JPH03157162A - Production of organic thin film - Google Patents

Abstract

PURPOSE:To form a clean org. thin film having superior molecule orienting property and crystallinity by forming an org. thin film whose average thickness exceeds the thickness of a monomolecular film at the interface between vapor and liq. phases and transferring the thin film onto a solid substrate. CONSTITUTION:An org. substance forming a thin film is dissolved in a proper solvent to prepare a soln. This soln. is dropped on the interface between vapor and liq. phases or liq. and liq. phases enclosed with a barrier by an amt. required to form an org. thin film of a desired thickness or a monomolecular film is formed on the interface, the soln. is developed from the liq. phase at a proper temp. and the org. substance is diffused in the liq. phase or incorporated into the liq. phase to form an org. thin film at the interface. The resulting org. thin film is transferred onto a solid substrate by a horizontal sticking method.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to a method for producing an organic thin film, and is particularly suitable for producing an organic thin film with excellent crystallinity, and is suitable for producing an organic thin film with excellent crystallinity, and is suitable for producing an organic thin film formed at the interface between a gas phase and a liquid phase or at an interface between a liquid phase. The present invention relates to a method for producing an organic thin film, which is produced by transferring the obtained organic thin film onto a solid substrate. [Prior Art] In recent years, attempts have been made to utilize organic substances as conductive materials, chromic materials, photoelectric conversion materials, nonlinear optical materials, optical recording materials, etc., but the success or failure of these attempts depends on the The organic material is a film with good molecular orientation (
It is no exaggeration to say that it depends on whether or not it can be stably and easily supplied as a film in which molecules are oriented in a specific direction. Many methods for producing organic thin films are known, but a method for producing organic thin films by forming a monomolecular film on a gas-liquid interface and transferring it onto a solid board was developed by Langmuir-Blodgett. It is generally well known as the LB method. For more information on the LB method, see Chemistry Review No. 40. Discussed on pages 82 to 104 of "Molecular Assemblies - Their Organization and Function", Reports of the Chemical Society of Japan, Society Publishing Center (published on May 25, 1988). When producing an organic thin film using the LB method, a monomolecular film made of the organic molecules is formed on the gas-liquid interface, and a solid substrate such as glass is poured perpendicularly to the water surface using the so-called vertical immersion method.
The method used was to transfer a monomolecular film onto a substrate to create an organic thin film with a thickness of several tens of nanometers.

[Problem to be solved by the invention 1] When an organic thin film is produced by the conventional LB method, even if the monomolecular film itself has good crystallinity, the thin film formed by accumulating the monomolecular films is formed without correlation between each molecular layer. Since the thin film was a laminate of monomolecular films, the molecular orientation and crystallinity of the thin film as a whole were not good. Moreover, each time a monomolecular film is accumulated, the organic molecules are exposed to the air for a long period of time, making it difficult to keep the thin film surface (which becomes the molecular layer interface after thin film formation) in a clean state. It may also react with oxygen. In addition, the LB method has problems in terms of workability, and as the number of cumulative layers (film thickness) increases, it takes proportionally more time to manufacture, so it is limited to use in areas where the film thickness is thin. There was a problem with being exposed. In other words, this has been an obstacle when attempting to apply organic materials on an industrial scale. An object of the present invention is to produce a clean organic thin film with excellent molecular orientation and crystallinity. Another object of the present invention is to improve the workability of producing an organic thin film at the gas-liquid interface. [Means for solving the problem 1] The above purpose is to form an organic thin film with an average film thickness exceeding a monomolecular film thickness at the interface between the gas phase and the liquid phase or at the interface between the liquid phases, and then transfer it onto a solid substrate. This is achieved by taking and preparing. More specifically, this is achieved by developing an organic substance from a gas phase or liquid phase, or by incorporating an organic substance into the liquid phase. Suitable organic substances are those used as materials for LB films. Typical examples include diacetylene derivatives, phthalocyanine derivatives, fatty acids such as stearic acid, alcohols and esters, and pigments such as merocyanine and hemicyanine. Diacetylene derivatives are particularly effective, examples include hydrocarbons such as 2,4-hexadiyne, 2,4-hexadiyne-1
Alcohols such as ゜6-diol and 3,5-octadiyn-1,8-diol, and carboxylic acids, sulfonic acids, and carbamate esters of these alcohol compounds, 1,6-di(N-carbazoyl)-2 , 4-hexadiyne, heterocyclic compounds such as 1,4-dipyridyl-1,3-butadiyne, acids such as 1,3-butadiyne-carboxylic acid, and their esters, amides, and salts. . Two or more of these organic substances can be used in combination, if necessary. As an organic molecule with particularly good orientation, there is butoxycarbonylmethylurethane-based polydiacetylene which is soluble in organic solvents. After forming this monomolecular film at the interface between the gas phase and the liquid phase or the interface between the liquid phases, a highly oriented organic thin film is created by developing an organic substance (other types of organic molecules are also acceptable) from the liquid phase. It is also possible to create one. Furthermore, by forming an interface between liquid phases such as water and xylene and mixing different organic substances into each liquid phase, a heterofilm can be produced at the interface. (Action 1: Dissolve the organic substance used to make the thin film in an appropriate solvent to make it into a solution. Form an organic thin film with a desired thickness at the interface between the gas phase and the liquid phase or between the liquid phases surrounded by a barrier. Alternatively, after forming a monomolecular film on the interface, the solution is developed in the liquid phase at an appropriate temperature to diffuse the organic substance in the liquid phase. An organic thin film is formed at the interface by incorporating an organic substance into the material.Finally, the organic thin film is transferred onto a solid substrate by a horizontal deposition method.In particular, as an organic substance with excellent crystallinity, chemical formula Polydiacetylene derivatives represented by the formula %) can be mentioned. In it, the side chain substituents R, R' are R, R"" (
Hz)-0CONHCHzC○○C4He, n=3
A polydiacetylene compound containing a urethane moiety shown in the side chain, that is, P-3 butoxycarbonylmethyl urethane (butoxycarbonylmethylurethane)
rethane: BCMU) and p”iBCMU (
n=4). These can form a highly oriented monomolecular film at the interface, and by developing organic molecules from the liquid phase and diffusing the organic molecules in the liquid phase,
A highly oriented multilayer film can be formed at the interface. It is also possible to use two or more types of organic substances in combination, and it is also possible to form a thin film by mixing different molecules, or to create a heterofilm by separately supplying different molecules at the interface. Thereby, a hetero film can also be produced more efficiently than before. Furthermore, if necessary, heat treatment is performed at the interface to impart vibration to the interface in order to make the thickness of the thin film uniform, or to increase the orientation of molecules. In the case of polymerizable molecules, the molecules are polymerized by irradiation with ultraviolet rays or by an electric field. In this way, an organic thin film exceeding the thickness of a monomolecular film is formed at the interface. By transferring this onto a similar substrate such as glass, the molecular orientation is better than that of the LB film. Obtain an organic thin film with excellent crystallinity. Moreover, the time and area that organic molecules are exposed to the air is minimal.
It is possible to keep the thin film clean. [Example J] Hereinafter, the present invention will be explained in detail with reference to Examples. (Example 1) Polydiacetylene was used as the material for the organic thin film. As the apparatus for producing the organic thin film, the same one used for producing the LB film on a boat was used as it was. All experiments were conducted in a clean room. Also, heptacosa 10.12 diacetylene derivative (heptac), which is a monomer film-forming molecule,
osa-10,12-diynoid acid)CH
,(CH,),, -C≡C-(,EC-(CH2),C
0OH benzene solution (concentration 2.28 x 10-3M
'I got it. ' M (1) Li OH was made into an aqueous solution. Above the water surface of approximately ``loam'' surrounded by a Teflon barrier,
A solution of diacetylene in benzene was added dropwise. Applying ultrasonic vibration was effective in keeping the film thickness constant when a large amount was dropped. After the benzene evaporates, the temperature of the gas phase is adjusted to about 50°C to increase the orientation of diacetylene molecules.
heat treatment was performed at the gas-liquid interface for 10 minutes. Next, the diacetylene molecules were subjected to in-phase polymerization by irradiation with ultraviolet rays generated from an ultra-high pressure mercury lamp (200 W) for 30 minutes. In this way, a polydiacetylene thin film was obtained at the gas-liquid interface (although polymerization may also be performed on the substrate). Hexamethyldisilazane (hexamethyldisilazane), a chemisorbent silane-based coupling material
ne:hereinafter referred to as HMDS) (C:H3)aSiN)TSi(CH2)3 was adsorbed onto a glass substrate and subjected to hydrophobization treatment, and then the polydiacetylene thin film formed at the gas-liquid interface was transferred onto the glass substrate using a horizontal deposition method. I took it. The produced polydiacetylene thin film had a thickness of about 300 nm and had a domain structure, but it was determined by spectrophotometer that it had a domain structure.
As a result of measuring the color ratio (the ratio of the absorbance in the main chain direction of polydiacetylene to the absorbance in the direction perpendicular to it), the dichroic ratio was 10 or more within one domain. The measurement results are shown in FIG. The area of the entire sample is 2×2c×2. When a polydiacetylene thin film is produced by a conventional method, the orientation of the molecules is not good because the direction of the main chain shifts each time a monomolecular film is accumulated. However, according to the present invention, although it has a domain structure, the main chains of each molecular layer are oriented in the same direction within one domain, making it possible to form a thin film with excellent crystallinity. . (Example 2) Polydiacetylene
) derivative, P-3BCMU = [CR-(, EC-CR'). = (R,R'=-(CH,)30CONHCH2COOC
An example of fabricating a highly oriented film of 4H, ) will be described. p
-4CMU (R,R'=-(CH,)40CONHCH,C00C
4H9) was carried out in the same manner, but since the production method is almost the same, p-3BCMU will be specifically described below. p-3BCMU was dissolved in chloroform (chloroform).
:CHCl3) and adjusted to 0.5 g/Q, and an amount in excess of that needed to form a monomolecular film was dropped onto the air-water interface in an area of about 10 cm2 surrounded by a barrier. Ultrapure water (resistivity: about 17 MΩcI11) is used as the aqueous phase, and the temperature is room temperature. Move the barrier in two opposite directions,
By repeatedly expanding and narrowing the area of the thin film, the main chains of polydiacetylene were oriented in a direction perpendicular to the direction of barrier movement. As in Example 1, after HMDS was adsorbed onto a glass substrate and subjected to hydrophobic treatment, the thin film of p-3BCMU formed at the gas-liquid interface was transferred onto the glass substrate by the horizontal deposition method. The characteristics of the highly oriented polydiacetylene thin film produced are that the film thickness is approximately 500 mm, and the dichroic ratio (measured with a spectrophotometer) is approximately 5. The area of the entire thin film is 2 x 2 cm2, and the melting point is 1
It was thermally stable up to 70°C (in the case of p-4BCMU, it was thermally stable up to a melting point of 115°C). When an organic thin film was produced using p-3BCMU as described above, it was possible to produce a highly oriented film without a domain structure. In addition, in this method, by reducing the area of the gas-liquid interface to 1 cm2 or less, p-3BC
It was also possible to produce single crystals of MU. (Example 3) The same P-3BCM as in Example 2 was produced by development from the liquid phase.
An example of producing a highly oriented U film will be described. p-4B
The same procedure was performed for CMU, but since the manufacturing method is almost the same, p-3BCMU will be specifically described below. p-3BCMU was dissolved in chloroform (chloroform).
:CHCl3) and adjusted to 0.5 g/Q,
By dropping it on the air-water interface, a thick molecular film was created on the water surface. Ultrapure water is used as the aqueous phase, and the temperature is room temperature. Compression speed: 100cm to prevent the monomolecular film on the water surface from being destroyed
/win, the membrane was compressed from two opposing directions by a barrier to a surface pressure of 20 mN#++. At this time, the main chain of polydiacetylene was oriented in a direction perpendicular to the compression direction. Next, an acetone solution of 3BCMU monomer was pipetted under the monomolecular film formed on the gas-liquid interface, that is, into the water. Diacetylene molecules diffused through the water and attached to the monomolecular film at the air-water interface. When the area of the monomolecular film was large, increasing the water temperature facilitated the diffusion of diacetylene molecules. After a multilayer film of diacetylene molecules is formed at the air-water interface,
By irradiating it with ultraviolet rays generated from an ultra-high pressure mercury lamp for 30 minutes,
A polydiacetylene thin film was obtained by in-phase polymerization of diacetylene molecules (although polymerization may be performed on the substrate). As in Example 1, after HMDS was adsorbed onto a glass substrate and subjected to hydrophobic treatment, the thin film of p-3BCMU formed at the air-water interface was transferred onto the glass substrate by the horizontal deposition method. The characteristics of the highly oriented polydiacetylene thin film produced are that the film thickness is approximately 150 mm, and the dichroic ratio is approximately 10. The area of the entire thin film is 2χ
2 cm2, and was thermally stable up to the melting point of 170°C. When an organic thin film was produced as described above using P-3BCMU, it was possible to produce a highly oriented film without a domain structure. (Example 4) An example will be described in which a thin film (heterofilm) made of different organic substances was produced at the interface between liquid phases. Ultrapure water and xylene were added to the water tank for LB film production.
e) and filled it up. In the water tank, water and xylene do not mix, but form a xylene phase in the upper part and an aqueous phase in the lower part, and they separate to form an interface. Figure @2 shows the state during fabrication. 3-alkylpyrrole was mixed into the xylene phase at a concentration of 0.1M, and the aqueous phase was mixed with 0.8M sodium p-toluenesulfonate (sodium ρ-t).
oluene 5ulfonate: TsONa)
melted. A voltage of approximately 10 V was applied for several hours using a PT electrode provided in the water tank. A thin film of polypyrrole was formed at the interface by electric field polymerization. Next, the diacetylene monomer CH3(CH2)□, -C=C-C≡C-(CH,),
A solution of C0OH in acetone was developed by pipetting it under the polypyrrole thin film, ie into the aqueous phase. Diacetylene molecules diffused through the water and attached to the polypyrrole thin film at the interface. After a heterofilm was formed at the water/xylene interface, ultraviolet rays were irradiated for 30 minutes to cause in-phase polymerization of diacetylene molecules, thereby obtaining a polydiacetylene thin film. By holding the glass substrate horizontally and pushing it into the liquid,
The thin film was transferred onto a substrate. Finally, a polydiacetylene/polypyrrole heterolayer was formed on the glass substrate. (Example 5) The third-order nonlinear optical properties of the polydiacetylene thin film produced in Example 1 with a film thickness of approximately 300 mm and a dichroic ratio of IO were evaluated. The experiment was conducted using a Q-switch Nd3'':Y for the above thin film.
AG laser wavelength 11064n, 10pps, number 10
Irradiates the fundamental wave of mJ/pulse with a wavelength of 355 nm.
The intensity of the third harmonic is measured using an optical multichannel detector (Optical Multichannel D
The third-order nonlinear optical constant χ3 of polydiacetylene was evaluated by detecting with a detector (hereinafter referred to as OMD). The incident light beam (φ~1011111) of the laser was linearly polarized light and was focused on the sample by a lens. The fundamental wave is removed by an infrared cut filter.1. The harmonics generated from the sample are collected using a polychromator.
The experimental system uses spectroscopy using r) and detection using OMD. Maker Fringe
) method, χff77 in the direction parallel to the main chain of polydiacetylene is approximately I
, which was more than 10 times larger than χ3□ in the direction perpendicular to the main chain. Similar results were obtained for the polydiacetylene thin films prepared in Examples 2.3 and 4. Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to these embodiments, and other diacetylene derivatives, fatty acids, dyes, etc. Applies to those adopted. Effects of the Invention According to the present invention, a clean organic thin film with excellent molecular orientation and crystallinity can be produced. Moreover, the workability of producing an organic thin film at the gas-liquid interface can be improved.

[Brief explanation of the drawing]

FIG. 1 is a spectrum diagram of a polydiacetylene alignment film produced according to one embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a method for producing an organic thin film according to another embodiment of the present invention.

Claims (1)

[Claims] 1. After forming an organic thin film with an average film thickness exceeding a monomolecular film thickness at the interface between a gas phase and a liquid phase or an interface between liquid phases, the organic substance thin film is transferred onto the same substrate. A method for producing an organic thin film, characterized by the step of removing the organic thin film. 2. The method for producing an organic thin film according to claim 1, wherein the method for forming an organic thin film whose average thickness exceeds the monolayer thickness is a method of spreading an organic substance on the interface. . 3. A patent claim characterized in that the method for forming an organic thin film with an average film thickness exceeding a monomolecular film thickness is a method of developing an organic substance from a liquid phase or a method of incorporating an organic substance into a liquid phase. A method for producing an organic thin film according to item 1. 4. The organic thin film according to claim 1, wherein the method for forming an organic thin film having an average film thickness exceeding a monomolecular film thickness is a method by compressing an organic substance developed at the interface. Method for producing thin films. 5. The method for producing an organic thin film according to claim 1, wherein the method for forming an organic thin film having an average film thickness exceeding a monomolecular film thickness is a method of vibrating the interface. 6. The method for producing an organic thin film according to claim 1, wherein the organic thin film formed at the interface is a polymerizable organic compound. 7. The method for producing an organic thin film according to claim 6, wherein the organic thin film formed at the interface is a diacetylene derivative. 8. The organic thin film formed on the interface has the general formula CH_3(CH_2)_l-C≡C-C≡C-(CH_
2) The method for producing an organic thin film according to claim 7, wherein the organic thin film is a diacetylene derivative represented by _kCOOH (where l and k are integers of 1 to 18). 9. The organic thin film formed on the interface has the general formula = [CR-C≡C-CR']_a= (wherein R and R' are -(CH_2)_iOCONHC
H_2COO(CH_2)_jCH_3, i, j are 1~
12) The method for producing an organic thin film according to claim 1, wherein the organic thin film is a polydiacetylene derivative represented by: 10. The method for producing an organic thin film according to claim 6, characterized in that the organic thin film formed on the interface is polymerized on the interface or on the solid substrate. 11. A method for forming a film made of a polydiacetylene derivative is
A polydiacetylene compound represented by the general formula below is spread in the form of a monomolecular film on the interface partitioned by a barrier, the monomolecular film is compressed by the barrier from one direction or two opposing directions, and then a liquid By developing organic substances from the phase,
Alternatively, the method is characterized in that by incorporating an organic substance into the liquid phase, an organic thin film having an average thickness exceeding the monomolecular film thickness is formed at the interface, and the organic thin film is transferred onto a solid substrate. A method for producing an organic thin film according to claim 1. =[CR-C≡C-CR']_n= (wherein, R and R' are -(CH_2)_iOCONHC
H_2COO(CH_2)_jCH_3, i, j are 1~
12. The method for producing an organic thin film according to claim 1, wherein the organic thin film formed at the interface is a hetero film. 13. The method for producing an organic thin film according to claim 1, wherein the temperature of the organic thin film formed at the interface is raised to 20° C. or higher. 14. The method for producing an organic thin film according to claim 1, wherein the organic thin film has nonlinear optical properties.