Patent Application
20080105865
The present invention relates to a pyrene based compound which becomes a main component of a light emitting layer in a light emitting transistor element, and a light emitting transistor element using the same.
Organic electroluminescence elements (hereinafter abbreviated to “organic EL elements”), which are typical examples of organic semiconductor devices, are light emitting elements using a light emitting phenomenon based on recombination of electrons and holes in a layer made of an organic fluorescent substance. Specifically, patent Documents 1 and 2 and others describe organic EL elements each consisting of a light emitting layer made of the abovementioned organic compound, an electron injecting electrode for injecting electrons into this light emitting layer, and a hole injecting electrode for injecting holes into the light emitting layer.
Examples of the organic fluorescent substance used in this light emitting layer include perynone derivatives, distyrylbenzene derivatives (patent Document 1), and 1,3,6,8-tetraphenylpyrene (patent Document 2).
On the other hand, besides such organic EL elements, light emitting transistor elements are known as examples using a light emitting phenomenon based on recombination of electrons and holes in a layer made of an organic fluorescent substance. It is conceivable to use organic fluorescent substances as used in the abovementioned organic EL elements in such light emitting transistor elements.
Patent Document 1: JP-A-5-315078
Patent Document 2: JP-A-2001-118682
However, the molecules of compounds containing such pyrene based compounds are designed for organic EL elements, and substituents that hinder intermolecular interactions are introduced into the pyrene. For this reason, many of these compounds have a very high amorphousness.
However, when these compounds are used as light emitting transistor elements, it is necessary to design their molecules such that they are high in both light emission properties and mobility.
Thus, an object of the present invention is to provide a pyrene based compound that is good in both properties of light emission and mobility when the compound is used as a light emitting transistor element, and a light emitting transistor element using this specific pyrene based compound.
The present invention solves the above-mentioned problems by using a pyrene based compound represented by the following chemical formula (1) as a main component of a light emitting layer in a light emitting transistor element:
(wherein R1 represents a group selected from a heteroaryl group which may have a substituent, an aryl group which may have a substituent (except a phenyl group which does not have any substituent), an alkyl group which may have a substituent and has a main chain having 1 to 20 carbon atoms, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, a silyl group which may have a substituent, and a group having a halogen atom.)
A light emitting transistor element can be constructed by using the pyrene based compound as a main component of a light emitting layer which is capable of transporting holes and electrons as carriers and which emits light by recombination of the holes and the electrons, and by providing the light emitting layer with a hole injecting electrode for injecting holes into the light emitting layer, an electron injecting electrode for injecting electrons into the light emitting layer, and a gate electrode disposed opposite to the hole injecting electrode and the electron injecting electrode for controlling the carrier distribution in the light emitting layer.
According to the present invention, since a specific pyrene based compound having symmetry is used, the crystallinity improves, so that it is possible to improve both properties of the light emission and the mobility of the resultant light emitting transistor element.
a) is chemical formulae showing examples of the pyrene based compound.
b) is chemical formulae showing examples of the pyrene based compound.
c) is chemical formulae showing examples of the pyrene based compound.
a) is chemical formulae showing examples of the pyrene based compound.
b) is chemical formulae showing examples of the pyrene based compound.
c) is chemical formulae showing examples of the pyrene based compound.
d) is chemical formulae showing examples of the pyrene based compound.
a) is chemical formulae showing examples of the pyrene based compound.
b) is chemical formulae showing examples of the pyrene based compound.
a) is chemical formulae showing examples of the pyrene based compound.
b) is chemical formulae showing examples of the pyrene based compound.
a), (b) and (c) are schematic views illustrating the mechanism of light emission of a light emitting transistor element.
The present invention will be described in detail hereinafter.
The present invention is an invention relating to a pyrene based compound, in particular, a pyrene based compound having symmetry. This pyrene based compound can be used as a main component of a light emitting layer in a light emitting transistor element.
The pyrene based compound is a compound represented by the following chemical formula (1):
In the formula (1), R1 represents a group selected from a heteroaryl group which may have a substituent, an aryl group which may have a substituent (except a phenyl group which does not have any substituent), an alkyl group which may have a substituent and has a main chain having 1 to 20 carbon atoms, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, a silyl group which may have a substituent, and a group having a halogen atom.
Specific examples of R1 include heteroaryl, aryl, linear or branched alkyl, alkenyl, alkynyl and silyl groups, and groups having a halogen atom.
Specific examples of the heteroaryl group include benzofuryl, pyrrolyl, benzoxazolyl, pyrazinyl, thienyl, alkyl-substituted thienyl, bithienyl, phenyl-thienyl, benzothienyl, pyridyl, bipyridyl, phenyl-pyridyl, quinolyl, and benzothiazolyl groups. They may have a substituent. This heteroaryl group may be a polycyclic aromatic group.
Specific examples of the aryl group include naphthyl (preferably 2-naphthyl), anthryl (preferably 2-anthryl), phenanthryl, methylphenyl, ethylphenyl, dimethylphenyl, biphenyl, terphenyl, phenyl-etheno-phenyl, pyridino-phenyl, and fluorine-substituted phenyl groups. These may have a substituent. This aryl group may be a polycyclic aromatic group, but is not a phenyl group having no substituent.
Specific examples of the linear or branched alkyl group include methyl, ethyl, n-propyl, 2-propyl, n-butyl, isobutyl, and tert-butyl groups. The main chain of this alkyl group preferably has 1 to 20 carbon atoms.
Specific examples of the alkenyl group include vinyl, phenyl-substituted vinyl, ethyl-substituted vinyl, biphenyl-substituted vinyl, allyl, and 1-butenyl groups. They may have a substituent.
Specific examples of the alkynyl group include ethynyl, phenyl-substituted ethynyl, trimethylsilyl-substituted ethynyl, and propargyl groups. They may have a substituent.
Specific examples of the silyl group include a trimethylsilyl group. The group may have a substituent.
Specific examples of the group having a halogen atom include fluorine, bromine, and chlorine atoms. Of these groups, groups each consisting only of a halogen atom are preferable, and a fluorine atom is more preferable.
R1 is preferably a group selected from benzofuryl, pyrrolyl, benzoxazolyl, pyrazinyl, thienyl, pyridyl, quinolyl, benzothiazolyl, naphthyl, anthryl, phenanthryl, vinyl, ethynyl and silyl groups each of which may have a substituent, a phenyl group which has a substituent, a carboxyl group, and a halogen atom.
Particularly preferably, R1 is a group selected from carboxyl, benzofuryl, pyrrolyl, benzoxazolyl, pyrazinyl, thienyl, alkyl-substituted thienyl, bithienyl, phenyl-thienyl, benzothienyl, pyridyl, bipyridyl, phenyl-pyridyl, quinolyl, benzothiazolyl, 2-naphthyl, 2-anthryl, phenanthryl, methylphenyl, ethylphenyl, dimethylphenyl, phenyl-substituted vinyl, phenyl-substituted ethynyl, biphenyl, terphenyl, phenyl-etheno-phenyl, pyridine-phenyl, fluorine-substituted phenyl, ethyl-substituted vinyl, biphenyl-substituted vinyl, trimethylsilyl and trimethylsilyl-substituted ethynyl groups, and a fluorine atom.
The molecular weight of the pyrene based compound is preferably 300 or more, more preferably 500 or more, and is preferably 5000 or less, more preferably 3000 or less.
Specific examples of the chemical formula (1) include compounds as shown in
Examples of the compound wherein R1 is an aryl group which may have a substituent, an alkenyl group which may have a substituent, or an alkynyl group which may have a substituent include pyrene based compounds wherein R1 is a tolyl group ((3-1) to (3-2) in
Examples of the compound wherein R1 is an alkyl group which may have a substituent and has a main chain having 1 to 20 carbon atoms, an aryl group which may have a substituent, a silyl group which may have a substituent, or a fluorine atom include a pyrene based compound wherein R1 is a phenanthrene ring (phenanthryl group) ((4-1) in
Furthermore, other examples of the pyrene based compound according to the present invention include individual compounds shown as (4-1) and (4-19) in
Of the above-mentioned individual compounds, a pyrene based compound wherein R1 is a group having a halogen atom is a compound which has not been known in the prior art.
The above-mentioned light emitting layer contains, as a main component thereof, the above-mentioned pyrene based compound. This main component means a component which takes a leading part for exhibiting luminous brightness, luminous efficiency, carrier mobility, peculiar light color, and other effects. In order to improve the above-mentioned effects, the light emitting layer may contain, besides the pyrene based compound as the main component, a secondary constituting component such as a different organic fluorescent substance or a dopant material if necessary.
Such a different organic fluorescent substance is not particularly limited, and examples thereof include condensed ring derivatives such as anthracene, phenanthrene, pyrene, perylene and chrysene, metal complexes of a quinolinol derivatives, such as tris(8-quinolinolato) aluminum, benzoxazole derivatives, stilbene derivatives, benzthiazole derivatives, thiadiazole derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, oxadiazole derivatives, bis-styryl derivatives such as bis-styryl anthracene and distyrylbenzene derivatives, metal complexes wherein a quinolinol derivative is combined with a different ligand, oxadiazole derivative metal complexes, benzazole derivative metal complexes, coumarin derivatives, pyrrolopyridine derivatives, perynone derivatives, and thiadiazolopyridine derivatives. Other examples of the organic fluorescent substance of a polymeric type include polyphenylene vinylene derivatives, polyparaphenylene derivatives, and polythiophene derivatives.
The above-mentioned dopant material is not particularly limited, and examples thereof include condensed ring derivatives such as phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene and rubrene, benzoxazole derivatives, benzthiazole derivatives, benzimidazole derivatives, benztriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, bis-styryl derivatives such as bis-styryl anthracene derivatives and distyrylbenzene derivatives, diazaindacene derivatives, furan derivatives, benzofuran derivatives, isobenzofuran derivatives such as phenylisobenzofuran, dimesitylisobenzofuran, di(2-methylphenyl) isobenzofuran, di(2-trifluoromethylphenyl)isobenzofuran and phenyl-isobenzofuran, dibenzofuran derivatives, coumarin derivatives such as 7-dialkylaminocoumarin derivatives, 7-piperidinocoumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives, 7-acetoxycoumarin derivatives, 3-benzthiazolylcoumarin derivatives, 3-benzimidazolylcoumarin derivatives and 3-benzoxazolylcoumarin derivatives, dicyanomethylenepyran derivatives, dicyanomethylene-thiopyran derivatives, polymethine derivatives, cyanine derivatives, oxobenzanthracene derivatives, xanthene derivatives, rhodamine derivatives, fluorescein derivatives, pyrylium derivatives, carbostyril derivatives, acridine derivatives, bis(styryl)benzene derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, perynone derivatives, pyrrolopyrrole derivatives, squalirium derivatives, violanthrone derivatives, phenazine derivatives, acridone derivatives, and diaza-flavin derivatives.
Description is now made of a light emitting transistor element using the above-mentioned pyrene based compound.
The light emitting transistor element may be an element having a basic structure of a field effect transistor (FET) as illustrated in
This light emitting transistor element 10 comprises a light emitting layer 1 which is capable of transporting holes and electrons as carriers, which emits light by recombination of the holes and the electrons, and which contains the above-mentioned pyrene based compound as a main component; a hole injecting electrode for injecting holes into this light emitting layer 1, i.e., what is called a source electrode 2; an electron injecting electrode for injecting electrons into the light emitting layer, i.e., what is called a drain electrode 3; and a gate electrode 4 which is provided opposite to the source electrode 2 and the drain electrode 3 and is made of an N+ silicon substrate to control the distribution of the carriers in the light emitting layer 1. The gate electrode 4 may be made of an electroconductive layer comprising an impurity diffusion layer formed on the surface of the silicon substrate.
Specifically, as shown in
In order for the above-mentioned element to exhibit the function of the light emitting transistor, it is preferred that the difference between the HOMO energy level and the LUMO energy level of the organic fluorescent substance which constitutes the light emitting layer 1, in particular, the pyrene based compound as the main component thereof, the carrier mobility thereof, or the luminous efficiency thereof satisfies a predetermined range. When the pyrene based compound having the above-mentioned individual characteristics is used, it is possible to improve the individual functions by adding the above-mentioned secondary constituting component, such as the dopant, thereto.
First, the difference between the HOMO energy level and the LUMO energy level is preferably as small as possible so that the electrons can move more easily, and thus the light emission and the semi-conductivity (that is, the conductivity of electrons or holes in one direction) can be generated more easily. Specifically, the difference is preferably 5 eV or less, more preferably 3 eV or less, even more preferably 2.7 eV or less. Because the smaller this difference, the better the results, the lower limit of this difference is 0 eV.
The carrier mobility is preferably as high as possible for improved semi-conductivity. Specifically, the carrier mobility is preferably 1.0×10−5 cm2/V·s or more, more preferably 3.0×10−5 cm2/V·s or more, even more preferably 1.0×10−4 cm2/V·s or more. The upper limit of the carrier mobility is not particularly limited, and it is sufficient if the upper limit is about 1 cm2/V·s.
The above-mentioned luminous efficiency means the ratio of light generated by the injection of photons or electrons. The ratio of emitted optical energy to injected optical energy is defined as the PL luminous efficiency (or PL quantum efficiency), and the ratio of the number of emitted photons to the number of injected electrons is defined as the EL luminous efficiency (or the EL quantum efficiency).
Injected and excited electrons emit light by recombining with holes. This recombination does not necessarily occur with a probability of 100%. Therefore, when organic compounds which each constitute the light emitting layer 1 are compared with each other, the EL luminous efficiencies are compared, thereby making it possible to compare the ratios of the emitted optical energy amount to injected optical energy, and compare synergetic effects about the ratio of the recombination of electrons and holes. Incidentally, by comparing the PL luminous efficiencies, the ratios of the emitted optical energy amount to injected optical energy can be compared. Thus, by comparing both the PL luminous efficiencies and the EL luminous efficiencies and combining the results, it is possible to compare the ratios of the recombination of electrons and holes.
For the PL luminous efficiency, the degree of light emission is preferably as high as possible. The PL luminous efficiency is preferably 20% or more, more preferably 30% or more. The upper limit of the PL luminous efficiency is 100%.
For the EL luminous efficiency, the degree of light emission is preferably as high as possible. The EL luminous efficiency is preferably 1×10−3 % or more, more preferably 8×10−3 % or more. The upper limit of the EL luminous efficiency is 100%.
The light emitting transistor element 10 is characterized by the wavelength of emitted light besides the above. This wavelength is in a visible ray range. The element has a wavelength varied in accordance with the kind of the organic fluorescent substance used, in particular, the pyrene based compound. When organic fluorescent substances having different wavelengths are combined with each other, various colors can be produced. For this reason, about the wavelength of emitted light, the wavelength itself exhibits a characteristic.
The light emitting transistor element 10 is characterized by light emission. Thus, the element preferably has a luminous brightness to a certain extent. This luminous brightness is defined as the light emission amount corresponding to the brightness of an object felt by a person when the person watches the object. This luminous brightness is preferably as high as possible when measured by a photo-counter. The luminous brightness is preferably 1×104 CPS (count per sec) or more, more preferably 1×105 CPS or more, even more preferably 1×106 CPS or more.
The light emitting layer 1 is formed by depositing an organic fluorescent substance or the like that constitute the light emitting layer 1 (or co-depositing a plurality of such substances). It is sufficient if the film thickness of this light emitting layer is at least about 70 nm.
The source electrode 2 and the drain electrode 3 are electrodes for injecting holes and electrons into the light emitting layer 1, and are made of gold (Au), magnesium-gold alloy (MgAu), or the like. The electrodes are formed so as to face each other at a very small interval of, for example, 0.4 to 50 μm. Specifically, for example, as shown in
At this time, the interval between the source electrode 2 and the drain electrode 3, that is, the interval between the comb tooth shaped region 2a and the comb tooth shaped region 3a is preferably 50 μm or less, more preferably 3 μm or less, even more preferably 1 μm or less. If the interval is more than 50 μm, sufficient semi-conductivity cannot be exhibited.
By applying a voltage to the source electrode 2 and the drain electrode 3 in the light emitting transistor element 10, holes and electrons are shifted inside the element and they are recombined in the light emitting layer 1, whereby light can be emitted. At this time, the amounts of the holes and the electrons shifted between the two electrodes across the light emitting layer 1 depend on the voltage applied to the gate electrode 4. Accordingly, by controlling the voltage applied to the gate electrode 4 and its change, it is possible to control the state of electric conduction between the source electrode 2 and the drain electrode 3. Because this light emitting transistor element 10 undergoes P-type driving, a negative voltage for the source electrode 2 is applied to the drain electrode 3 and a negative voltage for the source electrode 2 is applied to the gate electrode 4.
Specifically, by applying a negative voltage for the source electrode 2 to the gate electrode 4, holes in the light emitting layer 1 are attracted toward the gate electrode 4, so that the density of holes in the vicinity of the surface of the insulating film 5 increases. By suitably adjusting the voltage between the source electrode 2 and the drain electrode 3, holes are injected from the source electrode 2 into the light emitting layer 1 according to the intensity of the controlled voltage applied to the gate electrode 4, so that electrons are injected from the drain electrode 3 into the light emitting layer 1. In other words, the source electrode 2 functions as a hole injecting electrode, and the drain electrode 3 functions as an electron injecting electrode. In this way, in the light emitting layer 1, the holes and the electrons are recombined, and light is emitted following this recombination. This light emission state can be turned on or off or the luminous intensity can be varied by changing the controlled voltage applied to the gate electrode 4.
The theory of such recombination of holes and electrons can be described as follows:
When a negative voltage for the source electrode 2 is applied to the gate electrode 4, in the light emitting layer 1, as illustrated in
The recombination of holes and electrons can also be described on the basis of the following theory besides the FN tunnel effect. As shown in
A plurality of such light emitting transistor elements 10 are two-dimensionally arranged on a substrate 20 to form a display device 21.
Since each of the light emitting transistor elements 10 undergoes P-type driving, a bias voltage Vd (<0) is given to its drain electrode 3(D) with the source electrode 2(S) kept at the ground voltage (=0). To its gate electrode 4(G), a selecting transistor Ts for selecting a pixel and a capacitor C for storing data are connected in parallel.
The selecting transistors Ts in each row of the pixels P11, P12, . . . , . . . , P21, P22, . . . , . . . , have their gates connected to a common one of the scanning line LS1, LS2, . . . , . . . . The selecting transistors Ts in each column of the pixels P11, P21, . . . , . . . , P12, P22, . . . , . . . are connected to a common one of the data lines LD1, LD2 . . . on their side opposite to the respective light emitting transistor elements 10.
From a scanning line driving circuit 22 controlled by a controller 24, scanning driving signals for selecting the pixels P11, P12, . . . , . . . , P21, P22, . . . , . . . in the respective rows circularly and successively (selecting the plurality of pixels in each row at a time) are given to the scanning lines LS1, LS2, . . . , . . . . In other words, the scanning line driving circuit 22 makes it possible to specify each of the rows successively as a selected row and make the selecting transistors Ts of the plurality of pixels in the selected row electrically conductive at a time, thereby generating a scanning driving signal for cutting off the selecting transistors Ts of the plurality of pixels in the non-selected rows at a time.
On the other hand, signals from a data line driving circuit 23 are inputted into the data lines LD1, LD2, . . . , . . . . Control signals corresponding to image data are inputted from the controller 24 into this data line driving circuit 23. At a timing when the pixels in each of the rows are collectively selected by the scanning line driving circuit 21, the data line driving circuit 23 supplies light emission controlling signals, which correspond to the light emission gradations of the individual pixels in the selected row, to the data lines LD1, LD2, . . . , . . . in parallel.
In this way, in the individual pixels in the selected row, the light emission controlling signals are given to the gate electrodes 4(G) through the selecting transistors Ts. Thus, the light emitting transistor elements 10 in the pixels emit light having gradations corresponding to the light emission controlling signals (or stop the light emission). Since the light emission controlling signals are kept in the capacitor C, the electric potentials of the gate electrodes 4(G) are kept even after the selected row selected by the scanning line driving circuit 22 is shifted to a different row. As a result, the light emission states of the light emitting transistor elements 10 are kept.
Thus, two-dimensional display can be attained.
The present invention will be more specifically described by way of examples and comparative examples described below. First, the process for producing the pyrene based compound will be described.
[Synthesis of Raw Material] (Production of 1,3,6,8-tetrabromopyrene)
To 195 ml of water, 27 g of pyrene (reagent made by Tokyo Kasei Kogyo Co., Ltd., purity: 95%) and 7 ml of tetraglyme (reagent made by Tokyo Kasei Kogyo Co., Ltd.) were added, and 70 ml of hydrochloric acid was further added thereto. The mixture was stirred at 90° C. for 2 hours to prepare an aqueous dispersion of pyrene. Next, 47 g of potassium bromide (reagent made by Tokyo Kasei Kogyo Co., Ltd.) was added thereto at 40° C. While the temperature was kept, a solution of sodium bromate in which 30 g of sodium bromate (reagent made by Tokyo Kasei Kogyo Co., Ltd.) was dissolved in 110 ml of water was dropwise added to the dispersion for 3 hours. Thereafter, the resultant was filtered, washed sufficiently with about 300 g of methanol, and dried at 85 to 95° C. to yield 70 g of 1,3,6,8-tetrabromopyrene.
[Production of tetrakis(2-thienyl)pyrene (Chemical Formula (2-1))]
In accordance with the above-mentioned reaction formula <1>, tetrakis(2-thienyl)pyrene ((3-1) in
The reaction solution was filtered through celite, and the remaining solid was washed off with chloroform. The filtrate was successively washed with a 10% aqueous solution of potassium fluoride, pure water, and saturated salt water. Sodium sulfate was used to dehydrate the solution, and then the resultant was concentrated with an evaporator to yield 1 g of yellow microcrystals.
The collected crystals were purified by GPC to yield 0.4 g of a single component. From mass spectrometry based on ionization by DEI, this was identified as 1,3,6,8-tetrakis(2-thienyl)pyrene (yield: 18%). Data about the mass spectrometry (MS) are as follows:
MS:m/z=40, 162, 206, 248, 265, 401, 451, 485, 530
In accordance with the above-mentioned reaction formula <2>, tetrakis(4-biphenyl)pyrene ((3-9) in
To the reaction mixture, 100 ml of chloroform and 100 ml of pure water were added, and a solid insoluble in the two solvents was collected by suction filtration. (The filtrate was separated to phases, and the organic phase thereof was washed twice with 100 ml of pure water.)
The collected solid was purified by column chromatography (silica gel, chloroform) so as to remove palladium mixed therewith. Thereafter, the resultant was recrystallized from chloroform to collect 745 mg of yellow needle-like crystals. From mass spectrometry based on ionization by MALDI, this was identified as 1,3,6,8-tetrakis(4-biphenyl)pyrene (yield: 47%). Data about the mass spectrometry (MS) are as follows:
MS:m/z=658, 810
In accordance with the above-mentioned reaction formula <3>, tetrakis(3-biphenyl)pyrene ((3-8) in
MS:m/z=154, 289, 405, 503, 578, 655, 656, 732, 810
To 15 g of 3-tolylboronic acid (reagent made by Tokyo Kasei Kogyo Co., Ltd.), 9.2 g of 1,3,6,8-tetrabromopyrene, and 6.4 g of cesium carbonate (reagent made by Kishida Chemical Co., Ltd.), 400 ml of toluene (reagent made by Junsei Chemical Co., Ltd.), 50 ml of ethanol (reagent made by Junsei Chemical Co., Ltd.) and 50 ml of pure water were added, and then the mixture was purged with nitrogen. Thereafter, 2 g of tetrakistriphenylphosphine palladium (0) (reagent made by Tokyo Kasei Kogyo Co., Ltd.) was added thereto. The resultant was heated and refluxed for 7 hours.
The reaction solution was concentrated under reduced pressure, and 100 ml of water was added thereto. The resultant was extracted with dichloromethane several times, and sodium sulfate was added to the extracted liquid so as to dehydrate the liquid. The liquid was filtered and concentrated, and then the resultant residue was recrystallized from toluene to yield 3.7 g of a yellow solid. From FAB mass spectrometry thereof, a result of m/z=563 was obtained. It was understood from this fact that this component was 1,3,6,8-tetrakis(3-tolyl)pyrene.
To 8.4 g of 4-fluorophenylboronic acid (reagent made by Aldrich Co.), 5.2 g of 1,3,6,8-tetrabromopyrene, and 20 g of cesium carbonate (reagent made by Kishida Chemical Co., Ltd.), 200 ml of toluene (reagent made by Junsei Chemical Co., Ltd.), 25 ml of ethanol (reagent made by Junsei Chemical Co., Ltd.) and 25 ml of pure water were added, and then the system was purged with nitrogen. Thereafter, 1 g of tetrakistriphenyl-phosphine palladium (0) (reagent made by Tokyo Kasei Kogyo Co., Ltd.) was added thereto. The resultant was heated and refluxed for 9 hours.
The reaction solution was filtered, and then the resultant residue was washed with methanol and recrystallized from toluene to yield 4.3 g of a yellow solid. From FAB mass spectrometry thereof, peaks of 578(M+) and 540 were obtained. It was understood from this fact that this component was 1,3,6,8-tetrakis(4-fluorophenyl)pyrene.
To 9.5 g of 3,5-fluorophenylboronic acid (reagent made by Aldrich Co.), 5.2 g of 1,3,6,8-tetrabromopyrene, and 20 g of cesium carbonate (reagent made by Kishida Chemical Co., Ltd.), 200 ml of toluene (reagent made by Junsei Chemical Co., Ltd.), 25 ml of ethanol (reagent made by Junsei Chemical Co., Ltd.) and 25 ml of pure water were added, and then the system was purged with nitrogen. Thereafter, 1 g of tetrakistriphenyl-phosphine palladium (0) (reagent made by Tokyo Kasei Kogyo Co., Ltd.) was added thereto. The resultant was heated and refluxed for 9 hours.
The reaction solution was filtered, and then the resultant residue was washed with methanol and recrystallized from toluene to yield 4.2 g of a yellow solid. From FAB mass spectrometry thereof, 650(M+) was obtained. It was understood from this fact that this component was 1,3,6,8-tetrakis(4-fluorophenyl)pyrene.
To 10.3 g of 2-naphthylboronic acid (reagent made by Tokyo Kasei Kogyo Co., Ltd.), 5.2 g of 1,3,6,8-tetrabromopyrene, and 20 g of cesium carbonate (reagent made by Kishida Chemical Co., Ltd.), 200 ml of toluene (reagent made by Junsei Chemical Co., Ltd.), 25 ml of ethanol (reagent made by Junsei Chemical Co., Ltd.) and 25 ml of pure water were added, and then the system was purged with nitrogen. Thereafter, 1 g of tetrakistriphenylphosphine palladium (0) (reagent made by Tokyo Kasei Kogyo Co., Ltd.) was added thereto. The resultant was heated and refluxed for 9 hours.
The reaction solution was filtrated, and then the resultant residue was washed with hot water and recrystallized from toluene to yield 5.7 g of a yellow solid. It was understood from an FAB mass spectrometry described below that this was 1,3,6,8-tetrakis(4-fluorophenyl)pyrene.
MS:m/z=55, 180, 254, 523, 549, 706
A 500 ml four-necked flask having a reflux condenser tube, a three-way cock and a thermometer were charged with 15 g of trans-styryl boric acid (reagent made by Tokyo Kasei Kogyo Co., Ltd.), 10 g of 1,3,6,8-tetrabromopyrene, 33 g of cesium carbonate (reagent made by Kishida Chemical Co., Ltd.), 400 ml of toluene (reagent made by Junsei Chemical Co., Ltd.), 50 ml of ethanol (reagent made by Junsei Chemical Co., Ltd.) and 50 ml of pure water, and then the system was purged with nitrogen. Thereafter, 2 g of tetrakistriphenylphosphine palladium (0) (reagent made by Tokyo Kasei Kogyo Co., Ltd.) was added thereto. The resultant was heated and refluxed in an oil bath at 80° C. for 9 hours.
To the reaction mixture, 100 ml of CHCl3 and 100 ml of pure water were added, and the resultant solution was filtrated to yield 6.6 g of a yellow solid. From FAB mass spectrometry of the resultant solid, a result of m/z=611 was obtained. It was understood from this matter that this component was 1,3,6,8-tetrakis(trans-styryl)pyrene.
To 8.0 g of 4-tolylboronic acid (reagent made by Tokyo Kasei Kogyo Co., Ltd.), 5.0 g of 1,3,6,8-tetrabromopyrene, and 31 g of cesium carbonate (reagent made by Kishida Chemical Co., Ltd.), 200 ml of toluene (reagent made by Junsei Chemical Co., Ltd.), 100 ml of ethanol (reagent made by Junsei Chemical Co., Ltd.) and 40 ml of pure water were added, and then the system was purged with nitrogen. Thereafter, 0.6 g of tetrakistriphenylphosphine palladium (0) (reagent made by Tokyo Kasei Kogyo Co., Ltd.) was added thereto. The resultant was heated and refluxed for 7 hours.
The reaction solution was concentrated under reduced pressure, and 100 ml of water was added thereto. The resultant was extracted with chloroform, and sodium sulfate was added to the extracted liquid so as to dehydrate the liquid. The liquid was filtered and concentrated, and then the resultant residue was purified by GPC, so as to yield 0.8 g of a yellow solid. From FAB mass spectrometry thereof, it was understood that this component was 1,3,6,8-tetrakis(4-tolyl)pyrene.
MS:m/z=69, 109, 145, 180, 207, 256, 281, 307, 424, 456, 472, 523, 561, 562
A 200 ml three-necked flask having a reflux condenser tube, a three-way cock and a thermometer were charged with 5.2 g of 3,5-bis(trifluoromethyl)phenylboric acid (reagent made by Aldrich Co.), 1.5 g of 1,3,6,8-tetrabromopyrene, 4.3 g of sodium carbonate (reagent made by Kanto Chemical Co., Inc.), 50 ml of toluene (reagent made by Junsei Chemical Co., Ltd.), 15 ml of ethanol (reagent made by Junsei Chemical Co., Ltd.) and 10 ml of pure water. The pressure in the reactor was reduced to degas the reactor 5 times. Furthermore, nitrogen was caused to pass into the reactor. 0.3 g of tetrakistriphenylphosphine palladium (0) (reagent made by Tokyo Kasei Kogyo Co., Ltd.) was added thereto. The resultant was refluxed in an oil bath at 80° C. for 12 hours, and left at rest overnight in the atmosphere of nitrogen.
To the reaction mixture, 100 ml of CHCl3 and 150 ml of pure water were added to separate this solution into phases. The water phase was extracted twice with 100 ml of CHCl3. Anhydrous magnesium sulfate was used to dry the organic phase, and then the phase was concentrated. The residue was washed with acetonitrile, and the resultant precipitation was collected. This was further purified by GPC. From mass spectrometry based on DEI ionization, a result of m/Z=1050 was obtained so that this component was identified as 1,3,6,8-tetrakis(3,5-bis(trifluoromethyl) phenyl)pyrene (yielded amount: 0.59 g, yield: 19%).
1H NMR(400 MHz, CDCl3)68.12(br, 8 H), 8.09(s, 4 H), 8.05(br, 4 H), 8.02(s, 2 H)
Mass(DEI)Obs.m/Z=1050(M+), Calc. for C48H18F24
A 200 ml three-necked flask having a reflux condenser tube, a three-way cock and a thermometer were charged with 3.0 g of p-trifluoromethylphenylboric acid (reagent made by Aldrich Co.), 1.4 g of 1,3,6,8-tetrabromopyrene, 3.4 g of sodium carbonate (reagent made by Kanto Chemical Co., Inc.), 50 ml of toluene (reagent made by Junsei Chemical Co., Ltd.), 15 ml of ethanol (reagent made by Junsei Chemical Co., Ltd.) and 10 ml of pure water. The pressure in the reactor was reduced to degas the reactor 5 times. Furthermore, nitrogen was caused to pass into the reactor. Thereto, 0.3 g of tetrakistriphenylphosphine palladium (0) (reagent made by Tokyo Kasei Kogyo Co., Ltd.) was added. The resultant was refluxed in an oil bath at 80° C. for 12 hours, and left at rest overnight in the atmosphere of nitrogen.
To the reaction mixture, 50 ml of pure water was added to separate this solution into phases. Furthermore, the water phase was extracted with 50 ml of toluene two times. Anhydrous magnesium sulfate was used to dry the combined organic phase, and then the resultant phase was concentrated. The resultant solid was washed with CHCl3, and the collected solid was recrystallized from toluene. (Yielded amount: 0.55 g, yield: 27%).
1H NMR(400 MHz, CDCl3)δ 8.13(s,4 H), 7.99(s, 2 H), 7.83-7.77(m, 16 H)
Next, a light emitting transistor element illustrated in
Source electrode 2 and drain electrode 3: Electrodes (Au, thickness: 40 nm) each having a comb tooth-shaped region comprising 20 comb teeth were formed. As shown in
Insulating film 5: A silicon oxide film 300 nm in thickness was formed by vapor deposition.
Light emitting layer 1: The pyrene based compounds (2-1), (3-9), (3-8), (3-1), (3-16), (4-2) and (3-6), obtained by the above-mentioned production processes, were each independently deposited to cover the periphery of the insulating film, the source electrode 2 and the drain electrode 3, thereby providing the light emitting layer 1.
For each of the elements, the HOMO and LUMO energy levels, the fluorescence absorption wavelength, the PL luminous efficiency, the EL luminous efficiency, the luminous brightness, and the carrier mobility thereof were measured. The results are shown in Table 1.
The carrier mobility, the EL luminous efficiency, and the PL luminous efficiency were measured/calculated as follows:
(Carrier mobility μ (cm2/Vs))
A relational expression between the drain voltage (Vd) and the drain current of an organic semiconductor is represented by the following expression (1), and it increases linearly (linear area),
When Vd increases, Id is saturated by the pinch-off of the channel, so that Id becomes a constant value (saturated area) and is represented by the following expression (2):
In the expressions (1) and (2), each of the symbols is as follows:
L: channel length [cm],
W: channel width [cm],
Ci: electrostatic capacity [F/cm2] of the gate insulating film per unit area,
μsat: mobility [cm2/Vs] in the saturate area,
Id: drain current [A],
Vd: drain voltage [V],
Vg: gate voltage [V], and
VT: gate threshold voltage [V], which represents the following point: in a graph obtained by plotting the ½ power of the drain current (Vdsat1/2) versus the gate voltage (Vg) under a condition that the drain voltage (Vd) in the saturated area is constant, a point at which the asymptotic line therein intersects the transverse axis.
From the relationship between Id1/2 and Vg in this saturated area, the mobility (μ) in the organic semiconductor can be obtained.
In the present invention, under conditions that the pressure is set into the range of vacuum to 5×10−3 and the temperature is set to room temperature, a Semiconductor Parameter Analyzer (HP4155C, Agilent) was used, and this was operated to set the drain voltage from 10 V to −100 V at intervals of −1 V, and set to the gate voltage from 0 to −100 V at intervals of −20 V. The mobility was then calculated by use of the expression (2).
About the EL luminous efficiency ηext, the above-mentioned transistor elements were each used, and operations were made to set the drain voltage from 10 V to −100 V at intervals of −1 V, and set to the gate voltage from 0 to −100 V at intervals of −20 V. Light emitted from the element was measured with a photon counter (4155C, Semiconductor. Parameter Analyzer, manufactured by Newport Co.). The following expression (3) was used to convert the number of photons [CPS] obtained therein to the light fluxes [lw], and subsequently the following expression (4) was used to calculate out the EL luminous efficiency ηext.
ηext=(100×12397/λ×NPC×XPC)/lD (4)
In the expressions (3) and (4), each of the symbols is as follows:
NPC: number of photons [CPS] measured with the photon counter (PC),
XPCc: numerical value obtained by converting the number of the photons to light fluxes [lw],
r: diameter [cm] of the cone or circle, and
h: distance [cm] between the photon counter and the sample.
The PL luminous efficiency was calculated by vapor deposition of each of the materials obtained in the present invention into a thickness of 70 nm onto a quartz substrate in the atmosphere of nitrogen to form a mono-layered film, using an integrating sphere (IS-060, Labsphere Co.) to radiate a He-Cd laser (IK5651R-G, Kimmon Electric Co.) having a wavelength of 325 nm as an exciting ray, and then measuring a light emitting Multi-channel photodiode (PMA-11, Hamamatsu Photonics Co.) from the sample.
Measurements were made in the same way as in Example 1 except that tetraphenylpyrene (reagent made by Aldrich Co.) was used as a pyrene based compound. The results are shown in Table 1.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-340362 | Nov 2004 | JP | national |
| 2005-257934 | Sep 2005 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP05/21648 | 11/25/2005 | WO | 00 | 8/6/2007 |
