JP4969881B2 - Two-photon absorption materials and their applications - Google Patents

Description

  The present invention relates to a two-photon absorption material, in particular, a two-photon absorption monomolecular material or a polymer material having a high two-photon absorption cross-sectional area, a three-dimensional memory material, a light limiting material, a cured material of a photocurable resin for optical modeling, Applied to applications such as photochemotherapy materials and fluorescent dye materials for two-photon fluorescence microscopes.

As conventional examples of the two-photon absorption material, there are those disclosed in Patent Documents 1 to 3.
Moreover, as a conventional example regarding a three-dimensional memory medium (material), there are those disclosed in Patent Documents 4 to 6.
Moreover, there exists a thing of patent document 7 as a prior art example regarding an optical limiting element (material).
Moreover, there exists a thing of patent document 8 as a prior art example regarding an optical modeling technique.
Further, as conventional examples of a (fluorescence) microscope using two-photon characteristics, there are those disclosed in Patent Documents 9 to 11.
If the two-photon absorption material having the excellent two-photon absorption characteristics of the present invention is applied to an optical memory, an optical element, a device or the like according to the conventional examples of Patent Documents 1 to 11, the three-dimensional memory material according to claims 7 to 10 of the present invention. , A light-limiting material, a photocuring resin curing material, and a fluorescent dye material for two-photon fluorescence microscope can be achieved.

  The use of the two-photon absorption phenomenon makes it possible to apply to various devices characterized by extremely high spatial resolution. However, the two-photon absorption compounds currently available have low two-photon absorption ability, so that two-photon absorption can be reduced. An expensive and high-power laser is required as an exciting excitation light source. Therefore, in order to realize a practical application using two-photon absorption using an inexpensive and small (low output) laser, development of a more efficient two-photon absorption material is essential.

<Application to two-dimensional multilayer optical memory using two-photon absorption material>
Recently, network systems such as the Internet and high-definition TV are rapidly spreading. In addition, the demand for a large-capacity recording medium for recording image information of 50 GB or more, preferably 100 GB or more inexpensively and easily for consumer use is increasing due to the close up of HDTV (High Definition Television). Furthermore, for business use such as computer backup use and broadcast backup use, an optical recording medium capable of recording large-capacity information of about 1 TB or more at high speed and at low cost is required. Under these circumstances, a conventional two-dimensional optical recording medium such as DVD ± R is expected to have a recording capacity of about 25 GB at most even if the recording / reproducing wavelength is shortened, and a sufficiently large recording capacity to meet future requirements. It is a situation that cannot be said.
Under such circumstances, a three-dimensional optical recording medium has attracted attention as an ultimate high-density, high-capacity recording medium. Three-dimensional optical recording media can be recorded in dozens or hundreds of layers in the three-dimensional (film thickness) direction, resulting in tens or hundreds of times the ultra-high density and ultra-high capacity recording of conventional two-dimensional recording media. That is what we are trying to achieve. In order to provide a three-dimensional optical recording medium, it is necessary to be able to access and write at an arbitrary place in the three-dimensional (film thickness) direction. As a means for this, a method using a two-photon absorption material and holography (interference) There is a method of using. In a three-dimensional optical recording medium using a two-photon absorption material, so-called bit recording can be performed over tens or hundreds of times based on the principle explained above, and higher density recording is possible. It can be said to be the ultimate high-density, high-capacity optical recording medium.
As a three-dimensional optical recording medium using a two-photon absorbing material, a method of reading with fluorescence using a fluorescent substance for recording / reproduction (Lewitch, Eugene, Polis et al., JP-T-2001-524245 [Patent Document 1] Pavel, Eugen et al., Japanese translation of PCT publication No. 2000-512061 [Patent Document 2], and a method of reading with absorption or fluorescence using a photochromic compound (Korotif, Nikolai Eye et al., Japanese Patent Publication No. 2001-522119 [Patent Document 3]. ], Arsenov, U "Radimir et al., JP-T-2001-508221 [Patent Document 4]) and the like have been proposed, but none of them presents a specific two-photon absorption material and is presented abstractly. An example of the two-photon absorption compound used is a two-photon absorption compound having extremely small two-photon absorption efficiency. Further, since the photochromic compounds used in these patent documents are reversible materials, there are problems in non-destructive reading, long-term storage stability of recording, S / N ratio of reproduction, and the like, a method that is practical as an optical recording medium I can't say that. In particular, in terms of non-destructive readout and long-term storage stability, it is possible to detect and reproduce changes in optical characteristics when irradiated with light using an irreversible material, such as changes in reflectance, changes in transmittance, and changes in emission intensity. However, there is no example that specifically discloses a two-photon absorption material having such a function.
In addition, Kawada Jun, Kawada Yoshimasa, JP-A-6-28672 [Patent Document 5], Kawada Kei, Kawada Yoshimasa et al. And JP-A-6-118306 [Patent Document 6] are three-dimensional by refractive index modulation. However, there is no description of a method using a two-photon absorption three-dimensional optical recording material.

As described above, the reaction is caused by the excitation energy obtained by two-photon absorption, and as a result, the optical characteristics change when the laser focus (recording) part and the non-focus (non-recording) part are irradiated. Can be modulated by a method that cannot be rewritten, it can be applied to a three-dimensional optical recording medium that is considered to be the ultimate high-density recording medium with an extremely high spatial resolution in an arbitrary place in a three-dimensional space. Furthermore, since non-destructive readout is possible and the material is an irreversible material, it can be expected to have good storage stability and is practical.
However, the currently available two-photon absorption compounds have a low two-photon absorption capability, so that a very high-power laser is required as a light source and a long recording time is required. Especially for use in three-dimensional optical recording media, construction of a two-photon absorption three-dimensional optical recording material that can perform recording by two-photon absorption with high sensitivity to achieve a fast transfer rate. Is essential. To that end, two-photon absorption compounds that can absorb two-photons with high efficiency and generate excited states are promising, but few such materials have been disclosed so far, and the construction of such materials Was desired.

JP-A-2005-213434 JP 2005-82507 A JP 2004-168690 A JP-A-2005-100606 JP 2005-517769 Gazette JP-T-2004-534849 Japanese Patent Laid-Open No. 08-320422 JP 2005-134783 A Japanese Patent Application Laid-Open No. 09-230246 JP 10-142507 A JP 2005-165212 A JP-T-2001-524245 Special table 2000-512061 gazette Special table 2001-522119 gazette Special table 2001-508221 gazette JP-A-6-28672 JP-A-6-118306

  In view of the above prior art, an object of the present invention is to provide a highly sensitive two-photon absorption material that efficiently absorbs two-photons, that is, an organic material having a large two-photon absorption cross section.

Another object of the present invention is to have at least a two-photon absorption compound having a large two-photon absorption cross-section and to record light in a recording material that cannot be rewritten using the two-photon absorption of the two-photon absorption compound. It is an object of the present invention to provide a two-photon absorption optical recording material that can be reproduced by irradiating the film and detecting the difference in optical characteristics.
It is another object of the present invention to provide an excellent two-photon absorption three-dimensional optical recording material using them.

As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by an arylamine monomer or polymer containing a specific structural unit, and have reached the present invention.
That is, according to the present invention, (1) “two-photon absorption material having a structure represented by the following general formula (I);

（式中、Ａｒ_１、Ａｒ_２、Ａｒ_４及びＡｒ_５は、置換または無置換の芳香族炭化水素、もしくは、置換または無置換の芳香族複素環の二価基であって、
Ａｒ_３は、置換または無置換の芳香族炭化水素、もしくは、置換または無置換の芳香族複素環の一価基であって、
Ａｒ_６は、置換または無置換のベンゼン、チオフェン、ビフェニル、フルオレン、もしくはアントラセンの二価基であって、
かつ、Ａｒ_７及びＡｒ_８は、それぞれ独立に置換または無置換の芳香族炭化水素基である。）」、
（２）「下記一般式（II）で表される構造を有する二光子吸収材料；

(Wherein Ar ₁ , Ar ₂ , Ar ₄ and Ar ₅ are substituted or unsubstituted aromatic hydrocarbons or substituted or unsubstituted aromatic heterocyclic divalent groups,
Ar ₃ is a substituted or unsubstituted aromatic hydrocarbon or a monovalent group of a substituted or unsubstituted aromatic heterocyclic ring,
Ar ₆ is a substituted or unsubstituted divalent group of benzene, thiophene, biphenyl, fluorene, or anthracene,
Ar ₇ and Ar ₈ are each independently a substituted or unsubstituted aromatic hydrocarbon group. ) ",
(2) “two-photon absorption material having a structure represented by the following general formula (II);

（式中、Ａｒ_３は、置換または無置換の芳香族炭化水素、もしくは、置換または無置換の芳香族複素環の一価基であって、
Ａｒ_６は、置換または無置換のベンゼン、チオフェン、ビフェニル、フルオレン、もしくはアントラセンの二価基であって、
Ａｒ_７及びＡｒ_８は、それぞれ独立に置換または無置換の芳香族炭化水素基であって、
Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４は、水素原子、ハロゲン原子、置換または無置換のアルキル基、置換または無置換のアルコキシ基、もしくは置換または無置換のアルキルチオ基から選択される基である。）」、
（３）「下記一般式（III）で表される構造を有する二光子吸収材料；

(Wherein Ar ₃ is a substituted or unsubstituted aromatic hydrocarbon or a monovalent group of a substituted or unsubstituted aromatic heterocyclic ring;
Ar ₆ is a substituted or unsubstituted divalent group of benzene, thiophene, biphenyl, fluorene, or anthracene,
Ar ₇ and Ar ₈ are each independently a substituted or unsubstituted aromatic hydrocarbon group,
R ₁ , R ₂ , R ₃ and R ₄ are groups selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted alkylthio group. . ) ",
(3) “two-photon absorption material having a structure represented by the following general formula (III);

（式中、Ａｒ_６は、置換または無置換のベンゼン、チオフェン、ビフェニル、フルオレン、もしくはアントラセンの二価基であって、
Ａｒ_７及びＡｒ_８は、それぞれ独立に置換または無置換の芳香族炭化水素基であって、
Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４及びＲ_５は、水素原子、ハロゲン原子、置換または無置換のアルキル基、置換または無置換のアルコキシ基、もしくは置換または無置換のアルキルチオ基から選択される基である。）」、
（４）「下記一般式（IV）で表される繰返し単位の部分を有する二光子吸収材料；

Wherein Ar ₆ is a substituted or unsubstituted benzene, thiophene, biphenyl, fluorene, or anthracene divalent group,
Ar ₇ and Ar ₈ are each independently a substituted or unsubstituted aromatic hydrocarbon group,
R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted alkylthio group It is a group. ) ",
(4) “two-photon absorbing material having a repeating unit represented by the following general formula (IV);

（式中、Ａｒ_１、Ａｒ_２、Ａｒ_４及びＡｒ_５は、置換または無置換の芳香族炭化水素、もしくは、置換または無置換の芳香族複素環の二価基であって、
Ａｒ_３は、置換または無置換の芳香族炭化水素、もしくは、置換または無置換の芳香族複素環の一価基であって、
Ａｒ_６は、置換または無置換のベンゼン、チオフェン、ビフェニル、フルオレン、もしくはアントラセンの二価基である。）」、
（５）「一般式（Ｖ）で表される繰返し単位部分を有する二光子吸収材料；

(Wherein Ar ₁ , Ar ₂ , Ar ₄ and Ar ₅ are substituted or unsubstituted aromatic hydrocarbons or substituted or unsubstituted aromatic heterocyclic divalent groups,
Ar ₃ is a substituted or unsubstituted aromatic hydrocarbon or a monovalent group of a substituted or unsubstituted aromatic heterocyclic ring,
Ar ₆ is a substituted or unsubstituted divalent group of benzene, thiophene, biphenyl, fluorene, or anthracene. ) ",
(5) “two-photon absorption material having a repeating unit represented by the general formula (V);

（式中、Ａｒ_３は、置換または無置換の芳香族炭化水素、もしくは、置換または無置換の芳香族複素環の一価基であって、
Ａｒ_６は、置換または無置換のベンゼン、チオフェン、ビフェニル、フルオレン、もしくはアントラセンの二価基であって、
Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４は、水素原子、ハロゲン原子、置換または無置換のアルキル基、置換または無置換のアルコキシ基、もしくは置換または無置換のアルキルチオ基から選択される基である。）」、
（６）「一般式（VI）で表される繰返し単位の部分を有する二光子吸収材料；

(Wherein Ar ₃ is a substituted or unsubstituted aromatic hydrocarbon or a monovalent group of a substituted or unsubstituted aromatic heterocyclic ring;
Ar ₆ is a substituted or unsubstituted divalent group of benzene, thiophene, biphenyl, fluorene, or anthracene,
R ₁ , R ₂ , R ₃ and R ₄ are groups selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted alkylthio group. . ) ",
(6) “two-photon absorption material having a repeating unit represented by the general formula (VI);

（式中、Ａｒ_６は、置換または無置換のベンゼン、チオフェン、ビフェニル、フルオレン、もしくはアントラセンの二価基であって、
Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４及びＲ_５は、水素原子、ハロゲン原子、置換または無置換のアルキル基、置換または無置換のアルコキシ基、もしくは置換または無置換のアルキルチオ基から選択される基である。）」、
（７）「前記第（１）項乃至第（６）項のいずれかに記載の二光子吸収材料を含む三次元メモリ材料」、
（８）「前記第（１）項乃至第（６）項のいずれかに記載の二光子吸収材料を含む光制限材料」、
（９）「前記第（１）項乃至第（６）項のいずれかに記載の二光子吸収材料を含む光造形用光硬化樹脂の硬化材料」、
（１０）「前記第（１）項乃至第（６）項のいずれかに記載の二光子吸収材料を含む二光子蛍光顕微鏡用蛍光色素材料」によって達成される。

Wherein Ar ₆ is a substituted or unsubstituted benzene, thiophene, biphenyl, fluorene, or anthracene divalent group,
R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted alkylthio group It is a group. ) ",
(7) “Three-dimensional memory material including the two-photon absorption material according to any one of (1) to (6)”,
(8) “Optical limiting material including the two-photon absorption material according to any one of (1) to (6)”,
(9) "Curing material of photo-curing resin for optical modeling including the two-photon absorption material according to any one of (1) to (6)",
(10) “A fluorescent dye material for a two-photon fluorescence microscope comprising the two-photon absorption material according to any one of (1) to (6)”.

  That is, the present invention provides the two-photon absorption material according to the above (1) to (10), a three-dimensional memory material using the same, a light-limiting material, a curing material for a photo-setting resin for optical modeling, and a fluorescence for a two-photon fluorescence microscope Related to dye materials. Here, the above (1) to (3) show the basic structure of the unimolecular two-photon absorption material of the present invention, and (4) to (6) show the polymer structure of the two-photon absorption material of the present invention. (7) to (10) show examples of suitable industrially applied materials.

As will be apparent from the following detailed and specific description, the present invention can realize a two-photon absorption compound having a high photon absorption transition efficiency, and can be practically used with a small and inexpensive laser (three-dimensional memory material, optical Limiting materials, photocuring resin curing materials, photochemotherapy materials, fluorescent dye materials for two-photon fluorescence microscopes, etc.) can be realized.
In the past, when using a two-photon absorption material of a low molecular compound (monomolecular compound), it has been used by being dispersed in a polymer material. However, with regard to long-term storage stability, there has been a problem that the quality changes because coating film defects occur due to segregation due to crystallization or migration of the two-photon absorption material.
By using a two-photon absorption polymer in which sites having two-photon absorption ability are linked, a coating film defect does not occur even during long-term storage, and an excellent effect is obtained that a stable quality can be obtained.

Hereinafter, the present invention will be described in more detail.
The two-photon absorption material of the present invention is a material capable of exciting a molecule at a wavelength in a non-resonant region, and an actual excited state exists at an energy level about twice that of a photon used for excitation. It is a material.
The two-photon absorption phenomenon is a kind of third-order nonlinear optical effect, in which a molecule simultaneously absorbs two photons and transitions from a ground state to an excited state. -Luc Bredas et al. Clarified the relationship between molecular structure and mechanism in 1998 (Science, 281, 1653 (1998)), and in recent years, research on materials having two-photon absorption ability has advanced.

However, since the transition efficiency of such two-photon simultaneous absorption is extremely lower than that of one-photon absorption and requires a photon with a very large power density, it is almost ignored in the laser light intensity normally used, and the peak light intensity ( It has been confirmed that an ultra-short pulse laser of about femtosecond such as a mode-locked laser having a high light intensity at the maximum emission wavelength is observed.
The transition efficiency of two-photon absorption is proportional to the square of the applied photoelectric field (square characteristic of two-photon absorption). For this reason, when a laser is irradiated, two-photon absorption occurs only at the center of the laser spot, that is, at a position where the electric field strength is high, and no two-photon absorption occurs at the peripheral portion where the electric field strength is low. In the three-dimensional space, two-photon absorption occurs only in a region where the electric field strength at the focal point where the laser light is collected by the lens is large, and no two-photon absorption occurs in the region outside the focal point because the electric field strength is weak. Compared to the linear absorption of one photon where excitation occurs at all positions in proportion to the intensity of the applied photoelectric field, two-photon absorption is caused by excitation at only one point inside the space due to this square characteristic. , The spatial resolution is significantly improved.

  Utilizing this property, research on three-dimensional memory that records bit data by causing optical property changes such as spectrum change, refractive index change or polarization change by two-photon absorption at a predetermined position of the recording medium has been advanced. Yes. Since two-photon absorption occurs in proportion to the square of the intensity of light, a memory using two-photon absorption can reduce the spot size compared to a memory using one-photon absorption, and super-resolution recording. Is possible. In addition, from the characteristics of high spatial resolution derived from this square characteristic, development for applications such as a light limiting material, a cured material of a photo-curing resin for stereolithography, and a fluorescent dye material for a two-photon fluorescence microscope is being promoted.

  Furthermore, in the case of inducing two-photon absorption, it is possible to use a short-pulse laser in the near-infrared region that has a longer wavelength than the wavelength region in which the linear absorption band of the compound exists and does not have absorption. Since the near-infrared light of the so-called transparent region, which does not have a linear absorption band of the compound, is used, the excitation light can reach the inside of the sample without being absorbed or scattered, and because of the square characteristic of the two-photon absorption, Since one point can be excited with high spatial resolution, two-photon absorption and two-photon emission are also expected in photochemotherapy applications such as two-photon contrast and two-photon photodynamic therapy (PDT) of biological tissues. In addition, research on upconversion lasing has been reported from the viewpoint of a wavelength conversion device because photons with higher energy than the energy of incident photons can be extracted by using two-photon absorption and two-photon emission.

  Many inorganic materials have been found so far as two-photon absorption materials. However, inorganic materials are very difficult to put into practical use because so-called molecular design for optimizing desired two-photon absorption characteristics and various physical properties necessary for device manufacture is difficult. On the other hand, organic compounds can be optimized not only for the desired two-photon absorption by molecular design, but also for other physical properties, making it highly practical and a promising two-photon absorption material. It attracts attention.

As conventional organic two-photon absorption materials, pigment compounds such as rhodamine and coumarin, compounds such as dithienothiophene derivatives and oligophenylene vinylene derivatives are known. However, the two-photon absorption cross-section showing the two-photon absorption capacity per molecule is small, and the two-photon absorption cross-section particularly when using a femtosecond pulse laser is 200 (GM: × 10 ⁻⁵⁰ cm ⁴ · s · molecule Most of those less than ⁻¹ · photon ⁻¹ ) have not yet been put into practical use.

The two-photon absorption optical recording material of the present invention can be applied directly on the substrate by using a spin coater, roll coater or bar coater, or can be cast as a film and laminated on the substrate by a usual method. Thus, a two-photon absorption optical recording material can be obtained.
Here, “substrate” means any natural or synthetic support, preferably one that can exist in the form of a flexible or rigid film, sheet or plate.
Preferred examples of the substrate include polyethylene terephthalate, resin-primed polyethylene terephthalate, polyethylene terephthalate subjected to flame or electrostatic discharge treatment, cellulose acetate, polycarbonate, polymethyl methacrylate, polyester, polyvinyl alcohol, and glass. The substrate may be provided with a guide groove for tracking and address information in advance.

The solvent used can be removed by evaporation during drying. Heating or reduced pressure may be used for evaporation removal.
Furthermore, a protective layer (intermediate layer) for blocking oxygen and preventing interlayer crosstalk may be formed on the two-photon absorption optical recording material. The protective layer (intermediate layer) is made of a plastic film or plate such as polypropylene, polyethylene, polyolefins such as polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate or cellophane film. Alternatively, the layers may be laminated together or the polymer solution may be applied. Further, a glass plate may be bonded. Further, an adhesive or a liquid substance may be present between the protective layer and the photosensitive film and / or between the base material and the photosensitive film in order to improve airtightness. Further, the protective layer (intermediate layer) between the photosensitive films may be provided with tracking guide grooves and address information in advance.

  Both the monomer compound (low molecular compound) and the polymer compound (polymer compound, resin) are basically used as a device in the form of a film (film). Therefore, as a forming method thereof, a usual organic solvent coating method is used. (That is, spin coating, dip coating, roll coating, spray coating, bar coating, etc.) can be used. A low molecular compound (monomolecular compound) can be used alone or in combination with a fixing material such as a polymer material as long as it has a film-forming ability. Then, when there is no film-forming ability, it is also used by mixing with a fixing material such as a polymer material. Any (low molecular, high molecular) structure can be formed into a device by molding in the form of mixing with a resin or the like depending on the application.

  Also, compared with the low molecular weight compounds shown in the present inventions (I) to (III), the polymer compounds shown in (IV) to (V) of the present invention cause more coating film defects (crystallization, migration). It is also possible to provide an organic material having a stable two-photon absorption cross-sectional area with a quality that does not easily cause a coating film defect (crystallization, migration).

  By focusing on an arbitrary layer of the above-described three-dimensional multilayer optical recording medium and performing recording and reproduction, the three-dimensional recording medium of the present invention functions. Further, even if the layers are not separated by a protective layer (intermediate layer), three-dimensional recording in the depth direction is possible from the two-photon absorption dye characteristics.

  Hereinafter, preferred embodiments (specific examples) of the three-dimensional multilayer optical memory will be described. However, the present invention is not limited to these embodiments, and any structure capable of three-dimensional recording (recording in a plane and a film thickness direction) can be used. Any other structure may be used.

A schematic diagram of a recording / reproducing system of a three-dimensional multilayer optical memory is shown in FIG. 1A, and a schematic sectional view of a recording medium is shown in FIG.
In the recording medium (b) in the figure, a recording layer using the two-photon absorption compound of the present invention on a flat support (substrate (1)) and an intermediate layer (protective layer) for preventing crosstalk alternately. 50 layers are stacked, and each layer is formed by spin coating. The thickness of the recording layer is preferably 0.01 to 0.5 μm, and the thickness of the intermediate layer is preferably 0.1 μm to 5 μm. With this structure, the disk size is the same as the currently popular CD / DVD, and the terabyte class Can be realized. Further, a substrate (2) (protective layer) similar to the substrate (1) or a reflective layer made of a high reflectance material is formed by a data reproduction method (transmission / or reflection type).
A single beam is used at the time of recording, and in this case, ultrashort pulse light of femtosecond order can be used. At the time of reproduction, it is also possible to use light having a wavelength different from that of the beam used for data recording or light of the same wavelength with low output. Recording and playback can be performed in either bit units or page units, and parallel recording / playback using a surface light source, a two-dimensional detector, or the like is effective in increasing the transfer rate.
Note that a three-dimensional multilayer optical memory similarly formed according to the present invention may have a card shape, a plate shape, a tape shape, a drum shape, or the like.

<Application to optical limiting element using two-photon absorption material>
In optical communication and optical information processing, optical control such as modulation and switching is required to carry signals such as information with light. For this type of light control, an electro-light control method using an electric signal has been conventionally employed. However, the electro-optical control method has limitations such as a band limitation due to a CR time constant as in an electric circuit, a processing speed being limited due to a response speed of the element itself and a speed mismatch between an electric signal and an optical signal. In order to make full use of the broadband and high speed, which are the advantages of light, light-light control technology for controlling an optical signal with an optical signal becomes very important.
An optical element manufactured by processing the two-photon absorption material of the present invention in response to this requirement utilizes an optical change such as transmittance, refractive index, absorption coefficient, etc. caused by irradiating light, and an electronic circuit. By modulating the intensity and frequency of light without using technology, it can be applied to optical switches in optical communications, optical exchange, optical computers, optical interconnections, and the like.
The optical limiting element of the present invention that utilizes the change in optical characteristics due to two-photon absorption provides an optically limiting element that is formed from a normal semiconductor material and an element that has a much higher response speed than those based on one-photon excitation. be able to. In addition, since the two-photon absorption material of the present invention has high sensitivity, it is possible to provide an optical limiting element excellent in signal characteristics with a high S / N ratio.

  FIG. 2 is an example of a light control element that optically switches a signal light having a wavelength that can be excited by one photon by exciting the two-photon absorbing material of the present invention with a control light having a wavelength that can be excited by two photons. . Although the form of the two-photon absorption material sandwiched between the protective layers is shown, this configuration does not limit the present invention.

Japanese Patent Laid-Open No. 8-320422 is cited as a known document of the light limiting element in the present invention. According to this, it is disclosed as an optical waveguide which forms a refractive index distribution by irradiating a light refractive index material whose refractive index changes with light irradiation with light having a wavelength whose refractive index changes. That is, a solid material dispersed in a material having a high two-photon absorption capacity, a thin film, or a photocurable resin of the present invention is arranged as an optical element, and excited in an excited state with light of one wavelength (λ1). Further, by being excited from the state to the other state by the light of the other wavelength (λ2), it becomes possible to design the optical waveguide using the refractive index change distribution according to the wavelength.
Many of the two-photon absorption materials have fluorescence, and a fluorescent substance is arranged at or near one emission end of the optical device, and excitation light (λ1) is emitted from the other, and excitation light and fluorescence (λ2) are emitted. A refractive index distribution can also be formed. In this case, since the fluorescence is usually weaker than the excitation light, it is desirable to increase the sensitivity at the fluorescence wavelength. Examples of the fluorescent substance include those in which a fluorescent dye is dispersed in a photocurable substance.

<Application to stereolithography materials>
A schematic diagram of a two-photon stereolithography apparatus is shown in FIG. 3 and described below.
After passing the light from the near-infrared pulse laser light source (31) through the mirror scanner (34), it is condensed into the photo-curable resin (39) using a lens, and the laser spot is scanned to absorb the two-photon absorption. This is a two-photon micro-stereolithography method in which an arbitrary three-dimensional structure is formed by curing the resin only in the vicinity of the focal point.
The pulsed laser beam is condensed by a lens, and a region with high photon density is formed in the vicinity of the focal point. At this time, since the total number of photons passing through each cross section of the beam is constant, when the beam is scanned two-dimensionally within the focal plane, the total light intensity in each cross section is constant. However, since the probability of occurrence of two-photon absorption is proportional to the square of the light intensity, a region where the generation of two-photon absorption is high is formed only near the condensing point where the light intensity is high. In this way, by condensing the pulsed laser light with the lens and inducing two-photon absorption, it is possible to limit the light absorption near the condensing point and to cure the resin at a pinpoint. Since the condensing point can be freely moved in the photocurable resin liquid by the Z stage (36) and the galvanometer mirror, a desired three-dimensional workpiece can be freely formed in the photocurable resin liquid. .

The features of the two-photon stereolithography include the following items.
1) Processing resolution exceeding the diffraction limit The processing resolution exceeding the diffraction limit of light can be realized by the non-linearity of the two-photon absorption with respect to the light intensity.
2) Ultra-high speed modeling When two-photon absorption is used, the photo-curing resin is not cured in principle in a region other than the focal point.
For this reason, the light intensity to be irradiated can be increased, and the beam scanning speed can be increased.
For this reason, the modeling speed can be improved about 10 times.
3) Three-dimensional processing The photocurable resin is transparent to near-infrared light that induces two-photon absorption.
Therefore, even when the focused light is condensed deeply into the resin, internal curing is possible.
In the conventional SIH, when the beam is condensed deeply, the light intensity at the condensing point is reduced by light absorption,
The problems that make internal curing difficult can be solved reliably in the present invention.
4) Improvement of productivity In the conventional method, there is a problem that the molded object is damaged or deformed due to the viscosity or surface tension of the resin. However, in this method, the problem is solved because the modeling is performed inside the resin.
5) Application to mass production By using ultra-high-speed modeling, it is possible to manufacture a large number of parts or movable mechanisms continuously in a short time.

  The photocurable resin for two-photon stereolithography is a resin having a characteristic of causing a two-photon polymerization reaction when irradiated with light and changing from a liquid to a solid. The main components are a resin component composed of an oligomer and a reactive diluent and a photopolymerization initiator (including a photosensitizing material as required). An oligomer is a polymer having a degree of polymerization of about 2 to 20, and has a large number of reactive groups at its ends. Further, a reactive diluent is added to adjust the viscosity, curability and the like. When irradiated with light, the polymerization initiator or photosensitizing material absorbs this two-photon, and a reactive species is generated directly from the polymerization initiator or through the photosensitizing material, to the reactive group of the oligomer or reactive diluent. React and initiate polymerization. Thereafter, a chain polymerization reaction takes place between them to form a three-dimensional cross-link, and in a short time, a solid resin having a three-dimensional network structure is formed.

Photocurable resins are used in fields such as photocurable inks, photoadhesives, and layered three-dimensional modeling, and resins having various characteristics have been developed. Especially in layered 3D modeling (1) Reactivity is good,
(2) Deposition shrinkage during curing is small,
(3) It is important that the mechanical properties after curing are excellent.
Etc. are important.
These characteristics are equally important in this method. Therefore, resins developed for layered three-dimensional modeling that have two-photon absorption characteristics are also used as photocurable resins for two-photon photofabrication in this method. it can. As specific examples, acrylate-based and epoxy-based photocurable resins are often used, and urethane acrylate-based photocurable resins are particularly preferable.

  JP-A-2005-134873 can be cited as a publicly known document relating to optical modeling in the present invention. According to this, pulsed laser light is subjected to interference exposure on the surface of the photosensitive polymer film without passing through a mask. It is important that the pulsed laser beam is a pulsed laser beam in a wavelength region that allows the photosensitive polymer film to exhibit a photosensitive function. Therefore, the wavelength region of the pulsed laser light can be appropriately selected according to the type of the photosensitive polymer or the type of group or site that exhibits the photosensitive function in the photosensitive polymer. In particular, even if the wavelength of the pulsed laser light emitted from the light source is not in a wavelength region that causes the photosensitive polymer film to exhibit a photosensitive function, by utilizing a multiphoton absorption process upon irradiation with the pulsed laser light, The photosensitive polymer film can exhibit a photosensitive function. Specifically, when the pulsed laser light emitted from the light source is condensed and irradiated with the condensed pulsed laser light, multiphoton absorption (for example, two-photon absorption, three-photon absorption, four-photon absorption, Photosensitive polymer film even if the wavelength of the pulsed laser light emitted from the light source is not in a wavelength region that causes the photosensitive polymer film to perform a photosensitive function. Is substantially irradiated with a pulsed laser beam in a wavelength region that causes the photosensitive polymer film to exhibit a photosensitive function. As described above, the pulsed laser beam for the interference exposure may be substantially a pulsed laser beam in a wavelength region that causes the photosensitive polymer film to exhibit the photosensitive function, and the wavelength is appropriately selected depending on the irradiation conditions. can do. For example, the high-efficiency two-photon absorbing material of the present invention is used as a photosensitizing material, dispersed in an ultraviolet curable resin, etc., and a photosensitive solid, and only the focal spot is cured using the two-photon absorption ability of the photosensitive solid. It is possible to obtain an ultra-precise three-dimensional structure using

  The two-photon absorption material of the present invention can be used as a two-photon absorption polymerization initiator or a two-photon absorption photosensitizer. Compared to conventional two-photon absorption materials (two-photon absorption polymerization initiators or two-photon absorption photosensitizers), the two-photon absorption sensitivity is high, so high-speed modeling is possible, and the laser light source is small and inexpensive as an excitation light source. Can be used for practical applications that can be mass-produced.

<Application to two-photon fluorescence microscope using two-photon absorption material>
A two (multi) photon excitation laser scanning microscope collects and scans a near-infrared pulse laser on the sample surface, and detects fluorescence generated by excitation by absorption of two (multi) photons there. It is a microscope to obtain

A schematic diagram of the basic configuration of the two-photon excitation laser scanning microscope is shown in FIG.
Laser light source (41) that emits sub-picosecond monochromatic coherent light pulses in the near-infrared region, light beam conversion optical system (42) that changes the light beam from the laser light source to a desired size, and light beam conversion optical system A scanning optical system (43) for condensing and scanning the light beam on the image plane of the objective lens, an objective lens system (44) for projecting the collected converted light beam onto the sample surface (45), and a photodetector ( 47).
The pulsed laser beam passes through the dichroic mirror (46), is condensed by the light beam conversion optical system and the objective lens system, and is focused on the sample surface, so that the two-photon absorption fluorescent material in the sample is absorbed by the two-photon absorption. Induces induced fluorescence. The sample surface is scanned with a laser beam, the fluorescence intensity at each location is detected by a light detection device such as a light detector (47), and plotted on a computer based on the obtained position information. A fluorescent image is obtained. As the scanning mechanism, for example, a laser beam may be scanned using a movable mirror such as a galvanometer mirror, or a sample including a two-photon absorption material placed on a stage may be moved.
With such a configuration, it is possible to obtain high resolution in the optical axis direction by utilizing the nonlinear effect of two-photon absorption itself. In addition, if a confocal pinhole plate is used, higher resolution (both in-plane and in the optical axis direction) can be obtained.

Fluorescent dyes for two-photon fluorescence microscopy are used by staining or dispersing specimens, and can be used not only for industrial applications but also for three-dimensional imaging microimaging of biological cells, etc. A compound having an absorption cross section is desired.
Japanese Patent Laid-Open No. 9-230246 is cited as a known document of the photon fluorescence microscope in the present invention. For example, a scanning fluorescent microscope includes a laser irradiation optical system that emits collimated light expanded to a desired size, and a substrate on which a plurality of condensing elements are formed. A beam splitter that transmits the long wavelength and reflects the short wavelength is disposed between the substrate on which the light condensing element is formed and the objective lens system, so as to coincide with the image position of the system. The surface is characterized by generating fluorescence by multiphoton absorption.
With such a configuration, it is possible to obtain high resolution in the optical axis direction by utilizing the nonlinear effect of multiphoton absorption itself. In addition, if a confocal pinhole plate is used, higher resolution (both in-plane and in the optical axis direction) can be obtained. Such a two-photon optical element uses, as the optical element, a solid material dispersed in a material having a high two-photon absorption ability, a thin film, or a photocurable resin of the present invention, just like the above-described light control element. Is possible.

  The two-photon absorption material of the present invention can be used as a two-photon absorption fluorescent material for a two-photon excitation laser scanning microscope. Compared to conventional two-photon absorption fluorescent materials, it has a large two-photon absorption cross-sectional area, so that it exhibits high two-photon absorption characteristics at a low concentration. Therefore, according to the present invention, not only a high-sensitivity two-photon absorption material can be obtained, but there is no need to increase the light intensity applied to the material, and deterioration and destruction of the material can be suppressed. The adverse effect on the component properties can also be reduced.

The two-photon absorption material of the present invention can be applied to various devices in the form of a single thin film or a mixture with various resins, or in bulk. For example, in an optical disc, the thin film is in contact with a substrate, and the substrate material is polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyester, polyvinyl alcohol, glass or the like. In the case of stacking, the surface of the thin film is in contact with the intermediate layer (partition layer). Specific examples of the intermediate layer include polyolefins such as polypropylene and polyethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, plastic films such as polyethylene terephthalate or cellophane film, and various photo-curing resins. Even if it is applied to various optical devices and optical modeling devices, it is mixed with various resins or mixed with a photo-curing resin.
Accordingly, the use requirement of the two-photon absorption material of the present invention is that the material is mixed with various resins or glass, or the interface of the two-photon absorption material layer is in contact with various resins or glass. In other words, the two-photon absorption material of the present invention is in contact with various resins or glass at the micro level or the macro level.

The production method of the poly (triarylamine) of the present invention will be described below.
The poly (triarylamine) production method of the present invention includes, for example, a Wittig-Horner reaction using an aldehyde and a phosphonate, a Wittig reaction using an aldehyde and a phosphonium salt, a Heck reaction using a vinyl substituent and a halide, an amine and The Ullmann reaction using a halide can be used, and can be produced by a known method. In particular, the Wittig-Horner reaction and the Wittig reaction are effective because of the simplicity of the reaction operation.
As an example, a method for producing a polymer in the present invention using the Wittig-Horner reaction will be described.

  The polymer in the present invention generally comprises a solution in which the diphosphonic acid ester compound and the dialdehyde compound are present stoichiometrically equal to each other as shown by the following formula (A), and a base at least twice the molar amount thereof. The polymerization reaction can proceed by mixing in the presence of a small amount of a monophosphonic acid ester compound as a terminal blocking agent (reaction extension terminator). Also, a plurality of phosphonic acid ester compounds or aldehyde compounds can be reacted with the reaction system By adding it inside, a random copolymer can be obtained and various properties can be adjusted. The low molecular weight materials represented by the general formulas (I) to (III) can be synthesized using a monophosphonic acid ester compound.

（式中、「A」の２価基部分は、一般式（I）中の一般式（I）中の［-Ar1-CH＝CH-Aｒ2-N(Aｒ3)-Aｒ4-］部分を表し、「B」の２価基部分は、一般式（I）中の[-CH＝CH-Aｒ5-CH＝CH-]部分を表す。）

(In the formula, the divalent group portion of “A” represents the [—Ar 1 —CH═CH—Ar 2 —N (Ar 3) —Ar 4 —] moiety in the general formula (I) in the general formula (I); The divalent group part of “B” represents the [—CH═CH—Ar 5 —CH═CH—] moiety in the general formula (I).)

The base used in the above reaction is not particularly limited as long as a phosphonate carbanion is formed, and examples thereof include metal alkoxides, metal hydrides, and organic lithium compounds, such as potassium t-butoxide, sodium t-butoxide, lithium t. -Butoxide, potassium 2-methyl-2-butoxide, sodium 2-methyl-2-butoxide, sodium methoxide, sodium ethoxide, potassium ethoxide, potassium methoxide, sodium hydride, potassium hydride, methyllithium, ethyllithium , Propyl lithium, n-butyl lithium, s-butyl lithium, t-butyl lithium, phenyl lithium, lithium naphthylide, lithium amide, lithium diisopropylamide, etc. The amount of base used in the reaction is usually It is sufficient to use the same amount relative to the polymerization active point of the phosphonate compound, but there is no problem even if an excessive amount is used.

  The above-mentioned base may be added to the reaction system in a solid state or a suspension solution. However, in order to improve the homogeneity of the resulting polymer, it is particularly preferable to add it as a homogeneous solution. As the solvent for dissolving the base, a solvent that forms a stable solution with the base to be used must be selected, but as other factors, those having a high solubility of the base are preferable, and the high molecular weight product produced in the reaction system is also preferred. Those that do not impair the solubility in the reaction solvent are good. Further, the solvent in which the high molecular weight product to be formed dissolves well is good. Depending on the characteristics of the base used and the high molecular weight to be produced, generally known alcohols and ethers are used. It can be arbitrarily selected from a system, an amine system, a hydrocarbon solvent and the like.

Examples of a combination of a base and a solvent for uniformly dissolving the base include, for example, a methanol solution of sodium methoxide, an ethanol solution of sodium ethoxide, a 2-propanol solution of potassium t-butoxide, and 2-methyl-2-methyl ester of potassium t-butoxide. Propanol solution, tetrahydrofuran solution of potassium t-butoxide, dioxane solution of potassium t-butoxide, hexane solution of n-butyllithium, ether solution of methyllithium, tetrahydrofuran solution of lithium t-butoxide, cyclohexane solution of lithium diisopropylamide, potassium bis There are various combinations of solutions including a toluene solution of trimethylsilylamide and the like, and some solutions are easily available as commercial products.
From the viewpoint of mild reaction conditions and ease of handling, a metal alkoxide-based solution is preferably used, such as solubility of the polymer to be produced, ease of handling, efficiency of the reaction, solubility of the polymer to be produced, etc. From the viewpoint, an ether system of metal t-butoxide is more preferably used, and a tetrahydrofuran solution of potassium t-butoxide is more preferably used.

In the polymerization reaction, a base solution may be added to the solution of the phosphonate ester compound and the aldehyde compound, a solution of the phosphonate ester compound and the aldehyde compound may be added to the base solution, and may be added to the reaction system at the same time. There is no restriction on the order of addition.
The polymerization time in the above polymerization reaction may be appropriately set according to the reactivity of the monomers used or the molecular weight of the desired polymer, but is preferably 0.2 hours to 30 hours.
The reaction temperature in the above polymerization reaction does not need to be particularly controlled, and the polymerization reaction proceeds favorably at room temperature. However, it is possible to heat to increase the reaction efficiency or to cool to a milder condition.
In addition, a molecular weight regulator or a sealing agent for sealing the end of the polymer as a terminal modifying group can be added during or after the reaction to adjust the molecular weight in the above polymerization operation. It can also be added at the start. Therefore, a substituent based on a terminator may be bonded to the terminal of the poly-triarylamine in the present invention.

The preferred molecular weight of the polymer of the present invention is 1,000 to 1,000,000, more preferably 2000 to 500,000 in terms of polystyrene-reduced number average molecular weight. When the molecular weight is too small, the film quality deteriorates due to the occurrence of cracks and the practicality becomes poor. On the other hand, when the molecular weight is too large, the solubility in a general organic solvent is deteriorated, the viscosity of the solution becomes high and the coating becomes difficult, which also causes a problem in practical use.
Also, a small amount of a branching agent can be added during the polymerization in order to improve the mechanical properties. The branching agent used is a compound having three or more polymerization reaction active groups (which may be the same or different). These branching agents may be used alone or in combination.
The poly-triarylamine obtained as described above is used after removing impurities such as the base, unreacted monomer, terminal terminator used in the polymerization, and inorganic salts generated during the polymerization. For these purification operations, conventionally known methods such as reprecipitation, column chromatography, adsorption, extraction, Soxhlet extraction, ultrafiltration, dialysis and the like can be used.

Next, the repeating units (I) to (VI) of the polymer of the present invention will be described in more detail.
The substituted or unsubstituted aromatic hydrocarbon group in the general formula (I) may be either a monocyclic group or a polycyclic group (a condensed polycyclic group or a non-condensed polycyclic group). be able to. Examples thereof include a phenyl group, a naphthyl group, a pyrenyl group, a fluorenyl group, an azulenyl group, an anthryl group, a triphenylenyl group, a chrycenyl group, a biphenyl group, and a terphenyl group. In addition, examples of the aromatic heterocyclic group include thiophene, benzothiophene, dithienylbenzene, furan, benzofuran, carbazole, and the like, and examples of the unsaturated hydrocarbon include —CH═CH— and —CH═CH—CH═CH—. Can be mentioned.

Moreover, said aromatic hydrocarbon group and aromatic heterocyclic group may have the substituent shown below.
(1) Halogen atom, trifluoromethyl group, cyano group, nitro group.
(2) An unsubstituted or substituted alkyl group or alkoxy group having 1 to 25 carbon atoms.
(3) Aryloxy group (an aryloxy group having a phenyl group or a naphthyl group as the aryl group is mentioned. This is an unsubstituted or substituted alkyl group having 1 to 25 carbon atoms, an unsubstituted or substituted alkyl group having 1 to 25 carbon atoms, or A substituted alkoxy group or a halogen atom may be contained as a substituent, specifically, a phenoxy group, 1-naphthyloxy group, 2-naphthyloxy group, 4-methylphenoxy group, 4-methoxyphenoxy group, 4-chlorophenoxy group, 6-methyl-2-naphthyloxy group, etc.).
(4) Alkylthio group or arylthio group (Specific examples of the alkylthio group or arylthio group include a methylthio group, an ethylthio group, a phenylthio group, and a p-methylphenylthio group).
(5) alkyl-substituted amino group (specifically, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N 2, N-di (p-tolyl) amino group, dibenzylamino) Group, piperidino group, morpholino group, euroridyl group, etc.).
(6) Acyl group. (Specific examples of the acyl group include an acetyl group, a propionyl group, a butyryl group, a malonyl group, and a benzoyl group).

As described above, the present invention (I) to (VI) may have a substituent on the aromatic ring, but an alkyl group, an alkoxy group, an alkylthio group, and the like are more preferable from the viewpoint of improving solubility in an organic solvent. . If the number of carbons of these substituents increases, the solubility will be improved, but on the other hand, the properties such as charge transportability will decrease, so that the desired properties can be obtained within the range where the solubility is not impaired. It is preferred to select a substituent. Examples of suitable substituents in that case include an alkyl group having 1 to 25 carbon atoms, an alkoxy group, and an alkylthio group. More preferable examples include an alkyl group having 2 to 18 carbon atoms, an alkoxy group, and an alkylthio group. A plurality of the same substituents may be introduced, or a plurality of different substituents may be introduced.
In addition, these alkyl groups, alkoxy groups and alkylthio groups are further halogen atoms, cyano groups, phenyl groups, hydroxyl groups, carboxyl groups, linear, branched or cyclic alkyl groups or alkoxy groups having 1 to 12 carbon atoms, alkoxythio groups, alkylthio groups. A phenyl group substituted with a group may be contained.
Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, t-butyl group, s-butyl group, n-butyl group, i-butyl group, pentyl group, hexyl group, Heptyl, octyl, nonyl, decyl, 3,7-dimethyloctyl, 2-ethylhexyl, trifluoromethyl, 2-cyanoethyl, benzyl, 4-chlorobenzyl, 4-methylbenzyl, A cyclopentyl group, a cyclohexyl group, etc. can be mentioned as an example, As an alkoxy group and an alkylthio group, what made the alkoxy group and the alkylthio group by inserting an oxygen atom or a sulfur atom in the bond position of the said alkyl group is mentioned as an example. .
Table 1 shows examples ((V-2) to (V-14)) of phosphonate compounds represented in the reaction formula of the above formula (A) used in the present invention. These phosphonic acid esters can be synthesized according to the synthesis method described in Macromolecules, vol. 34, No. 19, 2001.

  The polymer of the present invention has improved solubility in a solvent due to the presence of an alkyl group, an alkoxy group, or an alkylthio group. It is important to improve the solubility of these materials because the manufacturing tolerance of the wet film forming process becomes large when manufacturing photoelectric conversion elements, thin film transistor elements, light emitting elements and the like. For example, the choice of coating solvent is expanded, the temperature range during solution preparation is expanded, the temperature and pressure range during solvent drying is expanded, and high-quality thin films with high purity and high uniformity due to their high processability. Is obtained.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist.

(Synthesis Example 1)
On the other hand, although the detailed manufacturing method of dialdehyde is described in Japanese Patent Application No. 2005-67918, the manufacturing method of dialdehyde is shown below for reference. Specifically, 7.0 g of 4,4′-diformyl-4 ″-(2-ethylhexyloxy) triphenylamine and 10.0 g of diethyl 4-bromobenzylphosphonate were dissolved in 50 ml of dehydrated N, N-dimethylformamide. 4.81 g of potassium t-butoxide was added in small portions. After the addition, the mixture was stirred at room temperature for 2 hours, neutralized with acetic acid, and the contents were poured into water and extracted with ethyl acetate. The organic layer was washed with water, dried and the solvent was distilled off, followed by column chromatography (silica gel, eluent: toluene / hexane = 1/4). Further, recrystallization from a mixed solvent of ethyl acetate / ethanol gave 7.8 g of yellow needle-like 4,4′-bis (4-bromostyryl) -4 ″-(2-ethylhexyloxy) triphenylamine. It was.
Melting point 117.0-120.0 ° C
Elemental analysis value (%) Actual measurement value (calculated value)
C68.63 (68.58) H5.62 (5.62) N1.73 (1.90) Br21.11 (21.72)
In the infrared absorption spectrum (KBr tablet method), an absorption based on transolefin was observed at 964 cm ⁻¹ .

(Synthesis Example 2 Synthesis of Dialdehyde)
4-Bromostyryl) -4 ″-(2-ethylhexyloxy) triphenylamine (3.0 g) was dissolved in 30 ml of dehydrated tetrahydrofuran, and 8.4 ml of a 1.6 mol dm ⁻³ hexane solution of n-butyllithium in a nitrogen stream. Was added dropwise at −70 ° C. to −66 ° C. over 30 minutes. After stirring at the same temperature for 1 hour, 3.0 ml of N, N-dimethylformamide was added. After gradually returning to room temperature with stirring, ethyl acetate and water were added, the organic layer was washed with saturated brine, dried over magnesium sulfate, and the solvent was evaporated. The obtained orange-red oily substance was subjected to column chromatography (silica gel, eluent: ethyl acetate / hexane = 1/4), and orange glassy 4,4′-bis (4-formylstyryl) -4 ″-( 2.0 g of 2-ethylhexyloxy) triphenylamine was obtained.
Elemental analysis value (%) Actual measurement value (calculated value)
C83.24 (83.38) H6.99 (6.84) N2.24 (2.21)
Infrared absorption spectrum (NaCl cast film) In carbonyl 1,695 cm ^-1, absorption of trans olefins was observed at 964cm ^-1.

Example 1
1.00 g of the dialdehyde obtained in Synthesis Example 2, 0.89 g of the diphosphonate shown in Table 1 (V-6) and 5.0 mg of benzaldehyde (molecular weight regulator) were dissolved in 30 ml of dehydrated tetrahydrofuran, 4.7 ml of a 1.0 mol dm ^-3 tetrahydrofuran solution of potassium t-butoxide was gradually added dropwise at 22-29 ° C. After dropping, the mixture was stirred at room temperature for 3 hours, and then a small amount of diethyl benzylphosphonate was added, stirred for 30 minutes, and neutralized with acetic acid. The contents were dropped into water to obtain a crude polymer. This was purified by reprecipitation twice with tetrahydrofuran / ion-exchanged water and then with tetrahydrofuran / methanol, dissolved in methylene chloride, and repeatedly washed with ion-exchanged water until the conductivity of the washing solution was equivalent to that of ion-exchanged water. It was. After washing, it was dropped into methanol to obtain 1.20 g of an orange-yellow poly (triarylamine) (Example 1) represented by the following formula.

元素分析値（％）実測値（計算値）
Ｃ84.76（84.98） Ｈ8.26（8.05） Ｎ1.56（1.57）
赤外吸収スペクトル（ＮａＣｌキャスト膜）では９５９ｃｍ^−１にトランスオレフィンにもとづく吸収が認められた。
そして得られた重合体を、その繰り返し単位を分子量と換算し、濃度０．０１(mol/l) テトラヒドロフラン溶液を作成し、下記の二光子吸収断面積の評価方法により、その二光子吸収断面積を測定した。

Elemental analysis value (%) Actual measurement value (calculated value)
C84.76 (84.98) H8.26 (8.05) N1.56 (1.57)
In the infrared absorption spectrum (NaCl cast film), absorption based on transolefin was observed at 959 cm ⁻¹ .
Then, the obtained polymer was converted into a molecular weight of the repeating unit, and a tetrahydrofuran solution having a concentration of 0.01 (mol / l) was prepared, and the two-photon absorption cross-sectional area was evaluated by the following two-photon absorption cross-sectional evaluation method. Was measured.

(Example 2)
In the same manner as in Example 1, the following structural compound (Example 2) was obtained. Then, the obtained polymer was converted into a molecular weight of the repeating unit, and a tetrahydrofuran solution having a concentration of 0.01 (mol / l) was prepared, and the two-photon absorption cross-sectional area was evaluated by the following two-photon absorption cross-sectional evaluation method. Was measured.

(Example 3)
In the same manner as in Example 1, the following structural compound (Example 3) was obtained. Then, the obtained polymer was converted into a molecular weight of the repeating unit, and a tetrahydrofuran solution having a concentration of 0.01 (mol / l) was prepared, and the two-photon absorption cross-sectional area was evaluated by the following two-photon absorption cross-sectional evaluation method. Was measured.

Example 4
In the same manner as in Example 1, the following structural compound (Example 4) was obtained. Then, the obtained polymer was converted into a molecular weight of the repeating unit, and a tetrahydrofuran solution having a concentration of 0.01 (mol / l) was prepared, and the two-photon absorption cross-sectional area was evaluated by the following two-photon absorption cross-sectional evaluation method. Was measured.

(Example 5)
The following structural compound (Example 5) was obtained in the same manner as in Example 1. Then, the obtained polymer was converted into a molecular weight of the repeating unit, and a tetrahydrofuran solution having a concentration of 0.01 (mol / l) was prepared, and the two-photon absorption cross-sectional area was evaluated by the following two-photon absorption cross-sectional evaluation method. Was measured.

(Example 6)
A compound (Example 6) having a repetition number n of n = 1 in Example 1 was synthesized by the following reaction scheme under the synthesis conditions according to Example 1. Then, a compound concentration 0.01 (mol / l) tetrahydrofuran solution was prepared, and the two-photon absorption cross section was measured by the following two-photon absorption cross-section evaluation method.

(Example 7)
The following structural compound (Example 7) was obtained in the same manner as in Example 6. Then, a compound concentration 0.01 (mol / l) tetrahydrofuran solution was prepared, and the two-photon absorption cross section was measured by the following two-photon absorption cross-section evaluation method.

(Example 8)
In the same manner as in Example 6, the following structural compound (Example 8) was obtained. Then, a compound concentration 0.01 (mol / l) tetrahydrofuran solution was prepared, and the two-photon absorption cross section was measured by the following two-photon absorption cross-section evaluation method.

Example 9
The following structural compound (Example 9) was obtained in the same manner as in Example 6. Then, a compound concentration 0.01 (mol / l) tetrahydrofuran solution was prepared, and the two-photon absorption cross section was measured by the following two-photon absorption cross-section evaluation method.

(Example 10)
The following structural compound (Example 10) was obtained in the same manner as in Example 6. Then, a compound concentration 0.01 (mol / l) tetrahydrofuran solution was prepared, and the two-photon absorption cross section was measured by the following two-photon absorption cross-section evaluation method.

(Comparative Example 1)
In the following structural compound (Comparative Example 1), a tetrahydrofuran solution having a concentration of 0.01 (mol / l) was prepared, and the two-photon absorption cross section was measured by the following two-photon absorption cross-section evaluation method.

(Evaluation method of two-photon absorption cross section)
A schematic diagram of the measurement system is shown in FIG.
Measuring light source Femtosecond titanium sapphire laser Wavelength 800nm
Pulse width 100fs
Repeat 80MHz
Optical power 800mW
Measurement method Z scan method Light source wavelength 800nm
Cuvette inner diameter 10mm
Measurement optical power approx. 500 mW
Repetition frequency 80MHz
Condenser lens f = 75mm
Condensing diameter 40-50 μm
A quartz cell filled with the sample solution was placed in the focused optical path part, and Z-scan measurement was performed by moving the position along the optical path.

<Calculation formula>
The transmittance was measured, and the nonlinear absorption coefficient was determined from the result by the following theoretical formula (I).

（上記式中、Ｔは透過率（％）、Ｉ0は励起光密度［ＧＷ／ｃｍ^２］、Ｌ0は試料セル長［ｃｍ］、βは非線形吸収係数［ｃｍ／ＧＷ］を示す。）

(In the above formula, T represents transmittance (%), I 0 represents excitation light density [GW / cm ² ], L 0 represents sample cell length [cm], and β represents nonlinear absorption coefficient [cm / GW].)

From this nonlinear absorption coefficient, the two-photon absorption cross section δ was determined by the following formula (II).
(The unit of δ is 1GM = 1 × 10 ⁻⁵⁰ cm ⁴ · s · photon ⁻¹ .)

（上記式中、ｈはプランク定数［Ｊ・ｓ］、νは入射レーザー光の振動数［ｓ−１］、ＮAはアボガドロ数、Ｃは溶液濃度［ｍｏｌ／Ｌ］を示す。）

(In the above formula, h represents Planck's constant [J · s], ν represents the frequency of incident laser light [s-1], NA represents the Avogadro number, and C represents the solution concentration [mol / L].)

(Evaluation results)
The evaluation results of Examples 1 to 10 and Comparative Example 1 are shown in Table 1.
In Examples 1 to 10, it was possible to obtain a material having a higher two-photon absorption capacity than the conventional (Comparative Example 1).
Further, the two-photon absorption material of the present invention has an effect of improving characteristics by one digit or more as compared with the conventionally known two-photon absorption cross-section of a compound that exhibits two-photon absorption ability, and does not require a high-power laser. It has become clear that this is an inexpensive laser and can be expected to be applied to three-dimensional memories, light limiting elements, optical modeling materials, dye materials for two-photon fluorescence microscopes, and the like.

(A) is a schematic diagram of a recording / reproducing system of a three-dimensional multilayer optical memory, and (b) is a schematic sectional view of a recording medium. It is the figure which showed an example of the optical control element which optically switches the signal light of the wavelength which can carry out one-photon excitation by carrying out the two-photon excitation of the two-photon absorption material of this invention with the control light of the wavelength which can carry out two-photon excitation. . It is the schematic of the apparatus of the two-photon stereolithography. It is the schematic of the basic composition of a two-photon excitation laser scanning microscope. 1 is a schematic diagram of a measurement system used in the present invention.

Explanation of symbols

30 Light Modeling Object 31 Light Source of Near-Infrared Pulsed Laser Light Transparency to Light Curing Resin Solution 32 Shutter 33 for Controlling Excessive Light Temporarily 33 ND Filter 34 Mirror Scanner 35 Lens 36 as Condensing Means Z Stage 37 monitor 38 computer 39 photocurable resin liquid 41 laser light source 42 light beam conversion optical system 43 scanning optical system 44 objective lens system 45 sample surface 46 dichroic mirror 47 photodetector

Claims (6)

A two-photon absorption material having a structure represented by the following general formula (II);

(Wherein, Ar ₃ is a substituted or unsubstituted benzene or biphenyl monovalent group with an alkyl group or an alkoxy group, Ar ₆ is a divalent substituted or unsubstituted benzene or thiophene with an alkyl group or an alkoxy group Ar ₇ and Ar ₈ are monovalent groups of benzene substituted or unsubstituted with an alkyl group or an alkoxy group, and R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom , an alkyl group, an alkoxy group A group selected from a group.) A two-photon absorption material having a repeating unit represented by the following general formula (V);

(Wherein, Ar ₃ is a substituted or unsubstituted benzene or biphenyl monovalent group with an alkyl group or an alkoxy group, Ar ₆ is a divalent substituted or unsubstituted benzene or thiophene with an alkyl group or an alkoxy group And R ₁ , R ₂ , R ₃ and R ₄ are groups selected from a hydrogen atom , an alkyl group and an alkoxy group .) Three dimensional memory material including two-photon absorption material according to claim 1 or 2. Optical limiting material including two-photon absorption material according to claim 1 or 2. Curing material for stereolithography photocurable resin containing a two-photon absorption material according to claim 1 or 2. Fluorescent dye material for two-photon fluorescence microscope including two-photon absorption material according to claim 1 or 2.

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