KR20150108743A - Method of refining organic materials with impurities through ionic liquids and apparatus therefore - Google Patents

Abstract

A spraying-type method for refining an organic material using an ionic liquid of the present invention includes: a sublimation step (S110) of sublimating the organic material containing impurities; a capturing step (S120) of capturing sublimation gas of the organic material by making the sublimation gas contact with a flowing ionic liquid; and a recrystallization step (S130) of generating a recrystallized organic material by firstly oversaturating the organic material to be refined among the sublimation gas captured in the ionic liquid to be dissolved therein. In the capturing step, the ionic liquid falls and flows by crossing a route for the sublimation gas to be scattered. The present invention does not need a step of transporting the sublimation gas generated at the sublimation step so as to reverse-sublimate the same, thereby having an advantage of fundamentally blocking a contamination problem of a refinement sample due to inert carrier gas, which has been used in a conventional sublimation purification method.

Description

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

The present invention relates to a method and apparatus for purifying a spray type organic material using an ionic liquid and, more particularly, to an ionic liquid for purifying a low molecular organic material that can be used as a light emitting body or a transporter of an organic electroluminescence Type organic material purification method and a purification apparatus using the same.

The organic electroluminescent device is composed of several thin organic thin film layers between a transparent anode and a cathode having a low work function. When a forward voltage is applied to the device, holes are injected into the organic layer from the anode electrode, Electrons are injected and recombined in the light emitting layer to emit light. Organic EL has all of the high quality panel characteristics required in the information age, such as low power consumption, wide viewing angle, high response speed and wide driving temperature range, and it is relatively simple to manufacture, thus realizing low price over conventional flat panel displays It has the advantage of being able to expect.

The purity of the organic material is a factor that affects the luminescence characteristics of the organic EL device. If an impurity is mixed in the organic material, the impurity may become a trap of the carrier or cause extinction, and the light emission intensity and the light emitting efficiency are lowered. Therefore, it is necessary to purify the organic material in order to remove the impurities.

After the synthesis of the organic material, the organic material is once subjected to a purification process using a chemical method. Examples of the chemical purification process include recrystallization, distillation, and column chromatography. Through such a chemical purification process, the purity of the target compound can be increased to 99% or more.

As an organic material purification method, recrystallization using a solvent or recrystallization by sublimation is generally used. Recrystallization using a solvent has an advantage that a large amount of an organic material can be purified, but there is a disadvantage that a solvent tends to get into an organic crystal because a solvent is used. That is, there is a problem that the solvent contained in the organic crystals acts as an impurity to lower the luminescence characteristics.

Another purification method is a chromatography method such as HPLC (High Performance Liquid Chromatography). When purified by such a chromatographic method, higher purity can be achieved compared to a simple chemical purification step . However, such a chromatographic method is mostly used for analytical purposes only and is considered to be an inadequate process for mass purification of materials.

The organic luminescent material is usually purified using a sublimation purification method. Sublimate refers to the transition between solid and gas phases occurring at temperatures and pressures below the triple point in the phase diagram. 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 using such a property, the operation of separating the synthesized material from other sublimation points without decomposition of the material by heating the material is called a vacuum sublimation method. Such a vacuum sublimation method is known to be a useful method for purifying an organic material for an organic EL device because it is a pure physical method and does not depend on the use of an auxiliary reagent or other chemical method, .

The vacuum train sublimation purification method is one of the most widely used ultra-high purity purification methods of organic materials. In this method, a chamber in a state of a long tube-like vacuum is divided into a plurality of heating regions, and a temperature gradient is formed by heating the respective heating regions at an elevated temperature and a low temperature. And adopts a method of taking only the precipitated material in a constant heating region by using the difference in sublimation point of the material sublimated in such a chamber.

Generally, the following process conditions are applied in the conventional vacuum sublimation purification method.

(1) The heating zone is divided into 3 to 9 zones. In the case of a small number of zone division, a method of high temperature, middle temperature, and low temperature is used. In the case of a large number of zone division, a heating temperature is set within a temperature gradient range of each region other than a region where a sample is taken.

(2) The sample loading area is set at the opposite position of the vacuum pump.

(3) The initial chamber pressure is in the range of 10 ^-2 to 10 ^-6 torr before the carrier gas is flowed, while the pressure of the carrier gas is in the range of 0.1 to several torr . The carrier gas uses high purity nitrogen gas or argon gas, which is not reactive.

(4) The loading of the sample should not exceed 1/2 of the diameter of the pipe as much as possible so that the carrier gas can move. At this time, a boat-shaped loading mechanism may be used.

The purpose of using a carrier gas in the conventional vacuum sublimation purification method is to improve the flow of the sample in the vacuum sublimation state. That is, when there is no carrier gas in a state close to vacuum, the flow of the sublimated sample molecules is not good, and solid particles are precipitated on the wall surface in a region too close to the sample loading region. Therefore, in the conventional vacuum sublimation purification process, the use of a carrier gas is a basic process condition.

However, such a conventional vacuum sublimation purification method has several disadvantages. The most serious problem of the conventional vacuum sublimation purification method is that a certain region formed with ultrahigh purity material is contaminated due to carrier gas. That is, the carrier gases tend to cause scattering of the raw sample loaded in the region where the sample is loaded, causing contamination of the region where the ultrahigh purity substance actually formed is precipitated. Further, the precipitation region of the ultra-pure substance already formed is gradually moved to the third region.

Carrier gases cause not only poor performance in this process but also a large amount of load on the equipment when the sample is loaded, causing a part of the sublimed sample to contaminate the vacuum pump. Even if the trap device for preventing such a phenomenon is installed in a high capacity structure, the performance of the vacuum pump still deteriorates.

Another disadvantage of the conventional vacuum sublimation purification method is the scattering phenomenon during vacuum venting. During the vacuum venting, nitrogen gas is introduced into the chamber to make the pressure at atmospheric pressure. In this case, a scattering phenomenon may occur among the respective samples in which the purification process is completed in the chamber. This phenomenon becomes even more pronounced when both the glass tube for refining (or the crystal tube) are opened, which makes contamination of already refined substances even more expensive.

In summary, in the case of the sublimation purification method, there is an advantage that the raw material can be refined into an organic material having high purity using the difference in sublimation point of the organic material, but the following various problems are caused.

(1) Since a considerable amount of the organic material is lost in the exhaust gas together with the carrier gas during the repetition of the sublimation-reverse refinement process, not only the yield of the final purified material compared to the starting material is extremely low, but also the problem of contamination of the vacuum pump occurs .

(2) In the process of injecting carrier gas under high vacuum, not only purified raw materials are scattered and contaminated, but the vacuum is vented to collect the purified organic materials after purification. There is a problem that the final purity of the organic material to be obtained is lowered.

(3) In order to recover the purified material after the purification process is completed, it is difficult to automate the recovery of the vacuum atmosphere of the entire system to normal pressure and stop the entire system.

(4) Because of this, a repetitive purification process is required, which consumes a large amount of energy, which ultimately causes a problem that the cost of the organic material increases.

Korean Patent No. 10-0550941 Korean Patent Registration No. 10-0550942 Korean Patent Registration No. 10-0582663 Korean Patent No. 10-0674680 Korea Patent No. 10-1296430 Korea Patent No. 10-1304350 Korea Patent No. 10-1343487 Korean Patent Publication No. 10-2013-0096370

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in order to solve the problems of the conventional art as described above, and it is an object of the present invention to provide a method of forming a sublimation gas of an organic material by heating an organic material containing impurities to a sublimation point, And an object of the present invention is to provide a method and apparatus for purifying a spray type organic material using an ionic liquid capable of easily separating and purifying an impurity and a high purity organic material in large quantities by contacting, collecting and dissolving the ionic liquid have.

According to another aspect of the present invention, there is provided a spray type organic material purification method using an ionic liquid, comprising: a sublimation step of sublimating an organic material containing an impurity; an ionic liquid And a recrystallization step of initially recrystallizing the organic material to be purified in the sublimation gas collected and dissolved in the ionic liquid to thereby obtain an organic material recrystallized, And in the collecting step, the ionic liquid flows downward across the path of the sublimation gas scattering.

According to the present invention, the recrystallization step further comprises a recirculation step in which the mixed liquid generated by dissolving the sublimation gas in the ionic liquid is recycled across the path in which the sublimation gas is scattered.

According to the present invention, in the recycling step, the recrystallized organic material is separated and recovered, and the mixed liquid is circulated.

According to another aspect of the present invention, there is provided a spray type organic material refining apparatus using an ionic liquid, comprising: a sublimation unit for sublimating an organic material containing an impurity; And a collecting unit for collecting the sublimated gas by bringing the sublimation gas of the organic material into contact with the flowing ionic liquid, wherein the collecting unit comprises: a housing in communication with the sublimating unit; Characterized in that the organic material to be purified is first supersaturated in the sublimation gas collected and dissolved in the ionic liquid to generate a recrystallized organic material by an ionic liquid supply means for supplying an ionic liquid .

According to the present invention, the trapping portion further includes a mixed solution produced by dissolving the sublimation gas in the ionic liquid, and a storage means for storing the recrystallized organic material.

According to the present invention, the ionic liquid supply means further comprises a recirculation means for recirculating the mixed liquid from the storage means, and dropping the mixed liquid across the path in which the sublimated gas is scattered.

Further, according to the present invention, the recirculation means discharges the mixed liquid and the recrystallized organic material in the storage means to the outside of the storage means, separates and recovers the recrystallized organic material, recycles the mixed liquid And a recovering means for recovering the image.

The present invention does not require a step of carrying out sublimation by transporting the sublimation gas generated in the sublimation step. Therefore, there is an advantage that the problem of contamination of the purified sample due to the inert carrier gas used in the conventional sublimation purification method is essentially blocked.

In addition, since the present invention is capable of collecting and dissolving the sublimation gas generated in the sublimation step without losing all of them in contact with the ionic liquid, it is possible to purify all the organic materials without losing them to the outside in the purification process, have.

Also, since the object organic material is preferentially recrystallized and precipitated only in the target organic material until the impurity is supersaturated and recrystallized, the purity of the purified organic material can be remarkably increased to 99.95% or more at a time.

In addition, the present invention recovers an ionic liquid in which an organic material is dissolved together with impurities and then recycles it as an ionic liquid of the present invention through a separate purification process, thereby reducing ionic liquid as an environmentally friendly solvent and reducing purification cost have.

In addition, the present invention can greatly reduce the cost of purification since the organic material can be refined in large quantities by adjusting the capacity of the apparatus and using organic materials to the supersaturation limit in an ionic liquid using a large amount of ionic liquid.

FIG. 1 is a conceptual diagram showing a constitutional relationship of a spray-type organic material refining apparatus using an ionic liquid according to an embodiment of the present invention,
FIG. 2 is a conceptual view showing a constitutional relationship of a spray-type organic material refining apparatus using an ionic liquid according to another embodiment of the present invention,
3 is a flowchart of a method of purifying a spray-type organic material using the ionic liquid according to the present invention,
4 is a schematic diagram for manufacturing an organic material refining apparatus,
FIG. 5 is a photograph of an organic material refining apparatus manufactured according to the design diagram shown in FIG. 4,
FIG. 6 is a graph showing changes in Raman PL characteristics with time of exposure to air for an HTL material before and after purification through the organic material purification apparatus shown in FIG. 5,
FIG. 7 is a graph showing a change in PL characteristic according to the exposure time of the HTL material before and after purification through the organic material purification apparatus shown in FIG. 5,
FIG. 8 is a SEM (x 1k) photograph of a change in the surface shape of HTL material before and after purification through the organic material refining apparatus shown in FIG.
FIG. 9 is a graph of XPS showing characteristics of a purified organic material through the organic material refining apparatus shown in FIG. 5,
10 is a graph showing the surface composition of the purified organic material analyzed by XPS after heat treatment at 120 ° C for 1 minute.

An ionic liquid is a salt-like substance composed of ionic bonds of positive and negative ions, exists in a liquid state at a temperature of 100 ° C or lower, stably exists as a liquid at a high temperature, and has a vapor pressure close to zero. 'And is attracting much attention as an environmentally friendly solvent. In addition, the ionic liquid can be dissolved in a wide range of inorganic, organic, polymeric substance, hydrophobicity, solubility, viscosity, it is possible to easily change the physical and chemical properties, such as density bulriwoomyeo to as "Designer Solvent", in theory, 10 or ¹⁸ kinds of It is possible to synthesize and has unlimited potential as a solvent. That is, the ionic liquid has various advantages such as not having the conventional organic solvent, and has a great advantage that the solvent can be selected and synthesized to meet the purpose of the user. (Recent Research Trends of Ionic Liquids 1 - Overview, Institute of Bioseparation Technology, Inha University, Sang Hyun Lee, Seong - Ho Ha)

On the other hand, ionic liquids can easily change physical and chemical properties such as nonvolatility, nonflammability, thermal stability, high ionic conductivity, electrochemical stability and high boiling point through structure change of cation and anion, . These ionic liquids can increase the activity and stability of the enzyme, can easily realize the separation process, and are also preferable from the environmental / economic point of view. In the future, ionic liquids will be widely used in various fields. Thi Phuong Thuy Pham, Chul-Woong Cho, Yeoung-Sang Yun, "Environmental fate and toxicity of ionic liquids: A review", Water Research, 44, 2010, pp. 352-372 )

As the ionic liquid according to this embodiment, 1-butyl-3-methylimidazorium bis (trifluoromethylsulfonyl) imide (BMIM (trifluoromethylsulfonyl) imide) TFSI), or 1-octyl-3-methylimidazorium bis (trifluoromethyl sulfonyl) imide (OMIM TFSI) of formula (2) . 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.

On the other hand, OLEDs can be divided into charge transport materials (hole injecting layer, hole transporting layer, electron injecting layer, electron transporting layer) and light emitting materials (fluorescent material, phosphorescent material and dopant respectively). Such an OLED has a very thin ultra-thin film with a total thickness of about 100 to 200 nm. Among the materials for charge transport, hole transport materials include NPB (N, N'-bis (naphthalen-1-yl) -N, N'- (N-N'-dibenzylbenzidine), CuPc (Copper Phthalocyanine), MTDATA (2-methylphenyl) -N, N'- (4,4 ', 4' '- tris (2-methylphenylamino) triphenylamine) and the like. Examples of the electron transferring material include Alq3 (Tri- (8-hydroxy-chinolinato) -aluminium), DTVBi (2,2-diphenyethen-1-yl) -diphenyl). Examples of the luminescent material include Alq3, coumarine derivatives, quinacridone derivatives, rubrene, and the like. have.

Therefore, an NPB material can be used as an organic material raw material according to this embodiment. Here, NPB has a sublimation temperature of 180 ° C or higher. Therefore, when a loading boat containing an organic material raw material is heated to 200 DEG C or higher, it is sublimated.

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. That is, the present invention can use various kinds of organic materials constituting the charge transporting material or light emitting material of the OLED as raw materials.

However, organic materials include organic TFT materials, organic solar cell materials, and organic semiconductor materials in addition to low-molecular organic light-emitting materials for manufacturing OLED devices as described above. Therefore, although the present invention can be used for purification of organic materials applied to various fields as described above, the organic material for OLED will be described below as an example.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of a spray type organic material refining apparatus using an ionic liquid according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a conceptual diagram showing a constitutional relationship of a spray type organic material refining apparatus using an ionic liquid according to an embodiment of the present invention. 1, the spray type organic material refining apparatus 100 of this embodiment mainly comprises a sublimation unit for sublimating an organic material for an OLED containing impurities, a sublimation unit arranged in communication with the sublimation unit, And a collecting unit for collecting the sublimated gas by contacting the flowing ionic liquid. Here, the trapping part serves to supersaturation of the organic material to be refined, which is the main component of the composition, among the sublimation gas collected and dissolved in the ionic liquid, to produce recrystallized high purity organic material.

The collecting unit includes a housing 110 in a vacuum atmosphere having a predetermined internal volume, collecting means 130 collecting the sublimated gas by bringing the sublimated gas of the sublimated organic material into contact with the ionic liquid, and collecting means 130 And recrystallization means (140) for initially recrystallizing the organic material to be purified, which is the main component of the composition, among the sublimation gas collected and dissolved in the ionic liquid to produce a recrystallized high purity organic material.

The sublimation unit includes a sublimation unit 120 that communicates with one side of the housing 110 to heat and sublimate the organic raw material for OLED containing impurities.

The spray type organic material refining apparatus 100 of this embodiment preferably further includes control means (not shown) for controlling the operation of the sublimating means 120, the collecting means 130 and the recrystallizing means 140 Do.

The housing 110 has a predetermined internal volume that is hermetically sealed to the outside, and includes a vacuum pump 111 for making the inside of the housing 110 vacuum. The sublimation means 120 comprises a loading boat 121 for receiving the organic material stock and a heater (not shown) for heating the loading boat 121. The collecting means 130 is configured to have a plurality of nozzles for spraying the ionic liquid.

Hereinafter, the configuration of the housing 110 will be described in more detail.

Preferably, the housing 110 has a cylindrical inner shape having a certain inner volume that is hermetically sealed with the outside, and has a predetermined length. Meanwhile, the housing 110 is configured to be capable of serving as a storage tank (storage means) 141 capable of storing the ionic liquid 112 therein. That is, the housing 110 has a space in which the loading boat 121 is installed and a space in which the ionic liquid 112 is stored.

Meanwhile, it is preferable that the housing 110 is configured to have a plurality of transparent windows (not shown) that can confirm the recrystallization process progressed therein from the outside. That is, the housing 110 may be made entirely of stainless steel, and may have a transparent window (not shown) in the middle. At this time, the transparent window may be made of a glass material. Meanwhile, the housing 110 may be made entirely of a transparent glass material.

The housing 110 is further configured to have a heater 113 for adjusting the internal temperature of the housing 110. At this time, the heater 113 may be provided on the surface of the stainless steel constituting the housing 110, for example, an area heating element may be provided. However, when the housing 110 is formed entirely of a transparent glass material, it is preferable that the heater 113 is installed in a band shape at regular intervals along the circumference of the housing 110. This is to allow the inside of the housing 110 to be observed at regular intervals even if the heater 113 is installed in the housing 110.

The heater 113 is arranged to heat the ionic liquid and control the temperature atmosphere inside the housing 110 to control the solubility of the organic sublimation gas dissolved in the ionic liquid. In addition, the heater 113 also functions to regulate the temperature of the ionic liquid (mixed liquid) in which the sublimed gas collected in the reservoir 141 is dissolved to smoothly cause the organic material to precipitate and recrystallize. Such a heater 113 may be divided into a plurality of units to control the respective temperatures.

In addition, the housing 110 is configured to have a reservoir 141 for storing the ionic liquid 112 on its lower side. Here, the reservoir 141 serves to store the ionic liquid 112 used to recrystallize the new ionic liquid 112 and the organic material so as to constitute some of the components of the recrystallization means 140, And also serves as a collector for collecting the ionic liquid (mixed liquid) and the recrystallized organic material. At this time, the reservoir 141 is formed by a part of the lower part of the housing 110, and may be configured to have a certain volume. Meanwhile, the reservoir 141 preferably has a downward tapered shape toward the center so that the ionic liquid in which the sublimation gas is dissolved and the recrystallized organic material can be gathered in a more convenient place.

The vacuum pump 111 serves to make the inside of the housing 110 in a vacuum state and communicates with one side of the housing 110 through a vacuum pipe. Meanwhile, it is preferable that a throttle valve is further installed in the vacuum pipe of the vacuum pump 111.

Hereinafter, the configuration of the sublimation means 120 will be described in more detail.

The sublimation means 120 is disposed on one side of the housing 110 to heat and sublimate the organic material raw material for an OLED containing impurities. The sublimation means 120 is installed on the outer surface of the housing 110, It is preferable to further provide a heater 122 such as a surface heating element for sublimating the sublimated organic material more effectively and preventing the sublimation gas of the sublimated organic material from being recrystallized on the inner surface of the housing 110.

The loading boat 121 is located below the one side of the housing 110 and has a heater (heating means, not shown) on the lower side. Further, the loading boat 121 is configured to have a form capable of containing the organic material raw material to be purified. On the other hand, the loading boat 121 may constitute a receiving portion of the organic material raw material in the form of a plurality of projections (comb shape) or a wave shape so that the organic material raw material is heated evenly, that is, the contact area is increased.

The heater (heating means) serves as a heat source for sublimating the organic raw material in the loading boat 121, and includes electric heating, electromagnetic heating, and electron beam heating. For example, thermal evaporation, a laser beam, a microwave, or a magnetic heating method may be applied instead. In order to sublimate the organic material raw material by using the heater and other methods as described above, it is preferable to heat the organic material raw material just before the sublimation point at a low temperature and then sublimate the organic material raw material by heating at a sublimation point or more after an interval of 1 to 5 minutes .

Hereinafter, the configuration of the collecting means 130 will be described in more detail.

The collecting means 130 serves as an ionic liquid supplying means for supplying the ionic liquid or a spraying means for spraying the ionic liquid so as to fall in a curtain shape or various forms across the path in which the sublimated gas is scattered.

The collecting means 130 includes a receiving portion 131 having a certain accommodation space between the upper surface and the upper surface of the housing 110 and a plurality of collecting portions 131 communicating the inside of the receiving portion 131 and the inside of the housing 110 A connection pipe 133 for connecting the storage portion 131 and the storage tank 141 to each other and a connection pipe 133 for connecting the ionic liquid 112 in the storage tank 141 And a pump 134 for spraying the sublimate gas downward so as to fall across the path through which the sublimation gas flows through the plurality of communication holes 132 via the sublimation portion 131.

Here, the pump 134 is a recirculating means for recirculating the mixed liquor collected in the reservoir 141, and a recrystallizing means 140 for repeatedly contacting the mixed liquor with the sublimation gas so that the organic material is supersaturated in the ionic liquid to be recrystallized ). ≪ / RTI > The communication hole 132 serves as a nozzle for spraying the ionic liquid according to the pressure applied to the ionic liquid by the pump 134. [ At this time, it is preferable that the communication hole 132 is configured to be capable of spraying an ionic liquid in a spraying manner like a diffusion nozzle.

The recirculation means may further include a recovery means for discharging the mixed liquid in the storage tank 141 and the recrystallized organic material to the outside of the storage tank 141 and then separating and recycling the recrystallized organic material and recirculating the mixed liquid. The recovery means includes a recovery container 135 for separating and storing the recrystallized organic material in the mixed liquid supplied through the connection pipe 133 by the pump 134, And a circulation pump 136 for recirculating the refrigerant to the evaporator 130. Here, the recovery container 135 includes an apparatus for separating the recrystallized organic material by filtration or centrifugal separation. It is preferable that the above-mentioned recovery means is used when the recrystallized organic material does not settle down to the bottom of the ionic liquid but flies to the surface of the ionic liquid or is mixed in the ionic liquid.

The spray type organic material refining apparatus 100 of this embodiment includes another recovery means 150 that is purified and recrystallized in the lower part of the storage tank 141 of the housing 110 to recover the deposited organic material, And a replacement means 160 for replacing the new loading boat with the empty loading boat in which the organic material is sublimated.

The other recovery means 150 includes a recovery tank 151 connected to a connection line 152 formed at the lower end of the storage tank 141 and a recovery tank 151 connected to the connection line 152 between the storage tank 141 and the recovery tank 151, And a vacuum pump 154 provided between the two valves 153 for applying a vacuum to the connection line 152. The vacuum pump 154 is connected to the valve 153, . At this time, the recovery tube 151 is configured to be detachable and coupled to the connection line 152.

Therefore, the purified organic material is gradually accumulated in the recovery tube 151. In addition, when a certain amount of organic material is accumulated in the recovery tank 151, the two valves 153 may be closed and the recovery tank 151 may be separated from the connection line 152 to recover the organic material. When the new recovery tank 151 is connected to the connection line 152, the new recovery tank 151 is first connected to the connection line 152 and then the valve 153 adjacent to the recovery tank 151 is opened. Then, a vacuum is applied to the connection line 152 by the vacuum pump 154, and then the remaining valve 153 is opened. The recovering means 150 as described above is suitably used when the recrystallized organic material is deposited to the lower portion of the ionic liquid.

The replacing means 160 includes a chamber 161 selectively opened and closed with one side of the housing 110 and the outside of the standby state to introduce a new loading boat and collect the empty loading boat, (Not shown) for selectively opening and closing the outside of the housing 110 and one side of the housing 110 and the outside of the standby state.

The replacing means 160 includes a chamber 161 configured as a load lock chamber generally adopted in the LCD equipment and a load lock chamber provided in the load lock chamber for connecting the loading boat to the housing 110, Or a mobile robot (not shown) for moving the robot to the outside of the waiting state.

Hereinafter, a process of purifying an organic material using the spray-type organic material refining apparatus of this embodiment will be described.

A loading boat 121 containing an organic material material is installed in the housing 110 and the inside of the housing 110 is coated with the ionic liquid as a whole by driving the pump 134 and the circulation pump 136 . Thereafter, the inside of the housing 110 is evacuated by using the vacuum pump 111.

Then, the loading boat 121 is heated by a heater up to just before the sublimation point of the organic material raw material, and is then heated for 1 to 5 minutes and then heated to the sublimation point or higher. Then, it becomes a sublimation gas of an organic material mixed with an organic material and some impurities. On the other hand, the pump 134 and the circulation pump 136 are operated from the time when the sublimation gas of the organic material is formed to spray the ionic liquid through the communication hole 132. Further, the inside of the housing 110 is formed through the heater 113 provided on the outer surface of the housing 110 to provide a temperature atmosphere in which recrystallization of the organic material is easy.

The sublimation gas flows in the other direction of the housing 110 and comes into contact with the ionic liquid sprayed through the communication hole 132. By this contact, the sublimated gas is collected in the ionic liquid and gradually dissolved and recrystallized, and collected in the reservoir 141 under the housing 110. That is, when the sublimation gas is dissolved in the ionic liquid, the content of the organic material to be purified with respect to the impurities is absolutely high. Therefore, the organic material first reaches the supersaturated state, and recrystallization is started first and precipitated into a high purity organic material.

On the other hand, the solubility of the sublimated gas dissolved in the ionic liquid can be controlled by using the heater 113 provided on the outer surface of the housing 110. Therefore, it is possible to control the degree of supersaturation of the organic material and the recrystallization speed of the organic material in the ionic liquid by controlling the solubility of the ionic liquid in the sublimation gas. Therefore, it is possible to minimize the incorporation of impurities in the process of recrystallization, and the organic material of high purity precipitated in the ionic liquid can be recovered from the reservoir 141 of the housing 110 as appropriate.

For example, when the recrystallized organic material is precipitated to the bottom of the ionic liquid, the purified organic material may be recovered through the recovery column 151 of the recovery means 150 connected to the storage tank 141. However, when the recrystallized organic material is not precipitated to the bottom of the ionic liquid but is floated on the surface of the ionic liquid or mixed in the ionic liquid, the mixed liquid in the reservoir 141 and the recrystallized organic material are stored in the reservoir 141 The recrystallized organic material is separated by filtration or centrifugal separation and collected in the recovery container 135, and then the mixed liquid is recycled using the circulation pump 136.

At the time when all of the organic material materials in the loading boat 121 are sublimated, the new material is replaced with a new loading boat containing the organic material raw material through the replacement means 160, and the organic material is continuously purified through the same process as described above do.

After the high-purity organic material deposited in the ionic liquid is recovered as described above, a part of the dissolved organic material and a small amount of impurities remain in the ionic liquid until the degree of supersaturation contained in the sublimed gas. Also, as the purification process proceeds, the impurity content in the ionic liquid 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.

FIG. 2 is a conceptual diagram showing a constitutional relationship of a spray type organic material refining apparatus using an ionic liquid according to another embodiment of the present invention. FIG. As shown in Fig. 2, the spray type organic material refining apparatus 100A of this embodiment is the same as the spray type organic material refining apparatus 100A shown in Fig. 1 except that the collecting means 130A is partially modified . Therefore, in this embodiment, the same reference numerals are assigned to the same constituent elements, and a description thereof will be omitted.

The collecting means 130A of this embodiment is configured to have a plurality of jetting pipes 131A each having a plurality of nozzles for jetting an ionic liquid. At this time, the plurality of injection pipes 131A are provided at regular intervals in the path direction in which the sublimation gas is scattered, and the ionic liquid is sprayed from the upper part to the lower part in a curtain shape or in various forms through the respective nozzles to contact with the sublimation gas Respectively. Here, it is preferable that a plurality of nozzles are arranged in a zigzag manner so that a sublimation gas scattered by the plurality of nozzles is contacted with the ionic liquid and is gradually collected.

Hereinafter, a spray-type organic material purification method using the ionic liquid according to the present invention will be described.

3 is a flowchart of a method of purifying a spray-type organic material using the ionic liquid according to the present invention. 3, a spray type organic material purification method using an ionic liquid according to the present invention includes a sublimation step (S110) for sublimating an organic material for an OLED (Organic Light Emitting Diodes) containing an impurity, A collecting step (S120) of collecting the sublimation gas by bringing the sublimation gas of the material into contact with the flowing ionic liquid; and a recrystallization step of sublimating the sublimation gas collected and dissolved in the ionic liquid to produce a recrystallized organic material S130). Here, the sublimation step (S110) comprehensively includes the sublimation of the organic material to be purified from a solid state to a gas, or from a solid state to a gel state and to a gaseous state.

On the other hand, as shown in Figs. 1 and 2, in the collecting step S120, the ionic liquid flows downward across the path in which the sublimation gas is scattered. The recrystallization step (S130) may further include a recirculation step of recirculating the mixed liquid across the path in which the sublimed gas is scattered. On the other hand, in the recycling step, the recrystallized organic material may be separated and recovered in the recovery container 135 to circulate the mixture.

Hereinafter, the principle of continuously crystallizing and purifying an organic material in this invention will be described.

The sublimation gas of the organic material is collected in the ionic liquid and dissolved, and becomes a mixed solution. When it reaches the saturation state, it becomes a saturated solution. After this saturated solution, the sublimed gas is trapped and dissolved in the saturated solution, nuclei are formed, and molecules of the organic material in the saturated solution are scattered by the nuclei and adhere around the nucleus and grow into crystals. At this time, the concentration of crystal growth is lower than that of other regions. That is, as the molecules in the saturated solution grow, the concentration of the solution in the surroundings becomes relatively low, whereby the saturated solution becomes a mixed solution state in which the sublimation gas can be dissolved by contact.

On the other hand, the driving force of crystal growth of the present invention always maintains a concentration gradient. To this end, in the present invention, two methods can be used as described above.

The first is to self-circulate the ionic liquid. That is, the ionic liquid in the mixed liquid state (the state not in the saturated solution) is self-circulated to allow the crystal to grow continuously in the mixed liquid state, the saturated solution state, and the supersaturated solution state in the ionic liquid. This method is applicable when the growth rate of the nucleus is higher than that of the sublimation gas.

The second is to supply a new ionic liquid. That is, the novel ionic liquid is continuously supplied to allow the crystal to grow continuously in the ionic liquid while the mixed solution state, the saturated solution state, and the supersaturated solution state exist. This method is applicable when the sublimation gas supply rate is higher than the nucleation rate. That is, this method is a method for preventing the sublimation gas from being dissolved in the ionic liquid and crystallizing directly into solid due to high supersaturation.

Hereinafter, the refined organic material purification apparatus using the ionic liquid of the present invention and purification of the organic material through the refining method will be described below.

1. Organic material purification apparatus and purification method

FIG. 4 is a schematic diagram for manufacturing an organic material refining apparatus, and FIG. 5 is a partial enlarged photograph of an organic material refining apparatus manufactured according to the design diagram shown in FIG.

As shown in Figs. 4 and 5, the organic material refining apparatus includes a sublimation unit for sublimating an organic material for an OLED containing impurities, an ionic liquid disposed in communication with the sublimation unit and flowing in a sublimation gas of an organic material And a collecting section for collecting the sublimated gas by contact.

The process of performing the purification experiment using the organic material refining apparatus as described above is as follows. First, the organic material to be purified is charged into the sublimation portion at the atmospheric pressure, the ionic liquid is injected into the collection portion, and the chamber is pumped to ¹ x 10 ^-6 Torr. Then, the ionic liquid is heated, the blade of the collecting part is rotated, and the organic material to be refined is heated to the sublimation point, but the organic material to be refined is kept for a certain time to sublimate. Then, the sublimation gas of the organic material scatters and is contacted with the ionic liquid flowing along the blade, collected and dissolved, and recrystallized. When the purification process is completed, the purified organic material is collected to separate the purified organic material and the ionic liquid, and then the ionic liquid remaining on the surface of the purified organic material is cleaned.

2. Experimental Conditions and Experimental Results of Organic Material Purification System

1 kg of OMIN TFSI (1-Octyl-3-methylimidazorium bis (trifluoromethyl sulfonyl) imide) was used as the ionic liquid and 20 g of HTL material (DS 220) was used as the organic material. On the other hand, in performing the purification experiment, the sublimation temperature of the organic material was set to 280 DEG C or higher, and the temperature of the ionic liquid was set to 120 DEG C. [ Subsequently, the pressure was reduced to ¹ × 10 ^-6 Torr and sublimation was started. The process time was 5 hours.

During the refining experiment under the above conditions, suspended organic material crystals were observed on the surface of the ionic liquid after 30 minutes from the initiation of sublimation, and then the amount of these crystals was observed to increase. That is, as can be seen from the experimental results of the partial enlarged photograph of FIG. 5, it can be seen that the recrystallized and purified organic material exists as a float on the surface of the ionic liquid. This means that it is possible to purify organic materials using ionic liquids.

After the purification process was completed, a mixture of the purified organic material and the ionic liquid was collected, and the purified organic material was separated and washed from the ionic liquid, and various analyzes were performed.

3. Characterization of purified organic materials

The characteristics of the purified organic materials were analyzed using the analytical instrument shown in Table 1 under the following conditions.

Analytical instrument Equipment model manufacturer Measuring conditions FE-SEM Quanta 200 FEI Company - HV: 20 kV
- spot size: 3mm
- Magnification: 1k ~ 30k Raman LabRamHR JOVIN YVON - 514 nm Ar laser
- Temperature: 21 ℃
- Humidity: 20%
- scan range: 1000 to 3000 cm ^-1 PL RPM2000 ACCENT - 325nm He-Cd Laser
- Temperature: 21 ℃
- Humidity: 20%
- scan range: 350 ~ 810nm XPS VG Multilab 2000 ThermoVG Scientific - Lens mode: LAXPS
- Survey pass energy: 50eV
- Narrow pass energy: 20eV
- Analysis element: C, O, F, Cl, S

4. Raman PL  Measure

The changes of Raman PL characteristics with HTL material exposure time before and after purification were measured. This Raman PL measurement is intended to compare the stability of the organic material with the exposure time of the HTL material before and after purification. FIG. 6 is a graph showing changes in Raman PL characteristics according to exposure time to HTL material before and after purification through the organic material refining apparatus shown in FIG.

As can be seen from FIG. 6, the change width of the peak half width (FWHM) of the HTL material before purification reached 8 cm ^-1 as the exposure time elapsed in the atmosphere, while the value of HTL material after purification was 0.5 cm ^{-1, which} is very stable. This means that the surface of the organic material purified using the ionic liquid is being passivated by the constituents of the ionic liquid.

5. PL measurement

The change of PL characteristics according to the exposure time to HTL material before and after purification was measured. This PL measurement is intended to compare the stability of the organic material with the exposure time of the HTL material before and after purification. FIG. 7 is a graph showing a change in PL characteristic according to an exposure time of an HTL material before and after purification through the organic material refining apparatus shown in FIG. 5; FIG.

7, it can be seen that the emission peak position of the HTL material after purification is shifted toward a short wavelength (460 nm -> 440 nm), and the value of the half width (FWHM) decreases from 75 nm to 50 nm. This means that the purity of the material has been improved through the purification process. In the case of HTL before purification, the change in peak position reaches ± 5 nm and the change in FWHM reaches 10 nm as the exposure time elapses in the atmosphere. On the other hand, in the HTL material after purification, 1 nm or less and the change width of the half width (FWHM) is 5 nm or less. Thus, in the case of an organic material purified using an ionic liquid, there is little change in the properties of the material due to external moisture and oxygen. This means that the surface of the organic material purified using the ionic liquid is protected by the constituents of the ionic liquid.

6. SEM Measurement

The change of surface shape of HTL material before and after purification was measured according to the exposure time to air. This PL measurement is intended to compare the stability of the organic material with the exposure time of the HTL material before and after purification. FIG. 8 is a SEM (x 1k) photograph of a change in surface shape of the HTL material before and after purification through the organic material refining apparatus shown in FIG. 5 according to the exposure time to air.

The HTL material before tableting was a material immediately after synthesis and had a purity of about 98.6%. As can be seen from FIG. 8, no specific characteristic was observed in the surface shape. However, the spherical shape of the HTL material purified through the organic material refining apparatus of the present invention was observed. The size of these grains had a very uniform size of 5 mu m. On the other hand, no significant change in surface shape with time was observed.

7. XPS measurement

The characteristics of the purified organic materials were investigated by XPS measurement using the organic material refining apparatus of the present invention. 9 is a graph of XPS showing characteristics of the purified organic material through the organic material refining apparatus shown in FIG.

As can be seen from Fig. 9, the elements F and S attributable to the anion component of the ionic liquid used for the purification of the organic material were detected. This is an intrinsic result of the spray type organic material purification method using an ionic liquid, showing that anions and cations are chemically bonded at the molecular level to the surface of recrystallized organic materials in the purification process. As described above, it can be seen that the surface of the purified organic material is protected by an ionic liquid, a component originating from the ionic liquid (constituent of the ionic liquid), or ions constituting the ionic liquid. In particular, it can be seen that the surface of the purified organic material is protected by anions of a chemically bonded single molecule layer. As a result, it can be seen that as the surface of the purified organic material is protected, the characteristics of the purified organic material according to the atmospheric exposure are stably maintained as described above. These characteristics, that is, the trace amounts of the elements of the characteristic component originating from the ionic liquid used are intrinsic characteristics of the organic materials purified by the purification method using an ionic liquid. By examining these characteristics, It can be determined that the object is a purified object. Therefore, the present invention includes providing an organic material having the characteristics of such purified material.

However, when the F and S components due to the ionic liquid are mixed in the device process in the process of manufacturing an OLED panel, there is a possibility that the device characteristics may be adversely affected. Therefore, it is necessary to remove the F and S components due to the ionic liquid which protects the surface of the purified organic material immediately before the deposition process for fabricating the device.

As a result, the inventors of the present invention have found that the components resulting from the ionic liquid protecting the surface of the organic material are completely removed by Ar ion etching or heat treatment at 100 ° C or higher. If these impurities are present in the organic material, they will not be removed by such a heat treatment or simple argon ion etching, so the results show that the components due to the ionic liquid are only present in trace amounts on the surface of the purified organic material .

10 is a graph showing the surface composition of the purified organic material analyzed by XPS after heat treatment at 120 ° C for 1 minute. As can be seen from FIG. 10, a very weak peak was detected at the positions due to the F and S components, which means that most of the F and S components present on the surface of the purified organic material were removed through heat treatment. Through this process, it is confirmed that purified organic materials can be handled stably in the distribution channel before introducing the purified organic materials into the device process, and it is confirmed that ions that protect the surface of the organic material by proper pre- It was confirmed that the components caused by the liquid phase can be completely removed, so that no adverse effect is exerted on the device process.

In the foregoing, the description of the spray type organic material purification method and purification apparatus using the ionic liquid of the present invention has been described 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.

100: organic material refining apparatus 110: housing
120: sublimation means 130: collection means
140: Recrystallization means 150: Recycling means
160: Replacement means

Claims (7)

A sublimation step of sublimating an organic material containing impurities,
A collecting step of collecting the sublimated gas by bringing the sublimation gas of the organic material into contact with the flowing ionic liquid;
And a recrystallization step of first supersaturation of the organic material to be purified in the sublimation gas collected and dissolved in the ionic liquid to produce a recrystallized organic material,
Wherein the ionic liquid in the collecting step flows downward across the path of scattering of the sublimated gas. The method according to claim 1,
Further comprising a recycling step of recycling the mixed liquid generated by dissolving the sublimated gas to the ionic liquid in the recrystallization step so as to recirculate the mixed liquid across the path in which the sublimation gas is scattered. How to refine the material. The method of claim 2,
Wherein the recrystallized organic material is separated and recovered, and the mixed solution is circulated in the recycling step. A sublimation portion for sublimating an organic material containing impurities,
And a collecting unit arranged to communicate with the sublimation unit and bringing the sublimation gas of the organic material into contact with the flowing ionic liquid to collect the sublimation gas,
Wherein the trapping portion includes a housing that communicates with the sublimation portion and an ionic liquid supply means that supplies the ionic liquid so as to fall across the route in which the sublimation gas is scattered,
Wherein the trapping portion first supersaturated an organic material to be purified in the sublimation gas collected and dissolved in the ionic liquid to generate a recrystallized organic material. The method of claim 4,
Wherein the trapping portion further comprises a mixed solution generated by dissolving the sublimation gas in the ionic liquid and a storage means for storing the recrystallized organic material. The method of claim 5,
Wherein the ionic liquid supply means further comprises a recirculation means for recirculating the mixed liquid from the storage means and dropping the mixed liquid across the path in which the sublimated gas is scattered. The method of claim 6,
The recycling means further includes a recovery means for discharging the mixed liquid and the recrystallized organic material in the storage means to the outside of the storage means and then separating and recovering the recrystallized organic material and recirculating the mixed liquid Wherein the ionic liquid is used as a solvent.

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