JP2556482B2 - Semiconductor-containing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a semiconductor-containing device including an electron donor, an electron acceptor and a semiconductor in a substrate, and the device is, for example, a light-driven display device or a recording device. It relates to the technical field used as.

[Prior art]

As a non-emissive display element, an electrochromic display element (hereinafter abbreviated as ECD) is being actively developed along with a liquid crystal display element (hereinafter abbreviated as LCD). L
While CDs are being developed to be put to practical use as wall-mounted TVs, ECDs have display characteristics superior to those of LCDs, such as easy-to-read, no viewing angle disparity, and memory characteristics, but are practical due to their short life. The conversion is delayed. Under these circumstances, in order to promote product development of ECD as a practical device in the future, it is important to design the device by taking advantage of the functional characteristics different from LCD. That is, paying attention to the display memory property of the ECD, it can be considered to be used as a display device having a recording property rather than a simple display device, for example, a public display such as a bulletin board or a station for education and meetings. Furthermore, it may be considered to commercialize a new type of electrolytic recording element.

By the way, when considering the use as a recording element, the recording density or the degree of freedom of recording becomes a problem, but since the base electrode is required as long as the conventional ECD principle is used, these problems are fundamentally solved. I can't do that. That is, in the ECD, since it is necessary to install a base electrode having a shape corresponding to the character or pattern to be expressed, the wiring becomes extremely complicated for high-density recording and displaying, which is a serious obstacle to practical use. Therefore, the inventors of the present invention considered to manufacture an optically driven ECD in order to fundamentally solve this point. That is,
Device using photo-responsive semiconductor for substrate electrode (Photoelect
rochromic Device; hereinafter referred to as PECD. ) Was tried to develop.

The principle of PECD is, for example, J. Electrochem. Soc., 127 , 158.
2-1588, (1980). According to this report, using n-type ZnO, ZnO
An optical recording method has been attempted in which a pbO ₂ film is formed on an electrode.

Further, according to the report of J. Electrochem. Soc., 127 , 333-338, (1980), p-type GaAs is used to deposit a viologen cation radical on a GaAs electrode by a photo-redox reaction to perform optical recording. Is disclosed.

However, in these conventional methods, the handled reaction system is a reaction in an aqueous solution, and it is merely to propose the operating principle of PECD.

[Problems to be solved by the invention]

An object of the present invention is to provide a novel solid-state thin film element that can be used in, for example, PECD.

[Means for solving problems]

The present invention is a semiconductor-containing element comprising a thin film base material, which comprises (1) a semiconductor that generates electrons and holes by light irradiation in the thin film base material, and has an electron in or on the surface (2) at least one of the electron donor and the electron acceptor is discolored by oxidation or reduction, and at least one of the electron donor and the electron acceptor. Is a polymer metal complex, and (3) when the electron donor and the electron acceptor are both (i) polymer metal complexes, they are immobilized on the respective opposite surfaces of the substrate. Or (ii) if the electron donor of both is not a polymer metal complex, the electron donor is irreversibly oxidized, or (iii) if it is not one of the polymer metal complexes. In the polymer Electron donor or electron acceptor in the reduction or oxidation product species not metal complex is insoluble in the solvent in the substrate, it relates to a semiconductor-containing device characterized.
As a result of intensive efforts to solidify the device into a thin film, the inventors have developed a technique for efficiently incorporating the constituent components of the device into a thin film substrate. Hereinafter, each constituent component will be specifically described, and a technique of incorporating these components into the base material will be described.

As the electron donor used in the present invention, an insoluble mixed-valence polynuclear metal complex represented by Prussian blue (hereinafter abbreviated as PB), polyvinyl pyridine, polyvinyl imidazole, polyacrylic acid, polyvinyl alcohol and the like are bonded. Transition of low valence state of iron (II), cobalt (II), nickel (II), copper (I), etc. to a high molecular weight substance having a possible functional group (hereinafter referred to as metal coordination polymer) Tris (vasophenanthroline) iron (II), including soluble polymeric metal complexes with metal ions coordinated
Complex, tris (2,2'-bipyridine) iron (II) complex, tris (phenanthroline) cobalt (II) complex, low molecular metal complex such as ferrocene, polycyclic aromatic such as anthracene, acenaphthylene, carbazole, tetrathiafulvalene Conductive polymer obtained by oxidative polymerization of compounds, polypyrrole, polythiophene, polyaniline, etc.,
Reduced quinones such as hydroquinone, pyrogallol and catechol, tartaric acid, organic acids such as ethylenediaminetetraacetic acid and formic acid, alcohols such as methyl alcohol, ethyl alcohol, polyvinyl alcohol and cellulose,
Examples thereof include amines such as triphenylamine, butylamine and triethanolamine, thiol compounds, tetrahydrofuran and the like.

On the other hand, as an electron acceptor, an insoluble mixed-valence polynuclear metal complex typified by PB, an iron (II
I), cobalt (III), nickel (III), copper (II), and other high-valence transition metal ions coordinated to form a plastic polymer metal complex, as well as methyl viologen, heptyl viologen, benzyl viologen, etc. Of 4,
4'-bipyridinium salt, 9,10-anthraquinone-2,6-
Disodium disulfonate, 9,10-anthraquinone-1
-Oxidized quinones such as sodium sulfonate, 1,3-
Examples thereof include dibutyl alloxazine, 1,3-didodecyl alloxazine, vitamin K, benzylnicotinamide, flavin mononucleotide, and tetracyanoquinodimethane.

The semiconductor used in the present invention may be amorphous fine particles or single crystal, and the types thereof include single semiconductors such as Ge and Si, III-V group compound semiconductors such as GaAs and InP, CdS and ZnO. Basically, all semiconductors such as II-VI group compound semiconductors of

When the device of the present invention is used in, for example, PECD,
It is preferable to solidify the device into a thin film. Therefore, it is necessary to efficiently incorporate each component of the electron donor, the electron acceptor and the semiconductor into the thin film substrate. Examples of such a base material include materials such as high molecular weight substances and ceramics, but a polymer base material is preferable because it can be easily made large in area, is flexible, and is inexpensive. Specific examples of such a polymer substrate include polystyrene, polyethylene, polypropylene, polymethylmethacrylate, polytetrafluoroethylene, nylon, polystyrenesulfonic acid, polyacrylic acid, polymethacrylic acid,
Examples thereof include polyacrylonitrile, polyvinyl pyridine, polyvinyl alcohol, poly-p-aminostyrene, Nafion (trademark) and the like. From the viewpoint of device production, it is preferable that the above-mentioned polymer base material is insoluble in a solvent such as water. Therefore, it is desirable that the polymer base material has a crosslinked structure. As the high molecular weight substance having a cross-linking structure, a metal coordinating monomer such as styrene sulfonic acid, acrylic acid, acrylonitrile, 4-vinyl pyridine, p-aminostyrene and a cross-linking monomer such as divinylbenzene and methylenebisacrylamide can be used. Examples thereof include high molecular weight substances obtained by crosslinking a high molecular weight substance having a reactive group in the side chain such as a polymer, polyvinyl alcohol, polyallylamine with a crosslinking agent such as glutaraldehyde, cyanuric chloride, toluene diisocyanate.

As a method for incorporating a semiconductor into a polymer base material, a so-called "casting method" is generally used, in which a semiconductor is dispersed in a solution in which a polymer is dissolved and the semiconductor is dispersed and the solvent is evaporated to dryness. As another method, metal ions are previously adsorbed in the polymer base material, and the base material is H ₂ S, Na ₂ S, Na ₂ S ₂ O ₄ ,
There is also a method of generating and dispersing a semiconductor in a base material by bringing it into contact with a reducing agent containing a chalcogen element such as Na ₂ Se or Na ₂ SeO ₃ . This method is particularly useful for chalcogenide compound semiconductors.

As a method of incorporating the electron donor and the electron acceptor into the semiconductor-containing substrate, when the electron donor or the electron acceptor is a low molecular weight substance, it is dissolved in a solvent or the liquid one is left as it is. The semiconductor-containing base material may be impregnated. The electron donor or electron acceptor has an ionic group such as a carboxyl group or a quaternary ammonium group, or a reactive group such as an amino group or a hydroxyl group, and the semiconductor-containing substrate has such an ionic group or a reactive group. In the case of having a functional group capable of being bonded directly to the group or indirectly via some reagent, it can be incorporated by immobilizing the electron donor and / or the electron acceptor on the substrate by a chemical bond. When the electron donor and / or the electron acceptor is a high molecular weight substance and is soluble in a solvent, it can be immobilized by coating a solution of the solvent in a solvent on the surface of the semiconductor-containing substrate and drying. When the electron donor and / or the electron acceptor is a polymer metal complex and is a solvent-insoluble and infusible polynuclear metal complex typified by PB, a semiconductor-containing substrate is formed by a physical method such as vacuum deposition. It can be fixed on the surface. Alternatively, according to a new thinning technology (hereinafter referred to as a surface complexing method) originally developed by the present inventors, it is possible to stably and efficiently immobilize a polymer metal complex on a substrate surface. You can

That is, the general formula ▲ M ^X _A (L ^A _a ) l ▼ (wherein, ▲ M ^X _A ▼ represents a transition metal ion in an X-valent valence state, and ▲ L ^a _A ▼ represents a neutral or a-valent in ligand having a positive charge,錯陽ion of the general formula is a and l represented by represents a positive integer including _{^{0) ▲ M Y B (L}} b B) m (L c C) n ▼ ( formula among, ▲ M ^Y _B ▼ represents a transition metal ion of the Y-valent valence state, ▲ L ^b _B ▼ is a ligand having a b-valent negative charge, ▲ L ^c _C ▼ neutral or c Represents a ligand having a negative negative charge, b is a negative integer, and c is a negative integer including 0. Note that m is a positive integer and n is a positive integer including 0. An insoluble polynuclear metal complex can be formed on the substrate by mixing with a complex anion represented by (representing an integer) in an amount equivalent to neutralize the charge. That is, the above-mentioned complex cation or complex anion is preliminarily adsorbed on the base material, and then the base material is immersed in a solution containing a complex ion having a charge opposite to that of the ion contained in the base material. By the way
A desired polymer metal complex can be deposited on the surface of the base material. To specifically exemplify the transition metal ion and the ligand constituting the complex ion used here, ▲ M ^X _A ▼ and ▲
M ^Y _B ▼ means Fe ²⁺ , Fe ³⁺ , Co ²⁺ , Co ³⁺ , Ni ²⁺ , Ru ²⁺ ,
Ru ³⁺ , Os ²⁺ , Os ^3+, and other metal ions mainly in the low-valence and high-valence states of Group VIII of the Periodic Table are suitable. ▲ M ^X _A
FeCl ₂ , FeCl ₃ , RuCl ₃ , CoCl ₂ , FeSO as the feed material of ▼
Examples thereof include metal salts such as ₄ , Co (CH ₃ COO) ₂ and Fe (NH ₃ ) ₆ Cl ₂ . ▲ L ^{a _A} ▼ as can be used normally, ammonia, ethylenediamine, diethylenetriamine, bipyridine, phenanthroline, pyridine, a neutral ligand having no charge such as triethanolamine. A substituent having a positive charge such as a quaternary ammonium group may be bonded to these ligands. ▲ L ^b _B ▼ The, CN ^- including the, dimercapto maleic acid, pyromellitic acid, Jichiogizamido (rubeanic acid), naphthazarin, illustrate the bridging ligand having a negative charge, such as 1,6-dihydroxy phenazine be able to. Further, as ▲ L ^c _C ▼, CN ⁻ , SO ₃ ²⁻ , A _S O ₂ ⁻ , a ligand having a negative charge such as citric acid, iminodiacetic acid, nitrilotriacetic acid, or ammonia, Illustrative examples are ligands having no charge such as water and carbon monoxide.

At this _{^{time, ▲ M Y B (CN -}} ) 5 (L c C) as a feed material of complex anions represented by ▼, K ₃ [Fe (CN _{^-) 6],} K ₄ [F
e (CN _{^-) 6],} K _{2 ^{[Fe (CN -) 5 (H}} 2 O), K 4 [Ru (C
N _{^-) 6],} K ₄ [O _S (CN ⁷⁾ _6], C _S3 [Fe (CN _{^-) 6],}
A metal salt such as (NH ₄ ) ₂ [Fe (CN ⁻ ) ₅ (CO)] can be used.

As a method of incorporating a conductive polymer such as polypyrrole into the semiconductor-containing base material, for example, the following method can be applied. That is, a semiconductor-containing base material is sandwiched between two-chamber separates, and a solution in which a monomer used for synthesizing a desired polymer is dissolved is placed in one cell chamber,
A solution containing a polymerization initiator of the monomer is placed in the cell chamber on the opposite side. By doing so, a desired conductive polymer can be thinned on the semiconductor-containing film. For example,
In order to deposit a conductive polymer on one surface of a semiconductor-containing film as a base material and to stack an electron acceptor on the other surface, either one of a monomer and a polymerization initiator does not enter the base material film, or The requirement is that it is extremely difficult to penetrate. Therefore, if a specific example to which such a method can be applied is shown, the monomer is pyrrole,
Mention may be made of oxidatively polymerizable compounds such as thiophene, aniline, thiophenol. As a polymerization initiator for such a monomer, Na ₂ S ₂ O ₈ , K ₂ S ₂ O ₈ , KRuO ₄ ,
Examples of such compounds include K ₃ [Fe (CN) ₆ ], H ₂ PtCl ₆ , K ₂ PtCl ₄ , and K ₂ IrCl _{6 which} are ion-dissociated during dissolution and have a negatively charged polymerization active group. When the reaction is carried out in such a combination, for example, when the semiconductor-containing film as the base material is composed of a cation exchange film, the negative charge of the film and the dissociative group of the polymerization initiator having the negative charge Due to the electrostatic repulsive force, the rate at which the polymerization initiator penetrates into the base film becomes extremely slow. On the other hand, since the monomer molecule is electrically neutral, the permeation into the substrate film is relatively fast, and as a result, the polymerization of the monomer occurs only on the side of the cell chamber containing the polymerization initiator. The conductive biopolymer can be deposited only on one side of the semiconductor-containing film. The conditions for depositing the conductive polymer in a thin film state at that time vary depending on the combination of the monomer and the polymerization initiator, and also vary depending on the film thickness of the desired conductive polymer, generally speaking, Monomer concentration is 0.1-5 mol /, polymerization initiator concentration is 0.01-1 mol /, reaction time is 1-30 minutes, temperature is 4
The condition of about 50 ° C. can be exemplified. It should be noted that the device according to the present invention can be made as thick as about 10 microns or more, if desired. In the present invention, at least one of the electron donor and the electron acceptor is preferably a polymer metal complex.

Considering the use of the semiconductor-containing device of the present invention in, for example, PECD, the arrangement state of the electron donor, the electron acceptor and the semiconductor, which are the constituent components of the device, in the base material becomes important. That is, in order to efficiently transfer the electrons and holes generated by the semiconductor by absorbing light to the electron acceptor and the electron donor, respectively, the electron donor and the electron acceptor are separated through the semiconductor. Need to be In particular,
It is desirable to immobilize the electron donor and the electron acceptor on opposite sides of the semiconductor-containing substrate, and for that purpose, at least one of the electron donor and the electron acceptor is preferably a high molecular weight substance. Moreover, considering the durability and functionality of the semiconductor-containing element, it is preferable that the high molecular weight substance is a polymer metal complex. The operation principle of the semiconductor-containing device of the present invention when used in, for example, PECD will be briefly described below. The semiconductor (hereinafter abbreviated as S), the electron donor (hereinafter abbreviated as D), and the electron acceptor (hereinafter abbreviated as A) contained in the base material have an energy relationship as shown in FIG. (That is, the redox potential (1) of D is more negative than the position (2) of the valence band of S,
If the redox potential (4) of A is more positive than the position (3) of the conduction band of S, and the redox potential (1) of D is more positive than the redox potential of A (4), S Are excited by light irradiation to generate holes in the valence band and transfer electrons to the conduction band, thereby injecting electrons into the valence band of S from D,
At the same time, the electrons excited in the conduction band of S are transferred to A. As a result, the electrons are moved from D to A by the photoexcitation action of S, D is photooxidized, and A is photoreduced.
At this time, if a substance that changes color by oxidation or reduction (electrochromic material: hereinafter referred to as EC material) is used as D and / or A, the semiconductor-containing element can be used as PECD. By the way, when both D and A are redox agents which are reversibly redox-oxidized, the chemical species (D ⁺ ) produced by oxidation of D and the chemical species produced by reduction of A (A ⁻ ) are contacted with each other. According to the teaching of thermodynamics, the influx of electrons from A ⁻ to D ⁺ (hereinafter,
This is called reverse electron transfer) occurs automatically. In the unlikely event that such reverse electron transfer occurs, no chemical reaction will occur as a result. Of course, in such a case, photoelectrochromism is not observed. Therefore, in order to utilize the obtained semiconductor-containing device for PECD, it is important to prevent this reverse electron transfer.

The most effective way to prevent reverse electron transfer is to completely separate A and D via S spatially. Specifically, A and D may be immobilized on the opposite surfaces of the base material that face each other. As the method, for example, A and D are laminated on a base material in a thin film, or a bonding force such as a covalent bond, an ionic bond, or a hydrogen bond between A and D and the base material is used to chemically bond the surface of the base material. Can be fixed in place. As the former effective method, the above-mentioned surface complexing method can be mentioned. That is, according to the above procedure, a polymer metal complex such as PB can be laminated in a thin film on both surfaces or one surface of the substrate film. Since PB is a polymer metal complex in a mixed-valence state in which Fe ²⁺ and Fe ³⁺ are three-dimensionally bridged by a CN ^- bridged ligand, it is reversible according to formulas (1) and (2). Are both reduced and oxidized: Therefore, PB acts both as an electron donor and as an electron acceptor, so that a device in which PB is laminated on both surfaces of a substrate can be manufactured. The element is, for example, PECD
PB can be used as
Then, it is reduced and oxidized under the irradiation of light to change from blue to colorless and from blue to green, respectively. At this time, for example, if CdS is used as the semiconductor and Nafion is used for the base material film, the semiconductor-containing base material acts as a bright yellow background material, and the contrast from dark green to yellow on the reducing side of PB. Shows good discoloration. On the other hand, on the oxidized side of PB, the change from dark green to yellow green is visible to the naked eye, and the contrast is not so good. Therefore, when using PB, it is desirable to set the reduction side as the display surface. It is also possible to deposit PB only on one surface of the substrate and use this as a reduction side display surface, and use a different substance (electron donor) on the oxidation side. For example, according to the above method, when polypyrrole (PPy) is laminated on the surface opposite to PB and CdS is used as a semiconductor contained in the substrate, PB is electron-donated by irradiating PB with light. Even better results can be obtained than when used as a body and an electron acceptor. Thus, semiconductors,
The device performance can be controlled by the combination of the electron donor and the electron acceptor.

As another method for preventing reverse electron transfer, an electron donor that is irreversibly oxidized (hereinafter referred to as a sacrificial electron donor, D _S
May be used. In such a case, even if the photooxidation and reduction products D ⁺ and A ⁻ are brought into contact with each other, D ⁺ cannot return to the original state, so that the reverse electron transfer does not occur.
In such a case, D and A do not necessarily need to be separated and immobilized on the surface of the base material, and may be contained in the base material film. Examples of such sacrificial electron donors include organic acids such as tartaric acid, alcohols such as ethyl alcohol, amines, thiol compounds, and tetrahydrofuran. However, in such a case, replenishment of the sacrificial electron donor is required when the device is repeatedly operated.

Furthermore, if the reducing or oxidation product species A ⁻ or D ⁺ becomes insoluble in the water or other solvent used to contain A and / or D in the substrate, A ⁻ and / or
As D ⁺ is deposited on the surface of the semiconductor particles in the base material under light irradiation, contact between D ⁺ and A ⁻ is prevented, so that D and A are not separated and fixed in the base material, and Even if it is not an irreversible reagent, reverse electron transfer may be prevented. Examples of this include the case where A is viologen (particularly, a derivative in which an alkyl group is highly hydrophobic) and the case where D is a quinone compound. In addition, when deleting the display,
Sandwiching the semiconductor-containing substrate between the support electrode, D ⁺ → D and A ^- → A
The voltage polarity may be set so as to cause the following reaction, and a predetermined potential may be applied.

〔The invention's effect〕

Since the PECD, which is one application example of the semiconductor-containing device of the present invention, is a light-driven ECD, the degree of freedom in display is significantly increased as compared with a normal ECD. In PECD, since only the light irradiation part can be changed in color, it is possible to display an arbitrary pattern at any place on the electrode.As a result, the base electrode required for normal ECD is not required, and therefore the display The degree of freedom has been greatly improved. Furthermore, since it is a solid type, it is easy to handle. In addition, since the display can be rewritten, it can be used as a rewritable optical recording element by using a laser as a display light source and narrowing down the light irradiation part to the order of microns or submicrons.

[Example 1] A Nafion membrane (Nafion 117 manufactured by DuPont) was added to 50 mM.
It was immersed in an aqueous solution of cadmium acetate for 3 hours, washed with water and then immersed in saturated water of hydrogen sulfide for 10 hours. During this time, the transparent Nafion film was colored yellow, and the deposition of fine particles of cadmium sulfide was visually recognized inside the film. Next, the membrane was immersed in a 10 mM ferrous chloride aqueous solution for 2 hours under an argon stream, washed thoroughly with water, and then again immersed for 1 minute in a 10 mM potassium ferricyanide aqueous solution under an argon stream. At this time, the yellow cadmium sulfide dispersion film changed to yellow green due to the deposition of Prussian blue on the film surface. The film thus obtained was sandwiched between two glass plates and irradiated with light. A 300 W tungsten lamp was used as a light source, and the light intensity on the sample surface was set to about 90 mM / cm ² . A water tank with a thickness of 5 cm was provided between the light source and the glass plate sandwiching the film to prevent the temperature of the film from rising due to light irradiation. The film gradually changes from yellowish green to light yellow with light irradiation,
After a minute, almost the entire surface of the film turned pale yellow. By removing from the two glass plates and applying a voltage of +1.3 V to this film, the original yellowish green color could be restored, and such a change in color tone was repeatedly observed.

Example 2 A Nafion membrane containing fine particles of cadmium sulfide produced in the same manner as in Example 1 was immersed in a 50 mM ferrous chloride aqueous solution for 2 hours under an argon stream. Next, the membrane was thoroughly washed with water and then again immersed in an aqueous 50 mM potassium ferricyanide solution for 1 minute under an argon stream to deposit Prussian blue on the membrane surface. At this time, the film changed from yellow to yellow-green. In order to allow the film thus obtained to contain a sacrificial electron donor, the film was immersed in methyl alcohol for 10 minutes, then sandwiched between two glass plates and irradiated with light. A 300 W tungsten lamp was used as a light source, and the light intensity on the film surface was about 75 mW / cm ² . As in Example 1, a water tank having a thickness of 5 cm was placed between the light source and the film to prevent the temperature from rising. The film gradually changed from yellow-green to yellow with light irradiation, and after about 1 minute, almost the entire surface of the film changed to yellow. The original yellow-green color could be restored by removing this film from the two glass plates and exposing it to air. Such changes in color tone were repeatedly observed.

[Example 3] A cadmium sulfide-dispersed film, in which Prussian blue thin films prepared in the same manner as in Example 1 were laminated, contained triethanolamine as a sacrificial electron donor.
After immersing in a mixed solution of triethanolamine / water (1/9; volume ratio) adjusted to 10 minutes, it was sandwiched between two glass plates and irradiated with light. As the light source, a 300 W tungsten lamp was used as in Example 2, and the light intensity was set to about 75 mW / cm ² . A 5 cm-thick water tank was provided between the light source and the film to prevent the temperature of the film from rising due to light irradiation.

The film gradually changes from yellow-green to yellow with light irradiation,
After about 3 minutes, almost the entire surface of the film turned yellow. It was possible to restore the original yellow-green color by removing this film from the two glass plates and exposing it to air. Such changes in color tone were repeatedly observed.

[Example 4] In order to allow tartaric acid to be contained as a sacrificial electron donor in the cadmium sulfide dispersion film in which the Prussian blue thin film prepared in the same manner as in Example 1 was added, the film was adjusted to pH 2.1 with a 50 mM tartaric acid aqueous solution for 30 minutes. After the immersion, it was sandwiched between two glass plates and irradiated with light. As the light source, a 300 W tungsten lamp was used as in Example 2, and the light intensity was set to about 75 mW / cm ² . still,
A 5 cm thick water tank was installed between the light source and the film to prevent the temperature rise of the film due to light irradiation. After about 3 minutes of light irradiation, almost the entire surface of the film changed from yellow green to yellow. It was possible to restore the original yellow-green color by removing this film from the two glass plates and exposing it to air, and such a change in color tone was repeatedly observed.

[Example 5] Polyacrylonitrile (manufactured by Aldrich, number average molecular weight 33,000) was dissolved in dimethylformamide at 50 ° C,
A uniform casting solution having a polymer concentration of 13 wt% was prepared.
This solution was cast on a glass plate and immediately immersed in water at 10 ° C. for solidification to obtain a porous film having a thickness of 150 μm. Next, sandwich the nuclear membrane in the center of the two-chamber separate cell, and place it on one side of the cell.
About 10 ml of mM cadmium acetate aqueous solution was added, the same amount of ion-exchanged distilled water was added to the other, and hydrogen sulfate was bubbled.
After about 30 minutes, the porous film was colored yellow, and the deposition of fine particles of cadmium sulfide was visually recognized in the film. Next, 30 μl of soluble Nafion (trademark: 5 wt% water-alcohol solution) was applied to the cadmium sulfide precipitation portion (area 2.2 cm ² ) of the film, and heated and dried at 40 ° C. for 1 hour. The cadmium sulfide-dispersed porous membrane thus obtained was immersed in an aqueous solution of 10 mM ferrous chloride for 2 hours under an argon stream, washed thoroughly with water, and then again immersed in an aqueous solution of 10 mM potassium ferricyanide for 1 minute under an argon stream. The film changed from yellow to yellow-green with the precipitation of Prussian blue. The obtained film was immersed in methyl alcohol for 10 minutes, then sandwiched between two glass plates and irradiated with light in the same manner as in Example 2. The film gradually changes from yellow-green to yellow with light irradiation.
After 10 minutes, almost the entire surface of the film turned yellow. This film is 2
It was possible to restore the original yellow-green color by removing it from one glass plate and exposing it to air. Such changes in color tone were repeatedly observed.

[Example 6] The Prussian blue-laminated cadmium sulfide dispersion film prepared in Example 1 was immersed in a 50 mM aqueous hydroquinone solution (pH 6.3) for 30 minutes under an argon stream to contain a reversible electron donor. . After the immersion, the film was sandwiched between two glass plates and irradiated with light in the same manner as in Example 2. The film gradually changed from yellow green to light yellow with light irradiation, and after about 5 minutes, almost the entire surface of the film changed to light yellow. +1 for this film.
By applying a voltage of 3V, it was possible to return to the original yellowish green color, and such a color tone change was repeatedly observed.

Example 7 A cadmium sulfide-containing Nafion film was prepared in the same manner as in Example 1. The membrane was sandwiched between two-chamber separate cells, and a purified pyrrole aqueous solution (about 0.3 M) was placed in one of the cell chambers, and then the atmosphere was replaced with argon. In the other cell room
A 0.1 M potassium persulfate aqueous solution was added and the mixture was allowed to stand for about 4 minutes under an argon stream. The substrate Nafion membrane anionic dissociative group (-SO ₃ ^-) for having, persulfate ion (S ^₂ O ₈ ^2-) was used as the polymerization initiator pyrrole hardly penetrates into the substrate film. On the other hand, since pyrrole is an electrically neutral low molecular weight compound, it diffuses in the substrate film relatively easily. As a result, the pyrrole polymer (polypyrrole) was deposited only on the surface (potassium persulfate solution side) on one side of the substrate film. After thoroughly washing the membrane obtained here with water, it was again sandwiched between two-chamber separate cells, and a 10 mM ferrous chloride aqueous solution was added to the cell chamber on the side opposite to the polypyrrole deposition surface (black), and the cell chamber on the polypyrrole side was placed. In order to balance the pressure, the same amount of distilled water was added, and both solutions were replaced with argon. After soaking for about 60 minutes in this way, the first chloride aqueous solution was taken out and placed there.
A mM potassium ferricyanide aqueous solution was added and the reaction was performed for about 1 minute. In this way, a film in which polypyrrole was laminated on one surface of the cadmium sulfide-containing film and Prussian blue was laminated on the opposite surface thereof could be produced. The membrane
After soaking in 0.1 M potassium perchlorate aqueous solution for several minutes, two transparent glass electrodes (indium-tin oxide coated glass plate;
It was crimped between surface resistance 10Ω / □) and adjusted with a potentiostat connected to an external circuit so that the potential difference between these two terminals would be zero. Irradiation with a 500W xenon lamp on the polypyrrole side surface of the above film installed in this way gives about 40
After a second, the color of the Prussian blue surface changed from green to yellow. During light irradiation, an ultraviolet and infrared cut filter (TOSHIBA IRA-25S and Y-4) is placed between the light source and the sample.
3) and a water layer (thickness 5 cm) are provided to control the light intensity on the sample surface.
It was adjusted to be 100 mW / cm ² . The change in the reflection spectrum of the film surface at this time is traced with time, and the change over time in the reflectance at 650 nm is plotted in FIG. After light irradiation, when a voltage of about 1.0 V was applied to the film in the dark, the color of the Prussian blue surface returned from yellow to the original green.
By repeating such light irradiation and voltage application alternately, it was possible to reversibly perform optical recording and erasing.

[Brief description of drawings]

FIG. 1 is a diagram showing a relative relationship of redox potentials of respective constituent components in PECD using the semiconductor-containing element of the present invention, and showing an operation principle of optical display / recording. A is an electron acceptor, D is an electron donor, S is a semiconductor, (1) is the redox potential of D, (2) is the valence band of S, (3) is the conduction band of S, and (4) Represent the respective energy levels of the redox potential of A. FIG. 2 shows the change with time of the reflectance at 650 nm when PB and polypyrrole are laminated on different surfaces to irradiate the cadmium sulfide-containing Nafion film with light.

Claims (3)

(57) [Claims] 1. A semiconductor-containing element comprising a thin film base material, comprising: (1) a thin film base material containing a semiconductor that generates electrons and holes upon irradiation with light, and in or on the surface of the thin film base material. (2) at least one of the electron donor and the electron acceptor is discolored by oxidation or reduction, and at least the electron donor and the electron acceptor are included. When one is a polymer metal complex and (3) the electron donor and the electron acceptor are (i) both polymer metal complexes, they are immobilized on the opposite surfaces of the substrate. (Ii) If the electron donor of both is not a polymer metal complex, the electron donor is irreversibly oxidized, or (iii) one is not a polymer metal complex. In case of high Reduction or oxidation product species electron donor or electron acceptor is not a metal complex is insoluble in the solvent in the substrate, semiconductor-containing device characterized by. 2. The polymer metal complex comprises a complex cation represented by the general formula M _A ^X (L _A ^a ) ₁ and a general formula M _B ^Y (L _B ^b ) _m (L _C ^c ) _n.
A semiconductor-containing device according to claim 1, which is a polynuclear metal complex formed with a complex anion represented by (wherein M _A ^X and M _B ^Y are X and Y valences, respectively). Represents a transition metal ion in a state, L _A ^a is a ligand having a neutral or a-valent positive charge, L _B ^b is a ligand having a b-valent negative charge, and L _C ^c is a neutral Or a ligand having a negative c-charge, where X and Y represent positive integers.
a is a positive integer including 0, b is a negative integer, and c is a negative integer including 0. Further, 1 is a positive integer including 0, m is a positive integer, and n is a positive integer including 0). 3. A complex anion is ^{_{M B Y (CN -) 5}} (L C c) the range of _n is as claimed No. (2) semiconductor-containing device according to claim (wherein M _B ^Y and L _C ^c is the Represents the same meaning as).