JP2000256100A - Method for formation of organic optical single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for the formation of a large-size org. optical single crystal having excellent crystallinity and to provide the org. optical single crystal. SOLUTION: Grooves 3 having preferably 0.5 to 2 mm opening width r, preferably 0.5 to 2 mm depth d and preferably 5 to 20 mm pitch P are formed on the principal plane 2A of a 'Teflon(R)' plate 2. The principal plane 2A where the grooves 3 are formed is tilted by preferably 20 to 50 deg. tilt angle θ. Then fine crystals of an org. substance are grown by spontaneous nucleation on the principal plane 2A of the plate 2 to form org. optical single crystals in the grooves 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for forming an organic optical single crystal and an organic optical single crystal.
The present invention relates to a method for forming an organic optical single crystal and an organic optical single crystal that can be suitably used for electronic components such as a wavelength conversion device for communication wavelength band infrared light, a measurement probe of an ultra-high speed IC, and an electric field sensor.

[0002]

2. Description of the Related Art 4-Dimethylamino-N-methyl-4-
Stilbazolium tosylate (4-dimethylamino-N-meth
yl-4-stilbazolium tosylate (hereinafter sometimes abbreviated as DAST) Single crystals exhibit large non-linearity, and can be applied to electronic components such as wavelength conversion devices for communication wavelength band infrared light and measurement probes for ultra-high-speed ICs. Expected. Typical methods for forming such an organic optical single crystal include a natural nucleus growth method and a seed crystal growth method.

The formation of an organic optical single crystal by the natural nucleus growth method is performed as follows. First, an organic substance constituting an organic optical single crystal is dissolved in methanol or the like, and a nucleus growth substance is immersed in this solution. Next, the temperature of the solution is lowered so that the organic matter becomes supersaturated. Then, an organic substance precipitates and grows on the nucleus growth substance, and an organic optical single crystal is obtained. On the other hand, the seed crystal growth method uses the organic optical single crystal obtained by the natural nucleus growth method as a seed crystal, and after bonding the seed crystal to the seed rod tip,
The solution is put into a saturated solution and the temperature is lowered to increase the size of the seed crystal and further grow the seed crystal to obtain a large organic optical single crystal. Therefore,
Large DAST that can be used for the above electronic components
In order to obtain a single crystal, it was necessary to use a seed crystal growth method.

[0004]

The natural nucleus growth method can form a single crystal having high crystallinity, but has a problem that it is difficult to control the nucleus generation position. For this reason, when the crystals generated in the vicinity of the growth process adhere to each other and become polycrystalline, or when the crystal grows with the (001) plane in contact with the bottom of the growth container, a large stress is applied inside the crystal and crystal defects are generated. Or occurred. Since the seed crystal growth method grows a single crystal using the single crystal obtained by the natural nucleus growth method as a seed crystal, the defect of the crystal obtained by the natural nucleus growth method is directly inherited. Strong tendency. Therefore, the finally obtained DA
In many cases, ST crystals are polycrystallized or have many crystal defects incorporated therein, and large D
It was extremely difficult to obtain an AST single crystal.

An object of the present invention is to provide a method for forming a large organic optical single crystal having excellent crystallinity and an organic optical single crystal thereof.

[0006]

According to the present invention, at least one groove is formed in a main surface of a member made of Teflon, the main surface of the member is inclined, and an organic substance is naturally nucleated on the main surface of the member. A method for forming an organic optical single crystal, comprising growing the organic material and forming a single crystal of the organic substance in a groove formed on a main surface of the member.

FIG. 1 is a view for explaining a process of growing an organic optical single crystal according to the formation method of the present invention. In FIG. 1, a wedge-shaped groove 3 is formed in a main surface 2A of a Teflon plate 2. And an acrylic triangular prism base 1
The slope 1A having the inclination angle θ of the pedestal and the plate 2
The main surface 2A of the plate 2 is inclined by an angle θ by bonding the back surface 2B of the plate 2 with an adhesive.

The nucleus growth substance 10 having such a form is immersed in a solution in which an organic substance constituting an organic optical single crystal is dissolved, and the organic substance is spontaneously grown on the main surface 2A of the plate 2 by a natural nucleus growth method. Let it. Then, the microcrystals 4 of the organic substance, which have become supersaturated by cooling the solution, form the main surface 2 of the plate 2.
It precipitates on A (state I in FIG. 1). Since the plate 2 is made of Teflon, its main surface 2A is extremely lubricated. Therefore, the microcrystals 4 of the organic substance formed on the main surface 2A
Slides down the main surface 2A to reach the groove 3 and is caught by the groove 3 (state II in FIG. 1).

The microcrystals of the organic substance formed on the main surface 2A of the plate 2 by such a natural nucleus growth method slide down the main surface 2A one after another and bond to the groove 3. on the other hand,
In the groove 3, crystal growth is performed with a relatively large crystal to which microcrystals are bonded as nuclei. As described above, in the groove 3, both the bonding of crystallites and the crystal growth are performed simultaneously, so that a large single crystal can be formed. Also,
Since the crystal growth is performed only in the groove 3, the adjacent crystals do not adhere to each other and are not polycrystallized, and a single crystal having few crystal defects and excellent crystallinity can be obtained.

FIG. 2 is a diagram showing an X-ray diffraction rocking curve of a DAST single crystal. FIG. 2 shows a rocking curve of the peak intensity at 10 degrees on the (001) plane of the DAST single crystal. In the figure, the rocking curve half width of the DAST crystal obtained by the formation method of the present invention, which is indicated by a solid line (hereinafter, may be abbreviated as FWHM).
Is 25.6 seconds, which indicates that the DAST single crystal obtained by the forming method of the present invention has excellent crystallinity.
FIG. 3 is an optical micrograph showing an example of a DAST single crystal obtained by the forming method of the present invention. As is apparent from FIG. 3, the DAS obtained by the formation method of the present invention
It can be seen that the T single crystal is a very large one piece of about 5 mm and a thickness of about 0.5 mm. As described above, according to the present invention, a large-sized organic optical single crystal having excellent crystallinity can be formed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings, based on embodiments of the present invention. In the forming method of the present invention, it is necessary to form at least one groove on the main surface of the Teflon member. The shape of the groove is not particularly limited as long as the organic optical single crystal can be formed according to the formation method of the present invention. For example, any shape such as a wedge shape shown in FIG. 1, a semicircle shape, a semicircular shape, and a rectangular shape can be used. However, by forming the wedge-shaped groove 3, the anchor effect by the groove 3 when the microcrystals of the organic substance formed on the main surface 2A of the plate 2 slide on the main surface 2A increases, and The effect of capturing the microcrystals is increased. Thereby, a larger organic optical single crystal can be formed in the groove 3.

The size of the groove is not particularly limited as long as an organic optical single crystal can be formed by the method of the present invention. However, when the wedge-shaped groove 3 is formed as shown in FIG. 1, the opening width r is preferably 0.5 to 2 mm, and more preferably 0.5 to 1 mm. Further, the depth d is preferably 0.5 to 2 mm, more preferably 0.5 to 2 mm.
It is preferably about 1 mm. Thus, as described above, the effect of capturing the microcrystals of the organic substance in the groove 3 is increased, and a large-sized organic optical single crystal can be formed.

Furthermore, the number of grooves is not particularly limited, and one or more grooves can be formed on the main surface of the Teflon member. By forming a plurality of grooves, a plurality of large organic optical single crystals having excellent crystallinity can be simultaneously formed by a single single crystal growing operation. When a plurality of wedge-shaped grooves 3 are formed as shown in FIG. 1, the pitch P is preferably 5 to 20 mm, and more preferably 5 to 10 mm. As a result, it is possible to prevent the single crystals grown in the adjacent groove portions from adhering to each other and polycrystallizing with an extremely high probability.

In FIG. 1, a plate-like member is used as a Teflon member, which is attached to a slope 1A of an acrylic triangular prism-shaped pedestal 1, thereby inclining a main surface 2A of a Teflon plate 2. ing. However, instead of using a plate-shaped member made of Teflon, it is also possible to form a triangular prism-shaped pedestal directly from Teflon and apply the forming method of the present invention to the slope. However, by making the Teflon member plate-shaped, the amount of Teflon used in the present forming method can be reduced as much as possible, and the effect of the forming method of the present invention can be maximized. Therefore, the cost when the forming method of the present invention is performed can be reduced as much as possible. In the case where a plate-shaped member made of Teflon is used as shown in FIG. 1, the method of inclining the main surface 2A of the plate 2 is not particularly limited. In addition to using an acrylic pedestal 1 as shown in FIG. 1, the present invention can be implemented by using a metal or the like.

The magnitude of the inclination angle of the main surface of the Teflon member is not particularly limited as long as a large organic optical single crystal having excellent crystallinity can be obtained according to the forming method of the present invention. . However, the inclination angle is preferably set to 20 to 50 degrees, and more preferably 30 to 4 degrees.
Preferably, it is 0 degrees. As a result, the rate at which the organic microcrystals formed on the main surface of the member by natural nucleus growth remain at the deposition position decreases, and the rate at which the microcrystals slide on the main surface and are caught in the grooves increases. A plate-like Teflon member 2 as shown in FIG. 1 is used, and a wedge-shaped groove 3 is formed on its main surface 2A.
Is formed, the inclination angle θ of the main surface 2A is set to 20 to 50 degrees.

The formation method of the present invention can be used for forming all kinds of organic optical single crystals. For example, in addition to a DAST single crystal, DANPH, DAD, and L
It can be used for APs and the like. When the formation method of the present invention is applied to the formation of a DAST single crystal, for example, when a nucleus growth material as shown in FIG. 4A. Therefore, when a single crystal is formed by further growing from the microcrystal, a stress due to the growth of the (001) plane does not occur. Therefore, the rate of occurrence of crystal defects and the like inside the obtained single crystal is extremely reduced. That is, the forming method of the present invention
It can be particularly preferably used for forming a T single crystal.

The formation of a single crystal by the formation method of the present invention
Specifically, this is performed as follows. For example, a predetermined amount of D
The AST powder is dissolved in an organic solvent such as methanol kept at 50 to 60 ° C. in a thermostatic water bath to prepare a DAST solution. Next, the DAST solution is filtered to remove impurities in the solution. Next, a substance 10 for nucleus growth as shown in FIG. 1 is immersed in the solution. Then, the DAST in the solution is completely dissolved by maintaining the temperature in the constant temperature water tank at 50 to 60 ° C., and then the solution temperature is lowered. Then, the supersaturated DAST crystallites precipitate on the main surface 2A of the plate 2, and a DAST single crystal is formed in the groove 3 by the action described in "Means for Solving the Problem". Finally, set the solution temperature to 0.1-0.5
The temperature is lowered to 30 to 40 ° C at a rate of ° C / day. The time required to form a single crystal in this manner is 24 to 240 hours.

According to the present invention, the half width of the rocking curve at a peak intensity of 10 degrees in the (001) plane in the X-ray diffraction pattern is 40 seconds or less, preferably 30 seconds or less, and the size of one piece is 5 mm or more, preferably 8 mm. As described above, a large-sized organic optical single crystal having excellent crystallinity and a thickness of 0.5 mm or more can be obtained.

[0019]

The present invention will be specifically described below with reference to examples. Example In this example, a DAST single crystal was grown using a nucleus growth substance 10 as shown in FIG. DAST powder 1
0.5 g was put in methanol kept at 55 ° C. in a thermostatic water bath to prepare a DAST solution. Next, in a state where the solution is maintained at 55 ° C., as shown in FIG. 1, the inclination angle θ of the main surface 2A is 30 degrees, the opening width r of the groove 3 is 1 mm, and the depth d is 1 mm. A nucleus growth material 10 having a pitch P of 1 mm was immersed in the solution. Thereafter, the solution was maintained at 55 ° C.
After the powder was completely dissolved, the temperature was lowered to 35 ° C. over 16 days. Thereafter, when the substance 10 for nucleus growth was taken out, a DAST crystal as shown in FIG. 3 was obtained. This D
When the AST crystal was measured, the width was about 5 mm and the length was about 4 m
m, and the thickness was about 0.5 mm.

Next, (00) of the obtained DAST crystal
1) When the FWHM of the peak intensity from the surface was determined, 2
It was 5.6 to 57.6 seconds. In particular, the FWHM at a peak intensity of 10 degrees shown by the solid line in FIG. 2 was 25.6 seconds.

Comparative Example A TAST single crystal was grown under the same conditions as in Example 1 at the bottom using a Teflon growing vessel instead of the grain growth material shown in FIG. When the obtained DAST crystal was actually measured, the width was about 3 mm, the length was about 3 mm, and the thickness was about 0.2 mm.
mm. The DAST crystal was analyzed by X-ray, and the FWHM of the peak intensity from the (001) plane was found to be 50 to 130 seconds. The FWHM at the peak intensity of 10 degrees indicated by the broken line in FIG.
It was 7.4 seconds.

As is clear from the above, according to the forming method of the present invention, a DAST single crystal having excellent crystallinity can be obtained.

As described above, the present invention has been described in detail based on the embodiments of the present invention while showing specific examples. However, the present invention is not limited to the above contents, and the present invention is not limited thereto. All modifications and changes are possible.

[0024]

According to the formation method of the present invention, adjacent crystals do not adhere to each other to form polycrystals.
An organic optical single crystal with few crystal defects and excellent crystallinity can be obtained. Further, since crystal growth is performed only in the groove, a large organic optical single crystal can be formed.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a process of growing an organic optical single crystal by a forming method of the present invention.

FIG. 2 is a diagram showing an X-ray diffraction rocking curve of a DAST single crystal.

FIG. 3 shows a DAST obtained by the forming method of the present invention.
It is an optical microscope photograph of a single crystal.

[Explanation of symbols]

 Reference Signs List 1 pedestal 1A slope of pedestal 2 plate made of Teflon 2A main surface of plate made of Teflon 2B back surface of plate made of Teflon 3 groove 4 microcrystals of organic matter 10 nucleus growth material θ inclination angle of main surface of Teflon plate r Groove opening width d Groove depth P Groove pitch

Claims (7)

[Claims] At least one groove is formed in a main surface of a member made of Teflon, the main surface of the member is inclined, and an organic substance is naturally grown on the main surface of the member. Forming a single crystal of the organic substance in the groove formed in the organic optical single crystal. 2. The method for forming an organic optical single crystal according to claim 1, wherein said groove has a wedge shape. 3. The method according to claim 1, wherein an opening width of the groove is 0.5 to 2 mm and a depth is 0.5 to 2 mm. 4. The inclination angle of the main surface of the member is 20 to 50.
The method for forming an organic optical single crystal according to any one of claims 1 to 3, wherein 5. The method for forming an organic optical single crystal according to claim 1, wherein the member has a plate shape. 6. The organic substance is 4-dimethylamino-N
The method for forming an organic optical single crystal according to any one of claims 1 to 5, wherein the method is -methyl-4-stilbazolium tosylate. 7. A rocking curve half width of a peak intensity of a (001) plane in an X-ray diffraction pattern is 40 seconds or less, a size of one piece is 5 mm or more, and a thickness is 0.5 mm or more. 4-dimethylamino-N-
Methyl-4-stilbazolium tosylate single crystal.