JP2006265172A - New carbazole derivative and organic electroluminescent element and organic semiconductor laser element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new organic material rich in thermal stability such as a new carbazole derivative and organic electroluminescent element and organic semiconductor laser element. <P>SOLUTION: The invention relates to the carbazole derivative and organic electroluminescent element and organic semiconductor laser element, wherein the carbazole derivative is represented by general formula (1), (in the formula R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>, R<SP>4</SP>, R<SP>5</SP>and R<SP>6</SP>are each the same or different and an alkyl, an alkenyl, an alkynyl, an alkoxy or an aryl group, m, n, p, q, r and s are each an integer of 0-4. But in the case of m, n, p, q and s are each an integer of 2-4 then R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>, R<SP>4</SP>, R<SP>5</SP>and R<SP>6</SP>are each the same or different.). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel carbazole derivative, and an organic electroluminescence device and an organic semiconductor laser device using the same, and more specifically, a novel carbazole derivative having a high triplet level and high thermal stability, and an organic electroluminescence device and an organic material using the same. The present invention relates to a semiconductor laser element.

  The display is an electronic device that is indispensable in modern society, such as a television, a monitor of a personal computer, and a display unit of a mobile phone. Furthermore, its importance is increasing as it evolves into a “ubiquitous society”. Currently, the transition of displays to flat displays that place importance on space saving, convenience, and portability is steadily progressing. Under these circumstances, liquid crystal displays and plasma displays have expanded rapidly in recent years.

  Furthermore, human desires for space saving and convenience are expected to evolve further, and to evolve into a thinner, lighter and more flexible display that can be bent. One potential candidate is an organic electroluminescence (hereinafter also referred to as “organic EL”) display. The light-emitting phenomenon of organic EL elements is very fast, from nanoseconds to microseconds. Compared with a liquid crystal display, self-luminescence and fast response are the most significant advantages. The organic EL element is an element expected to be applied to various uses such as a display and indoor lighting, and has been actively developed in recent years including an organic semiconductor laser element.

  In general, an organic EL element has a structure having an organic solid thin film (hereinafter also referred to as “organic layer”) between a pair of electrodes of an anode and a cathode. Each is injected into the organic layer and recombined in the organic layer to generate excitons. The exciton emits light by returning to the ground state through a radiation deactivation process.

  The excitons generated by the current include singlet excitons and triplet excitons. When ordinary fluorescent materials are used, singlet excitons contribute to light emission, and phosphorescent materials are used. , Triplet excitons contribute to light emission. When a fluorescent substance is used as the light-emitting material for the organic EL element, the ratio of the excited singlet state to the excited triplet state caused by recombination of electrons and holes is 1: 3, and light emission from the excited singlet state In other words, since the fluorescence is used and the energy of the excited triplet state is wasted, it cannot be said that the luminous efficiency is good, and the use of a phosphorescent substance for the organic EL element is effective in improving the luminous efficiency. It is valid.

  When a small amount of a fluorescent dye is doped in a low molecular vapor deposition film or a solid medium (host) made of a polymer, the fluorescence of the host disappears completely, and instead, strong light emission that matches the fluorescence spectrum of the doped dye is observed. This is because the excitation energy of the host molecule is transferred to the guest molecule, and light is emitted from the guest having high fluorescence quantum efficiency.

で表わされるCBP(4,4’-dicarbazolyl-1,1’-biphenyl)がホスト材料として多用されている。CBPは三重項レベルが比較的高く、熱安定性にも優れているが、分子骨格の検討により、更なる高機能な光電子、熱物性の発現が期待されている。 Further, in phosphorescence, selection of a host material is important in order to obtain highly efficient phosphorescence, and it is essential from the viewpoint of energy confinement to have a triplet energy larger than that of a guest molecule. Currently, from the viewpoint of the confinement effect of triplet excitons, durability, and bipolar carrier transportability,

CBP (4,4′-dicarbazolyl-1,1′-biphenyl) represented by the formula is often used as a host material. Although CBP has a relatively high triplet level and is excellent in thermal stability, it is expected that more highly functional photoelectrons and thermophysical properties will be developed by studying the molecular skeleton.

で表わされるm-CPが高い三重項レベル(T=2.91eV)を有し、さらにガラス状態を示すことを報告した（非特許文献１参照）。
第６５回応用物理学会学術講演会講演予稿集 4a-ZR-8春季(2004) On the other hand, the present inventors have substituted the following formula (3) in which the diphenylol skeleton of CBP is substituted with an m-phenylene group:

It has been reported that m-CP represented by the formula has a high triplet level (T = 2.91 eV) and further exhibits a glass state (see Non-Patent Document 1).
Proceedings of the 65th JSAP Academic Lecture Meeting 4a-ZR-8 Spring (2004)

  In order to obtain organic EL devices and organic semiconductor laser devices with excellent luminous efficiency and thermal stability, organic materials with high thermal stability are required, but there are few organic materials with high thermal stability. Although organic materials rich in thermal stability have been developed by the technique described in Patent Document 1, further improvement is desired.

  Accordingly, an object of the present invention is to provide an organic material having a high thermal stability, that is, a novel carbazole derivative, and an organic EL device and an organic semiconductor laser device excellent in light emission efficiency and thermal stability using the same. .

  As a result of intensive studies to solve the above problems, the present inventors have determined that acetylene-linked CBP (Ace-CBP: 4,4'-bis (carbazol-9-yl) diphenylacetylene) containing a rigid acetylene molecular skeleton. The present invention was completed by synthesizing it as a new basic skeleton and using it as an organic material.

（上記式中、R¹、R²、R³、R⁴、R⁵およびR⁶は、互いにそれぞれ同一または異なっていてもよいアルキル基、アルケニル基、アルキニル基、アルコキシ基、アリール基であり、m、n、p、q、rおよびsは０〜４の整数を表す。但し、m、n、p、q、rおよびsがそれぞれ２〜４の整数である場合、R¹、R²、R³、R⁴、R⁵およびR⁶は、それぞれにおいて同一でも異なっていてもよい。）で表されることを特徴とするものである。 That is, the carbazole derivative of the present invention has the following general formula (1),

(In the above formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group or an aryl group, which may be the same or different from each other; m, n, p, q, r and s represent an integer of 0 to 4, provided that when m, n, p, q, r and s are each an integer of 2 to 4, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ may be the same or different from each other).

In addition, R ¹ , R ² , R ³ , R ⁴ , R ^5, and R ⁶ can be preferably used wherein each is an alkyl group having 1 to 12 carbon atoms or a phenyl group, which may be the same or different from each other. .

  The organic electroluminescent element of the present invention is an organic electroluminescent element including at least one organic layer between a pair of electrodes, wherein at least one of the organic layers is a fluorescent or phosphorescent material as a guest material and the above-mentioned book as a host material. It contains the carbazole derivative of the invention.

  Another organic electroluminescent device of the present invention is an organic electroluminescent device including at least one organic layer between a pair of electrodes. It is characterized by containing a derivative.

  The organic semiconductor laser element of the present invention is an organic semiconductor laser element including at least one organic layer between a pair of electrodes, wherein at least one of the organic layers is a fluorescent or phosphorescent material as a guest material and the above-mentioned book as a host material. It contains the carbazole derivative of the invention.

  Another organic semiconductor laser element of the present invention is an organic semiconductor laser element comprising at least one organic layer between a pair of electrodes, wherein the carbazole derivative of the present invention is used as a carrier transport / injection material in at least one of the organic layers. It is characterized by containing.

  The carbazole derivative of the present invention is an organic material having excellent thermal stability. Moreover, by using the carbazole derivative of the present invention, an organic EL element and an organic semiconductor laser element excellent in luminous efficiency and thermal stability can be obtained.

で表されることを特徴とするものである。上記式中、R¹、R²、R³、R⁴、R⁵およびR⁶は、互いにそれぞれ同一または異なっていてもよいアルキル基、アルケニル基、アルキニル基、アルコキシ基またはアリール基であり、アルキル基、アルケニル基またはアルキニル基およびアルコキシ基のアルキル部は、直鎖状であっても、分岐していてもよい。R¹、R²、R³、R⁴、R⁵およびR⁶は、好ましくは炭素数１〜１２のアルキル基またはフェニル基である。アルキル基、アルコキシ基のアルキル部の具体例として、メチル基、エチル基、n−プロピル基、sec−プロピル基、n−ブチル基、sec−ブチル基、tert−ブチル基、デシル基、ドデシル基等を挙げることができる。 The carbazole derivative of the present invention has the following general formula (1),

It is characterized by being represented by. In the above formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each an alkyl group, alkenyl group, alkynyl group, alkoxy group or aryl group, which may be the same or different from each other, and alkyl The alkyl part of the group, alkenyl group or alkynyl group and alkoxy group may be linear or branched. R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are preferably an alkyl group having 1 to 12 carbon atoms or a phenyl group. Specific examples of alkyl group and alkyl part of alkoxy group include methyl group, ethyl group, n-propyl group, sec-propyl group, n-butyl group, sec-butyl group, tert-butyl group, decyl group, dodecyl group, etc. Can be mentioned.

Moreover, m, n, p, q, r, and s represent the integer of 0-4. However, when m, n, p, q, r and s are each an integer of 2 to 4, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are the same or different in each. Also good. That is, each benzene ring may have different types of substituents.

As the carbazole derivative of the present invention, for example, m, n, p, q, r and s are 0, that is, those having no substituent, m, n, p and q are 1, and r and s are What is 0 can be used conveniently. Preferred specific examples of the carbazole derivative of the present invention are shown below.

The carbazole derivative of the present invention can be obtained by combining known synthesis methods, and the synthesis method is not particularly limited. The synthesis of the carbazole derivative of the present invention will be described according to the following reaction scheme 1 taking the compound (1-1) as an example. First, by reacting acetylene gas with 1-bromo-4-iodobenzene (a) under a standard palladium catalyst such as (Ph ₃ P) ₂ PdCl ₂ described in Scheme 1 Bis (4-bromophenyl) acetylene (b) is obtained (see Journal of the American Chemical Society (2002), 124 (29), 8661-8666). Next, the obtained suspension of bis (4-bromophenyl) acetylene (b), carbazole (c), potassium carbonate, palladium acetate, and tri-tert-butylphosphine in toluene was refluxed under a nitrogen atmosphere to obtain Ace -CBP (d) can be obtained.

Reaction scheme 1

  Further, the above reaction scheme 1 is a synthesis method of the carbazole derivative of the present invention that does not have a substituent, but when synthesizing a carbazole derivative having a substituent, according to the target carbazole derivative, The compound (a), the compound (b), and the compound (c) can be obtained by appropriately introducing a substituent and performing the same operation. The introduction of the substituent can be performed according to a known synthesis method, and is not particularly limited. For example, the introduction of the substituent into the compound (c) can be carried out according to the following reaction scheme 2 when the substituent is a tert-butyl group and according to the following reaction scheme 3 when it is a methyl group (Dalton Transactions (2003)). ), (13), 2718-2727).

When the substituent is a tert-butyl group, aluminum chloride (AlCl ₃ ) and carbazole (c) are first turbid in a solvent such as dichloromethane and stirred. After stirring, 2-chloro-2-methylpropane is added and reacted, followed by purification according to a conventional method, whereby the compound (c-1) in which the tert-butyl group is substituted can be obtained.

Reaction scheme 2

  When the substituent is a methyl group, according to the following reaction scheme 3, carbazole (c) is first brominated to obtain compound (c-2), and then bromine of the obtained compound (c-2) is methylated. By substituting with a group, the desired compound (c-3) can be obtained.

Reaction scheme 3

  The carbazole derivative of the present invention obtained as described above needs to have high purity when used in organic EL. For example, as a chemical purification method, column chromatography, a recrystallization method, etc. are mentioned, These are repeated and highly purified. If there is an influence of impurities or residual solvent that cannot be removed by these methods, a sublimation purification method may be used.

  The organic EL device of the present invention is an organic electroluminescence device comprising at least one organic layer between a pair of electrodes, wherein at least one of the organic layers is a fluorescent or phosphorescent material as a guest material and the present invention as a host material. However, the form of the organic EL element is not particularly limited, and FIG. 1 is a schematic diagram of a preferred embodiment of the laminated structure in the organic EL element of the present invention. Show.

  In the organic EL element 10 shown in FIG. 1A, an anode 2, a light emitting layer 4, and a cathode 7 are laminated on a substrate 1. A conducting wire (not shown) is connected to each of the anode 2 and the cathode 7, and the other end of the conducting wire is connected to a power source (not shown).

  The organic EL element 10 shown in FIG. 1B is the same as FIG. 1A except that the hole transport layer 3 is laminated between the anode 2 and the light emitting layer 4.

  The organic EL element 10 shown in FIG. 1C is the same as FIG. 1 except that the electron transport layer 6 is laminated between the light emitting layer 4 and the cathode 7.

  In an organic EL element 10 shown in FIG. 1D, an anode 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 6 and a cathode 7 are laminated on a substrate 1.

  In the organic EL element 10 shown in FIG. 1E, an anode 2, a hole transport layer 3, a light emitting layer 4, an exciton blocking layer 5, an electron transport layer 6 and a cathode 7 are laminated on a substrate 1. .

  The substrate of the organic EL element shown in FIG. 1 can be one generally used for the organic EL element, and is not particularly limited, but has transparency, surface smoothness, waterproofness, etc. Excellent glass and plastic substrates are preferred.

The anode 2 is not particularly limited, but the role of the anode is to inject holes into an organic layer such as a hole transport layer, and preferably has a high work function. As a transparent conductive material that can be used for the anode 2, for example, a transparent electrode formed of indium tin oxide (ITO) is preferable in consideration of conductivity, light transmission, etching processability, and the like. Can be used for Other examples include indium zinc oxide (IZO: In ₂ O ₃ —ZnO). The cathode 7 is not particularly limited, but the role of the cathode 7 is to inject electrons into the organic layer, and those having a small work function are preferable. For example, a magnesium-silver alloy electrode, a magnesium-indium alloy electrode, an aluminum electrode, or a combination of a thin interface layer and an aluminum electrode can be suitably used.

  The organic EL device of the present invention includes at least one of the layers sandwiched between the anode 2 and the cathode 7 and includes a fluorescent or phosphorescent material and the carbazole derivative of the present invention as a host material. The layer containing the phosphorescent material and the carbazole derivative of the present invention is preferably the light emitting layer 4, but is not particularly limited, and other layers include the fluorescent or phosphorescent material and the carbazole derivative of the present invention, Luminescence derived from fluorescent or phosphorescent materials may be shown.

The fluorescent or phosphorescent material used as the guest material is not particularly limited, and examples of the fluorescent material include BSB-CN. As the phosphorescent material, an iridium complex can be suitably used. Examples of the iridium complex include Ir (ppy) ₃ capable of obtaining a green emission color, Btp ₂ Ir (acac) capable of obtaining a red emission color, and FIrpic capable of obtaining a blue emission color. be able to. As a specific example, the carbazole derivative (1-1) of the present invention can be suitably used as a host material for BSB-CN or Btp ₂ Ir (acac), and the carbazole derivative (1-2) is Ir (ppy) _3. It can be suitably used as a host material. Thus, the carbazole derivative of the present invention can be suitably used as a host material for various fluorescent and phosphorescent materials by changing the substituent to be introduced using the carbazole derivative (1-1) as a basic skeleton. .

As the electron transport material, those generally used for organic EL elements can be used, and are not particularly limited. For example, as an electron-transporting materials include Alq _3. However, when using Alq ₃ as the electron-transporting layer, since the light emitting material is Alq ₃ contact may excitons in the light emitting layer 4 resulting in energy transfer to the singlet and triplet Alq _3, FIG. 1 (e The exciton blocking layer 5 is preferably inserted between the light emitting layer 4 and the electron transport layer 6 as shown in FIG. The exciton blocking layer 5 can prevent exciton migration by using a 1,10-phenanthroline derivative such as BCP (Bathocuproine), for example. In addition, the exciton blocking layer 5 can also use a triazole derivative such as TAZ (3-phenyl-4- (1′-naphthyl) -5-phenyl-1,2,4-triazole). . Further, as an electron transport material, in addition to Alq _3, oxadiazole derivatives (tBu-PBD), dimerization, can be mentioned starburst of oxadiazole derivatives.

  As the hole transport material, those generally used for organic EL elements can be used, and are not particularly limited. For example, aromatic amines, particularly triarylamine derivatives can be preferably mentioned. Specific examples include α-NPD, m-MTDATA, 2-TNATA, TCTA, spiro-TAD, DPPD, and the like.

  CBP has a bipolar carrier transport property and is known to exhibit not only a hole transport property but also an electron transport property. The carbazole derivative of the present invention similarly has not only a hole transport property but also an electron transport property. Showing gender. Thereby, the carbazole derivative of the present invention can also be used as a carrier transport / injection material.

  In addition to the light emitting layer, the carrier transport layer and the injection layer may be doped. For example, by doping rubrene in the hole transport layer, light emission is observed from rubrene, and the light emission efficiency of the device is improved. Further, by doping the carrier transport layer and the injection layer, it is possible to obtain effects such as an increase in device life and an improvement in durability.

  The organic EL device schematically shown in FIG. 1 can be manufactured by a known manufacturing method, and the manufacturing method is not particularly limited. For the hole transport layer 3, the light emitting layer 4, the exciton blocking layer 5 and the electron transport layer 6, for example, vacuum deposition (thermal deposition), coating by spin casting (spin coating), solvent casting, etc. are suitable. Can be used. Since the carbazole derivative of the present invention is excellent in thermal stability, a vacuum deposition method or a spin coating method can be preferably used.

  Also, the method of using the organic EL device of the present invention is not particularly limited. However, because of its high luminous efficiency, it can be suitably used for displays, indoor lighting, etc. Furthermore, the carbazole derivative of the present invention is also suitable for organic semiconductor laser devices. Can be used for In addition, application to various uses can be expected.

Hereinafter, the present invention will be described in detail based on examples.
Synthesis example 1
Bis (4-carbazoylphenyl) acetylene (1-1)
First, bis (4-bromophenyl) acetylene (3.32 g, 10 mmol), carbazole (3.5 g, 21 mmol: manufactured by Merck & Co.), potassium carbonate (8.3 g, 60 mmol: manufactured by Wako Pure Chemical Industries, Ltd.), palladium acetate ( 0.11 g, 0.5 mmol: Wako Pure Chemical Industries, Ltd.) and tri-tert-butylphosphine (0.4 g, 2 mmol: Kanto Chemical Co., Ltd.) in toluene suspension (100 mL: Kanto Chemical Co., Ltd.) Was refluxed for 48 hours under a nitrogen atmosphere. Next, after allowing to cool to room temperature, toluene was distilled off with an evaporator, and chloroform (500 mL) and water (500 mL) were added to the residue for liquid separation. The organic layer was dried over anhydrous sodium sulfate, the solvent was distilled off with an evaporator, and the residue was purified by silica gel column chromatography (150 g, chloroform 100%). Further, recrystallization from toluene was performed twice to obtain bis (4-carbazoylphenyl) acetylene (1-1) as colorless crystals (3.53 g, yield 69%).

Synthesis example 2
Bis {4- (3,6-di-tert-butylcarbazoyl) phenyl} acetylene (1-2)
The same operation as in Synthesis Example 1 was performed except that 3,6-di-tert-butylcarbazole was used in place of carbazole. The amounts of reagents used were bis (4-bromophenyl) acetylene (0.61 g, 1.82 mmol), 3,6-di-tert-butylcarbazole (1.02 g, 3.65 mmol), potassium carbonate (1.47 g, 10.6 mmol). ), Palladium acetate (20 mg, 0.09 mmol), tri-tert-butylphosphine (69 mg, 0.34 mmol), toluene (25 mL). The reaction time was 20 hours, and bis {4- (3,6-di-tert-butylcarbazoyl) phenyl} acetylene (1-2) was obtained as colorless crystals (yield 0.93 g, yield 69%).

Evaluation of optical properties and OLED characteristics (Evaluation method of optical properties)
As a substrate, a quartz substrate of 4.0 cm in length and 2.0 cm in width or 1.6 cm in length and 1.6 cm in width (for measuring absorption and fluorescence spectra), a glass substrate of 3.0 cm in length and 3.0 cm in width (for measuring ionization potential), 1.3 cm in length and 1.3 cm in width A silicon substrate (for streak camera measurement), a quartz substrate 1.0 cm long and 1.6 cm wide (for PL quantum efficiency measurement), and a glass substrate 2.6 cm long and 2.0 cm wide (for ASE measurement) were used. The substrate was cleaned by the following method. First, finger washing was performed using a neutral detergent (Clean Ace, manufactured by Iuchi Seieido Co., Ltd.). Next, ultrasonic cleaning was performed for 5 minutes using neutral detergent and distilled water, rinsed with distilled water, and ultrasonic cleaning was again performed for 5 minutes with distilled water. Next, ultrasonic cleaning was performed twice with acetone and once with isopropanol for 5 minutes each. Next, boiling cleaning was performed using isopropanol, the substrate was dried by blowing dry air, and the substrate was attached to the substrate holder.

For organic layer deposition, use a vacuum deposition machine (Advanced Lab System), place an organic substance in a tungsten boat, set it in the deposition machine, and set the substrate rotation speed to 20 rpm under the condition of vacuum degree 3 × 10 ^-3 Pa. Then, after depositing about 10 nm of the deposited material, the shutter was opened and a film of 100 nm was formed on the substrate.

The basic physical properties were measured according to the following procedure.
(1) Measurement of absorption spectrum The absorption spectrum was measured using UV-VIS-NIR Recording Spectrophotometer UV-3100 (manufactured by Shimadzu Corporation).
(2) Measurement of fluorescence spectrum The fluorescence spectrum was measured using FP-6500-A-ST (manufactured by Jusco).
(3) Measurement of phosphorescence spectrum The phosphorescence spectrum is a cryostat (PS23SS, manufactured by Daikin Industries, Ltd.) using a 337 nm nitrogen gas laser, or a 266 nm Nd: YAG laser as the excitation light when the material absorption is low. Was cooled to a temperature of 5K, and phosphorescence spectrum was measured using a Streak camera (C4334, manufactured by Hamamatsu Photonics).
(4) Phosphorescence spectrum measurement in solution
The host material of the present invention is dissolved in EPA (diethyl ether: Isopentane: ethanol = 5: 5: 2) solution at 1 × 10 ^-4 mol / l, cooled with liquid nitrogen (T = 77K) and FP-6500- Measurement was performed using A-ST (manufactured by Jusco).
(5) Measurement of ionization potential (IP)
IP was measured using a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.). AC-3 (manufactured by Riken Keiki Co., Ltd.) was used for IP of 6.3 eV or higher.
(6) Measurement of internal quantum efficiency The internal quantum efficiency was measured using a sample deposited on a quartz substrate in a nitrogen atmosphere using an integrating sphere (IS-060, Labsphere Co.). Measurement was performed using a He—Cd laser (IK5651R-G, Kimmon Electric Co. Ltd.) having a wavelength of 325 nm as excitation light.
(7) ASE measurement A sample was photoexcited using a nitrogen gas laser with a wavelength of 337 nm (MNL200, Laser Technik Berlin, pulse width: ~ 500 ps, repetition rate: 20 Hz) as an excitation light source. The excitation light was condensed to a size of 0.1 cm × 0.5 cm by a cylindrical lens, and the sample was condensed and irradiated in a stripe shape. The light emission from the sample was observed from the end face by a multi-channel photodiode (PMA-11, manufactured by Hamamatsu Photonics). In order to prevent deterioration of the organic layer due to moisture and oxygen, measurements were performed in a nitrogen atmosphere using a vacuum chamber. Using an ND filter, change the incident light intensity between 0.01% and 100%, measure the spectrum as described above, determine the peak intensity of each spectrum, and create a graph of incident light intensity vs. peak intensity. , Two approximate lines were drawn for a sudden change in peak intensity, and the ASE threshold was calculated from the intersection. The incident light intensity was obtained from the following equation. The single layer film was irradiated with light from the organic layer side.
Incident light intensity (μJ / cm ² ) = Laser output (μJ / pulse) × Quartz plate transmittance × Organic layer absorption rate × Area correction (8) Streak measurement Sample is cryostat (PS23SS, manufactured by Daikin Industries, Ltd.) set, a streak camera (C4334, Hamamatsu Photonics Co., Ltd.) using a nitrogen gas laser having a wavelength of 337nm (MNL200, Laser Technik Berlin, pulse width~500ps, repetition rate: 20Hz) to an excitation light, the degree of vacuum to 10 by 300K ^- Measurement was performed under ¹ Pa.

(OLED characteristics evaluation method)
First, an ITO substrate (ITO film thickness 110 nm) was cut into a length of 1.3 cm and a width of 1.3 cm using a glass cutter. The substrate was washed by the same operation as that of the substrate used for the evaluation of the optical properties up to the step of drying the substrate by blowing dry air. Next, UV-ozone treatment was performed for 14 minutes 30 seconds using a UV-ozone cleaner (Nippon Laser and Electric Lab.), And the substrate was attached to the substrate holder. The organic layer was also formed to a predetermined thickness by the same operation as the evaluation of optical properties. The device structure was ITO / hole injection (transport) layer (HIL and HTL) / light emitting layer (EML) / electron injection (transport) layer (EIL and ETL) / cathode double heterostructure.

The materials are α-NPD (4,4'-bis [N- (1-naphthyl) -N-phenyl-amino] biphenyl) or TPD as the hole transport layer, and Alq ₃ (Tris- (8-hydroxyquinoline) as the electron transport layer. ) aluminum). Furthermore, as a luminescent material, fluorescent material BSB-CN (1,4-dini-trile-2,5-bis (4- (bis (4-methoxyphenyl) amino) styryl) benzene), green phosphorescent material Ir ( ppy) ₃ or red phosphorescent material Btp ₂ Ir (acac) was used as a guest molecule, and the carbazole derivative of the present invention was used as its host material. Further, BCP (2,9-dimethy-4,7-diphenyl-1,10-phenanthroline) having an electron transporting property and a hole blocking property was used.

Electrode deposition was performed by depositing an organic substance, and then attaching a shadow mask having a hole with a diameter of 1 mm on the substrate and fixing it to a substrate holder in a vacuum deposition apparatus. At that time, the cathodes Mg and Ag were set in a stainless steel boat and a tungsten boat, respectively, and fixed in the vapor deposition machine. After reaching 3 × 10 ⁻³ Pa, a current was passed through Ag to stabilize the deposition rate at 0.03 nm / sec. Next, a current was passed through Mg to obtain a deposition rate of 0.33 nm / sec in total with the deposition rate of Ag. Thereafter, the shutter was opened, and an Mg: Ag alloy was deposited on the substrate to a thickness of 100 nm. Further, Ag was deposited to a thickness of 10 nm at a thickness of 0.1 nm / sec as a protective layer.

The OLED characteristics were measured according to the following procedure.
(1) Emission spectrum measurement method
The OLED was made to emit light at 10 mA / cm ² and the emission spectrum was measured using a USB2000 manufactured by Ocean Optics.
(2) Current / Voltage / Luminance Measurement Method Current (I) -voltage (V) was measured with Agilent 4155C Semiconductor Analyzer, and luminance (L) was output to 4155C Semiconductor Analyzer using a silicon photodiode. Correction was performed by inputting the maximum emission wavelength of the EL spectrum as a correction value of the detector based on the emission wavelength into a Multi-Function Optical Meter model 1835-C manufactured by Newport.

As a result of measuring bis (4-carbazoylphenyl) acetylene (1-1) (hereinafter referred to as “Ace-CBP”) synthesized in Synthesis Example 1 by the above method, the ionization potential (IP) was HOMO = 5.8. eV, LUMO = 2.8 eV, internal quantum efficiency (η _PL ) = 61%, fluorescence lifetime (τ ₁ ) = 0.494 ns, phosphorescence lifetime (τ ₂ ) = 1.274 ns. FIG. 2 shows the absorption spectrum and fluorescence spectrum of Ace-CBP, and FIG. 3 shows the phosphorescence spectrum together with m-CP and CBP. In addition, when the phosphorescence spectrum of Ace-CBP was measured at T = 5K, phosphorescence could not be measured with a single layer film, so the triplet sensitizing action of Ir (ppy) ₃ was used, and 25 wt% -Ir ( ppy) ₃ : shows the result of measuring the PL spectrum of the co-deposited film with Ace-CBP. Phosphorescence emission (λphos. = 620nm) could be observed at T = 5K. FIG. 4 shows the fluorescence spectrum and phosphorescence spectrum in the EPA solution together with the spectrum shown in FIG. 4A shows the fluorescence spectrum, and FIG. 4B shows the phosphorescence spectrum.

Next, the organic EL device of the present invention (ITO (110 nm) / TPD (50 nm) / Ir (ppy) ₃ [[Ace-CBP] of the present invention as a host and Ir (ppy) ₃ of a green phosphorescent material as a guest) 10 wt%]: Ace-CBP (20 nm) / BCP (10 nm) / Alq ₃ (30 nm) / MgAg (100 nm) / Ag (10 nm)). FIG. 5 shows the relationship between current density and external quantum efficiency, FIG. 6 shows the relationship between voltage and current density, and FIG. 7 shows the relationship between wavelength and emission intensity. As a result, the maximum external quantum efficiency (η _ext ) remained at 0.15%. Therefore, when PL spectrum of 6wt% -Ir (ppy) ₃ : Ace-CBP was measured, Ir (ppy) ₃ emission was not observed, and Ir (ppy) ₃ triplet exciton was triplet of Ace-CBP. It was suggested that energy was transferred to the level and disappeared.

Next, the organic EL device of the present invention (ITO (110 nm) / TPD (50 nm) / Btp ₂ Ir (acac)) using Ace-CBP of the present invention as a host and Btp ₂ Ir (acac) of a red phosphorescent material as a guest. ) [10 wt%]: Ace-CBP (20 nm) / BCP (10 nm) / Alq ₃ (30 nm) / MgAg (100 nm) / Ag (10 nm)). FIG. 8 shows the relationship between current density and external quantum efficiency, FIG. 9 shows the relationship between voltage and current density, and FIG. 10 shows the relationship between wavelength and emission intensity. As a result, η _ext was 4.5%. Further, when the PL spectrum of 6 wt% -Btp ₂ Ir (acac): Ace-CBP was measured, η _PL was 30%. From these results, it was confirmed that Ace-CBP is useful as a host of a red phosphorescent material.

Bis {4- (3,6-di-tert-butylcarbazoyl) phenyl} acetylene (1-2) (hereinafter referred to as “tBu-Ace-CBP”) synthesized in Synthesis Example 2 is the same as the above method. As a result, the ionization potential (IP) was HOMO> 6.2 eV, η _PL = 37.5%, τ ₁ = 0.378 ns, and τ ₂ = 1.040 ns. FIG. 11 shows the absorption spectrum, fluorescence spectrum and phosphorescence spectrum of tBu-Ace-CBP, and FIG. 12 shows the fluorescence spectrum and phosphorescence spectrum in the EPA solution together with the spectrum shown in FIG. 12A shows a fluorescence spectrum, and FIG. 12B shows a phosphorescence spectrum.

Next, the organic EL device of the present invention (ITO (110 nm) / TPD (50 nm) / Ir (ppy)) using tBu-Ace-CBP of the present invention as a host and Ir (ppy) ₃ of a green phosphorescent material as a guest ₃ [6 wt%]: t-buAce-CBP (20 nm) / BCP (10 nm) / Alq ₃ (30 nm) / MgAg (100 nm) / Ag (10 nm)) is shown. FIG. 13 shows the relationship between current density and external quantum efficiency, FIG. 14 shows the relationship between voltage and current density, and FIG. 15 shows the relationship between wavelength and emission intensity. Further, when the PL spectrum of Ir (ppy) ₃ [6 wt%]: tBu-Ace-CBP was measured, η _PL was 72%. These results confirm that tBu-Ace-CBP is useful as a host for green phosphorescent materials.

Next, the organic EL element of the present invention (ITO (110 nm) / α-NPD (30 nm) / BSB-CN: Ace-CBP :) using Ace-CBP of the present invention as a host and the fluorescent material BSB-CN as a guest (20 nm) / BCP (20 nm) / Alq ₃ (30 nm) / MgAg (100 nm) / Ag (10 nm)) is shown. FIG. 16 shows the relationship between current density and external quantum efficiency, FIG. 17 shows the relationship between voltage and current density, and FIG. 18 shows the relationship between wavelength and emission intensity. As a result, η _ext was as high as 3.0%. This shows that the carbazole derivative of the present invention into which an acetylene linking group has been introduced is also useful as a host material for a fluorescent material.

Next, the characteristics when Ace-CBP is used as the active layer of an organic semiconductor laser are shown. FIG. 19 shows a PL spectrum of a 100 nm 6 wt% -BSB-CN: Ace-CBP co-deposited film on a glass substrate. Fluorescence emission based on BSB-CN having a peak at about 570 nm was observed, and η _PL was 65 ± 2%. On the other hand, when the excitation intensity was increased by the nitrogen gas laser, the emission spectrum was sharpened sharply as shown in FIG. 20, and ASE oscillation was observed. Further, from the relationship between the excitation intensity and emission intensity characteristics shown in FIG. 21, it was found that the threshold value for ASE oscillation was about 3.5 μJ / cm ² . This value is lower than that of conventional materials, indicating that Ace-CBP is effective as an active layer of an organic semiconductor laser.

It is a schematic diagram which shows suitable embodiment of the organic EL element of this invention. It is an absorption and fluorescence spectrum of the compound of the present invention, bis (4-carbazoylphenyl) acetylene. It is a phosphorescence spectrum of the compound of the present invention, bis (4-carbazoylphenyl) acetylene. It is the fluorescence and phosphorescence spectrum in the EPA solution of the compound of this invention, bis (4-carbazoylphenyl) acetylene. It is the graph which showed the relationship between the current density of the organic EL device element of this invention which uses Ace-CBP of this invention as a host, and Ir (ppy) ₃ as a guest, and external quantum efficiency. ₃ is a graph showing the relationship between the voltage and current density of the organic EL device element of the present invention using Ace-CBP of the present invention as a host and Ir (ppy) ₃ as a guest. It is the graph which showed the relationship between the wavelength of the organic EL device element of this invention which used Ace-CBP of this invention as a host, and Ir (ppy) ₃ as a guest, and light emission intensity. 4 is a graph showing the relationship between the current density and the external quantum efficiency of an organic EL device element of the present invention using Ace-CBP of the present invention as a host and Btp ₂ Ir (acac) as a guest. 6 is a graph showing the relationship between the voltage and current density of the organic EL device element of the present invention using Ace-CBP of the present invention as a host and Btp ₂ Ir (acac) as a guest. 3 is a graph showing the relationship between the wavelength and emission intensity of an organic EL device element of the present invention using Ace-CBP of the present invention as a host and Btp ₂ Ir (acac) as a guest. 2 shows an absorption spectrum, a fluorescence spectrum, and a phosphorescence spectrum of {4- (3,6-di-tert-butylcarbazoyl) phenyl} of the compound of the present invention. It is the fluorescence and phosphorescence spectrum in the EPA solution of the compound of this invention, {4- (3,6-di-tert-butylcarbazoyl) phenyl}. 6 is a graph showing the relationship between the current density and the external quantum efficiency of an organic EL device element of the present invention using tBu-Ace-CBP of the present invention as a host and Ir (ppy) ₃ as a guest. 4 is a graph showing the relationship between the voltage and current density of an organic EL device element of the present invention using tBu-Ace-CBP of the present invention as a host and Ir (ppy) ₃ as a guest. ₃ is a graph showing the relationship between the wavelength and emission intensity of an organic EL device element of the present invention using tBu-Ace-CBP of the present invention as a host and Ir (ppy) ₃ as a guest. It is the graph which showed the relationship between the current density of the organic EL device element of this invention which uses Ace-CBP of this invention as a host, and BSB-CN as a guest, and external quantum efficiency. 3 is a graph showing the relationship between the voltage and current density of an organic EL device element of the present invention using Ace-CBP of the present invention as a host and BSB-CN as a guest. It is the graph which showed the relationship between the wavelength of the organic EL device element of this invention which used Ace-CBP of this invention as a host, and BSB-CN as a guest, and emission intensity. 6 shows absorption and emission spectra of a co-deposited film by 6 wt% -BSB-CN: Ace-CBP. It is the graph which showed the excitation intensity | strength dependence of the emission spectrum of the co-deposition film | membrane by 6 wt% -BSB-CN: Ace-CBP under optical excitation. It is the graph which showed the relationship between the excitation intensity | strength of the co-deposition film | membrane by 6 wt% -BSB-CN: Ace-CBP under light excitation, and emitted light intensity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole transport layer 4 Light emitting layer 5 Exciton blocking layer 6 Electron transport layer 7 Cathode 10 Organic EL element

Claims (6)

The following general formula (1),

(In the above formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group or an aryl group, which may be the same or different from each other; m, n, p, q, r and s represent an integer of 0 to 4, provided that when m, n, p, q, r and s are each an integer of 2 to 4, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ may be the same or different from each other.) ^2. The carbazole derivative according to claim ¹ , wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each a C 1-12 alkyl group or phenyl group which may be the same or different from each other.   3. An organic electroluminescence device comprising at least one organic layer between a pair of electrodes, wherein at least one of the organic layers contains a fluorescent or phosphorescent material as a guest material and the carbazole derivative according to claim 1 or 2 as a host material. An organic electroluminescence device characterized by comprising:   An organic electroluminescence device comprising at least one organic layer between a pair of electrodes, wherein the organic layer contains the carbazole derivative according to claim 1 or 2 as a carrier transport / injection material in at least one of the organic layers. Electroluminescence element.   3. An organic semiconductor laser element comprising at least one organic layer between a pair of electrodes, wherein at least one of the organic layers contains a fluorescent or phosphorescent material as a guest material and the carbazole derivative according to claim 1 or 2 as a host material. An organic semiconductor laser element. An organic semiconductor laser element comprising at least one organic layer between a pair of electrodes, wherein the carbazole derivative according to claim 1 or 2 is contained in at least one of the organic layers as a carrier transport / injection material. Semiconductor laser element.

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