenylene, and the like, and at least one hydrogen atom of the phenylene group or biphenylene group is the same substituent as in the alkylene group described above. It is possible to substitute by.

The unsubstituted heteroarylene group used in the present invention contains 1, 2 or 3 heteroatoms selected from N, O, P or S, and the remaining ring atoms are C 6 to 30 divalent monocyclic ring atoms. Or bicyclic aromatic organic compounds. At least one hydrogen atom of the heteroarylene group may be substituted with the same substituent as in the alkylene group described above.

Specific examples of the unsubstituted C1-C20 alkyl group used in the chemical formula of the present invention include methyl, ethyl, propyl, isobutyl, sec-butyl, pentyl, iso-amyl, hexyl and the like, and at least one of the alkyl groups The hydrogen atom can be substituted with the same substituent as in the case of the alkylene group mentioned above.

Specific examples of the unsubstituted C1-C20 alkoxy group used in the chemical formula of the present invention include methoxy, ethoxy, phenyloxy, cyclohexyloxy, naphthyloxy, isopropyloxy, diphenyloxy, and the like. At least one hydrogen atom of these alkoxy groups may be substituted with the same substituent as in the alkyl group described above.

Unsubstituted C6-C20 aryl groups used in the formulas of the present invention may be used alone or in combination to mean aromatic carbon rings comprising one or more rings, which rings may be attached or fused together in a pendant manner. At least one hydrogen atom of the aryl group may be substituted with the same substituent as in the alkyl group described above.

Examples of the aryl group include phenyl group, ethylphenyl group, ethyl biphenyl group, o-, m- and p-fluorophenyl group, dichlorophenyl group, dicyanophenyl group, trifluoromethoxyphenyl group, o-, m-, and p-tolyl group, o-, m- and p-cumenyl groups, mesityl groups, phenoxyphenyl groups, (α, α-dimethylbenzene) phenyl groups, (N, N'-dimethyl) aminophenyl groups, (N, N'-diphenyl) aminophenyl groups , Pentarenyl group, indenyl group, naphthyl group, methylnaphthyl group, anthracenyl group, azurenyl group, heptarenyl group, acenaphthylenyl group, phenenalenyl group, fluorenyl group, anthraquinolyl group, methyl anthryl group, phenanyl group Triyl group, triphenylene group, pyrenyl group, chrysenyl group, ethyl-crisenyl group, pisenyl group, perylenyl group, chloroperylenyl group, pentaphenyl group, pentacenyl group, tetraphenylenyl group, hexaphenyl group, hexasenyl Group, rubisenyl group, coroneyl group, trinaphthylenyl group, heptaphenyl group, heptasenyl group, pyrantrenyl group, obarenyl group, carbazolyl And the like can be mentioned.

The unsubstituted aralkyl group used in the formula of the present invention means that some of the hydrogen atoms in the aryl group as defined above are substituted with lower alkyl groups such as methyl, ethyl, propyl and the like. For example benzyl, phenylethyl and the like. At least one hydrogen atom of the arylalkyl group may be substituted with the same substituent as in the alkyl group described above.

The unsubstituted heteroaryl group used in the present invention includes 1, 2 or 3 heteroatoms selected from N, O, P or S, and the remaining ring atoms are C 1 to monovalent monocyclic monocyclic or 6 to 30 ring atoms or A bicyclic aromatic organic compound is meant. At least one hydrogen atom of the heteroaryl group may be substituted with the same substituent as in the alkyl group described above.

Examples of the heteroaryl group include pyrazolyl group, imidazolyl group, oxazolyl group, thiazolyl group, triazolyl group, tetrazolyl group, oxadizolyl group, pyridinyl group, pyridazinyl group, pyrimidinyl group, Triazinyl group, carbazolyl group, indolyl group, etc. are mentioned.

Specific examples of the oxadiazole derivative compound of Formula 1 according to the present invention include an oxadiazole derivative compound represented by the following Formulas 3 to 20.

The oxadiazole derivative compound of Chemical Formula 1 according to the present invention may be formed in accordance with a generally known method and included in the organic layer of the organic light emitting device. For example, it can form into a film by vapor deposition and a solution process.

In order to achieve the second technical problem of the present invention,

A first electrode; Second electrode; And an organic light emitting device comprising at least an organic film between the first electrode and the second electrode, wherein the organic film comprises an oxadiazole derivative compound according to any one of claims 1 to 4. An organic light emitting device is provided.

The organic light emitting device according to the present invention can be used for applications such as full color display, lighting, backlight, billboard, optical communication, interior decoration.

The organic layer including the oxadiazole derivative compound of Formula 1 may be a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer or an electron injection layer.

In particular, the oxadiazole derivative compound of Formula 1 is suitable for use as a host and dopant in the hole blocking layer, the electron transport layer and the light emitting layer. For example, in the organic light emitting device according to the present invention, the organic layer including the oxadiazole derivative compound of Formula 1 may be a light emitting layer, wherein the oxadiazole derivative compound of Formula 1 may be a host. .

Figure 2a and 2b shows the absorption spectrum and emission spectrum of one embodiment (compound of formula 3) of the oxadiazole derivative compound of formula 1 according to the present invention. FIG. 2A shows the solution property, and FIG. 2B shows the property after forming a film by spin coating.

In FIG. 2A, the optical band gap was 3.1 eV and the solution QE (Quantum Efficiency) was 30%. (90% diphenylanthracene, source: DP Rillema and coworkers Inorganic Chemistry, 2000, 39, 1955-1963)

In the case of the thin film produced by the spin coating method, as shown in Fig. 2B, the peak wavelength of the emission spectrum is 438 nm, which is almost similar to 428 nm in Fig. 2A. This means that there is little change in the shape of the peak, which means that the color stability of the thin film with time is excellent.

In addition, in the organic light emitting device according to the present invention, the oxadiazole derivative compound of Formula 1 may be included as a fluorescent dopant in the light emitting layer. In this case, preferably, 3 to 15 parts by weight of the oxadiazole derivative compound of Formula 1, which is a dopant, is included with respect to 100 parts by weight of the total weight of the host and the dopant of the light emitting layer. When the oxadiazole derivative compound of Formula 1 is included as a dopant in an amount of less than 3 parts by weight based on 100 parts by weight of the total weight of the host and the dopant of the light emitting layer, there is a problem that proper energy transfer is not achieved from the host, Inclusion in excess may result in concentration quenching.

On the other hand, in the organic light emitting device according to the present invention, the oxadiazole derivative compound according to the present invention of Formula 1 is a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer or an electron injection layer dopant It can be included as a doping agent. In general, the hole injection layer, the hole transport layer, the electron blocking layer, the hole blocking layer, the electron transport layer or the electron injection layer may further include a doping agent, thereby improving its working effect, wherein the present invention of Formula 1 as the doping agent The oxadiazole derivative compound according to the present invention can be used. Preferably, the oxadiazole derivative compound of Chemical Formula 1 includes 3 to 15 parts by weight based on 100 parts by weight of the total weight of the hole injection layer, the hole transport layer, the electron blocking layer, the hole blocking layer, the electron transport layer, or the electron injection layer. When the oxadiazole derivative of Chemical Formula 1 is included as a dopant in an amount of less than 3 parts by weight based on 100 parts by weight of the total weight of each organic film, proper energy transfer from the host is not achieved, and more than 15 parts by weight If included, problems with concentration quenching can occur.

In the organic light emitting device according to the present invention, the organic layer may further include one or more layers selected from the group consisting of a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer and an electron injection layer. have.

The structure of the organic light emitting device according to the present invention is very diverse. One or more layers selected from the group consisting of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer and an electron injection layer may be further included between the first electrode and the second electrode.

More specifically, an embodiment of the organic light emitting device according to the present invention refers to Figures 1a, 1b and 1c. The organic light emitting device of Figure 1a has a structure consisting of a first electrode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / second electrode, the organic light emitting device of Figure 1b is a first electrode / hole injection layer / hole transport layer / It has a structure consisting of a light emitting layer / electron transport layer / electron injection layer / second electrode. In addition, the organic light emitting device of FIG. 1C has a structure of a first electrode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / second electrode. In this case, at least one of the light emitting layer, the hole injection layer and the hole transport layer may include a compound according to the present invention.

The light emitting layer of the organic light emitting device according to the present invention may include a phosphorescent or fluorescent dopant including red, green, blue or white. Among these, the phosphorescent dopant may be an organometallic compound including at least one element selected from the group consisting of Ir, Pt, Os, Ti, Zr, Hf, Eu, Tb, and Tm.

Hereinafter, a method of manufacturing an organic light emitting diode according to the present invention will be described with reference to the organic light emitting diode illustrated in FIG. 1C.

First, a first electrode material having a high work function on the substrate is formed by a deposition method or a sputtering method to form a first electrode. The first electrode may be an anode. Herein, a substrate used in a conventional organic light emitting device is used, and a glass substrate or a transparent plastic substrate having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and waterproofness is preferable. As the material for the first electrode, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO ₂ ), zinc oxide (ZnO), and the like, which are transparent and have excellent conductivity, are used.

Next, a hole injection layer HIL may be formed on the first electrode by using various methods such as vacuum deposition, spin coating, cast, and LB.

In the case of forming the hole injection layer by vacuum deposition, the deposition conditions vary depending on the compound used as the material of the hole injection layer, the structure and thermal properties of the hole injection layer, and the like. It is preferable that a vacuum degree of 10 ^-8 to 10 ^-3 torr, a deposition rate of 0.01 to 100 mW / sec, and a film thickness are usually appropriately selected in the range of 10 mV to 5 m.

In the case of forming the hole injection layer by spin coating, the coating conditions vary depending on the compound used as the material of the hole injection layer, the structure and thermal properties of the desired hole injection layer, but the coating speed is about 2000 rpm to 5000 rpm. , The heat treatment temperature for removing the solvent after coating is preferably selected in the temperature range of about 80 ℃ to 200 ℃.

The hole injection layer material may be an oxadiazole derivative compound of Chemical Formula 1 according to the present invention as described above. Or phthalocyanine compounds such as copper phthalocyanine disclosed in US Pat. No. 4,356,429 or the starburst type amine derivatives described in Advanced Material, 6, p.677 (1994), for example, TCTA, m-MTDATA, m-. MTDAPB, Pani / DBSA (Polyaniline / Dodecylbenzenesulfonic acid: polyaniline / dodecylbenzenesulfonic acid) or PEDOT / PSS (Poly (3,4-ethylenedioxythiophene) / Poly (4-styrenesulfonate): Poly (3,4) -Ethylenedioxythiophene) / poly (4-styrenesulfonate)), Pani / CSA (Polyaniline / Camphor sulfonicacid: polyaniline / camphorsulfonic acid) or PANI / PSS (Polyaniline) / Poly (4-styrenesulfonate): polyaniline) / poly Known hole injection materials such as (4-styrenesulfonate)) and the like can be used.

Pani / DBSA PEDOT / PSS

The hole injection layer may have a thickness of about 100 kPa to 10000 kPa, preferably 100 kPa to 1000 kPa. This is because when the thickness of the hole injection layer is less than 100 kV, the hole injection characteristic may be lowered, and when the thickness of the hole injection layer exceeds 10000 kV, the driving voltage may increase.

Next, a hole transport layer (HTL) may be formed on the hole injection layer by using various methods such as vacuum deposition, spin coating, casting, and LB. When the hole transport layer is formed by vacuum deposition or spin coating, the deposition conditions and coating conditions vary depending on the compound used, and are generally selected from the ranges of conditions substantially the same as those of forming the hole injection layer.

The hole transport material may be an oxadiazole derivative compound of Chemical Formula 1 according to the present invention as described above. Or for example, carbazole derivatives, such as N-phenylcarbazole and polyvinylcarbazole, N, N'-bis (3-methylphenyl) -N, N'- diphenyl- [1,1-biphenyl]- Conventional amine derivatives having aromatic condensed rings such as 4,4'-diamine (TPD), N, N'-di (naphthalen-1-yl) -N, N'-diphenyl benzidine (α-NPD), and the like. Known hole transport materials can be used.

The hole transport layer may have a thickness of about 50 kPa to 1000 kPa, preferably 100 kPa to 600 kPa. When the thickness of the hole transport layer is less than 50 kPa, the hole transport property may be deteriorated, and the thickness of the hole transport layer exceeds 1000 kPa. This is because the driving voltage can rise.

Next, an emission layer (EML) may be formed on the hole transport layer by using a method such as vacuum deposition, spin coating, casting, and LB. When the light emitting layer is formed by the vacuum deposition method or the spin coating method, the deposition conditions vary depending on the compound used, but are generally selected from the ranges of conditions substantially the same as those of forming the hole injection layer.

As described above, the emission layer may include the oxadiazole derivative compound of Chemical Formula 1 according to the present invention. In this case, the oxadiazole derivative compound of Formula 1 may be used with a known dopant material while being used as a host, or the oxadiazole derivative compound of Formula 1 may be used in combination with another dopant while being used as a dopant, It is also possible to use the oxadiazole derivative compound of Formula 1 alone. When the oxadiazole derivative compound according to the present invention is used as a dopant, for example, Alq3 or CBP (4,4'-N, N'-dicarbazole-biphenyl), or PVK (poly ( n-vinylcarbazole)) and the like. In the case of using the oxadiazole derivative compound according to the present invention as a dopant, another dopant material which can be mixed and used, or in the case of another dopant material using the oxadiazole derivative compound according to the present invention as a host, a fluorescent dopant For example, IDE102, IDE105, and C545T, available from Hayashibara, can be used as the phosphorescent dopant, red phosphorescent dopant PtOEP, UDC's RD 61, and green phosphorescent dopant Ir (PPy) 3 (PPy). = 2-phenylpyridine), F 2 Irpic which is a blue phosphorescent dopant, and a red phosphorescent dopant RD 61 manufactured by UDC. The following formula shows the structure of DPAVBi which can be used as a dopant.

Doping concentration is not particularly limited, but the content of the dopant is generally 0.01 to 15 parts by weight based on 100 parts by weight of the host.

The thickness of the light emitting layer may be about 100 kPa to 1000 kPa, preferably 200 kPa to 600 kPa. This is because, when the thickness of the light emitting layer is less than 100 kW, the light emission characteristics may be reduced, and when the thickness of the light emitting layer exceeds 1000 kW, the driving voltage may increase.

When used with a phosphorescent dopant in the light emitting layer, in order to prevent the triplet excitons or holes from diffusing into the electron transport layer, holes such as vacuum deposition, spin coating, cast, LB, etc. are formed on the hole transport layer. A blocking layer (HBL) can be formed. In the case of forming the hole blocking layer by vacuum deposition or spin coating, the conditions vary depending on the compound used, but are generally selected from the ranges of conditions almost the same as that of forming the hole injection layer. The hole blocking layer material may be an oxadiazole derivative compound of Chemical Formula 1 according to the present invention as described above. Alternatively, for example, known hole blocking materials such as oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, BCP and the like can be used.

The hole blocking layer may have a thickness of about 50 kPa to 1000 kPa, preferably 100 kPa to 300 kPa. This is because when the thickness of the hole blocking layer is less than 50 kV, the hole blocking property may be deteriorated. When the thickness of the hole blocking layer is more than 1000 kV, the driving voltage may increase.

Next, the electron transport layer (ETL) is formed using various methods such as vacuum deposition, spin coating, and casting. When the electron transport layer is formed by the vacuum deposition method or the spin coating method, the conditions vary depending on the compound used, but are generally selected from the ranges of conditions almost the same as that of the formation of the hole injection layer. The electron transport layer material may be an oxadiazole derivative compound of Chemical Formula 1 according to the present invention as described above. Or a known material that functions to stably transport electrons injected from an electron injection electrode (Cathode), and a known material such as quinoline derivatives, especially tris (8-quinolinorate) aluminum (Alq3), TAZ, Balq, etc. Can also be used.

The electron transport layer may have a thickness of about 100 kPa to 1000 kPa, preferably 200 kPa to 500 kPa. This is because when the thickness of the electron transport layer is less than 100 kV, the electron transport characteristic may be degraded, and when the thickness of the electron transport layer exceeds 1000 kW, the driving voltage may increase.

In addition, an electron injection layer (EIL), which is a material having a function of facilitating injection of electrons from the cathode, may be stacked on the electron transport layer, and may be the oxadiazole derivative compound of Chemical Formula 1 according to the present invention as described above. Or any material known as an electron injection layer forming material such as LiF, NaCl, CsF, Li 2 O, BaO, or the like can be used. The deposition conditions of the electron injection layer vary depending on the compound used, but are generally selected from the range of conditions almost the same as the formation of the hole injection layer.

The electron injection layer may have a thickness of about 1 kPa to 100 kPa, preferably 5 kPa to 50 kPa. When the thickness of the electron injection layer is less than 1 kPa, electron injection characteristics may be deteriorated, and the thickness of the electron injection layer may be 100 kPa. This is because the driving voltage can rise if it exceeds.

Finally, the second electrode may be formed on the electron injection layer by using a vacuum deposition method or a sputtering method. The second electrode may be used as a cathode. As the metal for forming the second electrode, a metal, an alloy, an electrically conductive compound having a low work function, and a mixture thereof may be used. Specific examples include lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), and the like. Can be mentioned. In addition, a transmissive cathode using ITO and IZO may be used to obtain the front light emitting device.

Hereinafter, the synthesis examples and examples of the present invention will be specifically illustrated, but the present invention is not limited to the following synthesis examples and examples.

Example

Synthesis Example  One

Compound 3 represented by Formula 3 was synthesized according to the reaction route of Schemes 1 to 3 below:

Intermediate (a)

8.1 mmol (2.14 g) of ester methyl phenylquinolinate and 20 mL of hydrazine monohydrate were reacted at 50 ° C. in 50 mL of methanol for 24 h. The reaction mixture was cooled to room temperature and then treated with 50 mL of water, filtered and washed with water and ether. The product obtained was recrystallized from water and methanol mixture.

Intermediate (b)

4.16 mmol (1.18 g) of 4-bromobenzoic acid, 5 mL of SOCl ₂ and 2 drops of dimethylformamide were heated at 50 ° C. for 2 hours. The reaction mixture was cooled down and SOCl ₂ was evaporated under reduced pressure. The solid was treated with hexanes and filtered to give a white residue.

Compound (3) was obtained by reacting the intermediate (a) and the intermediate (b) compounds obtained by the routes of Schemes 1 and 2 according to the steps of Scheme 3 below.

1 mmol (0.249 g) of intermediate (a), 1 mmol (0.219 g) of intermediate (b) and 5 mmol of sodium carbonate (0.53 g) were stirred in 5 mL of dioxane at room temperature for 24 hours. Dioxane was evaporated by treatment with water. The residue was filtered and washed with ether to give intermediate (c). 2 mmol (0.892 g) of intermediate (c) was refluxed for 12 h in 10 mL of phosphorus oxychloride. After evaporation of phosphorus oxychloride, a yellow solid was obtained. The yellow solid was purified using chloroform and methanol as silica column and eluent to obtain intermediate (d). Suzuki coupling reaction between intermediate (d) and spirofluorene boronic acid was carried out to obtain the final product, Compound 3. The structure of Compound 3 was confirmed by ¹ H-NMR. 3 is the ¹ H-NMR spectrum of Compound 3, and the result is as follows:

¹ H, NMR (CDCl ₃ ) ppm: 9.24 (d, 1H), 8.56 (s, 1H), 8.28 (t, 3H), 8.2 (d, 2H), 7.99 (d, 1H), 7.95-7.87 (m , 3H), 7.85 (d, 1H), 7.74 (t, 2H), 7.67 (d, 2H), 7.63-7.49 (m, 3H), 7.42 (t, 3H), 7.16 (d, 3H), 7.05 ( s, 1H), 6.8 (d, 2H), 6.77 (d, 1H).

ESI mass spectra: Exact mass, 663.23, m / z 664.23 (m + H ⁺ )

Evaluation example  1: Evaluation of luminescence properties of the compound

The following table shows the measurement of LUMO level and HOMO level value by the cyclovoltametric method to compare the film-forming properties of each of Compound 3 and PBD prepared according to Synthesis Example 1. The cycloboltametric experiments use platinum as a counter and reference electrode and are similar as reference electrodes with ferrocene and ferrocinium as internal standards in THF solution. Using platinum was performed by Princeton potentiostat.

LUMO HOMO Compound 3 2.77 eV 6.29 eV PBD 2.16 eV 6.06 eV

The structural formula of the PBD is as follows.

<PBD>

As described above, compound 3 has spirofluorene with respect to PBD, thereby improving thermal stability, thereby increasing the lifetime characteristics of the device when included in the device, and also having a quinoline moiety, thereby enhancing electron transport ability. As shown in Table 1, as the HOMO and LUMO levels are deepened, the electron injection barrier is lowered.

Table 2 below shows simulation values of LUMO level and HOMO level values of Compound 3.

H eV L eV gap HOMO LUMO Compound 3 -5.643 -2.220 3.423

It can be seen that the values in Table 1, which are experimental values of the LUMO level and HOMO level values of Compound 3, are almost similar to those in Table 2.

FIG. 4 is a thermogravimetric analysis (TGA) graph of Compound 3, shown and measured using (company TA Instruments, model No. TGA 2050, 10 ° C. heating per minute under nitrogen atmosphere). The Td value was measured at 441 ° C., which means that the compound 3 has thermal stability suitable for the organic light emitting device.

FIG. 5 is a differential scanning calorimeter (DSC) graph of the compound 3, shown and measured using (company TA Instruments, model No. DSC 2010, 10 ° C. heating per minute under nitrogen atmosphere). In general, the oxidazole compound has a low Tg, whereas the compound 3 can be seen to have a high Tg, Tc, Tm, because it contains spirofluorene. That is, it can be seen that spirofluorene plays a role of improving thermal stability.

FIG. 6 is a graph showing (Reduction cyclic voltammogram) of Compound 3 measured in Korean. As a result of measurement 5, the paths on the graph were almost identical, and thus the electrical stability was also excellent. This characteristic means the device life extension effect.

Example  One

Using the prepared compound 3 as a material for the electron transport layer, an organic light emitting device having the following structure was manufactured: (ITO) / (HIL α-NPD) (750 Å) / ADN (350 Å) / Compound 3 (180 Å) / LiF (10 ms) / Al (2000 ms).

Using compound 3 as a dopant of the light emitting layer and ADN as a host of the light emitting layer, an organic light emitting device having the following structure was fabricated: ITO / α-NPD (750 Å) / ADN (350 Å) / Compound 3 (180 Å) / LiF (10 ms) / Al (2000 ms).

The anode was cut into 50 mm x 50 mm x 0.7 mm sized 15 Ω / cm ² (1000 Å) ITO glass substrate, sonicated for 15 minutes in acetone isopropyl alcohol and pure water, followed by UV ozone cleaning for 30 minutes. On the ITO anode, α-NPD was vacuum deposited at a thickness of 750 kV at a deposition rate of 1 kV / sec to form a hole transport layer, and then ADN was vacuum deposited at a thickness of 350 kPa at a deposition rate of 30 kV / sec on the hole transport layer. A light emitting layer was formed. Thereafter, a compound 3 was deposited to a thickness of 180 kV on the light emitting layer to form an electron transport layer, and then LiF 10 kV (electron injection layer) and Al 2000 m (cathode) were sequentially vacuum deposited on the electron transport layer. An organic light emitting device as shown in 1a was manufactured. This is called sample 1.

Comparative example  One

In Example 1, except that Alq3 was used instead of Compound 3, ITO / α-NPD (750 Å) / ADN (350 Å) / Compound 3 in the same manner as the method for producing an organic light emitting device of Example 1 An organic light emitting device having a structure of (180 Pa) / LiF (10 Pa) / Al (2000 Pa) was manufactured. This is called Comparative Sample 1.

Evaluation Example 4 : Evaluation of Characteristics of Samples 1 and 2

For Sample 1 and Comparative Sample 1, driving voltage, color purity, and efficiency were respectively evaluated using the PR650 (Spectroscan) Source Measurement Unit. The results are shown in Table 2 below. The sample containing the compound of the present invention as an electron transporting material exhibits significantly improved lifetime characteristics over Alq 3 -based devices.

Drive Voltage / Op. V @ 1000nit Im / W @ 1000nit (max @ V) Efficiency (cd / A @ 1000nit) (max @ V) Color coordinates (~ 100cd / m ² @ 1000nit) Sample 1 4.0V / 7.0V 3.12 (4.67@4.0V) 6.95 (7.06@8.5V) (0.134, 0.172) Comparative Sample 1 3.8V / 8.0V 1.31 (1.50@6.0V) 3.54 (3.60@9V) (0.138, 0.149)

From Table 3, it can be seen that Sample 1 according to the present invention has a driving voltage characteristic equal to or greater than an excellent efficiency characteristic. In addition, when the color coordinates were (0.15, 0.15), it showed pure blue color, and since it was found that sample 1 was closer to the pure blue value, it was confirmed that it had excellent luminescence properties.

7 shows the EL spectrum of Sample 1 above. Sample 1 exhibits a narrower electroluminescence spectrum than comparative sample 1 and shows excellent color coordinates.

8 shows EL spectra for various values of voltage for Sample 1. FIG. Since a constant curve is displayed for various voltages, it can be seen that Sample 1 according to the present invention has a low dependency on voltage.

9 is a graph showing the life characteristics of Sample 1 and Comparative Sample 1. Sample 1 according to the present invention shows excellent life characteristics.

1A to 1C are cross-sectional views schematically illustrating structures of one embodiment of an organic light emitting diode according to the present invention.

2A is an absorption spectrum and an emission spectrum showing solution characteristics of a compound according to an embodiment of the present invention.

2B is an absorption spectrum and an emission spectrum showing the film forming properties of a compound according to another embodiment of the present invention.

3 is a ¹ H-NMR spectrum of an oxadiazole derivative compound according to another embodiment of the present invention.

4 is a thermogravimetric analysis (TGA) graph of an oxadiazole derivative compound according to another embodiment of the present invention.

5 is a differential scanning calorimeter (DSC) graph of an oxadiazole derivative compound according to another embodiment of the present invention.

6 is a graph of (reduction cyclic voltammogram) of an oxadiazole derivative compound according to another embodiment of the present invention.

7 shows EL spectra of an organic light emitting device according to an embodiment of the present invention and an organic light emitting device according to a known technique.

8 illustrates EL spectra for various values of voltages for an organic light emitting diode according to another embodiment of the present invention.

9 is a graph illustrating lifespan characteristics of an organic light emitting diode according to an embodiment of the present invention and an organic light emitting diode according to a known technology.

Claims (14)

An oxadiazole derivative compound represented by Formula 1 below: <Formula 1>

Where R ₁ is substituted or unsubstituted C1-C20 alkylene, substituted or unsubstituted C3-C20 cycloalkylene group, substituted or unsubstituted C1-C20 heteroalkylene, substituted or unsubstituted C3-C20 arylene, substituted Or unsubstituted C1-C20 heteroarylene, thiophenyl, silylene, carbazolylene, fluorenylene, -PH-, -O- or -SOO-, R ₂ is substituted or unsubstituted C1-C20 heteroaryl or thiophenyl, R ₃ to R ₁₇ are each independently a hydrogen atom, a cyano group, a hydroxyl group, a nitro group, a halogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy group, substituted or Unsubstituted C6-C20 aryl group, substituted or unsubstituted C7-C20 arylalkyl group, substituted or unsubstituted C2-C20 alkylalkoxy group, substituted or unsubstituted C7-C20 arylalkoxy group, substituted or unsubstituted C6 -C20 arylamino group, substituted or unsubstituted C1-C20 alkylamino group, substituted or unsubstituted C6-C20 arylamino group, or substituted or unsubstituted C2-C20 heterocyclic group. The method according to claim 1, wherein R ₁ is -CH _2- , -CH = CH-, -C≡C-,

,

,

,

,

,

,

,

,

,

,

,

,

,

, -O- or

An oxadiazole derivative compound, characterized in that. The compound of claim 1, wherein R ₂ is

,

,

,

,

,

, -O-,

,

,

,

,

,

,

,

or

An oxadiazole derivative compound, characterized in that. The oxadiazole derivative compound according to claim 1, represented by the following general formula (2). <Formula 2>

Where R ₁ is substituted or unsubstituted C1-C20 alkylene, substituted or unsubstituted C3 to C20 cycloalkylene group, substituted or unsubstituted C1-C20 heteroalkylene, substituted or unsubstituted C3-C20 arylene, substituted Or unsubstituted C1-C20 heteroarylene, thiophenyl, silylene, carbazolylene, fluorenylene, -PH-, -O- or -SOO-, R ₃ to R ₄ are each independently a hydrogen atom, a cyano group, a hydroxyl group, a nitro group, a halogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy group, substituted or Unsubstituted C6-C20 aryl group, substituted or unsubstituted C7-C20 arylalkyl group, substituted or unsubstituted C2-C20 alkylalkoxy group, substituted or unsubstituted C7-C20 arylalkoxy group, substituted or unsubstituted C6 -C20 arylamino group, substituted or unsubstituted C1-C20 alkylamino group, substituted or unsubstituted C6-C20 arylamino group, or substituted or unsubstituted C2-C20 heterocyclic group. The oxadiazole derivative compound according to claim 1, represented by the following Chemical Formulas 3 to 6. <Formula 3> <Formula 4>

<Formula 5> <Formula 6>

<Formula 7> <Formula 8>

<Formula 9> <Formula 10>

<Formula 11> <Formula 12>

<Formula 13> <Formula 14>

<Formula 15> <Formula 16>

<Formula 17> <Formula 18>

<Formula 19> <Formula 20>

<Formula 21> <Formula 22>

<Formula 23> <Formula 24>

<Formula 25> <Formula 26>

<Formula 27> <Formula 28>

<Formula 29> <Formula 30>

<Formula 31>

A first electrode; Second electrode; And an organic light emitting device comprising at least an organic film between the first electrode and the second electrode, wherein the organic film comprises an oxadiazole derivative compound according to any one of claims 1 to 4. Organic light emitting device. The organic light emitting device of claim 6, wherein the organic layer is a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, or an electron injection layer. The organic light emitting device according to claim 6, wherein the organic film is a light emitting layer. The organic light emitting device according to claim 8, wherein the oxadiazole derivative compound according to any one of claims 1 to 5 is included in the light emitting layer as a dopant. The organic light emitting device of claim 9, wherein the light emitting layer comprises 3 to 15 parts by weight of the oxadiazole derivative compound which is a dopant with respect to 100 parts by weight of the total weight of the host and the dopant. The method of claim 6, wherein the oxadiazole derivative compound according to any one of claims 1 to 5 is a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer or a doping agent for an electron injection layer ( An organic light emitting device comprising as a doping agent). The organic light-emitting device as claimed in claim 11, wherein the organic film including the oxadiazole derivative compound comprises 3 to 15 parts by weight of the oxadiazole derivative compound, which is a doping agent, based on 100 parts by weight of the organic film. The organic light emitting diode of claim 6, wherein the organic layer further comprises at least one layer selected from the group consisting of a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer. device. The method of claim 13, wherein the device is a first electrode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / second electrode, the first electrode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / agent An organic light-emitting device having the structure of a second electrode or a first electrode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / second electrode.

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