KR101599454B1 - The method of refining organic materials with impurities through ionic liquids and apparatus therefore - Google Patents

Abstract

An organic material refining apparatus using an ionic liquid according to the present invention comprises a sublimation means of a vacuum atmosphere for heating and sublimating an organic material raw material for an OLED containing an impurity and a sublimation gas of a sublimed organic material into an ionic liquid, A recrystallization means for recrystallizing the vacuum atmosphere in the liquid phase, and a control means for controlling the operation of the sublimation means and the recrystallization means. The present invention has the advantage of remarkably improving the purification yield of the organic material by using the ionic liquid as a liquid filter of the sublimation gas by mixing the sublimation gas generated in the sublimation purification process of the organic material into the stable ionic liquid even in vacuum have.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic material purification method and an apparatus for purifying an organic material using an ionic liquid,

The present invention relates to an organic material purification method and purification apparatus based on an ionic liquid process, and more particularly, to an organic material purification method and purification apparatus using ionic liquids as a filter.

Recently, OLED (Organic Light Emitting Diodes) display devices have been attracting attention as next generation display devices. This is because not only the high driving voltage required by the inorganic LED is required, but also the advantage of self-luminescence, thin film, fast response speed, wide viewing angle, and flexibility of various colors due to various organic compounds. Such an OLED refers to a device that generates excitons in which holes and electrons are recombined in the light emitting layer to emit light, and emits light having a specific wavelength by energy from the generated excitons.

1 is a conceptual view showing a structure of an OLED. 1, the OLED includes an anode 120, a hole injection layer (HIL) 130, a hole transport layer (Hole transport) 130, and a hole transport layer (HTL) 140, an emission layer (EML) 150, an electron transport layer (ETL) 160, an electron injection layer (EIL) 170, and a cathode ) 180 are sequentially formed.

Organic materials for light emission and charge transport are required in fabricating an OLED having such a stacked structure. However, since the organic materials directly participate in the recombination of injected holes and electrons as well as the injection of electrons and holes, the purity of the organic materials plays an important role in determining the color, luminous efficiency and lifetime of the OLED. That is, a small amount of impurities in the organic material increases the probability of disappearance of the injected charges, lowering the probability of recombination of holes and electrons, resulting in a decrease in luminous efficiency, as well as a new energy level due to the addition of impurities, .

Therefore, in order to achieve an electroluminescent device with high luminance, high efficiency, and long life, it is necessary to optimize the electroluminescent device structure, develop new materials excellent in hole (or electron) injection and transport properties, It is required to improve the purity of the organic material.

On the other hand, when purifying an organic material for OLED, a recrystallization method using a solvent or a recrystallization method by sublimation is generally used. The recrystallization method by sublimation has a characteristic that the organic material is sublimated and recrystallized under vacuum, so that no impurities are introduced. Therefore, a conventional sublimation purification method is generally used as a method for purifying an organic material for an organic electroluminescence device.

Here, sublimate refers to a gas-solid transition occurring at a temperature and pressure below the triple point in the phase equilibrium. Even if the material is pyrolyzed by heating at normal pressure, it can not be decomposed even at a relatively high temperature under a pressure lower than the triple point. In the sublimation apparatus capable of controlling the temperature gradient by using such a property, the operation of separating the sublimation point from the other sublimation state without heating the mixed substance by heating the mixed substance is called a vacuum sublimation method. Such a vacuum sublimation method is a pure physical method and is useful for the purification of an organic material for an OLED because it does not depend on the use of an auxiliary reagent or other chemical methods and thus has no contamination of a sample and has a large separation rate.

A conventional method for purifying an organic material for OLED, which is currently in use, is a train sublimation purification method. In this method, the material to be refined is placed at the end of a long hollow tube, and the tube is heated with a heater while the inside of the tube is evacuated by using a vacuum pump to make a temperature gradient across the tube. By doing so, the material can be separated using the difference in recrystallization position due to the difference in sublimation point between the material to be separated and the impurity. In some cases, nitrogen or inert gas, which does not react with the material constituting the purification apparatus, is flowed within a range in which the degree of vacuum does not significantly decrease from a high temperature side to a low temperature side, and is used as a carrier gas for transporting an organic material gas. Such transport gas serves to smoothly flow the organic material gas.

2 is a schematic view showing the constitution of the sublimation purification apparatus according to the prior art for performing the continuous sublimation purification method. 2, the organic material material is contained in the crucible 240, and the crucible 240 is disposed on one side of the second quartz glass tube 210. On the other hand, the outer side of the second quartz glass tube 210 has a structure in which the first quartz glass tube 220 is wrapped. Here, the crucible 240 is configured to have a pair of lids that are made of stainless steel material and have holes, though not shown, but are fitted to both ends of a hollow cylindrical quartz tube having open ends at both ends.

The heater 250 is installed so as to surround one side of the first quartz glass tube 220. At this time, the heater 250 is installed at a corresponding position where the crucible 240 is located. The vacuum pump 230 is disposed on the other side of the second quartz glass tube 210 to maintain the inside of the second quartz glass tube 210 in a vacuum state.

In the sublimation refining apparatus 200 having the above structure, the interior of the second quartz glass tube 210 is first evacuated by using the vacuum pump 230, and a small amount of the transportation gas is introduced into the second quartz glass tube 210 2 quartz glass tube 210 to form a fine pressure gradient. When the temperature is gradually increased by using the heater 250, a temperature gradient is formed over the entire second quartz glass tube 210, and the temperature distribution formed at this time shows the shape of a normal distribution curve.

On the other hand, when the temperature of the crucible 240 is higher than the sublimation point of the organic material raw material, which is contained in the crucible 240, the material starts to sublimate. After the gas molecules are formed outside the crucible 240, (230) is installed. At this time, the impurities having a lower sublimation point than the organic material source remain in the crucible 240.

The gas molecules moving in the direction in which the vacuum pump 230 is installed are again transferred to the solid phase in the section of the second quartz glass tube 210 having the temperature lower than the sublimation point, State. Reference numeral 260 denotes a refining material formed in a crystalline state on the inner surface of the second quartz glass tube 210. On the other hand, when the heating time is elapsed, the heating is stopped and the glass is slowly cooled. When the temperature is equal to the room temperature, the second quartz glass tube 210 is disassembled and the refined material 260 in the crystalline state is scraped off and recovered.

However, since the organic material (refined material) used in the OLED must be in a high purity state with an extremely small impurity content, it is difficult to obtain a material having the required purity with a single purification. Therefore, the purification method using the apparatus shown in FIG. 2 requires a repetition of the sublimation purification process several times to obtain a material having high purity, and therefore, it takes a long time for the purification due to the repetition of the purification process, which is unsuitable for mass production.

In addition, since a sublimation purification step of several stages is carried out, it is necessary to obtain a purified amount of less than 70% of the initially introduced organic material, which is expensive and consumes a large amount of electric power.

In other words, the sublimation purification method has an advantage in that the raw material can be refined as an organic substance having high purity by using the difference in sublimation point of the organic material. On the other hand, when the refining process repeats sublimation-condensation, There is a problem that the yield of the final purified material is very low compared to the starting material since it is lost by the exhaust gas together with the inert gas. Therefore, the energy consumed in the purification process is large, This ultimately causes a problem that the cost of the organic material increases.

Korean Patent Registration No. 10-0550942 Korean Patent No. 10-0674680 Korea Patent No. 10-1296430

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in order to solve the problems of the prior art as described above, and it is an object of the present invention to provide an OLED display device capable of easily producing large quantities of organic materials for OLEDs by utilizing a stable ionic liquid, An object of the present invention is to provide a method of refining a material and a refining apparatus.

According to another aspect of the present invention, there is provided a method for purifying an organic material using an ionic liquid, comprising the steps of: sublimating an organic material containing an impurity; mixing an inert gas into the sublimation gas of the organic material; A dissolving step of mixing the mixed gas into the ionic liquid to dissolve the sublimation gas of the organic material; and a step of supersaturation of the sublimed gas dissolved in the ionic liquid to form a recrystallized organic material And a recrystallization step.

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According to the present invention, there is further provided a discharge step of discharging the inert gas floating from the ionic liquid while the sublimed gas mixed in the ionic liquid is dissolved.

According to the present invention, there is further provided a recovery step of recovering the recrystallized organic material from the ionic liquid after the recrystallization step.

According to the present invention, the method further comprises heating the sublimation gas to maintain the temperature at or above the sublimation point of the organic material before the sublimation gas is mixed into the ionic liquid.

According to the present invention, in the dissolving step, the temperature of the ionic liquid is adjusted to control the solubility of the organic material.

Further, according to the present invention, the inert gas discharged in the discharging step is recycled as an inert gas for generating the mixed gas.

According to an aspect of the present invention, there is provided an apparatus for purifying an organic material using an ionic liquid, comprising: sublimation means for sublimating an organic material containing an impurity; an inert gas mixed with the sublimation gas of the organic material, And a recrystallization means for supersaturation of the sublimed gas which is mixed and dissolved in the ionic liquid to produce a recrystallized organic material.

According to the present invention, the sublimation means comprises a crucible for containing the organic material, a processing chamber provided with the crucible and having a predetermined internal volume, a vacuum pump for bringing the interior of the processing chamber into a vacuum state, And a second heater for heating the first heater.

According to the present invention, the recrystallization means comprises a reservoir containing the ionic liquid, a connection conduit having one side communicating with the interior of the processing chamber and the other side immersed in the ionic liquid of the reservoir, And a vacuum pump for bringing the inside of the vacuum pump into a vacuum state.

According to the present invention, there is further provided a second heater for heating the outside of the connection conduit to maintain the sublimation point of the organic material.

In addition, according to the present invention, the apparatus further includes a third heater for heating the lower portion of the storage tank containing the ionic liquid so as to control the solubility of the organic material.

According to another aspect of the present invention, there is provided an ionic liquid collecting unit installed in an upper portion of the inside of the storage tank for collecting the ionic liquid used for purification of the organic material in a vacuum to a temperature higher than a predetermined temperature, .

According to the present invention, the ionic liquid collecting portion includes a collecting plate fixed to the inner surface of the reservoir, and a collecting container fixed to the inner surface of the reservoir and collecting the ionic liquid collected by the collecting plate .

Further, according to the present invention, the apparatus further comprises an ionic liquid returning means for returning the ionic liquid collected in the collector to the reservoir.

According to another aspect of the present invention, there is provided an apparatus for recovering organic materials, comprising: a recovery tank for separating the recrystallized organic material selectively from the storage tank;

According to the present invention, the flow means includes an inert gas supply source connected to one side of the processing chamber to supply an inert gas, and the recrystallizing means recovers the inert gas collected on the ionic liquid of the reservoir And a discharge pump for discharging the liquid to the outside of the storage tank.

According to the present invention, there is further provided an inert gas returning means for returning the inert gas discharged through the discharge pump to the inert gas supply source.

The present invention has the advantage of remarkably improving the purification yield of the organic material by using the ionic liquid as a liquid filter of the sublimation gas by mixing the sublimation gas generated in the sublimation purification process of the organic material into the stable ionic liquid even in vacuum have.

In addition, the present invention has an advantage that organic materials can be refined in a large amount by putting an organic material into the ionic liquid to a supersaturation limit by using a large amount of ionic liquid by controlling the capacity of the apparatus, thereby enabling cost reduction of the organic material.

In addition, the present invention has an advantage that greening of the manufacturing process can be realized because the ionic liquid can be recycled through the refining process.

1 is a conceptual view showing a structure of an OLED,
FIG. 2 is a schematic view showing a constitutional relationship of a conventional sublimation purification apparatus,
3 is a conceptual diagram showing a constitutional relationship of an organic material refining apparatus using an ionic liquid according to the first embodiment of the present invention,
FIG. 4 is a flowchart of a purification method using the organic material purification apparatus using the ionic liquid shown in FIG. 3,
5 is a conceptual diagram showing a constitutional relationship of an organic material refining apparatus using an ionic liquid according to a second embodiment of the present invention,
6 is a perspective view schematically showing a constitutional relationship of an apparatus for recrystallizing an organic material using an ionic liquid,
FIG. 7 is a graph showing changes in substrate temperature according to the set temperature of the ceramic heater in the apparatus for recrystallization of organic materials shown in FIG. 6,
FIGS. 8 to 10 are graphs showing the deposition rate and the total organic material thickness variation according to the sublimation temperature of the organic material by the crystallization temperature (substrate temperature) in the recrystallization apparatus of the organic material shown in FIG. 6,
FIG. 11 is a photograph of the crystallization process of the NPB organic material in an ionic liquid according to the evaporation temperature of the organic material and the substrate temperature in the apparatus for recrystallization of the organic material shown in FIG. 6,
12 is an image (SEM analysis) of the crystallinity of NPB organic material produced by the apparatus for recrystallization of an organic material shown in Fig. 6,
FIG. 13 is a graph showing the crystal phase of the NPB organic material recrystallized by the apparatus for recrystallization of the organic material shown in FIG. 6 and the crystal phase of the NPB organic material before the recrystallization,
FIG. 14 is a photograph of the grain size of the NPB organic material recrystallized by the apparatus for recrystallization of the organic material shown in FIG. 6 and the grain size of the NPB organic material before the recrystallization, through an optical microscope.

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments of a method and apparatus for purifying an organic material using an ionic liquid according to the present invention will be described in detail with reference to the accompanying drawings.

≪ Embodiment 1 >

3 is a conceptual diagram showing a constitutional relationship of an organic material refining apparatus using an ionic liquid according to the first embodiment of the present invention. 3, the organic material refining apparatus 300 of this embodiment is an apparatus for refining an organic material for OLED (Organic Light Emitting Diodes) using an ionic liquid in a vacuum atmosphere, A sublimation means for sublimating the material, a flow means for forcedly flowing the sublimation gas of the organic material into contact with the ionic liquid, and a recrystallization means for dissolving the sublimation gas in the ionic liquid to recrystallize the organic material. Further, the organic material refining apparatus 300 of this embodiment may further include control means for controlling the operation of the sublimation means, the flow means, and the recrystallization means.

Here, the sublimation means includes a crucible 310 for containing the organic raw material 311, a processing chamber 320 provided with a crucible 310 and having a predetermined internal volume, A vacuum pump 350 for heating the crucible 310, and a first heater 312 for heating the crucible 310. The flow means is configured to include an inert gas supply source 360 connected to one side of the processing chamber 320 to supply an inert gas.

The recrystallization means includes a reservoir 340 in which the ionic liquid 341 is accommodated and a reservoir 340 in which one side communicates with the interior of the processing chamber 320 and the other side is immersed in the ionic liquid 341 in the reservoir 340 A drain pump 340 for discharging the gas collected on the ionic liquid 341 of the reservoir 340 to the outside of the reservoir 340, a conduit 330, a vacuum pump 350 for putting the inside of the reservoir 340 into a vacuum state, (353).

Meanwhile, the processing chamber 320 and the storage tank 340 are connected to each other at the upper side, and a vacuum pump 350 is installed at the connection site. The connection line of the vacuum pump 350 is provided with valves 351 and 352 for selectively communicating with the processing chamber 320 and the storage tank 340.

The ionic liquid 341 used for the purification of the organic material may be further provided on the upper side of the reservoir 340 to have an ionic liquid collector 370 for collecting the ionic liquid 341 through a purification process so as to be recyclable.

As the ionic liquid 341 according to this embodiment, 1-butyl-3-methylimidazorium bis (trifluoromethyl sulfonyl) imide of Chemical Formula 1 is used, (BMIM TFSI) or 1-octyl-3-methylimidazorium bis (trifluoromethylsulfonyl) imide (OMIM TFSI) of formula (2) Can be used. Alternatively, 1-ethyl-3-methylimidazorium bis (trifluoromethylsulfonyl) imide (EMIM TFSI) may be used.

Such ionic liquids (BMIM TFSI, OMIM TFSI, and EMIM TFSI) are nonvolatile organic solvents that are capable of dissolving organic compounds and impurities in ionic liquids more rapidly in supersaturation Due to the mechanism by which the organic material arrives first recrystallized, it can be used to purify and recrystallize various organic materials.

On the other hand, BMIM TFSI, OMIM TFSI and EMIM TFSI are low melting point, low vapor pressure, nonflammable, consist of organic molecular ions, And controllable properties by combinations of anions and cations.

The ionic liquid according to this embodiment is used for purifying and recrystallizing an organic material and is stable as a liquid phase at 100 to 120 ° C and 10 ^-7 Torr and can be used as a solvent in a vacuum process.

As the organic material raw material 311 according to this embodiment, NPB (Naphthylen-1-yl) -N, N'-bis (phenyl) -benzidine, which is used as a hole transport layer (HTL) Materials can be used. Here, NPB has a sublimation temperature of 180 ° C or higher. Therefore, when the crucible 310 in the processing chamber 320 is heated to 200 ° C or higher, it sublimes.

On the other hand, there are a variety of deposition materials (organic material raw materials) used for manufacturing OLED devices other than the above materials. Therefore, the present invention can use these various kinds of organic materials as raw materials.

The crucible 310 is installed on the bottom side of the processing chamber 320 and has a first heater 312 on the lower side. In addition, the crucible 310 is configured to have a form capable of containing the organic raw material 311 to be refined therein.

On the other hand, the connection conduit 330 is disposed such that one side thereof is connected to the upper part of the processing chamber 320, and the other side thereof extends through the upper part of the reservoir 340 and is immersed in the interior of the ionic liquid 341. A second heater 331 may be further disposed around the connection conduit 330 to heat the connection conduit 330. The second heater 331 is connected to the connection conduit 330 so that the mixed sublimation gas 313 can maintain the sublimation point in the process of mixing the gas mixture into the ionic liquid 341 through the connection conduit 330. [ ) To heat the surroundings.

Further, a third heater 342 may be further installed under the reservoir 340. Here, the third heater 342 heats the ionic liquid 341 to control the solubility of the mixed sublimation gas 313 in the ionic liquid 341. Further, a discharge pump 353 may be further installed on the upper side of the reservoir 340. At this time, it is preferable that a valve 354 is additionally provided on the installation line of the discharge pump 353.

Further, an ionic liquid collecting unit 370 may be installed on the upper side of the reservoir 340. Here, the ionic liquid collector 370 serves to collect the ionic liquid 341 used for purifying the organic material through the separation and refining process with the impurities and the dissolved organic material so that the ionic liquid 341 can be recycled. A collection tube 371 fixed to the inner surface of the reservoir 340 and having a curved shape and a collection tube 372 secured to the inner surface of the reservoir 340 to collect the ionic liquid collected by the collection plate 371. [ .

Hereinafter, a method of purifying an organic material using the organic material refining apparatus of this embodiment will be described.

4 is a flowchart illustrating a purification method using an organic material purification apparatus using the ionic liquid shown in FIG. 3 and 4, a crucible 310 containing an organic raw material 311 is provided in the interior of the processing chamber 320 and an ionic liquid 341 is injected into the reservoir 340 in an appropriate amount The vacuum pump 350 is used to evacuate the processing chamber 320 and the reservoir 340. Then, the crucible 310 is heated to the sublimation point of the organic material by using the first heater 312. Then, a mixed sublimation gas 313 of an organic material in which an organic material and some impurities are mixed is obtained (S410).

In this state, an inert gas is supplied from the inert gas supply source 360 to the inside of the processing chamber 320. At this time, as the inert gas, nitrogen or argon gas which does not react with the material constituting the organic material refining apparatus 300 is used within a range in which the degree of vacuum does not significantly decrease. This inert gas serves to flow the mixed sublimation gas 313 into the ionic liquid 341 in the reservoir 340 and is mixed with the mixed sublimation gas 313 to become a mixed gas (S420).

The mixed gas 314 thus formed is introduced into the ionic liquid 341 through the connection conduit 330 to form bubbles as the pressure inside the processing chamber 320 rises (S430). On the other hand, in the process of mixing the mixed gas 314 into the ionic liquid 341 through the connecting conduit 330, a second heater 331 installed around the connecting conduit 330 is connected to the periphery of the connecting conduit 330 The mixed sublimation gas 313 can be mixed into the ionic liquid 341 while maintaining the sublimation point.

On the other hand, the mixed gas mixed in the ionic liquid 341 forms bubbles while the mixed sublimable gas 313 in the bubbles is dissolved in the ionic liquid 341, and the inert gas is not dissolved in the ionic liquid 341 It floats out of the ionic liquid 341 and is collected on top of the reservoir 340. The inert gas collected in the upper part of the reservoir 340 is discharged to the reservoir 340 by the discharge pump 353 and recovered (S440). On the other hand, the inert gas discharged out of the reservoir 340 and returned may be returned to the inert gas supply source 360 through the inert gas return means to be recycled. Here, the inert gas returning means may be constructed using a general pump or the like.

When the mixed sublimation gas 313 is dissolved in the ionic liquid 341, since the content of the organic material to be purified with respect to the impurities is absolutely high, the organic material first reaches the supersaturated state and recrystallization is started first, 343) (S450). At this time, the solubility of the mixed sublimation gas 313 dissolved in the ionic liquid 341 can be controlled by using the third heater 342 provided at the lower part of the reservoir 340. Thus, the solubility of the ionic liquid 341 with respect to the mixed sublimation gas 313 can be controlled to control the degree of supersaturation of the organic material and the recrystallization speed of the organic material in the ionic liquid 341. Therefore, it is possible to minimize the incorporation of impurities in the process of recrystallization, and the purified material 343 of high purity precipitated in the ionic liquid 341 can be recovered from the reservoir 340 as appropriate. For example, an opening / closing port may be formed at one side of the storage tank 340 and the tablet material 343 may be recovered through the opening / closing port.

After the high-purity refining material 343 that has been deposited in the ionic liquid 341 is recovered as described above, the ionic liquid 341 contains an organic material dissolved in the ionic liquid 341 and a small amount of impurities This part will remain. Also, as the purification process proceeds, the impurity content in the ionic liquid 341 increases, and at a certain point, the impurity component also reaches the degree of supersaturation, so that impurities are mixed in the recrystallized organic material. At this point it is desirable to exchange the ionic liquid for the purification process with a high purity ionic liquid.

On the other hand, dissolved organic materials and impurities have different evaporation temperatures as compared with ionic liquids. That is, the evaporation temperature of the ionic liquid is lower than that of organic materials and impurities. By using these properties, it is possible to separately separate and purify the ionic liquid component. For this, when the third heater 342 is set to the evaporation temperature of the ionic liquid and heated, the ionic liquid evaporates and is collected in the collector 372 via the collector plate 371 of the ionic liquid collector 370 And only highly concentrated organic materials and impurities remain. The highly concentrated organic materials and impurities thus remained are separately collected and then subjected to a separation process between the organic material and the impurities through a reprocessing using a general solvent. Thereafter, the organic material having a certain degree of purity can be used as a raw material for recrystallization have. In addition, the ionic liquid recovered in the collection tube 372 can be returned to the inside of the reservoir 340 through the ionic liquid return means and recycled. Here, the ionic liquid returning means may be constituted by using a general pump or the like.

On the other hand, in the organic material refining apparatus 300 of this embodiment, the mixed gas is mixed into the ionic liquid 341 of the reservoir 340 and then the mixed sublimated gas 313 in the bubble comes into contact with the ionic liquid 341 And a bubble refining means for making the volume of the bubble smaller so as to be easily dissolved.

In addition, the organic material refining apparatus 300 of this embodiment may further include contact expanding means so that the mixed sublimation body 313 is easily contacted with the ionic liquid 341. For example, the mixed sublimation gas 313 may be mixed with the inert gas to induce the ionic liquid 341 to pass through the ionic liquid 341 for a predetermined time, thereby promoting dissolution of the sublimation gas.

≪ Embodiment 2 >

5 is a conceptual diagram showing a constitutional relationship of an organic material refining apparatus using an ionic liquid according to a second embodiment of the present invention. 5, the organic material refining apparatus 300A according to this embodiment is configured such that the shape of the reservoir 340A and the arrangement of the third heater 342A are partially modified so that the refining material 343A can be recovered smoothly The organic material refining apparatus 300 of the first embodiment is the same as that of the organic material refining apparatus 300 of the first embodiment. Therefore, in this embodiment, the same reference numerals are assigned to the same constituent elements, and a description thereof will be omitted.

The reservoir 340A of this embodiment is configured in the form of a funnel on the lower side and the reservoir 344 of the refining material 343A separately in the lower side. At this time, the recovery cylinder 344 is configured to be detachable and connectable to the lower end of the storage tank 340A. Therefore, the refined material 343A precipitated through the above-described process gradually accumulates in the collection tube 344. Meanwhile, a valve 345 is provided at the lower portion of the reservoir 340A to control the movement of the ionic liquid by the recovery reservoir 344. Therefore, when a certain amount of the refining material 343A is accumulated in the recovery tank 344, the valve 345 may be closed and the recovery tank 344 may be separated from the storage tank 340A to recover the purified material 343A.

The third heater 342A of this embodiment has the recovery vessel 344 at the lower portion of the storage tank 340A so that the purified material 343A can be smoothly So that it can be precipitated.

Hereinafter, the process and results of the experiment for purifying the organic material using the ionic liquid as described above will be described.

1. Experimental apparatus for recrystallization of organic materials

6 is a perspective view schematically showing a configuration of an apparatus for recrystallizing an organic material using an ionic liquid. As shown in FIG. 6, the apparatus for recrystallizing an organic material comprises a sublimation unit for sublimating an organic material raw material, a recrystallization unit for recrystallizing sublimation gas of an organic material into an ionic liquid, and a recrystallized organic material And the analysis part for analyzing the material). The recrystallization unit and the analysis unit are composed of a ceramic heater, a thickness monitor, a thermo couple, and a mask, and the sublimation unit is composed of a shutter, a crucible, and a heating heater. In the recrystallization part, the ionic liquid is applied on the Si wafer in the form of small drops (droplets), fixed to the mask and fixed to the ceramic heater, and the organic material material to be refined is loaded on the crucible in the sublimation part.

In the experiment using the organic material recrystallization apparatus configured as described above, the evaporation amount of the organic material material in the sublimation portion is controlled through the temperature of the sublimation portion, and the organic material supplied from the sublimation portion is crystallized in the ionic liquid The optimum temperature for crystallization was investigated by controlling the temperature of the ceramic heater.

2. Re-crystallization of organic materials Preparation of experiment (sublimation part)

After weighing the raw material of the organic material to be refined, it was put into the crucible and placed inside the sublimation part. The organic material raw materials used were NPB (N, N'-di (biphenyl-4-yl) -N, N'-bis (2-methyl-biphenyl-4-yl) biphenyl-4,4'-diamine ) Were used.

3. Recrystallization of organic materials Preparation of the experiment (recrystallization and analysis)

Apply an ionic liquid to the Si wafer (50x50mm ² ) in droplet form and mount it on the mask. Then, after fixing the mask to the support member connected to the ceramic heater, the crystallization temperature of the organic material and the amount of the organic material supplied from the sublimation portion are confirmed through the thermocouple and the thickness measuring device, and the recrystallization condition of the optimal organic material is Respectively. At this time, OMIM TFSI was used as the ionic liquid used.

4. Ceramic Heater - Thermocouple Temperature

7 is a graph showing changes in substrate temperature according to the set temperature of the ceramic heater in the apparatus for recrystallization of organic materials shown in FIG. As can be seen from FIG. 7, when the set temperature of the ceramic heater mounted on the experimental apparatus was raised to 300 to 500 ° C., and the temperature transferred to the actual recrystallization portion was confirmed through the thermocouple, the temperature gradient shown in FIG. Respectively.

This temperature change experiment was performed in advance to confirm the crystallization temperature of the ionic liquid applied to the Si wafer. Based on the experimental results, the actual crystallization temperature is not the temperature of the ceramic heater but the temperature measured by the thermocouple To conduct recrystallization experiments.

5. Change in deposition rate with sublimation temperature of organic material in sublimation part (crystallization temperature: R.T)

FIG. 8 is a graph showing the deposition rate and the total organic material thickness variation according to the sublimation temperature of the NPB organic material when the crystallization temperature (substrate temperature) in the apparatus for recrystallizing organic materials shown in FIG. 6 is normal temperature. In this experiment, the deposition rate and the total thickness of NPB organic material were analyzed by a thickness meter while the sublimation temperature of the sublimation part was changed when the crystallization temperature was normal temperature. As a result of the experiment, it was confirmed that as the sublimation temperature of the organic material increases, the deposition rate increases to 0.1 ~ 9 Å / sec and the thickness of the total organic material changes to 0.011 ~ 1.64 袖 m.

6. Change in deposition rate with sublimation temperature of organic material in sublimation part (crystallization temperature: 100 ° C)

FIG. 9 is a graph showing the deposition rate and total organic material thickness variation according to the sublimation temperature of NPB organic material when the crystallization temperature (substrate temperature) in the apparatus for recrystallization of organic materials shown in FIG. 6 is 100 ° C. FIG. In this experiment, the deposition rate and the total thickness of the NPB organic material were analyzed using a thickness meter while the sublimation temperature of the sublimation portion was changed when the crystallization temperature was 100 ° C. As a result, as shown in FIG. 9, it was confirmed that as the sublimation temperature of the organic material increases, the deposition rate increases to 0.1 ~ 9.2 A / sec and the thickness of the total organic material changes to 0.011 ~ 1.51 m.

7. Change in deposition rate depending on organic material sublimation temperature of the sublimation part (crystallization temperature: 110 DEG C)

10 is a graph showing the deposition rate and the total organic material thickness variation with NPB organic material sublimation temperature when the crystallization temperature (substrate temperature) in the apparatus for recrystallization of organic materials shown in FIG. 6 is 110 ° C. In this experiment, the deposition rate and the total thickness of the NPB organic material were analyzed using a thickness meter while the sublimation temperature of the sublimation portion was changed when the crystallization temperature was 110 ° C. As a result, as can be seen from FIG. 10, as the sublimation temperature of the organic material increased, the deposition rate increased from 0.1 to 12.8 A / sec, and the total organic material thickness varied from 0.013 to 2.37 μm.

8. Crystallization image of NPB organic material in ionic liquid through optical microscope

FIG. 11 is a photograph of the crystallization process of an NPB organic material in an ionic liquid according to an organic material sublimation temperature and a substrate temperature in an apparatus for recrystallization of an organic material shown in FIG. 6 through an optical microscope. As can be seen from Fig. 11, at the sublimation temperature (180 DEG C) of the sublimation portion, the organic material was not sublimated and the material was not supplied to the ionic liquid. However, as the sublimation temperature of the NPB organic material increased to over 200 ° C., the sublimation proceeded. As the crystallization temperature (substrate temperature) of the ionic liquid increased, the grain size of the purified NPB organic material increased.

9. Crystallization image of NPB organic material in ionic liquid by SEM analysis

FIG. 12 is an image (SEM analysis) of an NPB organic material crystallization degree image produced by an apparatus for recrystallizing an organic material shown in FIG. 12 shows the crystallization degree of NPB organic material according to the organic material sublimation temperature (200, 220 ° C) and the crystallization temperature (RT, 100, 110 ° C) based on the result of analyzing the degree of crystallization of NPB organic material with an optical microscope It is. As can be seen from FIG. 12, when the crystallization temperature of the ionic liquid was R.T, 100 ° C, the crystallinity of the NPB organic material showed the most excellent characteristic, and the crystallization degree was lowered at the crystallization temperature (110 ° C).

10. Analysis of crystalline phase of NPB organic material by RAMAN analysis

FIG. 13 is a graph showing the crystal phase of the NPB organic material recrystallized by the apparatus for recrystallization of the organic material shown in FIG. 6 and the crystalline phase of the NPB organic material before the recrystallization by Raman analysis. 13, the crystal peaks of the NPB organic material recrystallized under the refining conditions of the sublimation temperature (220 DEG C) and the crystallization temperature (substrate temperature) (110 DEG C) of the NPB organic material were 1125, 1199, 1222, 1289, 1328, 1375, 1529, 1574 and 1609 cm ^-1 , respectively, and showed a Raman shift value almost identical to that of the NPB organic material before recrystallization. This indicates that when recrystallized through an ionic liquid, it was recrystallized without losing the crystallinity of the raw NPB organic material.

11. Analysis of grain size of NPB organic materials by optical microscopy

14 is a graph showing the relationship between the grain size (b) of the NPB organic material recrystallized by the organic material recrystallization apparatus shown in FIG. 6 and the grain size (a) of the NPB organic material before recrystallization It is a photograph. As can be seen from FIG. 14, in the case of NPB organic material before recrystallization, the shape and size of the crystal grains were determined according to the magnification (x50, x100, x200), and as a result, a randomly oriented powder type crystal grain shape was shown. We showed various particle sizes without pattern. However, the recrystallized NPB organic material in the ionic liquid showed a grain shape with a dendrite structure, and the diameter of the crystallized NPB organic material also showed a maximum size of 50 μm. Thus, NPB The crystallinity of the organic material was confirmed.

Raman data showed that the raw material and the crystalline phase of recrystallized NPB organic material showed almost the same tendency and it was difficult to accurately predict the improvement of crystallinity. However, through optical microscope analysis, It was confirmed that the size could be improved by ionic liquid refining method.

12. Conclusion

As a result of comparing the data of purified NPB organic materials and raw materials by using ionic liquid, we confirmed the distinct changes of recrystallized NPB organic materials. The recrystallization method using the supersaturation degree of the organic material in the ionic liquid as compared with the sublimation purification method in which the organic material is refined repeatedly by repeating the sublimation-condensation process many times is not only simplification of the process but also recrystallization of the pure organic material, There is an advantage that the purity can be improved.

Meanwhile, this experiment was conducted through a recrystallization apparatus of organic materials having a small capacity. However, as can be seen from the above-described experimental results, it can be seen that the present invention is also applicable to mass purification of organic materials as in the present invention.

As can be seen from the above-mentioned Examples and Experimental Examples, since the present invention is a purification process using the difference in solubility, the process of repeatedly dissolving-recrystallizing organic materials and impurities in an ionic liquid It is possible to purify and recrystallize various organic materials by a single process owing to the mechanism in which the organic material that reaches the supersaturation is first recrystallized first.

Further, the present invention can minimize the amount of impurities supplied from external contaminants by purifying an organic material under a vacuum condition, and thus obtain a high-purity organic material (refined material).

In addition, since the purification process is carried out in the ionic liquid using the ionic liquid as a filter, the present invention is free from the loss due to the carrier gas, and the recrystallized organic material is recovered, Can be reused to purify the organic material, thereby reducing the loss of raw materials consumed in the purification process and reducing the manufacturing cost.

The description of the organic material purification method and purification apparatus using the ionic liquid of the present invention has been described above with reference to the accompanying drawings, which illustrate the best preferred embodiments of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. Examples or modifications will also fall within the scope of the claims of this invention.

300: organic material refining apparatus 310: crucible
311: organic material raw material 312: first heater
313: sublimation gas 320: processing chamber
330: connection conduit 331: second heater
340: reservoir 341: ionic liquid
342: third heater 343: refined material
350: vacuum pump 351, 352, 354: valve
352: exhaust pump 360: inert gas source
370: ionic liquid collecting part 371: collecting plate
372: Collecting column

Claims (18)

A sublimation step of sublimating an organic material to be purified containing an impurity;
Generating a mixed gas by mixing an inert gas with the sublimation gas of the organic material;
A dissolving step of dissolving the sublimation gas of the organic material by mixing the mixed gas into the ionic liquid to form bubbles, and
And a recrystallization step of supersaturated sublimation gas of the organic material dissolved in the ionic liquid to produce a recrystallized organic material. delete The method according to claim 1,
Further comprising a discharging step of discharging the inert gas floating from the ionic liquid while the sublimation gas is dissolved in the dissolving step. The method according to claim 1,
Further comprising a recovery step of recovering the recrystallized organic material from the ionic liquid after the recrystallization step. The method according to claim 1,
Further comprising the step of heating the mixed gas so as to maintain the temperature above the sublimation point of the organic material before the mixed gas is mixed into the ionic liquid. The method according to claim 1,
Wherein the dissolving step adjusts the temperature of the ionic liquid to adjust the solubility of the organic material. The method of claim 3,
Wherein the inert gas discharged in the discharging step is recycled as an inert gas for generating the mixed gas. 1. A sublimation means for sublimating an organic material to be purified containing an impurity, comprising: a processing chamber in which a crucible for containing the organic material is installed; a vacuum pump for evacuating the inside of the processing chamber; and a first heater for heating the crucible The sublimation means including;
An inert gas supply source connected to one side of the processing chamber to supply an inert gas;
And a vacuum pump for evacuating the interior of the reservoir, wherein the ion pump is provided with a reservoir for storing the ionic liquid, a connection conduit having one side communicating with the interior of the processing chamber and the other side immersed in the ionic liquid of the reservoir, And recrystallization means for subcritating and subliming the sublimation gas of the organic material in the liquid,
And a gas mixture of the sublimation gas of the organic material and the inert gas is introduced into the ionic liquid through the connection conduit in the processing chamber to generate bubbles so that the sublimation gas of the organic material dissolves in the ionic liquid Wherein the ionic liquid is an organic material. delete delete The method of claim 8,
Further comprising a second heater for heating the outside of the connection conduit to maintain the sublimation point of the organic material. The method of claim 8,
Further comprising a third heater for heating a lower portion of the reservoir containing the ionic liquid to control solubility of the organic material. The method of claim 12,
Further comprising an ionic liquid collecting part installed in the upper part of the inside of the reservoir and collecting the ionic liquid used for purification of the organic material in a vacuum so as to be heated at a predetermined temperature or higher and evaporated for recycling, Organic material refining apparatus using liquid. 14. The method of claim 13,
Characterized in that the ionic liquid collector comprises a collection plate fixed to the inner surface of the reservoir and a collection container secured to the inner surface of the reservoir and collecting the ionic liquid collected by the collection plate. Organic Material Purification System Using. 15. The method of claim 14,
And an ionic liquid returning means for returning the ionic liquid collected in the collecting container to the reservoir. The method of claim 8,
Wherein the organic material purification apparatus further comprises a recovery vessel which is selectively communicated with the storage tank and is capable of being coupled and separated to recover the recrystallized organic material separately. The method of claim 8,
Wherein the recrystallization means further comprises a discharge pump for discharging the inert gas collected on the ionic liquid of the storage tank to the outside of the storage tank. 18. The method of claim 17,
And an inert gas returning means for returning the inert gas discharged through the discharge pump to the inert gas supply source.

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