JP3584266B2 - Method for producing organic microcrystal for optoelectronic function - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a simple method for producing organic microcrystals used for optoelectronic functional materials.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, reprecipitation methods, gas phase methods, and the like have been known as methods for producing organic microcrystals that can be expected as high-performance optoelectronic functional materials in the fields of electronics and nonlinear optics. Above all, the reprecipitation method is a simple and effective method because organic microcrystals are precipitated by utilizing the difference in solubility.However, in the case of certain organic compounds, molecules or In some cases, crystallization progresses gradually over a long period of time of several hours to several tens of hours after forming a cluster.
[0003]
Further, in the reprecipitation method, it is often difficult to produce monodispersed organic ultrafine crystals, and there is a problem that crystallization requires a long time. Furthermore, when a large amount of time is required for the microcrystallization, the particle size of the microcrystal increases and the particle size increases, and the particle size distribution tends to be distributed over a wide range. Obtaining the particles was extremely difficult.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above situation in the related art. That is, an object of the present invention is to provide a method for producing an organic microcrystal for an optoelectronic function, which can easily and easily obtain ultrafine particle crystals having a good monodispersity having a particle diameter of 500 nm or less in a short time.
[0005]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above-described problems, and as a result, after the operation of forming organic crystals in the solution by the reprecipitation method, crystallization is promoted by irradiating the mixed solution with microwaves. The inventors have found that monodispersed ultrafine crystals can be obtained in a short time, and have completed the present invention.
[0006]
That is, the method for producing an organic microcrystal for optoelectronic functions of the present invention comprises mixing an organic material for optoelectronic functions dissolved in a good solvent into a poor solvent of the organic material compatible with the solvent, and adding the resulting mixture. The method is characterized by obtaining microcrystals or aggregates having a particle size of 500 nm or less by irradiating a microwave and heating.
In addition, another method for producing an organic microcrystal for optoelectronic functions of the present invention is obtained by mixing an organic material for optoelectronic functions dissolved in a good solvent into a poor solvent of the organic material compatible with the solvent. The mixture is heated by irradiating the mixture with microwaves and then irradiated with a gamma ray, an electron beam, an X-ray or a light beam to obtain microcrystals or aggregates having a particle size of 500 nm or less.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention has been considered difficult to achieve by microwave heating to a state in which molecules or clusters are formed in a poor solvent after the operation of the reprecipitation method for producing crystals of the organic material for optoelectronic functions. In this method, a monodisperse and ultrafine crystal having a very small size is easily produced.
[0008]
As the organic material used in the present invention, any low-molecular compound or high-molecular compound can be used as long as an organic crystal is used in the field of photoelectrons. For example, an electroluminescent material, a nonlinear optical material, It is used as a fluorescence generating material, a photoconductive material, an optical recording material, and the like. Specifically, 1,1,4,4-tetraphenyl-1,3-butadiene (TPB), phthalocyanines, aluminum quino Electroluminescent materials such as resealed complexes, 1,6-di (N-carbazolyl) -2,4-hexadiyne (DCHD), 5,7- (bis-1,12-n-butylcarboxymethylene-urethane) dodecadiyne, etc. Polydiacetylene compound, 1-methyl-4- [2- (4-N, N-dimethylaminophenyl) vinyl] pyridinium p-toluenesulfonate, meloxi Non-linear optical materials such as dyes such as anine and isocyanine, polycyclic aromatic compounds such as perylene, and fluorescent materials such as stilbene compounds are exemplified.
[0009]
The TPB used in the above electroluminescent material is a compound that exhibits blue color. In an organic EL device, about 0.1 to 1.0% by weight of a polymer compound or the like is used as a dye-doping material. Is done. This is because TPB has a high quantum yield (in hexane, 0.78), so that when used at a high concentration, concentration quenching occurs. The advantage of this dye doping is that not only can the emission color be controlled by moving the emission center from the organic layer of the host to the dopant dye, but also that a material having a high fluorescence quantum yield such as a laser dye is used as the emission center. Another object of the present invention is to suppress thermal deactivation from an excited state and improve the quantum efficiency of light emission from the device. Therefore, the microcrystallized TPB obtained by the method of the present invention can be expected to exhibit new light emission characteristics due to the size effect and the interfacial effect due to the microcrystallization.
[0010]
In the method of the present invention, various solvents such as alcohols, ketones, esters, aromatic hydrocarbons, and organic halides are used as the good solvent for dissolving the organic material for optoelectronic functions. As the poor solvent, any solvent can be used as long as it is compatible with the above-mentioned good solvent without dissolving the organic material for optoelectronic functions. Saturated hydrocarbons such as water, cyclohexane, and decalin are preferable.
The concentration of the organic material is preferably in the range from the saturation concentration to about 1/100. Further, the amount of the good solvent solution with respect to the poor solvent is preferably in the range of about 1/10 ⁵ from the saturated dissolution amount. In addition, a mixed dispersion is obtained by, for example, dropping a good solvent in which an organic material is dissolved using a syringe or the like while stirring the poor solvent. In this case, the temperature of the poor solvent may be in the range of 0 to 90 ° C., but is preferably around room temperature in order to obtain the minimum particle size.
[0011]
Next, in the present invention, a heat treatment for irradiating the mixed dispersion liquid with microwaves is performed. The microwave irradiation can be used without any limitation as long as it can be heated by irradiating the microwave, but for example, use of a microwave oven or the like is convenient. It is preferable that the irradiation be performed with a microwave of 0.3 to 30 GHz, preferably 2.45 GHz, for about 0.1 to 60 minutes. When this mixed dispersion is heat-treated with microwaves, crystallization is promoted to obtain microcrystals in which ultrafine particles having a particle size of 500 nm or less, preferably 300 nm or less, more preferably 100 nm or less are monodispersed. Can be FIG. 1 is a schematic diagram showing the preparation of an organic microcrystal by irradiating a mixed dispersion of an organic material with microwaves and heating.
[0012]
In the present invention, after the mixed dispersion is subjected to heat treatment by microwave irradiation, and further subjected to polymerization or the like by irradiating gamma rays, electron beams, X-rays or light rays, similarly, the particle size of 500 nm or less It is possible to obtain microcrystals in which ultrafine particles of preferably 300 nm or less, more preferably 100 nm or less are monodispersed. Also, with respect to the cyanine dye compound and the like, ultrafine particles having a J-aggregate can be obtained by performing a treatment of mixing an acidity changing agent such as an amine.
[0013]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples and the like, but the present invention is not limited thereto.
Example 1
[Electroluminescent organic material 1,1,4,4-tetraphenyl-1,3-butadiene (TPB)]
A mixed dispersion obtained by injecting 100 μl of a TPB acetone solution (TPB concentration: 6 mM) in which TPB was dissolved in acetone into 20 ml of water, which is a poor solvent, was irradiated with microwaves of 2.45 GHz at room temperature for about 20 seconds. The irradiation was stopped before reaching the boiling point. Thereafter, when the mixed dispersion was cooled again to room temperature with ice water, ultrafine crystals of TPB having an average particle size of about 200 nm were obtained in the dispersion.
In addition, the microwave irradiation used the household microwave oven (SANYO microwave oven EMO-C4 (TB) type) generally marketed.
[0014]
[Comparison and evaluation of particle size between method of the present invention and conventional method]
(1) TPB microcrystal produced by heating by microwave irradiation in Example 1 FIG. 2 shows a scanning electron microscope (SEM) photograph of the TPB microcrystal obtained in Example 1. As shown in FIG. 2, in Example 1, microcrystals having a monodispersed particle size were produced in a short time by microwave irradiation.
(2) Using a TPB microcrystal microsyringe prepared only by the conventional reprecipitation method, 100 μl of a 6 mM TPB acetone solution was reprecipitated in 20 ml of stirring water at room temperature, and allowed to stand at a water temperature of 45 ° C. for 220 hours. I let it. FIG. 3 shows an SEM photograph of the obtained TPB microcrystal. In FIG. 3, it was found that the crystal grains were large and polycrystals of polydispersed size.
[0015]
Example 2
[Non-linear optical material 1,6-di (N-carbazolyl) -2,4-hexadiyne (DCHD)]
First, a reprecipitation method was performed in which 250 μl of an acetone solution having a DCHD concentration of 10 mM, which is a diacetylene, was injected into 10 ml of stirred water using a syringe. In the initial state, amorphous fine particles were generated, and while the amorphous fine particles were allowed to stand still for about 20 minutes, the amorphous fine particles changed their morphology into microcrystals capable of solid phase polymerization.
When the dispersion after the reprecipitation operation is irradiated with microwaves (350 W) and heated, a dispersion containing DCHD microcrystals having good monodispersibility and capable of solid phase polymerization can be obtained in about 30 seconds. Was. In general, solid phase polymerization of DCHD easily proceeds by light or heat. Therefore, when this dispersion is irradiated with UV, a blue color peculiar to DCHD polymer microcrystals is exhibited. It was confirmed that a polymer was formed. The crystal grain size was about 100 nm as measured by DLS. By performing heating by microwaves in this way, microcrystallization can be performed in a very short time as compared with the preparation of DCHD microcrystals by a conventional reprecipitation method. FIG. 4 shows an SEM photograph of the DCHD polymer microcrystals produced in Example 2.
[0016]
Example 3
[Perylene, a fluorescent generating material]
When 200 μl of an acetone solution having a perylene concentration of 1 mM was reprecipitated in 10 ml of water, a dispersion containing microcrystals having a crystal size distribution of 100 to 500 nm and an average particle size of about 200 nm was obtained. Next, reprecipitation was carried out in the same manner as in the conventional method, and this was irradiated with microwaves and heated to produce perylene microcrystals. When this microwave irradiation was performed at 50 W for 5 minutes, microcrystals were obtained, and the preparation time was greatly reduced. The particle size distribution of the obtained microcrystal was found to be monodisperse of about 100 nm. FIG. 5 shows an SEM photograph of the perylene microcrystals obtained in Example 3.
In general, perylene does not immediately crystallize immediately after reprecipitation, but once forms a cluster in water, temporarily goes through a stabilized state, and gradually progresses in crystallization. Considering that the particle size distribution is broad, the superiority of Example 3 can be understood.
[0017]
【The invention's effect】
According to the present invention, after a reprecipitation operation for producing a crystal of an organic material, an ultrafine crystal having good monodispersity can be obtained in a short time by a simple method of performing heat treatment by microwave, This is an extremely useful method for producing organic microcrystals, which can easily produce organic ultrafine particle crystals required for optoelectronic functions. In particular, the present invention is a method for producing organic microcrystals for optoelectronic functions comprising monodispersed uniform ultrafine particles having a particle size of 500 nm or less, and therefore has high industrial value.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a method for irradiating a mixed liquid dispersion of an organic material according to the present invention with microwaves to produce organic microcrystals.
FIG. 2 is a SEM photograph of TPB microcrystalline particles obtained in Example 1.
FIG. 3 is an SEM photograph of crystal particles of an organic material produced by a conventional method.
FIG. 4 is an SEM photograph of ultra-fine crystal particles of the DCHD polymer obtained in Example 2.
FIG. 5 is a SEM photograph of the ultrafine crystal particles of perylene obtained in Example 3.

Claims (2)

The organic material for optoelectronic functions dissolved in a good solvent is mixed into a poor solvent of the organic material compatible with the solvent, and the resulting mixture is irradiated with microwaves and heated to have a particle size of 500 nm or less. A method for producing an organic microcrystal for an optoelectronic function, comprising obtaining a monodispersed microcrystal or an aggregate. An organic material for an optoelectronic function dissolved in a good solvent is mixed into a poor solvent of the organic material compatible with the solvent, and the obtained mixture is heated by irradiating a microwave, and then gamma ray, electron beam, X ray A method for producing an organic microcrystal for an optoelectronic function, wherein a monodispersed microcrystal or an aggregate having a particle size of 500 nm or less is obtained by irradiating a line or a light beam.

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