JPWO2013105557A1 - Electrostatic spray equipment - Google Patents

Abstract

In an electrostatic spray apparatus for forming an organic thin film using an electrostatic spraying method, productivity is improved while maintaining uniformity of a film to be formed. The electrostatic spray device includes a nozzle 10 that discharges an aerosol 20 in which fine particles 21 made of an organic material are dispersed, a voltage applying unit 15 that applies a voltage to the nozzle to charge the fine particles, and a substrate 11 that is opposite to ground or fine particles. A substrate holding means 19 for holding at a polar potential, and attracting and depositing fine particles discharged from the nozzle by electrostatic attraction to the substrate to form an organic thin film on the substrate; An electrode unit (23, 24) that controls the flying of the fine particles by affecting the electric field in the space or a magnetic pole unit (coil) that controls the flying of the fine particles by affecting the magnetic field of the flying space of the fine particles, By controlling the magnetic pole portion, the flying range of the fine particles is made larger in one direction on a plane parallel to the base material than in the other direction on the same plane orthogonal thereto.

Description

  The present invention relates to an electrostatic spray apparatus for forming an organic thin film using an electrostatic spray method.

As a method for producing a plurality of organic thin films such as organic electroluminescence (EL) elements and organic thin film solar cells, there are a vapor deposition method, a wet process (spin coating method, casting method, ink jet method, spray method, printing method) and the like. In recent years, a manufacturing method in a wet process has attracted attention because it does not require a vacuum process and is convenient for continuous production.
However, it is generally known that an organic EL element produced by a wet process does not exhibit sufficient performance in terms of element performance, particularly in terms of life, compared to an organic EL element produced by a vapor deposition method.
When manufacturing a plurality of organic thin films by a wet process, there is a problem that the base layer (lower layer) is dissolved by the solvent at the time of lamination, or layer mixing occurs because the solvent penetrates the base layer. It becomes one of insufficient factors. One way to avoid this problem is to select a solvent that does not dissolve the substrate during lamination, but ensuring the solubility of the organic material in the solvent that does not dissolve the substrate is a major limitation in material design. The condition is the condition.
For this reason, there is a long-awaited method that can reduce the influence of the solvent and can form a large-area film in a non-vacuum. In order to meet such technical demands, attention can be paid to electrostatic spraying.

Patent Documents 1-4 describe a technique by an electrostatic spray method.
According to the electrostatic spraying method, the fine particle diameter in the generated aerosol can be reduced to 1 μm or less. Since there is a limit to the amount of spray per nozzle that discharges the fine particles, in order to form a large area with a short tact time, it is conceivable to provide a plurality of nozzles as described in Patent Document 2.
However, in the case where a plurality of nozzles are provided, the amount of deposition varies between a region where the fine particles are given by one nozzle, a region where the fine particles are given by another adjacent nozzle, and a region where both overlap, The problem of uneven thickness and film quality arises.
Further, when the supply amount of the solution serving as the aerosol raw material is increased, there are problems that the atomization is not in time and the liquid drips or the particle diameter in the aerosol is not sufficiently reduced.
In addition, when the nozzle is brought close to the base material in order to speed up the takt time, the solution is not sufficiently atomized, and further, the solvent volatilization becomes insufficient, resulting in layer mixing, which causes performance deterioration. .

In Patent Document 3, in order to enable the formation of a thin film with high in-plane uniformity at a relatively high film formation rate, a coating liquid containing a solid content is discharged from a nozzle to which a voltage is applied. In forming the solid content layer by depositing the formed charged coating liquid particles on the surface to be coated which is charged on the opposite side of the nozzle, the charged coating liquid particles are placed between at least two openings and these openings. The main body is deposited on the surface to be coated from one opening of the conduit charged to the same pole as the coating liquid particles via the other opening.
In Patent Document 4, an electrospray deposition (ESD) apparatus is used to locally form a desired material at a desired position on a substrate with high accuracy in order to correct patterning in an organic EL element or the like. Is used. The ESD device includes a nozzle that stores a solution of a desired material, a spray power source that applies a voltage to the nozzle, a convergence guard ring that converges a spray range of droplets sprayed from the nozzle, and a voltage or voltage applied to the convergence guard ring. A power supply for a guard ring that applies current, a local electrode that is disposed on the back side of the substrate at a position to be deposited on the substrate, and a local electrode power source that applies a voltage having a polarity opposite to that applied to the nozzle to the local electrode. As the converging guard ring, an electrostatic lens or a combination of an electrostatic lens and a magnetic lens is used, and these are responsible for converging the spray range of droplets sprayed from the nozzle. Yes.

JP 2011-03442 A JP 2011-181271 A JP 2011-41908 A JP 2011-175922 A

However, even the above prior art has the following problems.
According to the technique described in Patent Document 3, scattering of the coating liquid particles to the surroundings is suppressed by the conduit whose body is charged to the same electrode as the coating liquid particles, and the coating liquid particles (film forming material particles) are transferred to the base material. The adhesion rate is improved. According to the technique described in Patent Document 4, scattering of the film forming material particles to the periphery is suppressed by the convergence guard ring, and the adhesion rate of the film forming material particles to the base material is improved.
However, in Patent Documents 3 and 4, since the means for suppressing scattering of the film forming material particles to the periphery is circular, the region where the film forming material particles adhere to the substrate is circular. Therefore, non-uniformity occurs in that the film formed is thick at the center of the adhesion region and thin at the periphery of the adhesion region. As a result, there has been a problem that layer mixing in the center portion occurs more intensely than in the peripheral portion.
In addition, when a film is formed by scanning on the substrate, a film-forming pattern is formed in a band shape in the scanning direction. On the center line of the band-shaped film forming pattern, spraying is simultaneously performed by the length of the diameter of the circular adhesion region. Therefore, the spraying time is relatively long, and nonuniformity occurs between the edge of the strip-shaped film formation pattern.
In addition, since the adhesion region is circular, the scanning width does not change even if scanning is performed in any direction, and the start and end are semicircular, which is inconvenient for film formation with a large scanning width and a large area. There is a case.

  The present invention has been made in view of the above problems in the prior art, and in an electrostatic spray apparatus for forming an organic thin film using an electrostatic spray method, while maintaining the uniformity of the film to be formed. It is an object to suppress layer mixing and improve productivity.

The invention according to claim 1 for solving the above-described problems includes a nozzle for discharging an aerosol in which fine particles containing an organic material are dispersed;
Voltage application means for applying a voltage to the nozzle and charging the fine particles;
A substrate holding means for holding the substrate at ground or at a potential opposite to that of the fine particles, and attracting and depositing the fine particles discharged from the nozzle by electrostatic attraction to deposit the organic thin film on the substrate. In an electrostatic spray device that forms a film on a material,
An electrode part for controlling the flying of the fine particles by affecting the electric field of the flying space of the fine particles or a magnetic pole part for controlling the flying of the fine particles by affecting the magnetic field of the flying space of the fine particles, And between the base material and
By controlling the electrode part or the magnetic pole part, the flying range of the fine particles is made larger in one direction on a plane parallel to the base material than in the other direction on the same plane orthogonal to the base material. It is a spray device.

In the invention according to claim 2, the relationship among the applied voltages of the nozzle, the electrode part or the magnetic pole part, and the base material,
When the voltage applied by the voltage application means is positive, nozzle> the electrode part or magnetic pole part> base material,
2. The electrostatic spray device according to claim 1, wherein when the voltage applied by the voltage application unit is negative, the base material> the electrode part or magnetic pole part> nozzle is set.

Invention of Claim 3 is provided with the said electrode part, and the said electrode part is comprised with the frame-shaped electrode member arrange | positioned so that the center axis | shaft of the said nozzle may be enclosed,
2. The electrostatic spray device according to claim 1, wherein a facing interval in the one direction of the electrode member is larger than a facing interval in the other direction.

Invention of Claim 4 is provided with the above-mentioned magnetic pole part, and the above-mentioned magnetic pole part comprises a coil arranged so that the central axis of the above-mentioned nozzle may be enclosed,
2. The electrostatic spray device according to claim 1, wherein a facing interval in the one direction of the coil is made larger than a facing interval in the other direction.

  The invention described in claim 5 affects the electric field in the flying space of the fine particles above the discharge port of the nozzle and affects the magnetic field in the flying space of the fine particles by controlling the flying of the fine particles. 5. The electrostatic spray device according to claim 1, further comprising a magnetic pole portion that controls flying of the fine particles.

  According to a sixth aspect of the present invention, the potential difference between the electrode part or magnetic pole part above the nozzle discharge port and the base material is the electrode part between the nozzle discharge port and the base material or The electrostatic spray device according to claim 5, wherein the electrostatic spray device is larger than a potential difference between the magnetic pole portion and the base material.

In the invention according to claim 7, the relationship between the applied voltage of the nozzle, the electrode part or the magnetic pole part, and the base material is as follows.
When the voltage applied by the voltage applying means is positive, the electrode part or magnetic pole part above the nozzle discharge port>nozzle> the electrode part or magnetic pole part between the nozzle discharge port and the substrate> As a base material,
When the voltage applied by the voltage application means is negative, the base material> the electrode part or magnetic pole part between the nozzle outlet and the base material>nozzle> the electrode part above the nozzle outlet or The electrostatic spray device according to claim 6, wherein the electrostatic spray device is a magnetic pole portion.

Invention of Claim 8 is provided with the above-mentioned magnetic pole part, and the above-mentioned magnetic pole part is constituted by a plurality of magnets arranged away from the central axis of the nozzle,
2. The electrostatic spray device according to claim 1, wherein a facing interval in the one direction of the plurality of magnets is larger than a facing interval in the other direction.

  The invention according to claim 9 is the electrostatic spray device according to any one of claims 1 to 8, wherein the substrate is a belt-like substrate.

  The invention according to claim 10 is the electrostatic spray device according to any one of claims 1 to 9, wherein the organic thin film is an organic thin film of an organic electroluminescence element.

  The invention according to claim 11 is the electrostatic spray device according to claim 10, wherein the organic thin film of the organic electroluminescence element is a light emitting layer.

According to the present invention, with respect to the flying range of fine particles made of an organic material discharged from a nozzle, the flying range in one direction on a plane parallel to the substrate on which the film is formed is in contrast to the other direction on the same plane perpendicular thereto. The adhesion range of the fine particles to the base material is formed in a shape that is long in the one direction and short in the other direction, and the nonuniformity of the film is alleviated in the one direction in the adhesion range.
Moreover, layer mixing can be suppressed by reducing the non-uniformity of the amount of the solvent in the adhesion range on the substrate.
Further, by scanning the substrate in the other direction, a large area film can be formed with a large scanning width.
As described above, according to the present invention, there are effects that layer mixing can be suppressed and productivity can be improved while maintaining uniformity of a film to be formed.

It is a typical perspective view which shows the principal part between the nozzle-base materials of the electrostatic spray apparatus which concerns on embodiment of this invention. It is a top view for demonstrating the influence of the electric field or magnetic field in the electrostatic spray apparatus which concerns on embodiment of this invention. It is a front view for demonstrating the influence of the electric field or magnetic field in the electrostatic spray apparatus which concerns on embodiment of this invention. It is a side view for demonstrating the influence of the electric field or magnetic field in the electrostatic spray apparatus which concerns on embodiment of this invention. It is a structure schematic diagram of the electrostatic spray apparatus which concerns on embodiment of this invention when applying supercritical carbon dioxide as a solvent.

  An embodiment of the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention.

As shown in FIG. 1, the electrostatic spray device of this embodiment includes a nozzle 10 that discharges an aerosol 20 in which fine particles 21 made of an organic material are dispersed, and a voltage application that applies a voltage to the nozzle 10 and charges the fine particles 21. A means 15 and a base material holding means 19 for holding the base material 11 at a potential opposite to that of the fine particles 21 are provided. The organic thin film is formed on the substrate 11 by attracting and depositing the fine particles 21 discharged from the nozzle 10 by electrostatic attraction onto the substrate 11. For this reason, voltages having opposite polarities are applied to the nozzle 10 and the plate 12 on which the substrate 11 is placed. Alternatively, the electrostatic attractive force can be generated even if the voltage applying unit 16 included in the configuration of the substrate holding unit 19 is simply replaced with a conductive member connected to the ground. What is formed is, for example, an organic layer of an organic electroluminescence element. As the substrate 11, a belt-like flexible substrate may be used. Examples of the strip-shaped flexible substrate include a resin.
Further, the electrostatic spray device of the present embodiment includes the electrode member 23 and the electrode member 24 as the electric field forming unit, and further includes the voltage applying unit 17 that applies a voltage to the electrode member 23 and the electrode member 24. By the action, the adhesion range 22 having a long shape in one direction is formed.
The voltage applying means 15, the voltage applying means 16, and the voltage applying means 17 are each obtained by inserting a DC power supply device between the ground. A resistor 25 is inserted between the electrode member 23 and the electrode member 24 because a potential difference needs to be generated between them.
This will be described in more detail below.

FIG. 1 shows orthogonal three-axis coordinates XYZ. The Z axis is the same direction as the central axis O of the nozzle, and the discharge direction is positive. The coordinate XY corresponds to a coordinate on a plane parallel to the base material 11.
The electric field guard ring, that is, the electrode member 23 and the electrode member 24 are formed in a frame shape, and the facing distance X1 in the X direction is larger than the facing distance Y1 in the Y direction. That is, X1> Y1. The electrode member 23 and the electrode member 24 are disposed so as to surround the central axis O of the nozzle, and are disposed in parallel with the XY plane. The electrode member 23 and the electrode member 24 are arranged apart from each other in the Z direction. The electrode member 23 is disposed at a position between the discharge port of the nozzle 10 and the substrate 11 with respect to the Z coordinate. The electrode member 24 is disposed above the nozzle 10, that is, closer to the negative direction of the Z axis from the discharge port of the nozzle 10.

The electrode member 23 and the electrode member 24 are in principle the same as the electrostatic lens, but the electrostatic lens gradually decreases the flight range (the cross-sectional area of the aerosol perpendicular to the Z axis) as it approaches the substrate. However, the electrode member 23 and the electrode member 24 do not need to be converged. As an effect | action of the electrode member 23 and the electrode member 24, it is sufficient if a flight range is narrowed from an original range.
The electrode member 23 and the electrode member 24 affect the electric field of the flying space of the fine particles 21 and exert a Coulomb force that accelerates the fine particles 21. By these actions, the flying range of the fine particles 21 toward the substrate 11 is narrowed. That is, the flying range is narrowed with respect to the flying range when the electrode member 23 and the electrode member 24 are not provided. The flying space refers to a space in which the fine particles 21 can fly. In this embodiment, the flying space of the fine particles 21 can be narrowed by providing the electrode member according to the present invention.
Further, the electrode member 23 and the electrode member 24 need not all be at the same potential. That is, when it is desired to make the flight range more horizontally long (for example, when it is desired to narrow the flight range in the Y direction), the electrode member 23 and the electrode member 24 in FIG. By electrically cutting the member (the one with the longer side), applying a different voltage, and applying a lower potential to the member in the Y direction than the member in the X direction, the Coulomb force acting on the fine particles 21 is further improved in the Y direction. Strengthened, the flight range can be further extended horizontally. In addition, the electrode member 23 and the electrode member 24 do not need to have a rectangular frame shape regardless of whether they are at the same potential or different potentials, and are formed according to a pentagonal shape, a hexagonal shape, and a desired adhesion range 22. The shape may be determined in consideration of the potential.
Moreover, the uniformity of the coating film thickness is also improved by restricting the flight range by the Coulomb force. That is, by applying a potential to the electrode member 23 and the electrode member 24, a Coulomb force that narrows the flying range acts on the fine particles 21, and the fine particles 21 come close to each other. The repulsive force works, and the Coulomb force that tries to spread works. Therefore, the fine particles 21 diffuse in the electrode member frame where the concentration of the fine particles 21 is low, and as a result, the fine particle concentration is applied to the adhesion range 21 in a more uniform manner.
The electrode member 23 may be replaced with a coil (magnetic field guard ring) as a magnetic field forming means, and Lorentz force may be applied on the same principle as the magnetic field lens.

A frame 30 shown in FIGS. 2A to 2C indicates an electrode position corresponding to the electrode member 23 and the electrode member 24 or a center position where current flows when replaced with a coil (that is, a magnetic pole position of a magnetic field generated by the current). It is. Reference numerals 31 to 34 denote corners of the frame line 30, and S <b> 1 to S <b> 4 each side of the frame line 30. The point O is common to the position of the central axis O and is also common to the center of the frame line 30. Points A, B, C, and D are points equidistant from the point O. d1 indicates the distance between the point A and the side S1 and the distance between the point C and the side S3. d2 indicates the distance between the point B and the side S2 and the distance between the point D and the side S4.
Since d1 <d2, the Coulomb force due to the influence of the electrode member 23 or the electrode member 24 or the Lorentz force when replaced with a coil is smaller at points B and D than at points A and C. Therefore, as shown in FIG. The adhesion range 22 of the fine particles on the material 11 is formed in a shape that is long in the X direction and short in the Y direction.

  As described above, since the adhesion range 22 of the fine particles is formed in a shape that is long in the X direction and short in the Y direction, the nonuniformity of the film in the X direction is alleviated. Further, by scanning the substrate 11 in the Y direction, a large area film can be formed with a large scanning width. By using the base material 11 as a belt-like body, the width direction thereof is arranged in the X direction, and the material is supported and conveyed by a roller, whereby continuous and highly efficient production is possible. In this case, it is preferable to control so that the dimension in the X direction of the adhesion range 22 exceeds the width dimension of the belt-like substrate. Thus, the film can be formed from one end to the other in the width direction by one nozzle, and the uniformity of the film can be improved.

By applying a Coulomb force or Lorentz force in the direction of the substrate 11 to the charged fine particles 21, scattering of the fine particles 21 to the surroundings can be suppressed, and a force for transporting the fine particles 21 in the direction of the substrate 11 works. Therefore, the adhesion efficiency of the fine particles 21 to the base material 11 is also improved.
An electrode member 24 was installed above the discharge port of the nozzle 10. The electrode member 24 is set to a higher potential than the electrode member 23 between the nozzle 10 and the substrate 11. As a result, the fine particles 21 are surrounded by an electric field and cannot be scattered around, thereby further improving the adhesion efficiency.

Since the adhesion range 22 of the fine particles only needs to be formed in a shape that is long in one direction, the flying range of the fine particles 21 may be narrowed relatively in the Y direction with respect to the X direction in FIG. Therefore, the shapes of the electrode members 22 and 23 and the coil are not particularly limited, and may be a shape that becomes a desired adhesion range 22 shape.
Further, such a Lorentz force can be applied by arranging magnetic poles of the magnets at the corners 31, 32, 33, and 34 shown in FIG. 2A. In this case, for example, by arranging the S pole at the corner portion 31, the N pole at the corner portion 32, the S pole at the corner portion 33, and the N pole at the corner portion 34, the particle adhesion range 22 is elongated in one direction. Can be formed. Each of the magnetic poles can be implemented by configuring the end of an iron core of an electromagnet or by pasting a pellet-shaped permanent magnet on the surface of a cubic member. In the latter case, the permanent magnet is pasted with the south pole faced up at the corner portion to be the south pole, and the permanent magnet is pasted with the north pole face up at the corner portion to be the north pole.

The aerosol 20 discharged from the nozzle 10 may be generated by supplying a solution to the nozzle 10 or may be supplied to the nozzle 10 in advance. In the latter case, a chamber is provided in the nozzle 10 via a pipe, and the nozzle 10 is conveyed to the nozzle 10 by a carrier gas. The aerosol generating apparatus for generating the aerosol is not particularly limited, and a technique that can be used may be selected and implemented. For example, an apparatus using an ultrasonic atomization phenomenon is known and can be applied. In that case, the solution stored in the chamber is ultrasonically vibrated by an ultrasonic vibrator attached to the bottom of the chamber, and aerosol is generated from the liquid surface of the solution. At this time, an electrostatic atomizer that applies a high voltage to the liquid surface of the solution, or an ultrasonic atomizer ionizer that supplies ion carrier gas from the side onto the liquid surface of the solution can be applied. In the latter case, the aerosol can be conveyed toward the nozzle 10 by the ion carrier gas.
Moreover, what sprays a solution with a nozzle is also applicable as it is commonly used for the existing electrostatic spray apparatus. In this case, the aerosol is stored in the chamber by disposing the nozzle outlet in the chamber.
Moreover, you may attach a heater to the constituent material of the nozzle 10 and piping connected to this, and a chamber. For example, a heater is attached so as to cover the outside of the constituent materials of the chamber, piping, and nozzle 10. With this heater, the temperature of the aerosol 20 to be conveyed can be maintained at an optimum value for vaporizing the solvent, and the removal of the solvent can be promoted during the conveyance, and the diameter of the fine particles 21 can be further reduced. Moreover, when the charged fine particles 21 adhere to the substrate 11, the solvent is instantaneously removed, and layer mixing can be suppressed. The temperature is set according to the volatility of the solvent used.

  Further, from the viewpoint of increasing the yield in the film forming process, the base material 11 should be kept at a temperature lower than the gas temperature discharged from the nozzle 10 in order to suppress the upward air flow from the base material 11 toward the nozzle 10. preferable. For example, when heating the nozzle 10 or the piping or chamber connected to the nozzle 10 as described above, the temperature is adjusted by a temperature adjusting device attached to the plate 12 at a temperature lower than that temperature.

As the electrode member 23 and the electrode member 24 for applying the Coulomb force, it is preferable to use a metal base coated with a non-conductive material. In that case, the non-conductive material can be charged by applying a voltage to the metal substrate, and by making it the same polarity as the fine particles 21, the adhesion of the fine particles 21 can be prevented.
Examples of the non-conductive material include those obtained by thermal spraying Al2O3 ceramics and then sealing with alkoxysilane. A metal such as silver, platinum, stainless steel, aluminum, or iron can be used for the metal substrate. Stainless steel is easy to process and can be preferably used. Use non-conductive materials such as silicate glass, borate glass, phosphate glass, germanate glass, tellurite glass, aluminate glass, vanadate glass, etc. Can do. Of these, borate glass is easy to process.
It is also preferable to use a ceramic obtained by sintering a highly heat-resistant ceramic with high airtightness. The thickness of the ceramic may be in a range that can withstand the applied voltage, and is preferably 0.1 mm or more, and more preferably 0.3 mm or more. Examples of the ceramic material include alumina-based, zirconia-based, silicon nitride-based, and silicon carbide-based ceramics. Among these, alumina-based ceramics are preferable.
The ceramic is preferably sealed with an inorganic material, whereby the durability of the metal substrate can be improved. The sealing process is a metal having a uniform structure by forming a solid three-dimensional bond by applying a sol whose main raw material is a metal alkoxide, which is a sealing agent, to ceramics and then gelling and curing. Ceramics can be sealed with an oxide. Moreover, it is preferable to perform energy treatment in order to promote the sol-gel reaction. By applying energy treatment to the sol, a three-dimensional bond of metal-oxygen-metal can be promoted. For the energy treatment, plasma treatment, heat treatment at 200 ° C. or lower, and UV treatment are preferable.

[Supercritical carbon dioxide]
Next, a case where supercritical carbon dioxide is applied as a solvent will be described with reference to FIG.

  FIG. 3 is a schematic configuration diagram of an electrostatic spray apparatus (RESS (Rapid Expansion of Supercritical Solution) apparatus based on a semi-batch distribution method) to which the present invention is applied. In the solution rapid expansion method using supercritical carbon dioxide, a solution in which a solute is dissolved in supercritical carbon dioxide (Solution) or a solution obtained by dissolving supercritical carbon dioxide in a solid solute is passed through a nozzle. This is a technique for creating a thin film by rapidly expanding to near atmospheric pressure and injecting a cluster of solute molecules generated by molecular self-assembly (crystallization) phenomenon caused by a large decrease in solubility at that time onto the substrate.

  Therefore, in the electrostatic spray apparatus shown in FIG. 3, the carbon dioxide supplied from the gas cylinder 1 passes through the drying tube 2, the filter 3, and the cooler 4, and is then pressurized by the pressurizing pump 5, thereby preheating the preheater. It passes through 6 and becomes supercritical carbon dioxide. The organic solute is disposed in the solute dissolution cell 81-84, and when the supercritical carbon dioxide passes through the solute dissolution cell 81-84, the solute is in the supercritical carbon dioxide at a predetermined solute dissolution temperature and solute dissolution pressure. Dissolves and becomes a supercritical solute solution phase (solution) (solute dissolution step). A check valve 7 is inserted between the preheater 6 and the solute dissolution cell 81-84, and the preheater 6, check valve 7, solute dissolution cell 81-84, etc. are arranged in the thermostatic chamber 13. .

  Next, the supercritical solute dissolved phase is ejected under atmospheric pressure through a nozzle 10 (length 1 cm, inner diameter 50 μm) heated to a pre-expansion temperature to prevent condensation, and a cluster of gaseous carbon dioxide and solute molecules. Divided into Solute molecule clusters are jetted onto the substrate 11 to form a thin film (jetting step). When performing such an operation, the stop valves V2 to V5 are opened and closed at a predetermined timing, and during that time, the solute dissolution pressure and the solute dissolution temperature (pre-expansion temperature) are monitored by the pressure gauge PI and the thermometer TI, respectively. A back pressure valve 7 is arranged in parallel with the pressurizing pump 5.

  A filter 9 is inserted between the solute dissolution cell 81-84 and the nozzle 10, and the nozzle 10 and the substrate 11 are arranged in the clean booth 14. The substrate 11 is disposed on the hot plate 12 and heated to a predetermined temperature.

〔solvent〕
Next, the solvent used for producing the fine particles according to the present invention will be described in detail.
Examples of the liquid medium for dissolving or dispersing the organic material according to the present invention include halogen-based hydrocarbon solvents such as dichloromethane, dichloroethane, chloroform, tetrachloroethane, trichloroethane, and chlorobenzene, and ether-based solvents such as dibutyl ether and tetrahydrofuran. , Methanol, alcohol solvents such as ethanol, isopropanol, cyclohexanol, aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, paraffin solvents such as hexane, octane, decane, ethyl acetate, butyl acetate, acetic acid Ester solvents such as amyl, amide solvents such as N, N-dimethylformamide, N-methylpyrrolidone, ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, acetonitrile, DMF Solvent DMSO, and the like.
Furthermore, in order to control the particle size, it is preferable to use a solution obtained by mixing two or more solvents having different vapor pressures from the above solvents. Furthermore, in order to control the wettability of the fine particles when the fine particles adhere to the substrate and to improve the uniformity and smoothness of the film thickness, a solution obtained by mixing two or more types of solvents having different surface tensions is used as the solvent. It is preferable to use for.
[Organic materials]
Next, the organic material used for producing the fine particles according to the present invention will be described in detail.
The organic material for forming the organic thin film according to the present invention is largely a polymer or a low molecule.
A low molecule means a weight average molecular weight of 5000 or less, and preferably used as a low molecule is 3000 or less, more preferably 2000 or less. A polymer refers to a polymer larger than 5000.
When applying a low molecular weight material, unlike a high molecular weight material, even if a solvent that does not dissolve the lower layer is used, the low molecular weight, that is, the molecule is small, so the solvent penetrates into the lower layer and the low molecular weight material also penetrates. , Layer mixing is likely to occur, causing performance degradation.

[Organic EL element (Organic electroluminescence element)
Next, the organic electroluminescence element will be described.
An organic electroluminescence element has a structure in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer to recombine excitons. It is an element that emits light by utilizing light emission (fluorescence / phosphorescence) when the exciton is deactivated. Preferred specific examples of the layer structure of the organic EL element are shown below.

(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) Anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) Anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode Here, the light emitting layer preferably contains at least two kinds of light emitting materials having different emission colors, and a single layer or a light emitting layer comprising a plurality of light emitting layers A unit may be formed. The hole transport layer also includes a hole injection layer and an electron blocking layer.

<Light emitting layer>
The light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

  The light emitting layer according to the present invention is not particularly limited in its configuration as long as the contained light emitting material satisfies the above requirements.

  Moreover, there may be a plurality of layers having the same emission spectrum and emission maximum wavelength.

  It is preferable to have a non-light emitting intermediate layer between each light emitting layer.

  The total thickness of the light emitting layers in the present invention is preferably in the range of 1 to 100 nm, and more preferably 30 nm or less because a lower driving voltage can be obtained. In addition, the sum total of the film thickness of the light emitting layer as used in the field of this invention is a film thickness also including the said intermediate | middle layer, when a nonluminous intermediate | middle layer exists between light emitting layers.

  The thickness of each light emitting layer is preferably adjusted to a range of 1 to 50 nm, more preferably adjusted to a range of 1 to 20 nm. There is no particular limitation on the relationship between the film thicknesses of the blue, green and red light emitting layers.

  For the production of the light emitting layer, a light emitting material or a host compound, which will be described later, is formed by forming a film by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, an ink jet method, or the like. it can.

  In the present invention, a plurality of light emitting materials may be mixed in each light emitting layer, and a phosphorescent light emitting material and a fluorescent light emitting material may be mixed and used in the same light emitting layer.

  In the present invention, the structure of the light-emitting layer preferably contains a host compound and a light-emitting material (also referred to as a light-emitting dopant compound) and emits light from the light-emitting material.

  As the host compound contained in the light emitting layer of the organic EL device according to the present invention, a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1 is preferable. More preferably, the phosphorescence quantum yield is less than 0.01. Moreover, it is preferable that the volume ratio in the layer is 50% or more among the compounds contained in a light emitting layer.

  As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of luminescent material mentioned later, and can thereby obtain arbitrary luminescent colors.

  The host compound used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). )But it is good.

  As the known host compound, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable. Here, the glass transition point (Tg) is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).

  Specific examples of known host compounds include compounds described in the following documents. For example, Japanese Patent Application Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860 Gazette, 2002-334787 gazette, 2002-15871 gazette, 2002-334788 gazette, 2002-43056 gazette, 2002-334789 gazette, 2002-75645 gazette, 2002-338579 gazette. No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, No. 2002-231453. No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060. 2002-302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  Next, the light emitting material will be described.

  As the light-emitting material according to the present invention, a fluorescent compound or a phosphorescent material (also referred to as a phosphorescent compound or a phosphorescent compound) is used.

  In the present invention, a phosphorescent material is a compound in which light emission from an excited triplet is observed. Specifically, it is a compound that emits phosphorescence at room temperature (25 ° C.), and the phosphorescence quantum yield is 0 at 25 ° C. A preferred phosphorescence quantum yield is 0.1 or more, although it is defined as 0.01 or more compounds.

  The phosphorescent quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. The phosphorescence quantum yield in a solution can be measured using various solvents. However, when a phosphorescent material is used in the present invention, the phosphorescence quantum yield (0.01 or more) is achieved in any solvent. Just do it.

  There are two types of light emission of the phosphorescent material. In principle, the carrier recombination occurs on the host compound to which the carrier is transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent material. Energy transfer type to obtain light emission from the phosphorescent light emitting material, and another one is that the phosphorescent light emitting material becomes a carrier trap, and recombination of carriers occurs on the phosphorescent light emitting material, and light emission from the phosphorescent light emitting material is obtained. Although it is a trap type, in any case, the excited state energy of the phosphorescent material is required to be lower than the excited state energy of the host compound.

  The phosphorescent light-emitting material can be appropriately selected from known materials used for the light-emitting layer of the organic EL element, and is preferably a complex compound containing a group 8-10 metal in the periodic table of elements. More preferably, an iridium compound, an osmium compound, or a platinum compound (platinum complex compound), or a rare earth complex, and most preferably an iridium compound.

  A fluorescent substance can also be used for the organic electroluminescent element according to the present invention. Representative examples of fluorescent emitters (fluorescent dopants) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes. Examples thereof include dyes, perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

  Conventionally known dopants can also be used in the present invention. For example, International Publication No. 00/70655 pamphlet, JP-A Nos. 2002-280178, 2001-181616, 2002-280179, 2001 181617, 2002-280180, 2001-247859, 2002-299060, 2001-313178, 2002-302671, 2001-345183, 2002. No. 324679, International Publication No. 02/15645, JP 2002-332291 A, 2002-50484, 2002-332292, 2002-83684, JP 2002-540572, JP 2 No. 02-117978, No. 2002-338588, No. 2002-170684, No. 2002-352960, Pamphlet of International Publication No. 01/93642, JP 2002-50483, No. 2002-1000047. No. 2002-173684, No. 2002-359082, No. 2002-17584, No. 2002-363552, No. 2002-184582, No. 2003-7469, No. 2002-525808. JP-A 2003-7471, JP-T 2002-525833, JP-A 2003-31366, JP-A 2002-226495, JP-A 2002-234894, JP-A 2002-2335076, JP-A 2002-24175 Gazette, 2001-319779, 2001-319780, 2002-62824, 2002-1000047, 2002-203679, 2002-343572, 2002-203678. A gazette etc. are mentioned.

  In the present invention, at least one light emitting layer may contain two or more kinds of light emitting materials, and the concentration ratio of the light emitting materials in the light emitting layer may vary in the thickness direction of the light emitting layer.

《Middle layer》
In the present invention, a case where a non-light emitting intermediate layer (also referred to as an undoped region) is provided between the light emitting layers will be described.

  The non-light emitting intermediate layer is a layer provided between the light emitting layers in the case of having a plurality of light emitting layers.

  The film thickness of the non-light emitting intermediate layer is preferably in the range of 1 to 20 nm, and further in the range of 3 to 10 nm suppresses interaction such as energy transfer between adjacent light emitting layers, and the current of the device This is preferable because a large load is not applied to the voltage characteristics.

  The material used for the non-light emitting intermediate layer may be the same as or different from the host compound of the light emitting layer, but may be the same as the host material of at least one of the adjacent light emitting layers. preferable.

  The non-light-emitting intermediate layer may contain a non-light-emitting layer, a compound common to each light-emitting layer (for example, a host compound), and each common host material (where a common host material is used) In the case where the physicochemical characteristics such as phosphorescence emission energy and glass transition point are the same, or the molecular structure of the host compound is the same, etc.) The barrier is reduced, and the effect of easily maintaining the injection balance of holes and electrons even when the voltage (current) is changed can be obtained. Furthermore, by using a host material having the same physical characteristics or the same molecular structure as the host compound contained in each light-emitting layer in the undoped light-emitting layer, device fabrication, which is a major problem in conventional organic EL device fabrication, is achieved. Complexity can also be eliminated.

  When the organic EL device is used in the present invention, since the host material is responsible for carrier transport, a material having carrier transport capability is preferable. Carrier mobility is used as a physical property representing carrier transport ability, but the carrier mobility of an organic material generally depends on the electric field strength. Since a material having a high electric field strength dependency easily breaks the balance between injection and transport of holes and electrons, it is preferable to use a material having a low electric field strength dependency of mobility for the intermediate layer material and the host material.

  On the other hand, in order to optimally adjust the injection balance of holes and electrons, it is also preferable that the non-light emitting intermediate layer functions as a blocking layer described later, that is, a hole blocking layer and an electron blocking layer. It is done.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

<Blocking layer: hole blocking layer, electron blocking layer>
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

  In a broad sense, the hole blocking layer has a function of an electron transport layer and is composed of a hole blocking material having a function of transporting electrons and having a remarkably small ability to transport holes, while transporting electrons. By blocking holes, the recombination probability of electrons and holes can be improved. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed. The hole blocking layer is preferably provided adjacent to the light emitting layer.

  On the other hand, the electron blocking layer, in a broad sense, has a function of a hole transport layer, and is made of a material having a function of transporting holes while having a remarkably small ability to transport electrons, while transporting holes. By blocking electrons, the probability of recombination of electrons and holes can be improved. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and also two of those described in US Pat. No. 5,061,569. Having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8 are linked in a starburst type ( MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, it is preferable to use these materials because a light-emitting element with higher efficiency can be obtained.

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq3), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum. Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metals of these metal complexes are In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. Further, the distyrylpyrazine derivatives exemplified as the material of the light emitting layer can also be used as the electron transport material, and inorganic semiconductors such as n-type-Si and n-type-SiC can be used as well as the hole injection layer and the hole transport layer. It can be used as an electron transport material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

  Further, an electron transport layer having a high n property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be manufactured.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such an electrode material include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, and ZnO. Alternatively, an amorphous material such as In2O3-ZnO capable of forming a transparent conductive film may be used.

  For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.

  Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

"cathode"
As the cathode, a material having a work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al2O3) mixture. , Indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al2O3) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as a cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

  Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

<< Production of organic EL element >>
[Production of Organic EL Element 1]
After patterning a substrate (NH technoglass NA45) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, a substrate provided with this ITO transparent electrode was formed. Ultrasonic cleaning with isopropyl alcohol, drying with dry nitrogen gas, and UV ozone cleaning were performed for 5 minutes. A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water on this substrate was spin-coated at 3000 rpm for 30 seconds. After film formation by the method, the substrate was dried at a substrate surface temperature of 200 ° C. for 1 hour to provide a hole injection layer having a thickness of 30 nm.
This substrate was transferred to a glove box under a nitrogen atmosphere in accordance with JIS B 9920, the measured cleanliness was class 100, the dew point temperature was −80 ° C. or lower, and the oxygen concentration was 0.8 ppm. A coating solution for a hole transport layer was prepared as follows in a glove box, and applied with a spin coater under conditions of 1500 rpm and 30 seconds. This substrate was dried by heating at a substrate surface temperature of 150 ° C. for 30 minutes to provide a hole transport layer. The film thickness was 20 nm when it apply | coated and measured on the conditions with the board | substrate prepared separately.

(Coating liquid for hole transport layer)
Monochlorobenzene 100g
Poly- (N, N′-bis (4-butylphenyl) -N, N′-bis (phenyl) benzidine) (ADS254BE: manufactured by American Die Source) 0.5 g

  Next, the substrate provided up to the hole transport layer was moved without being exposed to the atmosphere, and using the light emitting layer coating solution prepared as follows, using the electrostatic spray device shown in FIG. Applied. The substrate was dried at a substrate surface temperature of 120 ° C. for 10 minutes to provide a light emitting layer. When the coating was performed under the same conditions on a separately prepared substrate and measured, the film thickness was 40 nm. Moreover, the base material apply | coated to the positive hole transport layer separately was prepared, the coating liquid for light emitting layers was apply | coated on the same conditions, and the layer mixing amount and the residual film | membrane solvent amount were evaluated.

(Light emitting layer coating solution)
Butyl acetate 100g
HA 0.1g
DA 0.011g
D-B 0.0002g
D-C 0.0002g

The organic materials HA, DA, DB, and DC represent the following compounds.

Next, without exposing the substrate provided up to the light emitting layer to the atmosphere, the electron transport layer coating solution prepared as follows was applied under the conditions shown in Table 1 using the electrostatic spray device shown in FIG. However, only the electric field guard ring between the nozzle and the substrate was applied. Further, the substrate was heated and dried at 120 ° C. for 30 minutes to provide an electron transport layer. The film thickness was 30 nm when it applied and measured on the conditions prepared with the board | substrate prepared separately.
(Coating liquid for electron transport layer)
2,2,3,3-tetrafluoro-1-propanol 100 g
ET-A 0.75g

The organic material ET-A represents the following compound.

但し、条件１−５は、順に実施例に係る有機ＥＬ素子１−４、比較例に係る有機ＥＬ素子５の条件である。

However, the condition 1-5 is a condition of the organic EL element 1-4 according to the example and the organic EL element 5 according to the comparative example in order.

Next, the substrate provided up to the electron transport layer was moved to a vapor deposition machine without being exposed to the atmosphere, and the pressure was reduced to 4 × 10 −4 Pa. Note that potassium fluoride and aluminum were each placed in a tantalum resistance heating boat and attached to a vapor deposition machine.
First, a resistance heating boat containing potassium fluoride was energized and heated to provide 3 nm of an electron injection layer made of potassium fluoride on the substrate. Subsequently, a resistance heating boat containing aluminum was energized and heated, and a cathode having a film thickness of 100 nm made of aluminum was provided at a deposition rate of 1 to 2 nm / second.
The substrate provided up to the cathode is moved to a glove box with a cleanness measured in accordance with JIS B9920 of class 100, a dew point temperature of -80 ° C. or less, and an oxygen concentration of 0.8 ppm without being exposed to the atmosphere. The organic EL element 101 was obtained by sealing with a glass sealing can attached with barium oxide as a water-absorbing agent. Barium oxide, a water-absorbing agent, is a high-purity barium oxide powder manufactured by Aldrich, and is attached to a glass sealing can with a fluorine-based semipermeable membrane (Microtex S-NTF8031Q manufactured by Nitto Denko) with an adhesive. Were prepared and used in advance. For the adhesion between the sealing can and the organic EL element, an ultraviolet curable adhesive was used, and both were adhered and sealed by irradiating with ultraviolet rays to produce the organic EL element 1.

[Production of Organic EL Element 2]
An organic EL element 2 was produced in the same manner as the organic EL element 1 except that an electric field guard ring was further installed on the nozzle opening. In addition, the applied voltage to each electric field guard ring, electrostatic spray nozzle, and base material at this time is an electric field guard ring on nozzle> electrostatic spray nozzle> nozzle-substrate electric field guard when the applied voltage is a positive pole. It was applied so that the ring> the substrate. Further, when the applied voltage was a negative pole, application was performed such that the electric field guard ring on the nozzle <electrostatic spray nozzle <the electric field guard ring between the nozzle and the substrate <substrate.

[Production of Organic EL Element 3]
An organic EL element 3 was produced in the same manner as the organic EL element 1 except that an elliptical magnetic field guard ring was installed instead of the rectangular electric field guard ring, which was the condition for producing the organic EL element 1.

[Production of Organic EL Element 4]
The base material apply | coated to the positive hole transport layer similarly to the organic EL element 1 was prepared. Furthermore, the light emitting layer was apply | coated by the method as described below from the base material.
An electrostatic spray apparatus shown in FIG. 3 was used as a coating apparatus to form a film. In addition, when it apply | coated and measured on the conditions with the board | substrate prepared separately, the film thickness was 40 nm. Moreover, the base material apply | coated to the positive hole transport layer separately was prepared, the coating liquid for light emitting layers was apply | coated on the same conditions, and the layer mixing amount and the residual film | membrane solvent amount were evaluated.
As shown in FIG. 3, four solute dissolution cells 81-84 were provided, and the solutes described below were placed in the respective solute dissolution cells 81-84.
Solute dissolution cell 81 H-A
Solute dissolution cell 82 DA
Solute dissolution cell 83 DB
Solute dissolution cell 84 DC
Moreover, CO2 was used as a supercritical fluid.
In addition, the weight concentration of each material was adjusted so that it might become the following ratio.
HA: DA = 1: 0.11
H-A: D-B = 1: 0.002
H-A: D-C = 1: 0.002

[Production of Organic EL Element 5 (Comparative Example)]
An organic EL element 5 was produced in the same manner as the organic EL element 1 except that a circular electric field guard ring was installed instead of the rectangular electric field guard ring which was the condition for producing the organic EL element 1.

<Evaluation>
Evaluation of the Example (organic EL element 1-4) produced as mentioned above and the comparative example (organic EL element 5) is disclosed. The main points of the evaluation results of each evaluation item are summarized in Table 2.

(1) In-plane uniformity [Measurement of in-plane brightness uniformity and in-plane chromaticity distribution]
When each organic EL element is driven at 5 V using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing), luminance and chromaticity are measured in a mesh form at intervals of 5 mm from the position of 5 mm from the end of the light emitting region. The luminance uniformity and chromaticity distribution were determined by the following formula.
Luminance uniformity = Lmin / Lmax × 100
Lmax: Maximum value of measured luminance.
Lmin: the minimum value of the measured luminance.
In Table 2, the obtained calculation results are shown in the following ranks.
○: Luminance uniformity ≧ 85%, very small variation in luminance, which is very preferable.
X: 85%> Brightness uniformity, luminance varies.

(2) Lifetime A current that gives a front luminance of 1000 cd / m @ 2 was applied to the produced organic EL device, and the device was continuously driven. The time it takes for the front luminance to reach the initial half value (500 cd / m 2) is obtained, and the light emission lifetime of the organic EL elements 1 to 4 is defined as 100 when the measured value of the organic EL element 4 (comparative) is used. Evaluation was made by EL life of each element) / (life of organic EL element 1). In Table 2, the obtained calculation results are shown in the following ranks.
○: 1 <lifetime
×: Life ≤ 1

(3) Layer Mixing Amount The layer mixing amount was measured by the following method using a scanning X-ray photoelectron spectrometer (PHI 5000) manufactured by ULVAC-PHI.
1) Under various conditions, first, only a light emitting layer is formed to a thickness of 40 nm on a glass substrate.
2) After film formation, sputtering is performed using PHI-5000 until the Glass component is detected by Ar gas cluster ions. The sputtering time t at that time is obtained.
Thereby, the film thickness can be estimated from the sputtering time.
3) A light emitting layer is formed under the same conditions as 1 on the substrate formed up to the hole transport layer.
4) Sputtering is performed in the same manner as 2). At this time, the hole transport layer is sputtered for a sputtering time t or longer.
5) If the amount of Ir contained in the light-emitting transport layer and not contained in the hole-transport material in the hole transport layer is seen, the layer mixing amount can be grasped.
If the depth is sputtered until Ir disappears, the film thickness of the layer mixture can be estimated from the sputtering time.
In addition, the layer mixing amount was ranked as follows.
○: Layer mixing amount of light emitting layer and hole transport layer <3 nm
×: 3 nm ≦ layer mixing amount of light emitting layer and hole transport layer

(4) Adhesion efficiency The adhesion efficiency represents the ratio between the mist amount W applied from the nozzle and the mist amount Wt adhering to the substrate, and is expressed as follows.
Adhesion efficiency = Wt / W x 100%
The mist amount Wt adhering to the base material is determined from the solid content concentration of the liquid and the average film thickness d (measured at intervals of 10 mm) at 81 locations of the film adhering to the 100 mm × 100 mm × 1.1 t glass base material. Calculated from the following equation:
* Weight of adhered film (g) = 10 × 10 × d (cm) × solid content density (g / cm 3)
Wt = weight of adhered film (g) / solid concentration of liquid (%) × 100
W = time the nozzle was on the substrate (min) × mist generation amount (g / min)
In Table 2, the obtained calculation results are shown in the following ranks.
○: Adhesion efficiency> 85%
Δ: 60% <Adhesion efficiency ≦ 85%
×: Adhesion efficiency ≦ 60%

(5) Residual solvent amount Here, the measurement of the residual solvent rate which concerns on this invention is shown below. A headspace type gas chromatographic determination method is used.
The headspace type gas chromatograph used as a method for quantifying the residual solvent contained in the organic layer of the organic EL device of the present invention uses a detection method such as an internal standard method used in a normal gas chromatograph. To measure.
In the headspace type gas chromatograph quantitative method, the organic EL element is sealed in an open / closed container, heated, and immediately filled with residual solvent (organic solvent and / or water, etc.) in the container. Gas is injected into the gas chromatograph to measure the amount of residual solvent, and MS (mass spectrometry) is also performed.

Hereinafter, the measurement method using the head space type gas chromatograph used in this example will be described in detail.
<Headspace gas chromatograph measurement method>
1. Sample collection Sample organic EL elements in a 20 ml headspace vial. The sample amount is weighed to 0.01 g (necessary for calculating the area per unit mass). Seal the vial with a septum using a dedicated crimper.
2. Heating the sample Place the sample in a 170 ° C constant temperature bath and heat for 30 minutes.
3. Setting of gas chromatographic separation conditions A column coated with silicon oil SE-30 so as to have a mass ratio of 15% and packed in a column having an inner diameter of 3 mm and a length of 3 m is used as a separation column. The separation column is attached to a gas chromatograph, and He is used as a carrier to flow at 50 ml / min.
The temperature of the separation column is set to 40 ° C., and measurement is performed while the temperature is increased to 260 ° C. at a temperature increase rate of 15 ° C./min. Hold for 5 minutes after reaching 260 ° C.
4). Introduction of sample The vial bottle is taken out from the thermostatic chamber, immediately 1 ml of gas generated from the sample is collected with a gas tight syringe, and this is injected into the separation column.
5. Calculation A calibration curve is prepared in advance using the aromatic hydrocarbon compound used as the internal reference material, and the concentration of each component is determined.
6). Equipment (1) Headspace conditions Headspace device HP 769 “Head Space Sampler” manufactured by Hewlett-Packard Company
Temperature conditions Transfer line: 200 ° C
Loop temperature: 200 ° C
Sample amount: 0.8 g / 20 ml vial (2) GC / MS conditions GC: HP5890 manufactured by Hewlett-Packard Company
MS: HP5971 manufactured by Hewlett-Packard Company
Column: HP-624 30m x 0.25mm
Oven temperature: 40 ° C (3 minutes)-15 ° C / min-260 ° C
Measurement mode: SIM
In Table 2, the obtained calculation results are shown in the following ranks.
○: Residual solvent amount <1 wt%
Δ: 1 wt% ≦ residual solvent amount <5 wt%
×: 5 wt% ≦ residual solvent amount

  INDUSTRIAL APPLICATION This invention can be utilized for manufacture of organic thin films, such as an organic electroluminescent (EL) element and an organic thin film solar cell.

DESCRIPTION OF SYMBOLS 10 Nozzle 11 Base material 15 Voltage application means 16 Voltage application means 17 Voltage application means 20 Aerosol 21 Fine particle 22 Adhesion range 23 Electrode member (electric field guard ring)
24 Electrode member (electric field guard ring)

Claims (11)

A nozzle for discharging an aerosol in which fine particles containing an organic material are dispersed;
Voltage application means for applying a voltage to the nozzle and charging the fine particles;
A substrate holding means for holding the substrate at ground or at a potential opposite to that of the fine particles, and attracting and depositing the fine particles discharged from the nozzle by electrostatic attraction to deposit the organic thin film on the substrate. In an electrostatic spray device that forms a film on a material,
An electrode part for controlling the flying of the fine particles by affecting the electric field of the flying space of the fine particles or a magnetic pole part for controlling the flying of the fine particles by affecting the magnetic field of the flying space of the fine particles, And between the base material and
By controlling the electrode part or the magnetic pole part, the flying range of the fine particles is made larger in one direction on a plane parallel to the base material than in the other direction on the same plane orthogonal to the base material. Spray device. The relationship between the applied voltage of the nozzle, the electrode part or the magnetic pole part, and the base material,
When the voltage applied by the voltage application means is positive, nozzle> the electrode part or magnetic pole part> base material,
The electrostatic spray device according to claim 1, wherein when the voltage applied by the voltage application unit is negative, base material> the electrode part or magnetic pole part> nozzle. Comprising the electrode part, the electrode part is composed of a frame-like electrode member disposed so as to surround the central axis of the nozzle;
The electrostatic spray device according to claim 1, wherein an opposing interval in the one direction of the electrode member is made larger than an opposing interval in the other direction. Comprising the magnetic pole part, the magnetic pole part is composed of a coil arranged so as to surround the central axis of the nozzle,
The electrostatic spray device according to claim 1, wherein the facing interval in the one direction of the coil is made larger than the facing interval in the other direction.   Above the discharge port of the nozzle, it influences the electric field of the flying space of the fine particles to control the flying of the fine particles or influences the magnetic field of the flying space of the fine particles to control the flying of the fine particles. The electrostatic spray device according to claim 1, further comprising a magnetic pole portion.   The potential difference between the electrode part or magnetic pole part above the nozzle outlet and the base material is the difference between the electrode part or magnetic pole part between the nozzle outlet and the base material and the base material. The electrostatic spray apparatus according to claim 5, wherein the electrostatic spray apparatus is larger than a potential difference therebetween. The relationship between the applied voltage of the nozzle, the electrode part or the magnetic pole part, and the base material,
When the voltage applied by the voltage applying means is positive, the electrode part or magnetic pole part above the nozzle discharge port>nozzle> the electrode part or magnetic pole part between the nozzle discharge port and the substrate> As a base material,
When the voltage applied by the voltage application means is negative, the base material> the electrode part or magnetic pole part between the nozzle outlet and the base material>nozzle> the electrode part above the nozzle outlet or The electrostatic spray device according to claim 6, wherein the electrostatic spray device is a magnetic pole portion. Comprising the magnetic pole part, the magnetic pole part is composed of a plurality of magnets arranged away from the central axis of the nozzle,
The electrostatic spray device according to claim 1, wherein the facing interval in the one direction of the plurality of magnets is larger than the facing interval in the other direction.   The electrostatic spray apparatus according to claim 1, wherein the base material is a belt-like base material.   The electrostatic spray apparatus according to any one of claims 1 to 9, wherein the organic thin film is an organic thin film of an organic electroluminescence element.   The electrostatic spray apparatus according to claim 10, wherein the organic thin film of the organic electroluminescence element is a light emitting layer.

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