JPH01239535A - Production of fine metal particle-added matrix - Google Patents

Abstract

PURPOSE:To form a high-quality nonlinear matrix having a large nonlinear optical constant by doping the fine metal particle formed by photoirradiation or/and heating into the matrix. CONSTITUTION:An org. acid is added to a soln. of a metal alkoxide and this metal alkoxide is hydrolyzed and condensed to form porous glass. The porous glass is heated to form transparent glass. The metal salt of the org. acid is obtd. in this process. The metal salt of the org. acid is dissociated to org. ions and metal ions by irradiating UV rays to the metal salt of the org. acid. The metal ions or reduced metals are flocculated to form the fine metal particles. The matrix doped with the fine metal particles having small grain sizes and a uniform grain size distribution is thereby obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for producing a metal fine particle-doped matrix having a large optical nonlinear effect essential for realizing optical logic devices and ultrahigh-speed optical switches.

"Prior Art" Semiconductor fine particle crystal doped glass and metal fine particle doped glass are attracting attention as optical glasses with large nonlinear optical constants. It has been revealed that semiconductor-doped glass, known as a visible color glass filter, has a very large third-order optical nonlinear constant. This colored glass filter is a semiconductor mixed crystal Cd5exS in silicate glass.
It is doped with +-x, and these fine particles are dispersed in the glass in a size of about 100 particles. In such a semiconductor-doped glass, it is thought that the nonlinear effect becomes large due to the Prince size effect and carrier confinement effect of minute semiconductor particles. Batch melting methods have traditionally been used to make this type of glass. That is, metallic selenium and cadmium sulfide are used as semiconductor raw materials, and they are mixed into glass raw materials of silica sand, soda ash, potassium carbonate, and zinc oxide, and then melted and cooled. During this glass cooling process, CdS precipitates as fine crystal nuclei. After this process, by heat-treating the glass again, CD", S",
Se'- thermally diffuses and forms Cd5- around the CdS crystal nucleus.
A CdSe mixture is formed and a colored glass is obtained.

``Problems to be Solved by the Invention'' However, in the method for manufacturing non-linear bayu glass, the manufacturing process is complicated, and a heat treatment process is used to control the particle size, which makes it difficult to precisely control the particle size. The manufacturing process itself often relies on human intuition, making it difficult to produce nonlinear glass with good reproducibility. Furthermore, this badge melting method has the problem that the thin film formation necessary for manufacturing optical devices such as optical logic devices and optical switches is extremely conical, making it difficult to apply to the manufacturing of optical nonlinear application devices.

On the other hand, in the glass doped with the metal fine particles,
It is believed that a large nonlinear effect is obtained due to the dispersion of the dielectric constant caused by surface plasmons at the interface between the dielectric material (glass) and the metal particle. At this time, the diameter (or size) of the added fine particles must be sufficiently small compared to the wavelength and uniform. However, the conventional technique for doping glass with fine metal particles that meet these conditions and uniformly dispersing them has been the batch melting method, and basically a heat treatment process is used to control the particle size, similar to Cd5Se-added glass. Therefore, reproducibility and controllability were extremely difficult.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to obtain a nonlinear matrix and a nonlinear thin film such as an extremely high quality nonlinear optical glass having a large nonlinear optical constant essential for realizing optical logic elements and ultrahigh-speed optical switches. The object of the present invention is to provide a method for manufacturing a matrix doped with fine metal particles having a small particle size and a uniform particle size distribution, and a method for manufacturing a matrix that allows addition of a new dopant.

"Means for Solving the Problems" As a result of various studies on manufacturing methods for 7-trisox doped with fine metal particles having a small particle size and uniform particle size distribution, the inventors of the present invention have found that the photochemical reaction can be substantially reduced for full use. They found that the metals dissociated by this process have extremely small particle sizes and a uniform particle size distribution, and that this method using photochemistry is also extremely easy to add to the matrix.

Taking a hexagonal acid metal salt as an example, the principle of the present invention is explained by the following reaction formula (1-1).

RCOOM -RCOO-10 M+
(+-1) Zunawara, organic acid metal salt (RCOO
By irradiating M) with ultraviolet light, it dissociates into organic ions and metal ions. These metal ions or reduced metals aggregate to form fine metal particles.

Similarly, in the case of silver halide, it can be represented by formula (2-1).

AgX-・Ag” + X + e-(2-1
) The present invention involves doping metal fine particles substantially dissociated by light irradiation into a matrix of glass, organic polymer, or the like. Another aspect of the present invention is to dope an organic acid metal salt or silver halide capable of dissociating fine metal particles into a matrix or a precursor thereof by irradiation with light, and then dissociate the metal by irradiation with light or the like. This is Surushino. Since such a reaction proceeds on a molecular order, fine particles with an extremely small particle size and a uniform particle size distribution can be obtained. It is generally said to be fine particles with a particle size of 200 Å or less.

In the present invention, compounds that dissociate metals by such light irradiation are not particularly limited, but include organic substances having hydroxyl groups, carboxyl groups, etc., organic acid metal salts, silver halide used in silver salt photography, etc. Illustrated. Among these, particularly preferred are organic acid metal salts with excellent sensitivity;
silver halide and mixtures thereof.

The hexagonal acid metal salt in the present invention is prepared by reacting an organic acid with sodium hydroxide or the like to form a sodium salt [formula (3)], and reacting the obtained sodium salt of the organic acid with a metal nitrate [
(4) formula] is obtained.

RCOOII -4NaOH→ RCOONa
+ lI20RCOONa +
AgNO3→ RCOOAg + Na
N0*(·1) Therefore, the hexagonal acid metal salt in the present invention includes, in addition to the hexagonal acid metal salt, those which can be used in the form of the above-mentioned organic acids or organic acids in the form of sodium. Such organic acids include formic acid, acetic acid, brobynic acid, acrylic acid, methacrylic acid, salicylic acid, benzoic acid, glycolic acid, L-arginic acid, alginic acid, L-aspartic acid, L-glutamic acid, leflic acid, Examples include tartaric acid, calfoquinedylcellulose, nouric acid, polyacrylic acid, and polymethacrylic acid. An organic acid sodium salt can be obtained by reacting such an organic acid with sodium hydroxide. Furthermore, a desired organic acid metal salt can be obtained by reacting this organic acid sodium salt with a metal nitrate such as silver nitrate. In the case of dibasic acids, 1 silver salt and 2 silver salt are included.

Examples of silver halides include silver chloride, silver bromide, and silver iodide.

Furthermore, examples of organic substances having functional groups include phenol, pentachlorophenol, methylglyochime, acetoquim, and the like.

Examples of the metal in the present invention include silver, palladium, mercury, thallium, copper, lead, and iron, and among these, silver is particularly preferred because of its excellent sensitivity.

Prior to implementing the present invention, the sensitivity of some of the organic acid silver salts used in the present invention was measured.

Namely, silver acetate (a), glutamate silver salt (b)
, silver glutamate (c), silver formate (d), and silver tartrate (e). One gram of each of these organic acid silver salts was dissolved in about 20 mg of a mixed solvent of ethanol/water/ammonia water to prepare a photosensitive solution. Since each photosensitive material has a different molecular weight, the concentration of the photosensitive solution was adjusted so that the amount of silver atoms contained in the photosensitive film was the same. Photosensitive liquid 0, lm
Q was dropped onto a glass plate and dried in the cool and dark at about 40°C to obtain a photosensitive film. This film was irradiated with ultraviolet light using an ultra-high pressure mercury lamp. When exposed to light, silver metal precipitates and becomes black. The degree of blackening was measured using a concentration system, and was determined to correspond to the amount of dissociated silver. FIG. 1 is a diagram showing a representative example of the sensitivity of the organic acid silver salt obtained in this manner. Although there are differences in the photodecomposition rate depending on the type of organic acid silver salt, silver precipitation is observed from all silver salts when irradiated with ultraviolet rays.

Figure 2 shows the sensitivity when heat is used instead of light. The organic acid silver salts and processing temperatures targeted here are as follows. That is, silver glutamic acid salt (heat treatment temperature =
30°C) (a), silver formate (heat treatment temperature = 50°C) (b), disilver glutamate (heat treatment temperature: 100°C) (c), disilver tartrate (heat treatment temperature: 60°C) (d) , glutamic acid disilver salt (heat treatment temperature, 120°C) (e). From FIG. 2, it can be seen that certain organic acid silver salts easily dissociate silver by heat.

The matrix in the present invention may be organic or inorganic. Typical examples include organic polymers and glass. Particularly preferred among these is a matrix obtained by hydrolysis/condensation of a metal alkoxide to which the above metal fine particles can be uniformly added. These can be used in the form of a metal alkoxide solution, a solution of a partial hydrolysis product of a metal alkoxide, or a porous glass. The metal in the metal alkoxide of the present invention is exemplified by Si, Ge, Ti, Zr, A(, B, etc., but Si is the most common. In the metal alkoxide of the present invention, all substituents are alkoxide groups. For example, if the metal is silane, in addition to tetraalkoxysilane, which is a raw material for silica glass, there are also trialkoxysilane, dialkoxysilane, in which some of the alkoxyl groups are substituted with organic groups, Examples include monoalkoxysilanes.

This type of organic group is not particularly limited, but includes alkyl groups such as ethyl and methyl, alkenyl groups such as vinyl,
Examples include aryl groups such as phenyl and derivatives thereof. Furthermore, when these organic groups contain polymerizable double bonds, this can be used to cause intermolecular crosslinking.

Further, even if a halogen such as chlorine is used instead of an alkoxyl group, the same effect as when using an alkoxysilane can be expected.

Examples of the monoalkoxide used in the present invention include methoxytrimethylsilane, ethoxytrimethylsilane, dimethylethoxyphenylsilane, and diphenylethoxymethylsilane. Examples of the dialkoxide include jetoxydimethylsilane, jetoxydimethylsilane, dimethoxymethyl-3.3.3-triph[10propylsolane, diethylvinylene divinylene, noethoxydiethylnolan, and 3-aminobrobylnoethoxomethylsilane. ,
Examples include 3-(2-aminoethylaminopropyl)nomethoxynomethylsilane, dimethoxynomethylphenylsolane, noedquinmethylphenylsilane, dimethoxydiphenylsilane, noethoquinophenylsilane, tris-(2-methoxyethoxy)vinylsilane, etc. Ru. Examples of trialkoxides include methyltrimethoxynosilane, ethyltrimethoxynolane, 3.3.3-triprobyltrimethoxynolane, methyltrimethoxynosilane, 3-(N-methylaminopropyl)trimethoxysilane, and methyltris(2-amineethquin). Triacetoquinylnorane, triacetoquinylnorane, ethyl I-lietoxinrane, 2-mercaptonidoxinrane, 3-(
2-aminoethylaminopropyl) trimethoxysilane, phenyltrimethoxysilane, 2-cyanoethyltriethoxysilane, allyltriethoxysilane, 3-glyndoxybrobyltrimethoxysilane, probyltriethoxonerane, hequinrutrimethoxysilane Ran, 3-aminopropyltriethoxysilane, 3-methacryquinopropyltrimethoxyrane, methyltrimethoquinosilane, phenyltriethoxonorane, and the like are exemplified. Examples of the tetraalkoxide include tetramethquinsilane, tetraacetoquinsilane, tetramethquinsilane, tetraacetoquinsilane, tetrabutoxysilane, and tetraethquinzircon.

Of course, metal alcoquids other than those mentioned above may also be used. Examples of this type of alkoxide include triethoxyaluminum and triethoxyboron.

In the present invention, the metal alkoxide hydrolysis and condensation products refer to those in which the hydrolysis and condensation reactions of metal alkoxides have partially progressed or have substantially completed. Hydrolysis reactions and condensation reactions of metal alkoxides are shown as in formulas (5) and (6), taking tetraaloxysilane as an example.

Si(OR)4 + 41LO→ 5i(
OH), +4ROIlSi(Off)
= -Sin, + 211-0 (6)
However, as is well known, the condensation reaction rate is generally much faster than the hydrolysis reaction rate, so it is thought that hydrolysis and condensation do not occur sequentially, but actually occur simultaneously. Therefore, by controlling the rate of hydrolysis by adjusting reaction conditions such as catalyst, temperature, and time, it is possible to obtain products with different progress states of the reaction, that is, products with different properties. These products have different structures and properties, such as solubility in organic solvents, depending on the type of alkoxide used as the starting material and the degree of progress of the reaction. After taking it out as a liquid, the reaction can be proceeded by reheating or the like.

Specifically, there are several different methods for manufacturing the metal fine particle-added matrix according to the present invention. A typical example of using silver as the metal fine particles will be described below.

■ Add an organic acid to a solution of metal alkoxide, hydrolyze and condense the metal alkoxide to create porous glass, and heat the porous glass to make transparent glass. In this process, an organic acid and sodium hydroxide are reacted to form an organic acid sodium, and the organic acid is further reacted with silver nitrate to obtain an organic acid silver salt. This is then irradiated with light or heated,
Alternatively, fine silver particles are precipitated by using both of them together.

As a result, a matrix to which silver fine particles are added is obtained.

■ Partial hydrolysis and condensation of metal alkoxide (7) An organic acid is added to a relatively high viscosity solution, and this partial hydrolysis and condensation solution of metal alkoxide is further hydrolyzed and condensed to create porous glass. Porous glass is heated to make transparent glass.In this process, organic acid and sodium hydroxide are reacted, and the organic acid is converted into sodium hydroxide.
Further, it is reacted with silver nitrate to obtain an organic acid silver salt. By irradiating this with light, heating, or a combination of both,
Precipitate silver particles. As a result, a matrix to which silver fine particles are added is obtained.

■ Porous glass produced by hydrolyzing and condensing metal alkoxide is impregnated with organic acid, and then heated to produce transparent glass. Rub. In this process,
An organic acid is reacted with sodium hydroxide to form an organic acid sodium, and further reacted with silver nitrate to obtain an organic acid silver salt. Fine silver particles are precipitated by light irradiation, heating, or a combination of both. As a result, a matrix to which silver fine particles are added is obtained.

■ After impregnating porous glass such as Vycor glass with an organic acid, the porous glass is heated to become transparent glass. In this process, an organic acid and sodium hydroxide are reacted to form an organic acid sodium, and further reacted with silver nitrate to obtain an organic acid silver salt. Fine silver particles are precipitated by light irradiation, heating, or a combination of both.

As a result, a matrix to which silver fine particles are added is obtained.

■ Add sodium organic acid to a solution of metal alkoxide, hydrolyze and condense the metal alkoxide to create porous glass, and heat this porous glass to make transparent glass. In this process, organic acid silver salt is obtained by reacting sodium H organic with silver nitrate. Fine silver particles are precipitated by light irradiation, heating, or a combination of both.

As a result, a matrix to which silver fine particles are added is obtained.

■ After adding sodium organic acid to a relatively high viscosity solution obtained by partially hydrolyzing and condensing metal alkoxide, this partially hydrolyzed and condensed solution of metal alkoxide is further hydrolyzed and condensed to create porous glass. This porous glass is heated to become transparent glass. In this process,
An organic acid silver salt is obtained by reacting organic acid sodium and silver nitrate. Fine silver particles are precipitated by light irradiation, heating, or a combination of both. As a result, a matrix to which silver fine particles are added is obtained.

■ Manufactured by hydrolyzing and condensing metal alkoxide, impregnating porous glass with sodium organic acid, and then heating the porous glass to make transparent glass. In this process, organic acid sodium and silver nitrate are reacted to obtain an organic acid silver salt. Fine silver particles are precipitated by light irradiation, heating, or a combination of both. As a result, a matrix to which silver fine particles are added is obtained.

■ After impregnating porous glass such as Vycor glass with sodium organic acid, this porous glass is heated to become transparent glass. In this process, organic acid sodium and silver nitrate are reacted to obtain an organic acid silver salt. Fine silver particles are precipitated by light irradiation, heating, or a combination of both. From this, a matrix to which silver fine particles are added is obtained.

■ Add organic acid silver salt to a solution of metal alkoxide, hydrolyze and condense the metal alkoxide to create porous glass, and heat this porous glass to make transparent glass. In this process, fine silver particles are precipitated by light irradiation, heating, or a combination of both. As a result, a matrix to which silver fine particles are added is obtained.

[Co., Ltd.] Organic acid metal is added to a relatively high viscosity solution obtained by partially hydrolyzing and condensing metal alkoxide, and this partially hydrolyzing and condensing solution of metal alkoxide is further hydrolyzed and condensed to create porous glass. , this porous glass is heated to become transparent glass.

In this process, silver fine particles are precipitated by light irradiation, heating, or a combination of both. As a result, a matrix to which silver fine particles are added is obtained.

■ Porous glass produced by hydrolyzing and condensing metal alkoxide is impregnated with organic acid silver salt, and then heated to make transparent glass.

In this process, silver particles are precipitated by light irradiation, heating, or a combination of both.

As a result, a matrix to which silver fine particles are added is obtained.

■ After impregnating porous glass such as Vycor glass with organic acid silver salt, the porous glass is heated and transformed into transparent glass. In this process, fine silver particles are precipitated by light irradiation, heating, or a combination of both. As a result, a matrix to which silver fine particles are added is obtained.

(2) A porous glass produced by hydrolyzing and condensing a metal alkoxide is impregnated in a solution of a-organic silver salt irradiated with ultraviolet rays, and then the porous glass is heated to become transparent glass. As a result, a matrix to which silver fine particles are added is obtained.

It goes without saying that a polymer can also be used as a matrix.

Now, taking an organic acid silver salt as an example, the dissociation of silver proceeds according to equations (1-1) and (1-2), as described above.

Since the rate-determining process of this reaction is the reduction reaction of formula (+-2), it is effective to add a reducing agent such as zinc oxide to the system of the present invention. Similarly, when silver halide is used, reduction sensitization with gelatin, sulfur, etc. is also effective.

RCOOM-4RCOO-+ M" (+-1
)RCOO−−M” + e −RCOO−
+M The wavelength of light in the present invention is not particularly limited. Generally, the sensitivity of organic acid metal salts is 250n.
Ultraviolet light is used because it is around m. Also, the sensitivity of silver halide is 300 to 500 nI! +, so ultraviolet and visible light are used. Also, a specific wavelength (range)
If desired, the addition of dyes for spectral sensitization allows the use of longer wavelength light sources.

"Example" Hereinafter, the present invention will be explained in more detail with reference to Examples.

(Example-■) An aqueous solution of 17-glutamic acid (referred to as fine particle raw material) was added to a mixed solution (referred to as matrix starting material) consisting of tetraequinranine, ethanol, and aqueous ammonia, and this solution was heated at 60°C for 70 minutes. Heated for days. Furthermore, 12
Porous glass was obtained by heating at 0° C. for 3 days. This porous glass was immersed in an aqueous sodium hydroxide solution and then dried. Furthermore, the obtained porous glass was immersed in an aqueous silver nitrate solution, washed with water, and dried. Next, this porous glass was irradiated with ultraviolet rays using a high-pressure mercury lamp, and then vitrified by heating to obtain silver-doped glass. The obtained silver-doped glass was cut to a thickness of about 1 mat, polished, and then 3
When evaluating the following nonlinear susceptibility [χ(3)], z
A value of (3)-1,2X I O-9esu was obtained.

As a result, it was confirmed that this silver-doped glass has sufficient nonlinear characteristics as an optical nonlinear material. Furthermore, when the size of the silver particles doped into the same glass was measured using a TEM, the particle size was approximately 130 mm, and the particle size distribution revealed that the particles were uniform.

(Example 2) An aqueous glutamic acid solution was added to a mixed solution consisting of tetraethquinsilane, ethanol, hydrochloric acid, and water, and the solution was heated at 60°C for 4 days.

The resulting gel was heated at 40°C for 7 days. The obtained product was immersed in an aqueous sodium hydroxide solution and then dried.
Further, after being immersed in a silver nitrate aqueous solution, it was washed with water and dried.

Next, the obtained product was irradiated with ultraviolet rays using a high-pressure mercury lamp, and then vitrified to obtain silver-doped glass. When the third-order nonlinear susceptibility of the obtained silver-doped glass was measured in the same manner as in Example 1, it was found that z''-1,8X l
A value of O-'esU was obtained. Further, the average particle size of the silver particles doped into the same glass was about 70.

(Example 3) A mixed solution consisting of tetraethquinsilane, ethanol, and aqueous ammonia was heated at 70°C for 10 days.

A mixed solvent of ethanol, water, and aqueous ammonia in which L-glutamic acid was dissolved was added to this solution while irradiating ultraviolet rays with a high-pressure mercury lamp.

The resulting solution was heated at 120°C for 3 days to obtain porous glass. This porous glass was immersed in an aqueous sodium hydroxide solution and then dried. Furthermore, the obtained porous glass was vitrified by heating to obtain silver-doped glass. The nonlinear susceptibility of the silver-doped glass obtained by this method was χ(3)−+, 3X l O−′esu.

Further, the average particle size of the silver fine particles was 110A.

(Example 4) An aqueous L-glutamic acid solution was added to a mixed solution consisting of tetraethoxysilane, ethanol, hydrochloric acid, and water, and the solution was heated at 65° C. for 5 days.

The resulting gel was uniformly applied onto a 5 inch diameter Noricon wafer on which a 120 μm thick low refractive index glass thin film was formed, and heated at 45° C. for 5 days.

The obtained composite was immersed in an aqueous sodium hydroxide solution, then dried, further immersed in an aqueous silver nitrate solution, washed with water, and dried. Next, the product on the Si wafer was irradiated with ultraviolet rays using a high-pressure mercury lamp, and then vitrified in a He atmosphere to obtain a silver-doped glass thin film with a thickness of 15 μm. This thin film was processed into stripes with a width of 10 μm by photolithography and etching. Next, a low refractive index glass film was formed on the obtained composite glass film by sputtering to obtain a leading waveguide as shown in FIG. 3.

Figure 4 shows the results of evaluating the characteristics of the manufactured waveguide using the pump-probe method. The light source used is Mode Lock Q.
Switched second harmonic YAG laser (wavelength 0.53μm)
It is. As is clear from the figure, there is a supersaturated absorption characteristic due to absorption of pump light. This shows that the metal particle-doped glass waveguide manufactured by the method of the present invention is sufficiently useful as a nonlinear waveguide.

Similarly, as shown in Table 1, various organic acids (silver salts), silver halides, etc. were doped into various matrices to obtain matrices doped with silver fine particles (Examples 5 to +4). ). These are both χ3)-1, OX
It was confirmed that the nonlinear susceptibility was higher than that of IO-9esu.

"Effects of the Invention" As explained hereinafter, according to the method for manufacturing a metal fine particle-added matrix according to the present invention, since the metal dissociated by a photochemical reaction is doped, the metal particles are small in particle size and have a uniform particle size distribution. A fine-particle doped matrix is obtained, which has the advantage of providing high quality optically nonlinear materials.

Furthermore, since the present invention uses a photochemical reaction, it has the advantage of excellent compatibility with manufacturing processes for optical logic elements, integrated optical components, and the like.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the sensitivity to light of the organic acid silver salt used in the present invention, Figure 2 is a diagram showing the sensitivity to heat of the organic acid silver salt used in the present invention, and Figure 3 is a diagram showing the sensitivity to heat of the organic acid silver salt used in the present invention. Schematic diagram of a leading waveguide fabricated using a silver-doped glass thin film, No. 4
The figure is a diagram showing the characteristics of the leading wavepath shown in FIG. 3. 1...Si wafer 12...Low refractive index glass, 3...Metal fine particle added glass. Figure 1 Light hit, pull'ener~' (X lo"erq /c
m2) 2nd body 4th place Tamari gij (minute 3rd figure 4th figure -0500,51 delay time darkness 1 n5ec)

Claims (1)

[Scope of Claims] 1) A method for producing a metal fine particle-added matrix, which comprises doping the matrix with metal fine particles generated by light irradiation and/or heating. 2) A method for producing a metal fine particle-added matrix, which comprises doping into the matrix a compound capable of producing metal fine particles by light irradiation and/or heating.