JPH1187067A - Hole transfer material having silacyclopentadiene ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent element for emitting light at a high efficiency at a low voltage by containing a specified silacyclopentadiene derivative including a part having hole transporting ability in a ring and hard to be formed with an exciting complex and having excellent hole transporting ability in a layer to be sandwiched between electrodes. SOLUTION: Silacyclopentadiene derivative expressed with a formula (in the formula, X, Y mean saturated or un-saturated hydrocarbon group, alkoxy group, alkenyloxy group, alkynyloxy group, hydroxy group, aryl group, hetero ring, ring structure formed by bonding X to Y, and Z1 , Z2 mean a nitrogen atom, three or more aromacyclic group, and R1 , R2 mean hydrogen, alkyl group, aryl group, heterocyclic group, cyclic condensation structure) is used as a hole transporting material of an organic electroluminescent element. In the case where an organic electroluminescent element has a hole transporting layer, the described hole transporting material is desirably contained in the hole transfer layer of the organic electroluminescent element. This silacyclopentadiene derivative shows strong fluorescence and has electron transfer ability and it can be efficiently used even in the single layer structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hole transport material using a silacyclopentadiene derivative and a hole electroluminescent device using the hole material, which can be used for an organic electroluminescent device and the like.

[0002]

2. Description of the Related Art In recent years, an organic electroluminescent device (hereinafter referred to as an organic electroluminescent device) has been proposed as a candidate for a flat display with high brightness.
(Abbreviated as L element)), and its research and development has been activated. The structure of an organic EL element is such that an organic light emitting layer containing a light emitting dye is sandwiched between two electrodes, and holes injected from an anode and electrons injected from a cathode are recombined in the light emitting layer to generate light. Emits. The organic material used for the organic EL element includes a low molecular weight material and a high molecular weight material, and the light emission of the organic EL element using these materials has high luminance.

[0003] There are two types of organic EL elements. 1
First, a fluorescent dye added to a charge transporting layer for transporting electrons and / or holes to form an organic light-emitting layer disclosed by CWTang et al. (Journal of the Applied Physics (J. Appl.Phys.), 65,
3610 (1989)), and the other uses a fluorescent dye alone in the organic light emitting layer (for example, Japanese)
Journal of Gia Pride Physics (Jpn.
J. Appl. Phys.), 27, L269 (1988)). Organic EL devices using a fluorescent dye alone in the organic light emitting layer are further divided into three types. The first is that the organic light emitting layer is a three-layer structure sandwiched between a hole transport layer that transports only holes, which is one of the charges, and an electron transport layer that transports only electrons. A hole transport layer and an organic light emitting layer are laminated to form two layers, and a third is a layer in which an electron transport layer and an organic light emitting layer are laminated to form two layers. Organic E
It is known that the luminous efficiency is improved by forming the L element in two or three layers.

[0004] As the hole transporting material used in the organic EL device, various kinds of materials are known, centering on triphenylamine derivatives. However, these materials have a drawback that they form an exciplex with a luminescent dye or an electron transporting material used at the same time, and reduce the efficiency of the device.
For example, when N, N'-diphenyl-N, N'-di (3-methylphenyl) -4,4'-diaminodiphenyl (hereinafter abbreviated as TPD) is used in an organic EL device, a large amount of light is emitted. There is a problem that an exciplex is formed with the dye and the electron transport material, and the luminescent dye and the electron transport material to be used are limited. Specific examples of such an electron transport material include 2- (4-diphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (hereinafter abbreviated as PBD). It has been known. Among the characteristics of the hole transport material used in the organic EL device, first of all, it is necessary that it is difficult to form an exciplex and that the hole transport material has excellent hole transport ability.

On the other hand, a recent report of a silacyclopentadiene derivative relates to a reactive intermediate intended for application to a π-electron conjugated organic polymer, as disclosed in Japanese Patent Application Laid-Open No. Hei 7-197977. Is limited to Further, examples of copolymers of silacyclopentadiene and thiophene are disclosed in JP-A-6-166746 and JP-A-9-87616, but these compounds have a disadvantage that they have low hole transporting ability. Therefore, there is a problem that it is not suitable as a hole transport material of an organic EL device. Furthermore, the silacyclopentadiene derivative with an amino group shown in DE4442050 is used as a luminescent dye,
An exciplex which causes a reduction in the efficiency of the device is easily formed with an electron transporting material or the like, and there is a disadvantage that the luminescent dye and the electron transporting material that can be used are limited.

Further, as examples in which a silane derivative is used for an organic EL device, see Japanese Patent Application Laid-Open Nos. 5-343184 and 6-124784.
JP-A-6-234968, JP-A-6-293778, JP-A-6-325871, and JP-A-7-11244. No cyclopentadiene ring is included. Furthermore, examples of these silane compounds that are actually used are limited to use as an interface layer for improving adhesion between a hole transporting material or a light emitting layer and a cathode,
It has never been known to be used as a hole transport material. The present inventors have already found that a silacyclopentadiene derivative has excellent performance as an electron transport material as disclosed in Japanese Patent Application Laid-Open No. 9-94487.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hole transporting material which is a base of an organic EL device having a low voltage and a high luminous efficiency.

[0008]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of intensive studies, they have found that when a silacyclopentadiene derivative is used as a hole transport material, an organic EL device having low voltage and high luminous efficiency can be obtained, and the present invention has been completed. That is, the present invention provides the following (1) to (3)
It consists of.

(1) A hole transport material characterized by using a compound represented by the following chemical formula (2).

Embedded image [Wherein, X and Y each independently represent a saturated or unsaturated hydrocarbon group, an alkoxy group, an alkenyloxy group,
An alkynyloxy group, a hydroxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocycle, or a structure in which X and Y are combined to form a saturated or unsaturated ring, and Z ₁ and Z ₂ are , Each independently at least one
R ₁ and R ₂ are each independently a hydrogen, a substituted or unsubstituted alkyl group, an aryl group, a heterocyclic group,
Or a structure in which a substituted or unsubstituted ring is condensed.] (2) An organic electroluminescent device comprising the hole transport material according to (1). (3) having a hole transport layer;
An organic electroluminescent device comprising the hole transporting material according to claim 1.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the silacyclopentadiene derivative used in the present invention include 1,1-dimethyl-2,5-bis (4-
(N, N-diphenylanilino) -3,4-diphenylsilacyclopentanediene (hereinafter referred to as TP
AS), 1,1-dimethyl-2,5-bis (3-N, N-diphenylanilino) -3,4-diphenylsilacyclopentane, 1,1-dimethyl-2,5-bis { 4-N-
(1-Naphthyl) -N-phenylanilino} -3,4-diphenylphenylcyclocyclopentane, 1,1-
Dimethyl-2,5-bis (2-N, N-diethylanilino) -3,4-diphenylsilacyclopentane, 1,1-diisopropyl-2,5-bis {4-N- (3-methylphenyl) -N-Phenylanilino} -3,4-diphenylsilacyclopentane, 1,1,3,4-tetraphenyl-2,
Examples include 5-bis {4-N- (3-methylphenyl) -N-phenylanilino} silacyclopentane, a compound represented by the following formula 3, but are not limited to these compounds.

Embedded image

The silacyclopentadiene derivative used in the present invention can be obtained, for example, by the following production methods, but the present invention is not limited to these production methods. The silapentadiyne derivative represented by the following formula 4 is reacted with an alkali metal complex, the silane derivative represented by the following formula 5 is reacted, and subsequently, zinc chloride or a zinc chloride complex is reacted. A reactive silacyclopentadiene derivative represented by the following formula can be obtained. Next, a silacyclopentadiene derivative used in the present invention is obtained by reacting the reactive silacyclopentadiene derivative with a halide represented by the following formula 7 in the presence of a catalyst.

[0012]

Embedded image [Wherein, X and Y each independently represent a saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms, an alkoxy group,
An alkenyloxy group, an alkynyloxy group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic ring, or X and Y combine to form a saturated or unsaturated ring, and R ₁ and R ₂ each independently represents a structure in which hydrogen, a substituted or unsubstituted alkyl group, an aryl group, a heterocyclic group, or a substituted or unsubstituted ring is fused.

[0013]

Embedded image [Wherein, X, Y and Z each independently represent a tertiary butyl group or an aryl group]

[0014]

Embedded image [Wherein, X and Y each independently represent a saturated or unsaturated hydrocarbon group, an alkoxy group, an alkenyloxy group,
An alkynyloxy group, a hydroxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocycle, or a structure in which X and Y are combined to form a saturated or unsaturated ring, and R ₁ and R ₂ are Each independently represents a structure in which a hydrogen, a substituted or unsubstituted alkyl group, an aryl group, a heterocyclic group, or a substituted or unsubstituted ring is condensed]

[0015]

Embedded image [Wherein, Z ₁ is a nitrogen atom or a group having at least three aromatic rings, and W represents a halogen atom]

As the substituent attached to the silapentadiyne derivative used as the first raw material, a substituent which does not easily inhibit the reaction between the alkali metal complex and the silapentadiyne is preferable, and a substituent which is inert to the alkali metal complex is more preferable. Examples of the alkali metal complex used include lithium naphthalenite, sodium naphthalenite, potassium naphthalenite, and lithium naphthalenite.
4,4'-tert-butyl-2,2'-phenylene and lithium (N, N-dimethylamino) naphthalenite. The solvent used in the reaction is not particularly limited as long as it is inert to the alkali metal or the alkali metal complex, and ether solvents such as ether and tetrahydrofuran are suitable. As the substituent of the silane derivative used in this reaction, a bulky one is preferable, and specific examples thereof include tertiary butyl phenyl chlorosilane, and tertiary phenyl phenyl chlorosilane.

Furthermore, as the zinc chloride or the complex of zinc chloride to be used, a solid of zinc chloride is used directly, an ether solution of zinc chloride is used, or a tetramethylethylenediamine complex of zinc chloride is used. It is preferable that these zinc chlorides are sufficiently dried, and it is difficult to obtain an intended product if the amount of water is large. This series of reactions is preferably performed in an inert gas stream, and generally, alcohol gas is used.

Examples of a catalyst for reacting a halide with a reactive silacyclopentadiene derivative include palladium catalysts such as tetrakistriphenylphosphine varium and dichlorobistriphenylphosphine varium. In each stage of the series of reactions, the reaction temperature is not particularly limited. However, when the alkali metal complex, the silane derivative, zinc chloride and the like are added and stirred, the reaction is preferably performed at room temperature or lower, usually at 0 ° C. or lower. The reaction temperature after the addition of the halide is preferably room temperature or higher. In general, when tetrahydrofuran is used as a solvent, the reaction is carried out under reflux. There is no particular limitation on the reaction time, and when adding the alkali metal complex, the silane derivative, zinc chloride, and the like and stirring the mixture, it is desirable that the reaction time be between several minutes and several hours. The reaction after the addition of the halide may be followed by a general analytical means such as NMR or chromatography to determine the end point of the reaction.

Substituents on the silicon of the thus obtained silacyclopentadiene derivative used in the present invention include a methyl group, an ethyl group, a normal propyl group,
Alkyl groups such as isopropyl group, cyclopentyl group or tertiary butyl group, alkynyl groups such as vinyl group, allyl group, butenyl or styryl group, alkynyl groups such as ethynyl group, propargyl group and phenylacetylinyl group; An alkoxy group such as a methoxy group, an ethoxy group, an isopropoxy group or a tertiary butoxy group; an alkenyloxy group such as a vinyloxy group or an allyloxy group; an alkynyloxy group such as an ethynyloxy group or a phenylacetyloxy group. , Phenyl group, naphthyl group,
Aryl groups such as anthracenyl group, biphenyl group, toluyl group, pyrenyl group, perylenyl group, anisyl group, terphenyl group or phenanthrenyl group, hydrofuryl group, hydropyrenyl group, dioxanyl group, thienyl group, furyl group, oxazolyl group, oxadiazolyl group,
Thiazolyl group, thiadiazolyl group, acridinyl group, quinolyl group, quinoxaloyl group, phenanthrolyl group, benzothienyl group, benzothiazolyl group, indolyl group,
Heterocycles such as a silacyclopentadienyl group and a pyridyl group are exemplified. Further, these substituents may be bonded to each other at an arbitrary position to form a spiro ring.

The substituents attached to the 3- and 4-positions of the silacyclopentadiene ring of the present invention each independently represent a hydrogen, a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a cyclopentyl group or a tertiary butyl group. Such alkyl group, phenyl group, biphenyl group, terphenyl group, naphthyl group, anthracenyl group, pyrenyl group, toluyl group, anisyl group, fluorophenyl group, diphenylaminophenyl group, dimethylaminophenyl group, diethylaminophenyl group, phenanthrenyl group Aryl group, thienyl group, furyl group, silacyclopentadienyl group, oxazolyl group, oxadiazolyl group, thiazolyl group, thiadiazolyl group, acridinyl group, quinolyl group, quinoxaloyl group, phenanthrolyl group, benzothienyl group, benzothienyl group Zochiazoriru group, an indolyl group, a carbazolyl group, a pyridyl group, a pyrrolyl group, a benzoxazolyl group, a pyrimidyl group, a hetero ring such as imidazolyl groups. Further, these substituents may be bonded to each other at an arbitrary position to form a ring.

The substituents attached to the 2- and 5-positions of the silacyclopentadiene ring each independently include a triphenylamino group, a diphenylaminonaphthyl group, a naphthylphenylaminophenyl group and a phenyltoluylaminonaphthyl group. The method of introducing these substituents is as follows:
It may be introduced before the formation of the silacyclopentadiene ring, or may be introduced after the formation of the silacyclopentadiene ring.

In the present invention, it has been found that a silacyclopentadiene derivative used for an organic EL device is effective as a hole transport material. It is considered that, in addition to the sites having a hole transporting ability at the 2nd and 5th positions of the silacyclopentadiene ring, the electronic properties of the silacyclopentadiene ring also have an effect on the hole transporting property. .

The silacyclopentadiene derivative of the present invention exhibits strong fluorescence by itself, and is therefore useful as a luminescent dye for an organic EL device. For example, TPAS emits yellow light. Furthermore, since the silacyclopentadiene ring exhibits an electron transporting property by itself, the silacyclopentadiene derivative used in the present invention exhibits both charge transporting properties. Therefore, the organic EL device using the silacyclopentadiene derivative of the present invention has high efficiency even in a single layer.

The configuration of the organic EL device of the present invention has various aspects. Basically, the configuration is such that the silacyclopentadiene derivative is sandwiched between a pair of electrodes (anode and cathode). Accordingly, a hole transporting material, a luminescent dye, and an electron transporting material may be added or may be stacked as separate layers. Specific examples are: anode / silacyclopentadiene derivative layer of the present invention / cathode, anode / hole injection layer / silacyclopentadiene derivative layer of the present invention / cathode, anode / silacyclopentadiene derivative layer of the present invention / hole transport Layer / organic light emitting layer / electron transporting layer / cathode, anode / (luminescent dye + silacyclopentadiene derivative layer of the present invention) / cathode.

The organic EL device of the present invention is preferably supported on a substrate, and the substrate to be supported is not particularly limited.
For example, glass, transparent plastic, conductive polymer, quartz, or the like can be used. Each layer used in the organic EL device of the present invention can be formed by thinning by a known method such as an evaporation method and a coating method. The thickness of the thin film of each layer formed in this manner is not particularly limited and can be appropriately selected depending on the situation, but is usually 2 nm to 5000 nm.
Is selected in the range.

As the anode in the organic EL device of the present invention, a metal, an alloy, an electrically conductive compound having a high work function (4 eV or more), or a mixture thereof is preferably used as an electrode material. Specific examples of such an electrode material include metals such as Au, CuI, indium tin oxide (hereinafter abbreviated as ITO), SnO ₂ , Z
A dielectric transparent material such as nO is used. The anode can be produced by forming a thin film from these electrode substances by a method such as vapor deposition or sputtering. When light is extracted from this electrode, the transmittance is set to 1
It is desirable to make it larger than 0%, and the sheet resistance as an electrode is preferably several hundred Ω / square or less. Further, the film thickness depends on the material, but is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

On the other hand, as the cathode, a metal, an alloy, an electrically conductive compound or a mixture thereof having a low work function (4.3 eV or less) is used as an electrode material. Specific examples of such electrode materials include calcium, magnesium, lithium, aluminum, magnesium alloy, lithium alloy, aluminum alloy, aluminum /
Lithium mixtures, magnesium / silver mixtures, indium and the like. The cathode can be manufactured by forming a thin film of these electrode substances by a method such as vapor deposition or sputtering. The sheet resistance as an electrode is preferably several hundred Ω / square or less, and the film thickness is usually 10 nm to 1 μm, preferably 50 to 200 n.
m.

Although the configuration of the organic EL device of the present invention has various modes as described above, the luminous efficiency is improved by providing a hole transport layer. As a hole transporting material used for the hole transporting layer, when a hole is injected from an anode placed between two electrodes to which an electric field is applied, the hole can be appropriately transmitted to the light emitting layer. A compound, for example, 10 ⁴ to 10 ⁶ V
/ Cm when applying an electric field of at least 10 ⁻⁶ cm ² / V ·
Those having a hole mobility of seconds or more are preferred. Such a hole transport material is not particularly limited as long as it has the above-mentioned preferable properties. When a plurality of hole transport materials are used, not only the silacyclopentadiene derivative but also a conventional photoconductive material is used. As the material, any material can be selected from those commonly used as a hole charge transport material and known materials used for a hole transport layer of an organic EL device.

Examples of the hole transport material include carbazole derivatives such as N-phenylcarbazole and polyphenylcarbazol, TPD, polymers having an aromatic tertiary amine in the main chain or side chain, and 1,1-bis (4 -C-p-tolylaminophenyl) cyclohexane,
Examples include triarylamine derivatives such as N, N'-diphenyl-N, N'-dianaphthyl-4,4'-diaminodiphenyl, metal-free, phthalocyanine derivatives such as copper phthalocyanine, and polysilane.

The electron transporting material used in the electron transporting layer in the organic EL device of the present invention is not particularly limited, and any one of conventionally known compounds can be used. Preferred examples of the electron transporting material include diphenylquinone derivatives described in Journal of the Electrographic Society of Japan, Vol. 30, p. 3, 1991, or Journal of the Applied Physics (Jpn. J. App.
l.Phys.), 27, 269, (1988), and PB
D and other oxadiazole derivatives (Japanese Journal of the Applied Physics (Jpn.J.Ap.
pl.Phys.), 27, L713 (1988), Applied Physics Letter (Appl. Phys. Lett.), 55, 1489 (1989), etc., and thiophene derivatives (Japanese Unexamined Patent Publication No. 4-212286). Described), triazole derivatives (Jpn.J.Appl.P
hys., 32, L917 (1993), etc.), thiadiazole derivatives (43th Preprints of the Society of Polymer Science, (III) P1a007, etc.), metal complexes of oxine derivatives (IEICE technical report) Research reports, 92 (311), 43 (1992) etc.), polymers of quinoxaline derivatives (Jpn. J. App.
l. Phys., 33, L250 (1994), etc.) and phenanthroline derivatives (described in the 43rd Polymer Symposium Proceedings, 14J07).

The light emitting material used in the organic EL device of the present invention includes not only the silacyclopentadiene derivative of the present invention, but also a polymer functional material series “optical functional material” edited by the Society of Polymer Science, Kyoritsu Shuppan (1991), P236. Can be used including known light-emitting materials such as daylight fluorescent materials, fluorescent brighteners, laser dyes, organic scintillators, and various fluorescent analysis reagents as described in, for example, anthracene, Phenanthrene, pyrene, chrysene, perylene,
Polycyclic condensed compounds such as coronene, rubrene, quinacridone, oligophenylene compounds such as quarter phenyl, 1,4-bis (2-methylstyryl) benzene, 1,4-bis (4-methylstyryl) benzene, 1,4 -Phase (4-methyl-5-phenyl-2-oxazolyl) benzene, 1,4-
Bis (5-phenyl-2-oxasoryl) benzene, 2,5-bis (5-tert-butyl-
2-phenoxoxazolyl) thiophene, 1,4-diphenyl-1,3-phthalaciene, 1,6-
Scintillators for liquid scintillation such as diphenyl-1,3,5-hexatriene, 1,1,4,4-tetraphenyl-1,3, -phthalicene;
No. 264692, metal complexes of oxine derivatives, coumarin dyes, dicyanomethylenepyran dyes, dicyanomethylenethiopyran dyes, polymethine dyes, oxobenzanthracene dyes, xanthene dyes, carbostyril dyes and perylene dyes, German Patent 2534713 Oxazine-based compound described, 40th Applied Physics-related Union Lecture Meeting Preprints, stilbene derivatives described in 1146 (1993), oxadiazole-based compound described in JP-A-4-363891
And a silacyclopentadiene derivative described in JP-A-9-94487.

An example of a preferred method for producing the organic EL device of the present invention will be described for a device having the following structure. E comprising anode / silacyclopentadiene derivative layer of the present invention / cathode
The method of manufacturing the L element will be described. First, a thin film made of a desired electrode material, for example, a material for an anode is deposited on an appropriate substrate so as to have a thickness of 1 μm or less, preferably 10 to 200 nm. After the anode is formed by a method such as sputtering and the like, a thin film of a silacyclopentadiene derivative is formed thereon. Examples of the method for thinning include, for example, dip coating, spin coating, casting, and vapor deposition.However, from the viewpoint that a uniform film is easily obtained, impurities are hardly mixed, and pinholes are hardly generated. Evaporation is preferred.

Next, after this silacyclopentadiene derivative layer is formed, a thin film made of a cathode material is deposited thereon for 1 μm.
m or less, for example, by a method such as vapor deposition or sputtering and providing a cathode, a desired EL element can be obtained. In the production of this EL device, the production order can be reversed, and the cathode, the silacyclopentadiene derivative layer, and the anode can be produced in this order. When a DC voltage is applied to the EL device obtained in this manner, when a voltage of about 3 to 40 V is applied, light emission can be observed from the transparent or translucent electrode side. Furthermore, light is emitted by applying an AC voltage. The waveform of the applied alternating current may be arbitrary.

[0034]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

Example 1 An IT was placed on a glass substrate of 25 mm × 75 mm × 1.1 mm.
A film obtained by forming O to a thickness of 50 nm by a vapor deposition method (manufactured by Tokyo Sanyo Vacuum Co., Ltd.) was used as a transparent support substrate. This transparent support substrate was fixed to a substrate holder of a commercially available vapor deposition apparatus (manufactured by Vacuum Kiko Co., Ltd.), TPAS was placed in a crucible made of quartz, and the pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. The crucible containing TPAS was heated and TPAS was deposited to a thickness of 100 nm. The deposition rate was 0.1-0.2 nm / sec.
Thereafter, the pressure in the vacuum chamber was reduced to 2 × 10 ⁻⁴ Pa, and then magnesium was added to the graphite crucible in an amount of 1.2 to 2.
Silver was deposited from the other crucible at a deposition rate of 4 nm / sec and simultaneously at a deposition rate of 0.1-0.2 nm / sec. Under the above conditions, a mixed metal electrode of magnesium and silver was stacked on the light emitting layer to a thickness of 200 nm to form a counter electrode, thereby forming an element. When a DC voltage of 6.5 V is applied to the obtained device using an ITO electrode as an anode and a mixed electrode of magnesium and silver as a cathode, a current of about 30 mA / cm ² flows and 200 cd / cm ²
A yellow emission of m ² was obtained. The emission wavelength was 545 nm.

Example 2 The transparent support substrate used in Example 1 was fixed to a substrate holder of a vapor deposition apparatus, and TPAS was placed in a quartz crucible, TPD was placed in another crucible, and 1,1-dimethyl-3 was placed in another crucible. , 4-diphenyl-2,5
The pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa with the addition of shiny polysillucole (hereinafter abbreviated as PYS). The crucible containing TPD is heated and vapor-deposited to a thickness of 50 nm.
The crucible containing S is heated to a thickness of 15 nm by TP.
AS was deposited, and then the crucible containing PYS was heated to deposit PYS to a thickness of 35 nm. The deposition rate was 0.1-0.2 nm / sec. After that, the vacuum chamber is 2 ×
After reducing the pressure to 10 ^-4 Pa, magnesium was deposited from the graphite crucible at a deposition rate of 1.2 to 2.4 nm / sec.
The deposition was performed at a deposition rate of nm / sec. Under the above conditions, a mixed metal electrode of magnesium and silver was stacked on the light emitting layer to a thickness of 200 nm to form a counter electrode, thereby forming an element. When a direct current voltage of 4.5 V is applied to the obtained device using the ITO electrode as an anode and a mixed electrode of magnesium and silver as a cathode, about 10 mA /
A current of cm ² flowed and yellow light emission of about 100 cd / m ² was obtained. The emission wavelength was 545 nm.

Example 3 The transparent support substrate used in Example 1 was fixed to a substrate holder of a vapor deposition apparatus, and TPAS was placed in a crucible made of quartz and PYS was placed in another crucible, and the vacuum chamber was filled to 1 × 10 ^-4 Pa. The pressure was reduced.
The crucible containing TPAS was heated to deposit TPAS to a thickness of 50 nm, and then the crucible containing PYS was heated to deposit PYS to a thickness of 50 nm. The deposition rate was 0.1-0.2 nm / sec. Then, the pressure in the vacuum chamber was reduced to 2 × 10 ⁻⁴ Pa, and then magnesium was deposited from the graphite crucible at a deposition rate of 1.2 to 2.4 nm / sec.
The deposition was performed at a deposition rate of 0.2 nm / sec. Under the above conditions, a mixed metal electrode of magnesium and silver was placed on the light emitting layer by 200 nm.
An element was formed by stacking and vapor deposition to form a counter electrode. Using the ITO electrode as the anode and the mixed electrode of magnesium and silver as the cathode,
When a DC voltage of 5 V is applied to the obtained device, about 10 mA
/ Cm ² and a yellow light emission of about 300 cd / m ² was obtained. The emission wavelength was 545 nm.

Example 4 The transparent support substrate used in Example 1 was fixed to a substrate holder of a vapor deposition apparatus, TPAS was placed in a quartz crucible, and TPD was placed in another crucible, and the vacuum chamber was filled to 1 × 10 ^-4 Pa. The pressure was reduced.
The crucible containing TPD is heated and vapor-deposited to a thickness of 50 nm, and then the crucible containing TPAS is heated to a thickness of 50 nm.
TPAS was deposited to a thickness of nm. The deposition rate is 0.
1 to 0.2 nm / sec. After that, the vacuum chamber is
^After reducing the pressure to ^-4 Pa, magnesium was deposited from the graphite crucible at a deposition rate of 1.2 to 2.4 nm / sec.
Deposition was performed at a deposition rate of m / sec. Under the above conditions, a mixed metal electrode of magnesium and silver was stacked on the light emitting layer to a thickness of 200 nm to form a counter electrode, thereby forming an element. When a DC voltage of 5.5 V is applied to the obtained device using an ITO electrode as an anode and a mixed electrode of magnesium and silver as a cathode, about 4 mA / c is obtained.
A current of m ² passed and yellow light emission of about 100 cd / m ² was obtained. The emission wavelength was 545 nm.

Example 5 The transparent support substrate used in Example 1 was fixed to a substrate holder of a vapor deposition apparatus, and TPAS was placed in a quartz crucible, TPD was placed in another crucible, and tris (8-human peroxynoline was placed in another crucible). ) Aluminum (hereinafter abbreviated as Alq) is placed in the vacuum chamber at 1 × 10 ^-4.
The pressure was reduced to Pa. The crucible containing TPAS is heated and vapor-deposited to a thickness of 35 nm, and then the crucible containing TPD is heated to vapor-deposit TPD to a thickness of 15 nm.
Next, the crucible containing Alq was heated to deposit Alq to a thickness of 50 nm. Deposition rate is 0.1-0.2n
m / sec. Then, the pressure in the vacuum chamber was reduced to 2 × 10 ⁻⁴ Pa, and then magnesium was deposited from the graphite crucible at a deposition rate of 1.2 to 2.4 nm / sec. The deposition was performed at a deposition rate of 0.2 nm / sec. Under the above conditions, a mixed metal electrode of magnesium and silver was stacked on the light emitting layer to a thickness of 200 nm to form a counter electrode, thereby forming an element. When a DC voltage of 4.5 V was applied to the obtained device using an ITO electrode as an anode and a mixed electrode of magnesium and silver as a cathode, a current of about 10 mA / cm ² flowed, and green light emission of 100 cd / m ² was obtained. . The emission wavelength was 520 nm.

Example 6 The TPAS used in Example 1 was replaced with 1,1-dimethyl-2,5-bis (N-naphthyl)
(N-phenylanilino) -3,4-diphenylsilacyclopentandiene was used to produce a device in the same manner as in Example 1. When a DC voltage was applied to this device, a current of about 10 mA / cm ² flowed, and yellow light emission was obtained.

Example 7 The TPAS used in Example 1 was replaced with 1,1-dimethyl-2,5-bis (N-phenyl).
A device was prepared in the same manner as in Example 1 except that -N-poly (anilino) -3,4-diphenylsilacyclopentandiene was used instead. When a DC voltage was applied to this device, a current of about 10 mA / cm ² flowed, and yellow light emission was obtained.

Comparative Example 1 The procedure of Example 1 was repeated except that the TPAS used in Example 1 was replaced with 1,1-dimethyl-2,5-bis (5-tert-cyclobutylphenylsilylthieno) -3,4-diphenylsilacyclopentane. An element was prepared in the same manner as in Example 1. When a DC voltage was applied to this device, a current of about 6 mA / cm ² flowed, and yellow light emission of about 10 cd / m ² was obtained.

Comparative Example 2 An element was prepared in the same manner as in Example 1 except that TPD used in Example 1 was changed to TPD. When a DC voltage was applied to this element, a current flowed, but no detectable light emission was obtained.

[0044]

The compound of the present invention has excellent hole transporting properties, and therefore has a high practical value as a hole transporting material for electrophotography or organic EL devices. By using the hole transport material of the present invention for an organic EL device, a full-color high-luminance flat panel display or the like can be produced.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shigehiro Yamaguchi Kyoto University Gokasho Kyoto University Staff Dormitory 744

Claims (3)

[Claims] 1. A hole transport material using a silacyclopentadiene derivative represented by the following formula 1. Embedded image [Wherein, X and Y each independently represent a saturated or unsaturated hydrocarbon group, an alkoxy group, an alkenyloxy group,
An alkynyloxy group, a hydroxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocycle, or a structure in which X and Y are combined to form a saturated or unsaturated ring, and Z ₁ and Z ₂ are , Each independently at least one
R ₁ and R ₂ are each independently a hydrogen, a substituted or unsubstituted alkyl group, an aryl group, a heterocyclic group,
Or a structure in which a substituted or unsubstituted ring is fused] 2. An organic electroluminescent device comprising the hole transport material according to claim 1. 3. An organic electroluminescent device having a hole transport layer, wherein the hole transport material according to claim 1 is contained in the hole transport layer.